BioDrugs, 2002, 16(2), 97 - 103 Novel strategies for overcoming multidrug resistance in cancer; Baguley BC; The problems of why metastatic cancers develop pleiotropic resistance to all available therapies, and how this might be countered, are the most pressing in cancer chemotherapy . It is likely that such resistance involves a combination of mechanisms including changes in drug transport/drug targets, reduction in the degree of drug-induced apoptosis/cell loss, and increased rate of tumour repopulation following therapy . Current research must consider not only which mechanisms contribute, eventually relating this to individual patients with cancer, but also what strategies might be utilised to counter each of the important resistance mechanisms . A considerable amount of work has been devoted to the development of inhibitors of membrane-associated transport proteins such as P-glycoprotein, which mediate drug efflux . This work is now being complemented by approaches that target cell death pathways such as those mediated by release of mitochondrial proteins and by activation of surface receptors such as Fas . Rapid progress has been made in developing small-molecular-weight drugs that influence the rate of apoptosis, for instance by binding to the bcl-2 family of proteins regulating mitochondrial permeability . Antisense approaches aimed at reducing bcl-2 expression, and thus increasing the rate of cell death, are also showing promise . Modification of repopulation kinetics provides a further approach but has not received as much attention as other aspects of tumour resistance . New therapeutic approaches will have to be complemented by improved diagnostic tests to evaluate the contributions of different resistance mechanisms in individual patients with cancer. Presse Med, 2002 Apr 6, 31(13), 588 - 92 {Screening and follow-up of nosocomial infections by multiresistant bacteria using the Bacterio software . Microbiology laboratory data}; Ledru S et al.; OBJECTIVE: To study the relationship between the prevalence of multi-resistant bacteria (MRB) and nosocomial MRB infections . METHOD: This work presents the results of a follow up of hospital-acquired infections due to multidrug-resistant bacteria (MRB), based on microbiology detection with the Bacterio software and clinical confirmation . RESULTS: Clinical responses reached 93% . During the year 2000, the incidence of hospital-acquired MRB infections was 1.23 for 1000 hospitalization days and 1.00 for 100 admissions . Ticarcilline-resistant P . aeruginosa were responsible for 32% of hospital-acquired MRB infections . The incidence curve of MRB colonization was parallel with that of hospital-acquired infections . Hence, the incidence of MRB colonization is a rapid and good means of assessing the best probabilistic antibiotherapy especially in intensive care units . COMMENTS: Examination of medical records is however necessary to obtain complementary clinical information on: risk factors, use of medical devices, medical or chirurgical antecedents and prior antibiotherapy . The easiness of detection and management of hospital-acquired infections allowed us to extend its use in 2001 to the follow-up of all hospital-acquired infections, with or without MRB . Bacterio is also able to detect the hospital-acquired infections that, according to the recent decree (No . 2001-671, july 30th, 2001), must be declared to the sanitary authorities . Such suspicions should then be validated by the clinicians and the practising hygienist. Med Pediatr Oncol, 2002 Jun, 38(6), 379 - 86 In vitro drug resistance profile of Philadelphia positive acute lymphoblastic leukemia is heterogeneous and related to age: a report of the Dutch and German Leukemia Study Groups; Ramakers-van Woerden NL et al.; BACKGROUND: The t(9;22)(q34;q11) translocation leading to the Philadelphia (Ph) chromosome resulting in BCR-ABL gene fusion is associated with a poor prognosis in acute lymphoblastic leukemia (ALL) . PROCEDURE: We studied the relation between t(9;22), determined by karyotype, fluorescence in situ hybridization (FISH) or polymerase chain reaction (PCR), and in vitro drug resistance, measured by the MTT assay, in precursor B-cell ALL at diagnosis . The findings in twenty-one Ph-positive (Ph+) childhood common/precursorB (c/preB) cases were compared with 254 Ph-negative (Ph-) ALL cases . RESULTS: A large range of LC(50) values was found within the Ph+ patients . Moreover, LC(50) values did not differ significantly between Ph+ and Ph- samples for prednisolone, dexamethasone, L-asparaginase, vincristine, anthracyclines, thiopurines, epipodophyllotoxins, and 4H00-ifosfamide, even after matching for important prognostic features (age, white blood cell count (WBC), and immunophenotype) . Adult Ph+ (n = 12) ALL was more resistant to prednisolone (> 270-fold, P = 0.030), and displayed an overall tendency to resistance when compared to matched cases of Ph- (n = 15) adult precursor B-cell ALL . Within Ph+ ALL, in vitro prednisolone resistance increased significantly with age (P = 0.006) . The expression of lung resistance protein (LRP), but not P-glycoprotein (P-gp) or multidrug resistance protein (MRP), was significantly higher in all Ph+ patients . CONCLUSIONS: Both childhood and adult Ph+ precursor B-cell ALL samples display a heterogeneous in vitro resistance profile, with relatively sensitive and resistant cases . The adult Ph+ samples, however, are generally more resistant compared to matched Ph- controls, reaching significance for prednisolone . The correlation of prednisolone resistance with age within the Ph+ cases might help explain the poorer prognosis of adult Ph+ ALL . Anticancer Drugs, 2002 Apr, 13(4), 331 - 8 Isothiocyanates: mechanism of cancer chemopreventive action; Thornalley PJ; Dietary and synthetic isothiocyanates have cancer chemopreventive activity . Dietary isothiocyanates are formed from glucosinolate precursors of ingested green vegetables . Isothiocyanates are absorbed across intestinal cell membranes by passive diffusion and bind reversibly to plasma protein thiols by thiocarbamoylation . Free isothiocyanate enters cells and is converted to the glutathione conjugate by glutathione S-transferases (GSTs) . The glutathione conjugate is exported from cells by multidrug resistance proteins (MRPs), and metabolized in the mercapturic acid pathway to the corresponding mercapturic acid . The isothiocyanate is reformed by fragmentation of mercapturic acid pathway metabolites; it is inactivated by slow hydrolysis to the corresponding amine that is inactive in chemoprevention . Depletion of cellular glutathione and protein thiocarbamoylation activates signal transduction for cancer chemoprevention . Isothiocyanates inhibited and inactivated cytochrome P450 isoforms . They induced increased expression of GST, NADPH: quinone oxidoreductase, aldo-keto reductase and gamma-glutamylcysteine synthetase . These responses were coordinated at the transcription level by nuclear factor-erythroid 2 p45-related factor-2 acting through the antioxidant/electrophile enhancer response element and stimulated by the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase kinase-1 and c-Jun N-terminal kinase-1 (JNK1) pathway . Isothiocyanates also induced apoptosis of pre-cancerous cells and tumor cells activated by caspase-8 and potentiated by JNK1 . The chemopreventive activity of isothiocyanates is influenced by the isothiocyanate bioavailability-as is toxicity, GST polymorphism, protein thiocarbamoylation and probably also by MRP expression . These features of isothiocyanate metabolism and chemoprevention deserve further investigation. Bioorg Med Chem, 2002 Jul, 10(7), 2367 - 80 Synthesis and chemical characterization of 2-methoxy-N(10)-substituted acridones needed to reverse vinblastine resistance in multidrug resistant (MDR) cancer cells; Krishnegowda G et al.; In an attempt to find clinically useful modulators of multidrug resistance (MDR), a series of 19 N(10)-substituted-2-methoxyacridone analogues has been synthesized . 2-Methoxyacridone and its derivatives (1-19) were synthesized . Compound 1 was prepared by the Ullmann condensation of o-chlorobenzoic acid and p-anisidine followed by cyclization using polyphosphoric acid . This compound undergoes N-alkylation in the presence of phase transfer catalyst (PTC) . Stirring of 2-methoxy acridone with 1-bromo-3-chloropropane or 1-bromo-4-chlorobutane in a two-phase system consisting of organic phase (tetrahydrofuran) and 6N potassium hydroxide in the presence of tetrabutylammonium bromide leads to the formation of compounds 2 and 11 in good yield . N-(omega-Chloroalkyl) analogues were found to undergo iodide catalyzed nucleophilic substitution reaction with various secondary amines . Products were characterized by UV, IR, 1H and 13C NMR, mass-spectral data and elemental analysis . The lipophilicity expressed in log(10) P and pK(a) of compounds have been determined . All compounds were examined for their ability to increase the uptake of vinblastine (VLB) in MDR KBCh(R)-8-5 cells and the results showed that the compounds 7, 10, 12, and 15-19 at 100 microM caused a 1.05- to 1.7-fold greater accumulation of vinblastine than did a similar concentration of the standard modulator, verapamil (VRP) . However, the effects on VLB uptake were specific because these derivatives had little effect in the parental drug sensitive line KB-3-1 . Steady state accumulation of VLB, a substrate for P-glycoprotein (P-gp) mediated efflux, was studied in the MDR cell line KBCh(R)-8-5 in the presence and absence of novel MDR modulators . Results of the efflux experiment showed that VRP and each of the modulators (1-19) significantly inhibited the efflux of VLB, suggesting that they may be competitors for P-gp . From among the compounds examined, 14 except 1, 2, 4, 8, and 11, exhibited greater efflux inhibiting activity than VRP . All the 19 compounds effectively compete with {(3)H} azidopine for binding to P-gp, pointed out this transport membrane protein as their likely site of action . Cytotoxicity has been determined and the IC(50) values lie in the range 8.00-18.50 microM for propyl and 4-15 microM for butyl derivatives against KBCh(R)-8-5 cells suggesting that the antiproliferative activity increases as chain length increases from 3 to 4 carbons at N(10)-position . Compounds at IC(10) were evaluated for their efficacy to modulate the cytotoxicity of VLB in KBCh(R)-8-5 cells and found that the modulators enhanced the cytotoxicity of VLB by 5- to 35-fold . Modulators 12, 14-16, and 19 like VRP, were able to completely reverse the 24-fold resistance of KBCh(R)-8-5 cells to VLB . Examination of the relationship between lipophilicity and antagonism of MDR showed a reasonable correlation suggesting that hydrophobicity is one of the determinants of potency for anti-MDR activity of 2-methoxyacridones. J Immunol Methods, 2002 Apr 1, 262(1-2), 159 - 65 Determination of P-gp and MRP1 expression and function in peripheral blood mononuclear cells in vivo; Meaden ER et al.; P-glycoprotein (P-gp) and multidrug resistance-associated protein (MRP) mediate the efflux of many therapeutic agents and have been implicated in the treatment failure of many infectious diseases and cancers . The ability to characterise the expression and function of these transporters in vivo is important when assessing the pharmacological activity of drugs . We investigated some of the problems involved in screening the multidrug resistance status of individuals using flow cytometry . Expression of P-gp and MRP1 on the surface of lymphocytes isolated from blood samples (30 ml) was determined by indirect immunofluorescence . Functional ability was assessed by measuring the efflux of specific fluorescent dyes . Results were expressed as a mean fold increase in fluorescence from the isotype control (expression) and a change in fluorescence compared to the load (function) . Using these assays, we determined the expression of P-gp to be 2.01+/-0.40, n=30 and MRP1 to be 1.46+/-0.23, n=25 . Functional ability was 6.98+/-4.97, n=25 for P-gp and 1.55+/-0.25, n=25 for MRP1 . The dye efflux studies were associated with a lack of specificity and a number of methodological difficulties . There was no correlation between the expression and function of P-gp (r=0.338; p=0.10) or MRP1 (r=0.283; p=0.17) . Therefore, we considered determination of P-gp and MRP1 expression to be a more reproducible and accurate approach to clinical investigation into the role of multidrug resistance. J Hematother Stem Cell Res, 2002 Apr, 11(2), 231 - 41 Emergence of multidrug resistance in leukemia cells during chemotherapy: mechanisms and prevention; Shtil AA; Multifactorial resistance to extracellular stimuli is one of the major factors of tumor progression . Cells can acquire a multidrug resistant (MDR) phenotype in response to a wide variety of stress-inducing agents including chemotherapeutic drugs . In addition to the mechanisms expressed in the tumor prior to chemotherapy (presumably these mechanisms allowed tumor cells to escape the control of growth and differentiation), a complex phenotype of pleiotropic resistance is presented in the residual or recurrent tumor . This review analyzes the molecular mechanisms of MDR acquisition with the focus on hematopoietic malignancies . In particular, the chemotherapy-induced up-regulation of P-glycoprotein, a broad-specificity transmembrane efflux pump, is considered a major event in establishment of MDR in leukemia cells that were sensitive before drug exposure . The pharmacological and genetic approaches to prevent the acquisition of Pgp-mediated MDR during chemotherapy are discussed. Electrophoresis, 2002 Apr, 23(7-8), 1174 - 84 Comparison of protein expression profiles between monolayer and spheroid cell culture of HT-29 cells revealed fragmentation of CK18 in three-dimensional cell culture; Poland J et al.; The use of three-dimensional cell culture models, so-called multicellular tumor spheroids, is a special approach in experimental cancer research, because spheroids are similar to in vivo tumors in structural as well as functional sense . Cells grown in spheroids exhibit alterations of cell cycle regulation, induction of apoptosis and differentiation and can acquire multidrug resistance . In this study we investigated the protein expression in human colorectal cancer cells grown in monolayer and in spheroid cultures using proteomics . Evaluation by computer-assisted image analysis revealed overexpression of three cytokeratin 18 fragments that were generated in vivo . Cytokeratin 18 has previously been described as a target for caspase-mediated cleavage during apoptosis and our results indicate that apoptosis may take place in spheroids . Other proteins upregulated in spheroids include calreticulin precursor, a rho GDP dissociation inhibitor variant, several cytokeratins and peroxiredoxin 4 . Some of these proteins have already been linked to chemoresistance and apoptotic phenomena. Curr Opin Pulm Med, 2002 May, 8(3), 173 - 7 Advances in adult pulmonary tuberculosis; Maartens G; The immune response is able to contain but not eliminate Mycobacterium tuberculosis . Antigens that are specific to M . tuberculosis can identify latent infection accurately even after BCG vaccination . Genes that are required for persistence of the organism have been identified and new drugs are being developed to disrupt their function . This offers the hope of shortened courses of therapy . New drugs are urgently needed for multidrug-resistant tuberculosis, particularly as some areas are reporting a high prevalence of fluoroquinolone resistance . The sputum smear is the standard rapid diagnostic test for pulmonary tuberculosis, but is frequently negative in HIV infection . The yield of smear can be increased by sputum induction and by concentration . Innovative methods of providing directly observed therapy have been devised . Preventive therapy is effective in HIV infection and probably improves survival . However, the duration of benefit of preventive therapy seems to be relatively short-lived . Effective long-term reduction of tuberculosis risk in HIV-infected patients can be achieved with highly active antiretroviral therapy. J Clin Microbiol, 2002 May, 40(5), 1873 - 4 Tetrazolium microplate assay as a rapid and inexpensive colorimetric method for determination of antibiotic susceptibility of Mycobacterium tuberculosis; Caviedes L et al.; The emergence of multidrug-resistant tuberculosis underscores the need for low-cost, rapid methods to determine the susceptibility of Mycobacterium tuberculosis to antibiotics . A new, rapid, easily read, and inexpensive colorimetric method with a tetrazolium indicator performs this determination as quickly and accurately as the more expensive Alamar Blue technique. Biochem J, 2002 Aug 1, 365(Pt 3), 721 - 30 Lysosome-associated protein transmembrane 4 alpha (LAPTM4 alpha) requires two tandemly arranged tyrosine-based signals for sorting to lysosomes; Hogue DL et al.; Lysosome-associated protein transmembrane 4 alpha (LAPTM4 alpha) and homologues comprise a family of conserved proteins, which are found in mammals, insects and nematodes . LAPTM4 alpha functions to regulate the intracellular compartmentalization of amphipathic solutes and possibly the sensitivity of cells toward anthracyclines, antibiotics, ionophores, nucleobases and organic cations . This is similar to the multidrug-resistance phenotype exhibited by cells synthesizing high levels of P-glycoprotein . Accordingly, it is possible that LAPTM4 alpha may be a suitable target for development of novel chemotherapeutic agents . LAPTM4 alpha contains four putative membrane-spanning domains and a 55 amino acid C-terminal region that faces the cytoplasm . Localization of LAPTM4 alpha to endosomes and lysosomes appears to be tightly controlled as transient high-level expression of LAPTM4 alpha in cultured cells resulted in no detectable protein on the cell surface . Mutagenic analysis of the C-terminus of LAPTM4 alpha indicated that two tandomly arranged tyrosine-containing motifs in the cytoplasmic domain are required for efficient localization of LAPTM4 alpha to vesicles containing the lysosomal marker lysosomal glycoprotein 120 . Although a number of membrane proteins that localize to endosomes/lysosomes contain more than one independently functioning sorting signal, to our knowledge, LAPTM4 alpha is the first example of a membrane protein that requires two tandemly arranged tyrosine-based sorting signals for efficient localization in these compartments. Cell Mol Biol Lett, 2002, 7(1), 92 - 5 Functional MDR1 polymorphisms (G2677T and C3435T) and TCF4 mutations in colorectal tumors with high microsatellite instability; Potocnik U et al.; The multidrug resistance 1 (MDRI) gene and transcription factor 4(TCF4) gene are suggested to be involved in the WNT signalling pathway, the most important pathway altered in colorectal cancer . Mutations in both genes have been identified and associated with colorectal tumors exhibiting high microsatellite instability (MSI-H) . In this study, we report on the distribution of functional polymorphisms in the MDR} gene and somatic frameshift mutations in the TCF4 gene coding mononucleotide repetition in 62 MSI-H colorectal tumors . Somatic frameshift mutations in(of) the TCF4 gene were identified in 24/62 (39%) of the studied MSI-H tumors . The estimated allele frequencies of functional polymorphisms in(of) exon 21 (2677 G>T, Ala893Ser) and exon 26(3435 C>T, Ilel 142I1e) of the MDR} gene were 0.42 and 0.46 in the controls and 0.54 (p=0.035) and 0.60 (p=0.017) in the MSI-H tumors . However, the allele frequency of both functional MDR} polymorphisms did not significantly differ between MSI-H tumors with TCF4 mutations and those without . These results support the involvement of the MDRI gene in the tumorgenesis of MSI-H tumors and also suggest that functional polymorphisms in the MDRI gene and mutations in the TCF4 gene are likely to occur independently in MSI-H tumors. Int J Cancer, 2002 May 10, 99(2), 292 - 8 Suberoylanilide hydroxamic acid (SAHA) overcomes multidrug resistance and induces cell death in P-glycoprotein-expressing cells; Ruefli AA et al.; Multidrug resistance (MDR) mediated by the ATP-dependent efflux protein P-glycoprotein (P-gp) is a major obstacle to the successful treatment of many cancers . In addition to effluxing toxins, P-gp has been shown to protect tumor cells against caspase-dependent apoptosis mediated by Fas and tumor necrosis factor receptor (TNFR) ligation, serum starvation and ultraviolet (UV) irradiation . However, P-gp does not protect against caspase-independent cell death mediated by granzyme B or pore-forming proteins (perforin, pneumolysin and activated complement) . We examined the effects of the chemotherapeutic hybrid polar compound suberoylanilide hydroxamic acid (SAHA) on P-gp-expressing MDR human tumor cell lines . In the CEM T-cell line, SAHA, a histone deacetylase inhibitor, induced equivalent death in P-gp-positive cells compared with P-gp-negative cells . Cell death was marked by the caspase-independent release of cytochrome c, reactive oxygen species (ROS) production and Bid cleavage that was not affected by P-gp expression . However, consistent with our previous findings, SAHA-induced caspase activation was inhibited in P-gp-expressing cells . These data provide evidence that P-gp inhibits caspase activation after chemotherapeutic drug treatment and demonstrates that SAHA may be of value for the treatment of P-gp-expressing MDR cancers . Pediatr Res, 2002 May, 51(5), 607 - 11 CHS 828 inhibits neuroblastoma growth in mice alone and in combination with antiangiogenic drugs; Svensson A et al.; CHS 828 is a new chemotherapeutic drug, a pyridyl cyanoguanidine . CHS 828 has low toxicity and lacks known patterns of multidrug resistance . Here we report that oral, daily treatment with CHS 828 reduced the growth of SH-SY5Y human neuroblastoma tumors in male NMRI nu/nu mice by 82% without apparent toxicity . CHS 828 induced complete tumor regression for at least 5 weeks in four of nine animals (44%) . Combination therapy with CHS 828 and the antiangiogenic drugs TNP-470 or SU5416 decreased neuroblastoma growth by a further 10 and 3%, respectively . Combination therapy induced tumor regression at d 4 with CHS plus TNP and d 6 with CHS plus SU5416, compared with d 14 with CHS 828 alone (p < 0.05), and complete tumor regression was seen in nine of 19 animals (47%) . Combination treatment of CHS 828 and TNP-470 decreased the total viable tumor volume by 71% compared with treatment with CHS 828 alone . Our findings support CHS 828 as a promising new drug in treatment of childhood cancers . Furthermore, they imply efficiency of daily administration of nontoxic doses of chemotherapy, and a possible additive effect when chemotherapy is combined with angiogenesis inhibitors. Acta Pharmacol Sin, 2002 May, 23(5), 423 - 9 Interaction of multidrug resistance reversal agents with P-glycoprotein ATPase activity on blood-brain barrier; He L et al.; AIM: To gain further insights into the mechanism of the ATP-dependent interaction of P-glycoprotein (P-gp) with various multidrug resistance (MDR) reversal agents . METHODS: Bovine brain capillary endothelial cells (BCEC) were isolated from cerebral gray matter using modifications of the mechanical homogenization technique . Plasma membranes were prepared from BCEC . The P- gp adenosine triphosphatase (ATPase) activity of the isolated BCEC membranes was estimated by measuring inorganic phosphate liberation . RESULTS: The basal P-gp ATPase activity was increased by verapamil (Ver), vincristine (VCR), doxorubicin (Dox), tetrandrine (Tet), dauricine (DRC), berbamine (BBM), and daurisoline (DRS), with respective half-maximal activity concentrations Km of about 17, 5.9, 41, 2.3, 11, 23, and 22 micromol/L . Berberine (BBR) produced a relatively slight activation . dl-Tetrahydropalmatine (dl-THP) and l-tetrahydropalmatine (l-THP ) does not alter the basal P-gp ATPase activity . Cyclosporin A (CsA) inhibited both the basal and the drug-stimulated ATPase activity of P-gp with high affinity . Kinetic analysis indicated a competitive inhibition of Ver- or VCR-stimulated ATPase activity and a noncompetitive inhibition of Dox- or Tet-activated ATPase activity by CsA . Moreover, Dox inhibited Tet-activated P-gp ATPase activity in a noncompetitive manner . CONCLUSION: Various MDR reversal agents could interact with P-gp and alter its ATPase activity in different manners . This is the result of the b road molecular recognition specificity of P-gp . CsA, Ver, and VCR could bin d P-gp either on overlapping sites or distant but interacting sites, while CsA, Dox, and Tet could independently bind P-gp on separated sites on blood-brain barrier. Mol Genet Genomics, 2002 Apr, 267(2), 179 - 85 Epub 2002 Feb 22. A novel ABC transporter gene, PMR5, is involved in multidrug resistance in the phytopathogenic fungus Penicillium digitatum; Nakaune R et al.; We have cloned a novel ABC transporter gene PMR5 from the phytopathogenic fungus Penicillium digitatum by RT-PCR using degenerate primers . The deduced amino acid sequence of PMR5 showed 37% identity to PMR1 from the same fungus, 71% identity to AtrB from Aspergillus nidulans, and 65% identity to BcatrB from Botrytis cinerea . Disruption mutants for PMR5 were generated in two independent P . digitatum strains and their phenotypes were characterized . These mutants displayed increased sensitivity to thiabendazole (a benzimidazole), benomyl (a benzimidazole), dithianon (a quinone), resveratrol (the phytoalexin of grape), and camptothecin (an alkaloid) . Delta pmr1 disruption mutants were previously reported to show resistance to demethylation inhibitors (DMIs) . These mutants were found also to display increased sensitivity to phloretin (the phytoanticipin of apples), camptothecin and oligomycin (an antibiotic) . Transcription of PMR1 and PMR5 was strongly induced in response to several toxicants, including DMIs that specifically induced PMR1 . In contrast, dithianon and resveratrol specifically induced PMR5 transcription . These findings indicate that expression of the two ABC transporter genes is regulated differently, and that they have complementary roles in multidrug resistance, with each having different substrate-specificities. Cancer Chemother Pharmacol, 2002 May, 49(5), 391 - 7 Epub 2002 Feb 14. Induction of multidrug resistance in MOLT-4 cells by anticancer agents is closely related to increased expression of functional P-glycoprotein and MDR1 mRNA; Liu ZL et al.; PURPOSE: The aim of this study was to investigate the multidrug resistance (MDR) pattern, MDR gene and P-glycoprotein (P-gp) expression, and P-gp function in drug-induced human T-lymphoblastoid leukemia MOLT-4 sublines . METHODS: The MDR sublines were developed by exposing the parental MOLT-4 cells to stepwise increasing concentrations of anticancer drugs daunorubicin (DNR), vinblastine (VBL) and doxorubicin (DOX) . Degrees of resistance were assessed in terms of IC(50) values in an MTT assay and the P-gp function was evaluated in terms of rhodamine 123 (Rh123) accumulation and efflux . The percentage of cells undergoing apoptosis was determined by flow cytometry after staining with annexin V-FITC and propidium iodide . The levels of P-gp and MDR mRNA expression were estimated using the PE-conjugated anti-P-gp monoclonal antibody 17F9 and quantitative real-time reverse transcription-polymerase chain reaction . RESULTS: Three MOLT-4 sublines were established and revealed a 2- to 115-fold resistance to the anticancer reagents DNR, VBL and DOX as compared to the parental cell line . The highest MDR was expressed in MOLT-4/DNR cells, which was overcome by the P-gp modulator, cyclosporin A (CsA) . The resistant sublines showed a decreased accumulation and an increased efflux of Rh123 in proportion to the degree of resistance, and these were completely reversed in the presence of 8 microM CsA . The decreased apoptotic response in these cell lines was clearly associated with the degree of drug resistance . P-gp antigen and MDR1 mRNA were highly expressed in both the MOLT-4/DNR and MOLT-4/DOX sublines . Less-resistant MOLT-4/VBL cells expressed lower levels of MDR1 mRNA and P-gp, even though the cell line was established by exposing the parental MOLT-4 cells to VBL for longer (5 months) than to the other two reagents (3 months) . CONCLUSIONS: MOLT-4 cells were able to acquire a high level of drug resistance by culturing the cells in the presence of certain anticancer drugs, and acquisition of the resistance was relatively reagent-specific . The degrees of resistance to the anticancer drugs were well correlated with the expressions of MDR1 mRNA and functional P-gp, and were also associated with a decreased response to apoptosis. J Nat Prod, 2002 Apr, 65(4), 614 - 5 Efficacy of scopadulcic acid A against Plasmodium falciparum in vitro; Riel MA et al.; Scoparia dulcis is a perennial herb widely distributed in many tropical countries . It is used as an herbal remedy for gastrointestinal and many other ailments, and in Nicaragua extracts are used to treat malaria . Phytochemical screening has shown that scopadulcic acid A (SDA), scopadulcic acid B (SDB), and semisynthetic analogues are pharmacologically active compounds from S . dulcis . SDB has antiviral activity against Herpes simplex virus type 1, antitumor activity in various human cell lines, and direct inhibitory activity against porcine gastric H(+), K(+)-ATPase . A methyl ester of scopadulcic acid B showed the most potent inhibitory activity against gastric proton pumps of 30 compounds tested in one study . Compounds with antiviral, antifungal, and antitumor activity often show activity against Plasmodium falciparum . In P . falciparum, the plasma membrane and food vacuole have H(+)-ATPases and the acidocalcisome has an H(+)-Ppase . These proton pumps are potential targets for antimalarial therapy and may have their function disrupted by compounds known to inhibit gastric proton pumps . We tested pure SDA and found in vitro activity against P . falciparum with an IC(50) of 27 and 19 microM against the D6 and W2 clones, respectively . The IC(50) against the multidrug-resistant isolate, TM91C235, was 23 microM. J Nat Prod, 2002 Apr, 65(4), 606 - 10 Reversal of multidrug resistance by tropane alkaloids from the stems of Erythroxylum rotundifolium; Chavez D et al.; Six tropane alkaloid esters were isolated from the stems of Erythroxylum rotundifolium . The structures of three new tropane esters, 7beta-hydroxy-6beta-(3,4,5-trimethoxybenzoyloxy)-3alpha-(E)-(3,4,5-trimethoxycinnamoyloxy)tropane (1), 6beta-benzoyloxy-3alpha-(Z)-(3,4,5-trimethoxycinnamoyloxy)tropane (2), and (-)-6beta-benzoyloxy-3alpha-hydroxytropane (3), were established by spectroscopic techniques . When alkaloids 1-6 were evaluated against a panel of human cancer cell lines, the new compound 6beta-benzoyloxy-3alpha-(Z)-(3,4,5-trimethoxycinnamoyloxy)tropane (2) and three known compounds, 6beta-benzoyloxy-3alpha-(3,4,5-trimethoxycinnamoyloxy)tropane (4), 6beta-benzoyloxy-3alpha-(E)-(3,4,5-trimethoxycinnamoyloxy)tropane-7beta-ol (5), and 7beta-acetoxy-6beta-benzoyloxy-3alpha-(E)-(3,4,5-trimethoxycinnamoyloxy)tropane (6), demonstrated greatest activity with multidrug-resistant oral epidermoid carcinoma (KB-V1) cells incubated in the presence of vinblastine . Thus, tropane esters of this type can reverse the multidrug-resistance phenotype, presumably by interacting with P-glycoprotein. Gynecol Oncol, 2002 May, 85(2), 298 - 304 Cellular glutathione content, in vitro chemoresponse, and the effect of BSO modulation in samples derived from patients with advanced ovarian cancer; Lewandowicz GM et al.; OBJECTIVES: The objective was to assess the relationship between glutathione content and drug sensitivity with glutathione modulation in ovarian cancer in a pilot study using 31 samples of freshly obtained ovarian tumor material from 26 patients with advanced disease . METHODS: Processed tumor samples were screened to determine the glutathione content using an enzyme recycling assay modified for use in a 96-well plate format . Chemosensitivity testing (MTT assay) was used to assess sensitivity to cisplatin and doxorubicin and modulation using buthionine sulfoximine . Multidrug-resistance-associated protein MRP1 (putative drug-glutathione conjugate transporter) expression was also assessed . RESULTS: There was a significant increase in the tumor cell GSH levels in samples from patients who had received previous chemotherapy (9) versus those from chemotherapy-naive patients (20), P = 0.005 . In vitro chemosensitivity testing with doxorubicin and cisplatin (using LC(50) values, i.e., drug dose causing 50% reduction in cell survival relative to untreated control) failed to show a relationship with glutathione levels . Coincubation of cisplatin and doxorubicin with buthionine sulfoximine resulted in a significant increase in sensitivity to both of these drugs overall (cisplatin, P = 0.05; doxorubicin, P = 0.025), with 20 samples showing sensitization to a drug to which they were previously resistant . MRP1 expression failed to show a correlation with drug sensitivity and glutathione levels . CONCLUSIONS: Our study supports the use of glutathione modulation using agents such as buthionine sulfoximine in patients with heavily pretreated, drug-resistant ovarian cancer . (c) 2002 Elsevier Science (USA). Exp Parasitol, 2002 Jan, 100(1), 28 - 35 Plasmodium falciparum: in vitro interactions of artemisinin with amodiaquine, pyronaridine, and chloroquine; Gupta S et al.; In the scenario of drug-resistant Plasmodium falciparum malaria combination therapy represents an effective approach . Artemisinin and its derivatives are of special interest because they represent the most effective group of compounds against multidrug-resistant malaria with a rapid onset of action and a short half-life . Interactions of artemisinin with amodiaquine, pyronaridine, and chloroquine were therefore investigated against three strains of P . falciparum using a 48-h in vitro culture assay . Two of the strains were chloroquine sensitive and one was partially chloroquine resistant . Observed effective concentrations (O) of the combined compounds at different concentration ratios were calculated for different degrees of inhibition (EC50, EC90, EC99) and compared to expected calculated effective concentrations (E) using a probit method . Synergism with mean O/E EC90 values of 0.25 and 0.8 were found with the combination of artemisinin and the two Mannich bases, amodiaquine and pyronaridine, respectively, whereas chloroquine showed addition with a mean value of 1.2 . Although both amodiaquine and chloroquine are 4-aminoquinolines, their interaction with artemisinin appears to be different . The combination of artemisinin with amodiaquine represents an important option for the treatment of falciparum malaria . Clin Lymphoma, 2002 Mar, 2(4), 242 - 8 Noninvasive detection of multidrug resistance in patients with hematological malignancies: are we there yet? Kostakoglu L. The success of chemotherapy in the treatment of malignancies may be limited by cellular mechanisms leading to drug resistance . In hematological malignancies, mechanisms leading to the development of multidrug resistance (MDR) include overexpression of the membrane-based export pump P-glycoprotein (Pgp) and the MDR-associated protein (MRP) . Recently, the overexpression of the lung-resistance protein (LRP) has also been associated with reduced intracellular drug accumulation . A major problem in assessing the significance of the expression of these resistance proteins in clinical MDR has been the variability of detection techniques either at the mRNA or protein level . Currently, the detection of resistance proteins relies heavily on antibody and cDNA probes, and these methods may not be informative about the in vivo function of Pgp, MRP, or LRP . Nuclear medicine imaging techniques such as single-photon emission tomography (SPECT) and positron emission tomography (PET) have been evaluated for noninvasive determination of the presence and the function of Pgp- and MRP-mediated transport systems . Technetium 99m (99mTc)-sestamibi, an agent in clinical use for myocardial perfusion and tumor imaging, is recognized as a substrate for Pgp and MRP, and has been used to visualize Pgp expression . 99mTc-tetrofosmin is also a substrate for the Pgp efflux pump mechanism and is used to evaluate Pgp function in in vitro and in vivo studies . Recently, radiopharmaceuticals including carbon 11-labeled colchicine, verapamil, and daunorubicin have been used in cell line and animal studies for the evaluation of Pgp-mediated transport functions using PET technology . Preliminary results suggest that the potential to detect MDR in tumors prior to or after exposure to chemotherapeutic agents exists in imaging using either 99mTc-labeled compounds and SPECT or positron emitting compounds and PET. J Histochem Cytochem, 2002 May, 50(5), 731 - 4 The fluorescent probe Bodipy-FL-verapamil is a substrate for both P-glycoprotein and multidrug resistance-related protein (MRP)-1; Crivellato E et al.; Several fluorescent probes have been used in functional studies to analyze drug transport in multidrug-resistant cells by fluorescent microscopy . Because many of these molecules have some drawbacks, such as toxicity, nonspecific background, or accumulation in mitochondria, new fluorescent compounds have been proposed as more useful tools . Among these substances, Bodipy-FL-Verapamil, a fluorescent conjugate of the drug efflux blocker verapamil, has been used to study P-glycoprotein activity in different cell types . In this study we tested by fluorescent microscopy the accumulation of Bodipy-FL-Verapamil in cell lines that overexpress either P-glycoprotein (P-gp) or multidrug resistance-related protein 1 (MRP1) . Expression of P-gp and MRP1 was evaluated at the mRNA level by RT-PCR technique and at the protein level by flow cytometric analysis using C219 and MRP-m6 monoclonal antibodies . Results indicate that Bodipy-FL-Verapamil is actually a substrate for both proteins . As a consequence, any conclusion about P-gp activity obtained by the use of Bodipy-FL-Verapamil as fluorescent tracer should be interpreted with caution. Aliment Pharmacol Ther, 2002 May, 16(5), 1021 - 31 P-glycoprotein-170 inhibition significantly reduces cortisol and ciclosporin efflux from human intestinal epithelial cells and T lymphocytes; Farrell RJ et al.; AIM: To assess the role of P-glycoprotein-170 (P-gp) in transporting cortisol and ciclosporin from human intestinal epithelium and T lymphocytes . METHODS: The effect of P-gp inhibitors (verapamil, 0-100 microM; PSC 833, 0-20 microM) on the intracellular accumulation of 3H-cortisol and 3H-ciclosporin was studied in confluent layers of human Caco-2 cells (n=6), a P-gp-dependent absorptive intestinal epithelial cell phenotype, and moderately resistant MDRhigh CEM/VBL 100 T cells (n=6) . The transport of 3H-vinblastine, a strong multidrug resistance (MDR) substrate, and 3H-progesterone, a poor MDR substrate, was also studied . RESULTS: Caco-2 cells had a 2.4-, 6.6-, 6.7- and 1.03-fold higher net basal to apical transport (efflux) of 3H-cortisol, 3H-ciclosporin, 3H-vinblastine and 3H-progesterone, respectively . PSC 833 (20 microM) reduced cortisol efflux by 69% (0.23 +/- 0.04 to 0.07 +/- 0.01 pmol/cm2/h, P < 0.05) and ciclosporin efflux by 76% (11.1 +/- 1.4 to 2.7 +/- 0.6 pmol/cm2/h, P < 0.001) . MDRlow CEM T cells had a 1.4-, 1.9-, 3.2- and 1.02-fold higher intracellular accumulation of cortisol, ciclosporin, vinblastine and progesterone than MDRhigh CEM/VBL 100 T cells . Increasing concentrations of PSC 833 (> 0.1 microM) and verapamil (> 1 microM) restored the intracellular level of 3H-cortisol and 3H-ciclosporin in MDRhigh CEM/VBL 100 T cells to that of MDRlow CEM cells with little change in accumulation in the MDRlow parental cell line . CONCLUSIONS: P-gp inhibitors significantly increase intracellular cortisol and ciclosporin levels in human intestinal epithelium and T lymphocytes in a dose-dependent manner, demonstrating a potential mechanism for overcoming poor response to immunosuppressant therapy in refractory inflammatory bowel disease. Medicina (B Aires), 2002, 62(1), 20 - 4 {Primary resistance of Mycobacterium tuberculosis in 30 health institutions of El Salvador . A pilot study}; Aguilar RA et al.; In view of the worldwide re-emergency of tuberculosis (TB) and the rise of pulmonary TB (TBP) resistant to the two main first line drugs, namely isoniazid (H) and rifampin (R), so called multidrug resistant TBP (MDR-TBP), it was considered necessary to carry out a national, non randomized, multicenter, prospective pilot survey to determine the rates of resistant Mycobacterium tuberculosis (MTB) in patients with no previous antituberculous treatment (primary resistance) . A total of 30 health institutions were chosen (disseminated among the 14 districts of the country) with the most TBP cases reported in 1997, and asked to provide in a consecutive non random way, sputum samples from new smear positive TB patients starting the first working week of January until the last one of December 1998; these samples were processed for culture at the Tuberculosis Section of the Health Ministry Central Laboratory . Those that resulted positive for MTB underwent a test for resistance to the first line drugs used in this country (isoniazid, rifampin, pyrazinamide, ethambutol and streptomycin) . A total of 348 MTB positive samples were collected . The rate of primary resistance to at least one drug was 3.3% and to H it was 0.3%, being these rates among the lowest in Latin America . For this reason further studies comprising the whole universe of new and already treated smear positive TB patients are to be performed in order to determine more accurately the primary resistance and acquired rates. Clin Orthop, 2002 May, (398), 11 - 9 General principles of osteoarticular tuberculosis; Tuli SM; Since approximately 1985, with the pandemic of the human immunodeficiency virus and with the increase in the number of people who are immunocompromised, there is a resurgence of tuberculosis worldwide . The diagnosis in endemic areas generally can be made on clinical and radiologic examinations . However, whenever there is doubt because of an atypical clinical presentation or lack of clinical exposure, tissue diagnosis is mandatory . If osteoarticular tuberculosis is diagnosed and treated at an early stage, approximately 90% to 95% of patients would achieve healing with near normal function . The mainstay of treatment is multidrug antituberculous chemotherapy (for 12 to 18 months) and active - assisted non-weightbearing exercises of the involved joint throughout the period of healing . Operative intervention is required when the patient is not responding after 4 to 5 months of chemotherapy (synovectomy and debridement), the therapeutic outcome is not satisfactory (excisional arthroplasty for the hip or the elbow), or the healed status has resulted in a painful ankylosis (arthrodesis for the ankle, the wrist, or the knee) . Joint replacement may be considered if the disease has remained inactive for 10 years or more . Multidrug resistance should be suspected if the activity of disease does not subside after 4 to 6 months of uninterrupted multidrug therapy . Such patients (5% to 10%) present a desperate therapeutic challenge . Second-line and potential antitubercular drugs, and possible immunomodulations may control such a disease. Gynakol Geburtshilfliche Rundsch, 2001, 41(4), 236 - 9 {Ovarian tuberculosis}; Steller J; Although the tuberculosis rate in Germany and in the Western industrialized nations is stable, it is still one of the most significant infectious diseases worldwide . Immigrants and asylum seekers make up a large proportion of new cases, and with 15%, the occurrence of multidrug-resistant tuberculosis patients from the former Soviet Union is above average . This study, describing a patient with ovarian tuberculosis, undertakes a classification of risk groups as well as presents the potential differential diagnosis and its limitations. Clin Exp Metastasis, 2002, 19(2), 161 - 8 Distinctive alterations of invasiveness, drug resistance and cell-cell organization in 3D-cultures of MCF-7, a human breast cancer cell line, and its multidrug resistant variant; dit Faute MA et al.; Growth of human tumor cells as three-dimensional (3D) multicellular spheroids modifies their invasive properties . Here we study the differences in the biological features of MCF-7, a human breast cancer cell line, and its multidrug resistant variant (MDR-MCF-7) cultured as spheroids or as monolayers . Three-dimensional culture decreased the proliferative rate of both cell lines, reduced the drug sensitivity of MCF-7 cells and did not affect the resistance of MDR-MCF-7 cells . Transmission electron microscopic studies and intercellular junctions labeling showed that MCF-7 spheroids had a junctional system involving E-cadherin, tight-junctions and desmosomes . In MDR-MCF-7 cell spheroids, cell cohesion was mostly due to membrane interdigitations . MDR-MCF-7 cells, but not their parental counterpart, displayed a higher invasive potential when cultured as spheroids, as shown in the Boyden chamber assay . 3D-induced invasiveness was correlated with serine protease and plasminogen activator (PA) secretion . MCF-7 cells did not show any tendency to invade, whatever the mode of culture . These results show that 3D-cultures as spheroids distinctively altered structural features of parental and MDR-MCF-7 cells . In MCF-7 cells, 3D-culture increased cell-cell contacts and drug resistance; in MDR-MCF-7 cells, it induced invasive properties. Expert Rev Mol Diagn, 2002 Mar, 2(2), 151 - 9 Diagnosis of MDR-TB: a developing world problem on a developed world budget; Fisher M; The resurgence of tuberculosis worldwide has been accompanied by an increase in the incidence of multidrug-resistant tuberculosis on all continents . While significant advances have been made in the rapid and accurate diagnosis of Mycobacterium tuberculosis, the molecular biology methods used in the research laboratory to elucidate the mechanisms of drug resistance cannot be transferred to the centers delivering patient care . These methods require skilled operators, cumbersome protocols and extravagant expense . A number of companies that already have a large investment in M . tuberculosis diagnostics are adapting their high-throughput technology to drug susceptibility testing . These methodologies are not applicable to the developing world not only because of the costs involved but through a lack of infrastructure that is required to operate these machines and deliver specimens to the point of testing . Alternative technologies for drug susceptibility testing that do not rely on an investment in expensive hardware are presented and their potential use in the field is discussed . Though still relatively expensive to perform, these newer innovations may lead to the development of less intricate technologies that have universal application and begin to move away from our obsession with molecular-based diagnostics to produce on all encompassing gold standard. J Pharmacol Exp Ther, 2002 May, 301(2), 578 - 85 Short- and long-term influences of heavy metals on anionic drug efflux from renal proximal tubule; Terlouw SA et al.; We recently demonstrated in isolated killifish renal proximal tubules that two classes of nephrotoxicants, aminoglycoside antibiotics and radiocontrast agents, rapidly decrease transport mediated by multidrug resistance protein 2 (Mrp2) by causing endothelin (ET) release and signaling through an ET(B) receptor and protein kinase C (PKC) . In the present study, we used killifish proximal tubules, fluorescein methotrexate, a fluorescent model substrate for Mrp2, and confocal microscopy to examine the effects of two heavy metal salts (CdCl(2) and HgCl(2)) on Mrp2 function . Three patterns of effects were seen . First, exposing tubules to 10 microM CdCl(2) or 100 nM HgCl(2) for 30 min reduced Mrp2-mediated transport . This reduction was abolished by the ET(B) receptor antagonist, RES-701-1, and by the PKC-selective inhibitor, bis-indolylmaleimide I; neither of these pharmacological tools by itself affected transport . As with aminoglycoside antibiotics and radiocontrast agents, the acute effects of 10 microM CdCl(2) or 100 nM HgCl(2) on transport were also blocked by nifedipine, suggesting that Ca(2+) also initiated cadmium and mercury action . Second, exposure to higher concentrations of CdCl(2) and HgCl(2) appeared to be toxic . Third, exposing tubules for 6 to 24 h to lower levels of CdCl(2) increased Mrp2-mediated transport and Mrp2 immunostaining at the luminal membrane of the proximal tubule cells . Together, these findings indicate that exposure of renal proximal tubules to heavy metals initially leads to reduced Mrp2 function but is followed by an induction in Mrp2-mediated transport after long-term exposure. J Pharmacol Exp Ther, 2002 May, 301(2), 402 - 9 Characteristics of the fetal/maternal interface with potential usefulness in the development of future immunological and pharmacological strategies; Audus KL et al.; A study of the fundamental biology of the maternal-fetal interface reveals the complex interactions among multiple cell types and regulatory factors necessary to support a successful pregnancy . Cells of decidua and trophoblast lineages play central roles in creating the maternal-fetal interface and are sources of regulatory factors that can determine the quality and success of pregnancy . The regulatory factors considered here are major placental histocompatibility complex proteins, pregnancy-specific regulatory factors for uterine inflammatory cells, and hormone-controlled placental multidrug-resistant transport systems . Potential targets are discussed and presented as areas where researchers may identify novel pharmacological and immunological strategies that eventually will extend to the clinic to improve the quality and success of pregnancy. Biochem Pharmacol, 2002 Apr 1, 63(7), 1219 - 28 Biochemical changes associated with a multidrug-resistant phenotype of a human glioma cell line with temozolomide-acquired resistance; Ma J et al.; Temozolomide (TMZ) is a newly approved alkylating agent for the treatment of malignant gliomas . To investigate resistance mechanisms in a multidrug therapeutic approach, a TMZ-resistant human glioma cell line, SF188/TR, was established by stepwise exposure of human SF188 parental cells to TMZ for approximately 6 months . SF188/TR showed 6-fold resistance to TMZ and cross-resistance to a broad spectrum of other anticancer agents that included 3-5-fold resistance to melphalan (MEL), gemcitabine (GEM), paclitaxel (PAC), methotrexate (MTX), and doxorubicin (DOX), and 1.6-2-fold resistance to cisplatin (CDDP) and topotecan (TPT) . Alkylguanine alkyltransferase (AGT) activity was increased significantly in the resistant cell line compared with the parental cell line (P<0.05), whereas no significant differences occurred in the cellular uptake of TMZ and PAC between resistant and parental cells . Depletion of AGT by O(6)-benzylguanine significantly increased the cytotoxicity of TMZ in both the sensitive and resistant cell lines, but did not influence the cytotoxicity of the other drugs tested . Treatment with TMZ caused SF188 cells to accumulate in S phase, whereas SF188/TR cells were unaffected . Expression of Bcl-2 family members in SF188/TR cells compared with SF188 cells indicated that the pro-apoptotic proteins (i.e . Bad, Bax, Bcl-X(S)) were reduced 2-4-fold in the resistant cell line, whereas the anti-apoptotic proteins Bcl-2 and Bcl-X(L) were expressed at similar levels in both cell lines . In conclusion, the mechanism of resistance of SF188/TR cells to TMZ involved increased activity of AGT, a primary resistance mechanism, whereas the broad cross-resistance pattern to other anticancer drugs was due to a common secondary resistance mechanism related to alterations in the relative expression of the pro-apoptotic and anti-apoptotic proteins. J Med Chem, 2002 Apr 25, 45(9), 1737 - 40 A computational ensemble pharmacophore model for identifying substrates of P-glycoprotein; Penzotti JE et al.; P-glycoprotein (P-gp) functions as a drug efflux pump, mediating multidrug resistance and limiting the efficacy of many drugs . Clearly, identification of potential P-gp substrate liability early in the drug discovery process would be advantageous . We describe a multiple-pharmacophore model that can discriminate between substrates and nonsubstrates of P-gp with an accuracy of 63% . The application of this filter allows large virtual libraries to be screened efficiently for compounds less likely to be transported by P-gp. Oncogene, 2002 Mar 27, 21(13), 1945 - 54 Induction of human MDR1 gene expression by 2-acetylaminofluorene is mediated by effectors of the phosphoinositide 3-kinase pathway that activate NF-kappaB signaling; Kuo MT et al.; The expression of P-glycoprotein encoded by the multidrug resistance (MDR1) gene is associated with the emergence of the MDR phenotype in cancer cells . Human MDR1 and its rodent homolog mdr1a and mdr1b are frequently overexpressed in liver cancers . However, the underlying mechanisms are largely unknown . The hepatocarcinogen 2-acetylaminofluorene (2-AAF) efficiently activates rat mdr1b expression in cultured cells and in Fisher 344 rats . We recently reported that activation of rat mdr1b in cultured cells by 2-AAF involves a cis-activating element containing a NF-kappaB binding site located -167 to -158 of the rat mdr1b promoter . 2-AAF activates IkappaB kinase (IKK), resulting in degradation of IkappaBbeta and activation of NF-kappaB . In this study, we report that 2-AAF could also activate the human MDR1 gene in human hepatoma and embryonic fibroblast 293 cells . Induction of MDR1 by AAF was mediated by DNA sequence located at -6092 which contains a NF-kappaB binding site . Treating hepatoma cells with 2-AAF activated phosphoinositide 3-kinase (PI3K) and its downstream effectors Rac1, and NAD(P)H oxidase . Transient transfection assays demonstrated that constitutively activated PI3K and Rac1 enhanced the activation of the MDR1 promoter by 2-AAF . Treatment of hepatoma cells with 2-AAF also activated another PI3K downstream effector Akt . Transfection of recombinant encoding a dominant activated Akt also enhanced the activation of MDR1 promoter activation by 2-AAF . These results demonstrated that 2-AAF up-regulates MDR1 expression is mediated by the multiple effectors of the PI3K signaling pathway. Br J Pharmacol, 2002 Apr, 135(8), 2038 - 46 Resolution of P-glycoprotein and non-P-glycoprotein effects on drug permeability using intestinal tissues from mdr1a (-/-) mice; Stephens RH et al.; 1 . Intestinal xenobiotic transporters are a significant barrier to the absorption of many orally administered drugs . P-glycoprotein (PGP) is the best known, but several others, including members of the multidrug resistance-associated protein (MRP) family, are also expressed . Definitive information on their precise effect on intestinal drug permeability is scarce due to a lack of specific inhibitors and the difficulty of studying non-PGP activity in the presence of high PGP expression . 2 . We have investigated the in vitro use of intestinal tissues from PGP knockout (mdr1a (-/-)) mice as a tool for dissecting the mechanisms of intestinal drug efflux . The permeability characteristics of digoxin (DIG), paclitaxel (TAX) and etoposide (ETOP) were measured in ileum from mdr1a (-/-) and wild-type (FVB) mice mounted in Ussing chambers . 3 . DIG and TAX exhibited marked efflux across FVB tissues (B-A : A-B apparent permeability (P(app)) ratio 10 and 17 respectively) which was absent in mdr1a (-/-) tissues, confirming that PGP is the sole route of intestinal efflux for these compounds . The A-B P(app) of both compounds was 3 - 5 fold higher in mdr1a (-/-) than in FVB . 4 . Polarized transport of ETOP in FVB tissues was reduced but not abolished in mdr1a (-/-) tissues . Residual ETOP efflux in mdr1a (-/-) tissues was abolished by the MRP inhibitor MK571, indicating involvement of both PGP and MRP . 5 . MK571 abolished calcein efflux in mdr1a (-/-) tissues, while quinidine had no parallel effect in FVB tissues, suggesting involvement of MRP but not PGP . 6 . Tissues from mdr1a (-/-) mice provide a novel approach for investigating the influence of PGP ablation on intestinal permeability and for resolving PGP and non-PGP mechanisms that modulate drug permeability. Antimicrob Agents Chemother, 2002 May, 46(5), 1336 - 9 Anti-human immunodeficiency virus interactions of SCH-C (SCH 351125), a CCR5 antagonist, with other antiretroviral agents in vitro; Tremblay CL et al.; SCH-C (SCH 351125) is a small-molecule antagonist of the human immunodeficiency virus type 1(HIV-1) coreceptor CCR5 . It has in vitro activity against R5 viruses with 50% inhibitory concentrations ranging from 1.0 to 30.9 nM . We have studied anti-HIV-1 interactions of SCH-C with other antiretroviral agents in vitro . Synergistic interactions were seen with nucleoside reverse transcriptase inhibitors (zidovudine and lamivudine), nonnucleoside reverse transcriptase inhibitors (efavirenz), and protease inhibitors (indinavir) at all inhibitory concentrations evaluated . We have also studied antiviral interactions between the HIV-1 fusion inhibitor T-20 and SCH-C against a panel of R5 HIV-1 isolates . We found synergistic interactions against all the viruses tested, some of which harbored resistance mutations to reverse transcriptase and protease inhibitors . Anti-HIV-1 synergy was also observed between SCH-C and another R5 virus inhibitor, aminooxypentane-RANTES . These findings suggest that SCH-C may be a useful anti-HIV drug in combination regimens and that a combination of chemokine coreceptor/fusion inhibitors may be useful in the treatment of multidrug-resistant viruses. Bioorg Med Chem Lett, 2002 Mar 25, 12(6), 883 - 6 Tricyclic isoxazoles are novel inhibitors of the multidrug resistance protein (MRP1); Norman BH et al.; Tricyclic isoxazoles were identified from a screen as a novel class of selective multidrug resistance protein (MRP1) inhibitors . From a screen lead, SAR efforts resulted in the preparation of LY 402913 (9h), which inhibits MRP1 and reverses drug resistance to MRP1 substrates, such as doxorubicin, in HeLa-T5 cells (EC(50)=0.90 microM), while showing no inherent cytotoxicity . Additionally, LY 402913 inhibits ATP-dependent, MRP1-mediated LTC(4) uptake into membrane vesicles prepared from the MRP1-overexpressing HeLa-T5 cells (EC(50)=1.8 microM) . LY 402913 also shows selectivity ( approximately 22-fold) against the related transporter, P-glycoprotein, in HL60/Adr and HL60/Vinc cells . Finally, when dosed in combination with the oncolytic MRP1 substrate vincristine, LY 402913 delays the growth of MRP1-overexpressing tumors in vivo. Int J Oncol, 2002 May, 20(5), 1049 - 55 Single static view 99mTc-sestamibi scintimammography predicts response to neoadjuvant chemotherapy and is related to MDR expression; Cayre A et al.; We examined the relevance of a pre-treatment single static view 99mTc-sestamibi scintimammography and expression of multidrug resistance proteins as predictors of response to neoadjuvant chemotherapy for invasive breast cancer . Forty-five patients affected by primary breast cancer underwent clinical examination, mammography, sonography, 99mTc-sestamibi scintimammography, and biopsy for histopathological diagnosis before neoadjuvant chemotherapy . Expression of MDR1 and MRP mRNA were determined by RT-PCR on fine-needle aspirations . Following completion of anthracycline-based chemotherapy, clinical, mammographic, sonographic and pathological responses were determined . 99mTc-sestamibi scintimammography predicted the reduction of tumor size measured by sonography and the pathological response according to Sataloff classification (p<0.05) and tend to predict pathological response according to Chevallier (p<0.1) . A negative 99mTc-sestamibi scintimammography predicted chemoresistance with a specificity of 100% . Uptake of 99mTc-sestamibi was inversely correlated to the expression of MDR1 (p<0.05) in invasive ductal carcinoma . A pre-treatment single-view 99mTc-sestamibi scintimammography is an excellent predictor of MDR1 chemoresistance and was highly specific of a lack of pathological response to chemotherapy. Int J Oncol, 2002 May, 20(5), 913 - 20 Human breast cancer MCF-7 cell line contains inherently drug-resistant subclones with distinct genotypic and phenotypic features; Devarajan E et al.; The resistance of cancer cells to multiple chemotherapeutic agents poses a major problem in the successful treatment of breast cancer . Whether drug resistance is due to changes induced in the drug-exposed tumor cells or represents the selective growth of one or more drug-resistant clones present in the initial tumor remains controversial . Here we provide evidence that the development of multidrug resistance in a human breast cancer cell line (MCF-7) is a result of propagation of an inherently resistant subclone . The drug-resistant MCF-7 (MCF-7/DOX) cells exhibited several phenotypic and genotypic features that were notably distinct from those observed in the parental drug-sensitive (MCF-7/WT) cells . The most striking change was the presence of a full-length functional caspase-3 in MCF-7/DOX cells that was missing in the parental MCF-7/WT cells due to a deletion mutation in the caspase-3 gene . A drug-resistant MCF-7 cell subline (MCF-7/WT/DOX) was established by exposing the MCF-7/WT cells directly to a high dose of doxorubicin and used for determining the phenotypic and genotypic alterations associated with drug resistance . The MCF-7/WT/DOX cells exhibited alterations identical to those of the MCF-7/DOX cells but which were strikingly distinct from the parental MCF-7/WT cell line . These results suggest that drug resistance is an inherent property of some cancer cells that are present in the initial tumor burden and exhibit distinct phenotypic/genotypic alterations. J Urol, 2002 May, 167(5), 2271 - 5 Immunolocalization of multidrug resistance protein 5 in the human genitourinary system; Nies AT et al.; PURPOSE: The intracellular messenger cyclic guanosine monophosphate (cGMP) has an important role in regulating smooth muscle tone . An increase in intracellular cGMP levels is a prerequisite for penile erection . Inhibition of cGMP degradation by cGMP specific phosphodiesterase 5 has been used for treating erectile dysfunction . In addition to degradation by phosphodiesterase, cGMP is exported from cells by multidrug resistance protein 5 (MRP5), also called ABCC5, which we recently identified as an adenosine triphosphate dependent export pump for cGMP . MRP5 is potently inhibited by substances known as phosphodiesterase inhibitors, including sildenafil and trequinsin . Therefore, we analyzed whether MRP5 is expressed in tissues of the human genitourinary system and whether MRP5 and phosphodiesterase 5 proteins are localized in the same cell types . MATERIALS AND METHODS: Localization of MRP5 and phosphodiesterase 5 was analyzed by immunofluorescence microscopy in cryosections of various tissues of the human genitourinary system . RESULTS: MRP5 and phosphodiesterase 5 were co-expressed in smooth muscle cells of the corpus cavernosum, ureter, urethra and bladder . In addition, MRP5 and phosphodiesterase 5 were localized in epithelial cells of the mucosa in the ureter and urethra, and in blood vessels of the lamina propria . CONCLUSIONS: The co-expression of MRP5 and phosphodiesterase 5 in smooth muscle cells of the genitourinary system indicates 2 distinct pathways for cGMP removal . Thus, MRP5 inhibition represents a new approach for enhancing cGMP levels in smooth muscle cells and developing drugs for erectile dysfunction. Endocrinology, 2002 May, 143(5), 1932 - 41 Cyclosporine a and FK506 inhibit transcriptional activity of the human mineralocorticoid receptor: a cell-based model to investigate partial aldosterone resistance in kidney transplantation; Deppe CE et al.; Renal transplant recipients treated with cyclosporine A (CsA) and FK506 (tacrolimus) develop signs of hypoaldosteronism despite normal plasma aldosterone levels, suggesting a relative resistance of the distal nephron to aldosterone action . To examine the effects of immunosuppressants on human MR (hMR) function, we established the M cell model, renal tubular cells stably transfected with hMR . Upon CsA and FK506 administration, hMR mRNA levels and aldosterone binding in M cells remained unchanged (maximum number of sites, approximately 80 fmol/mg protein; K(d) = approximately 1 nM) . Aldosterone-dependent intracellular localization of green fluorescent protein-hMR was not affected by immunosuppressants . A major impact of CsA or FK506 on the multidrug resistance gene product in cellular accumulation of aldosterone was also excluded . In contrast, aldosterone-stimulated hMR transcriptional activity was reduced to 53 +/- 11.2% (P < 0.03) after pretreatment of M cells for 3 d with CsA and to 71 +/- 9.6% (P < 0.05) after pretreatment with FK506 . These effects were both time and concentration dependent (IC(50) of CsA, 10(-6) M; IC(50) of FK506, 10(-5) M) and needed at least 2 d to develop . Such an inhibitory effect does not depend on the N-terminal part of hMR, as CsA also reduced transcriptional activity of a 1-453 deletion mutant of hMR . Our results demonstrate that immunosuppressants inhibit hMR transcriptional activity without affecting hMR expression, aldosterone binding properties, and hMR nucleocytoplasmic trafficking . They suggest that ion transport alterations in renal graft recipients are in part induced by impaired hMR function. Br J Cancer, 2002 Mar 18, 86(6), 954 - 62 Selection and characterisation of a phage-displayed human antibody (Fab) reactive to the lung resistance-related major vault protein; Scheffer GL et al.; The major vault protein is the main component on multimeric vault particles, that are likely to play an essential role in normal cell physiology and to be associated with multidrug resistance of tumour cells . In order to unravel the function of vaults and their putative contribution to multidrug resistance, specific antibodies are invaluable tools . Until now, only conventional major vault protein-reactive murine monoclonal antibodies have been generated, that are most suitable for immunohistochemical analyses . The phage display method allows for selection of human antibody fragments with potential use in clinical applications . Furthermore, cDNA sequences encoding selected antibody fragments are readily identified, facilitating various molecular targeting approaches . In order to obtain such human Fab fragments recognising major vault protein we used a large non-immunized human Fab fragment phage library . Phages displaying major vault protein-reactive Fabs were obtained through several rounds of selection on major vault protein-coated immunotubes and subsequent amplification in TG1 E coli bacteria . Eventually, one major vault protein-reactive clone was selected and further examined . The anti-major vault protein Fab was found suitable for immunohistochemical and Western blot analysis of tumour cell lines and human tissues . BIAcore analysis showed that the binding affinity of the major vault protein-reactive clone almost equalled that of the murine anti-major vault protein Mabs . The cDNA sequence of this human Fab may be exploited to generate an intrabody for major vault protein-knock out studies . Thus, this human Fab fragment should provide a valuable tool in elucidating the contribution(s) of major vault protein/vaults to normal physiology and cellular drug resistance mechanisms . AIDS, 2002 May 3, 16(7), 1039 - 44 Drug resistance at low viraemia in HIV-1-infected patients with antiretroviral combination therapy; Aleman S et al.; OBJECTIVE: To study the appearance of drug-induced mutations at low viraemia in treated HIV-1-infected patients . DESIGN AND METHODS: Fourteen patients, who received their first (n = 5), second (n = 7) or third (n = 2) line antiretroviral combination therapy, developed a persistent low-grade viraemia after an initial decrease of the viral load (VL) to less than 500 copies/ml . The amount of HIV-1 RNA (n = 71) and reverse transcriptase (RT)/protease sequences (n = 56) were determined in longitudinally obtained plasma samples during a mean period of 16.6 months . RESULTS: In the vast majority (93%) of patients, new primary resistance mutations were found in the RT and/or protease genes at virological failure at a median VL of 500 and 200 copies/ml, respectively . Drug-experienced patients developed mutations at a lower VL than naive patients . In one previously protease inhibitor-naive patient, primary RT and protease mutations were detected, although the VL was less than 50 copies/ml . A serial accumulation of drug resistance mutations was seen despite the VL increase being mostly modest, reaching a median of 1450 copies/ml at the end of the study, and the CD4 T cell counts continued to increase . One patient still had a VL of 300 copies/ml after 28 months, despite the presence of the multidrug-resistance Q151M mutation . CONCLUSION: Low viraemia after virological treatment failure can select for virus with several new drug resistance mutations, despite a concomitant increase in CD4 T cell counts . This serial accumulation of mutations is likely to exhaust future drug options Eur J Biochem, 2002 Apr, 269(7), 1866 - 76 Structural requirements for the apical sorting of human multidrug resistance protein 2 (ABCC2); Nies AT et al.; The human multidrug resistance protein 2 (MRP2, symbol ABCC2) is a polytopic membrane glycoprotein of 1545 amino acids which exports anionic conjugates across the apical membrane of polarized cells . A chimeric protein composed of C-proximal MRP2 and N-proximal MRP1 localized to the apical membrane of polarized Madin-Darby canine kidney cells (MDCKII) indicating involvement of the carboxy-proximal part of human MRP2 in apical sorting . When compared to other MRP family members, MRP2 has a seven-amino-acid extension at its C-terminus with the last three amino acids (TKF) comprising a PDZ-interacting motif . In order to analyze whether this extension is required for apical sorting of MRP2, we generated MRP2 constructs mutated and stepwise truncated at their C-termini . These constructs were fused via their N-termini to green fluorescent protein (GFP) and were transiently transfected into polarized, liver-derived human HepG2 cells . Quantitative analysis showed that full-length GFP-MRP2 was localized to the apical membrane in 73% of transfected, polarized cells, whereas it remained on intracellular membranes in 27% of cells . Removal of the C-terminal TKF peptide and stepwise deletion of up to 11 amino acids did not change this predominant apical distribution . However, apical localization was largely impaired when GFP-MRP2 was C-terminally truncated by 15 or more amino acids . Thus, neither the PDZ-interacting TKF motif nor the full seven-amino-acid extension were necessary for apical sorting of MRP2 . Instead, our data indicate that a deletion of at least 15 C-terminal amino acids impairs the localization of MRP2 to the apical membrane of polarized cells. Drug Metab Dispos, 2002 May, 30(5), 513 - 8 Neotrofin is transported out of brain by a saturable mechanism: possible involvement of multidrug resistance and monocarboxylic acid transporters; Yan R et al.; Neotrofin (AIT-082; leteprinim potassium) is transported out of brain by a saturable mechanism and in this study the mechanisms mediating this efflux were evaluated . Intracerebroventricular coadministration of {(14)C}Neotrofin with verapamil, a P-glycoprotein inhibitor, probenecid, an organic anion transporter inhibitor, 3-{{3-{2-(7-chloroquinolin-2-yl)vinyl}phenyl}-(2-dimethylcarbamoylethylsulfanyl)methylsulfanyl} propionic acid (MK571), a multidrug resistance-associated protein inhibitor, and salicylate or benzoate, both monocarboxylic acid transporter substrates, inhibited the efflux of {(14)C}Neotrofin . Additionally, Neotrofin inhibited the efflux of {(3)H}quinidine from brain . Compounds can diffuse from cerebrospinal fluid (CSF) into extracellular fluid of brain parenchyma and thus, efflux of {(14)C}Neotrofin after intracerebroventricular administration may indicate active transport across choroid plexus epithelium, brain capillary endothelium, or both . To determine whether {(14)C}Neotrofin efflux occurs at the brain capillary endothelium, experiments were performed in which {(14)C}Neotrofin was administered intraparenchymally . The t(1/2) for {(14)C}Neotrofin disappearance from brain after intraparenchymal administration was significantly lower than that for {(3)H}sucrose and the efflux of Neotrofin was inhibited by 600-fold excess of unlabeled Neotrofin, verapamil, MK571, and salicylate . Together, these data suggest that a saturable mechanism for the efflux of Neotrofin is located at the blood-brain barrier and possibly the blood-CSF barrier . It is likely that multiple transporters are involved in the efflux of Neotrofin and these may include multidrug resistance and monocarboxylic acid transporters . These data are discussed in detail with respect to the site of transporter expression, the recent identification of numerous multidrug resistance-associated protein and monocarboxylic acid transporter homologs, the existence of other potential brain efflux transporters, and the availability of specific pharmacological agents with which to distinguish these transporters. Neoplasma, 2001, 48(6), 472 - 8 Significance of P-glycoprotein expression in childhood malignant tumors; Kucerova H et al.; Resistance to chemotherapy significantly affects the treatment results in various cancers . Multidrug resistance caused by P-glycoprotein expression is now widely studied in human malignancies . We present the results of P-glycoprotein expression examination in 91 tumor tissue samples obtained from children treated for different malignant tumors in the Dept . of Pediatric Oncology, Prague . The correlation between the level of P-glycoprotein expression and tumor histology, clinical outcome, use of therapy, relapse rate and metastatic disease was made . P-glycoprotein expression was found significantly more frequent in soft tissue sarcomas, neuroblastomas, and hepatoblastomas, and generally in disseminated disease . On the contrary, a high expression of P-glycoprotein was not found in malignant brain tumors and nephroblastomas . The data strongly support the possibility that the percentage of P-glycoprotein expressing cells in selected tumors (soft tissue sarcomas, neuroblastomas), may have a clinical importance. Int J Cancer, 2002 May 1, 99(1), 43 - 52 Enzymatic oxidation products of spermine induce greater cytotoxic effects on human multidrug-resistant colon carcinoma cells (LoVo) than on their wild-type counterparts; Calcabrini A et al.; The occurrence of resistance to cytotoxic agents in tumor cells, associated with several phenotypic alterations, is one of the major obstacles to successful anticancer chemotherapy . A new strategy to overcome MDR of human cancer cells was studied, using BSAO, which generates cytotoxic products from spermine, H(2)O(2) and aldehyde(s) . The involvement of these products in causing cytotoxicity was investigated in both drug-sensitive (LoVo WT) and drug-resistant (LoVo DX) colon adenocarcinoma cells . Evaluation of clonogenic cell survival showed that LoVo DX cells are more sensitive than LoVo WT cells . Fluorometric assay and treatments performed in the presence of catalase demonstrated that the cytotoxicity was due mainly to the presence of H(2)O(2) . Cytotoxicity was eliminated in the presence of both catalase and ALDH . Transmission electron microscopic observations showed more pronounced mitochondrial modifications in drug-resistant than in drug-sensitive cells . Mitochondrial functionality studies performed by flow cytometry after JC-1 labeling revealed basal hyperpolarization of the mitochondrial membrane in LoVo DX cells . After treatment with BSAO and spermine, earlier and higher mitochondrial membrane depolarization was found in LoVo DX cells than in drug-sensitive cells . In addition, higher basal ROS production in LoVo DX cells than in drug-sensitive cells was detected by flow-cytometric analysis, suggesting increased mitochondrial activity in drug-resistant cells . Our results support the hypothesis that mitochondrial functionality affects the sensitivity of cells to the cytotoxic enzymatic oxidation products of spermine, which might be promising anticancer agents, mainly against drug-resistant tumor cells . J Biol Chem, 2002 Jun 21, 277(25), 22980 - 4 Epub 2002 Apr 10. Evaluating the specificity of antisense oligonucleotide conjugates . A DNA array analysis; Fisher AA et al.; Antisense oligonucleotides are potentially powerful tools for selective control of cellular and viral gene expression . Crucial to successful application of this approach is the specificity of the oligonucleotide for the chosen RNA target . Here we apply DNA array technology to examine the specificity of antisense oligonucleotide treatments . The molecules used in these studies consisted of phosphorothioate oligomers linked to the Antennapedia (Ant) delivery peptide . The antisense oligonucleotide component was complementary to a site flanking the AUG of the MDR1 message, which codes for P-glycoprotein, a membrane ATPase associated with multidrug resistance in tumor cells . Using a DNA array of 2059 genes, we analyzed cellular responses to molecules comprised of Ant peptide-oligonucleotide conjugates, as well as to the Ant peptide alone . Besides the expected reduction in MDR1 message level, 37 other genes (approximately 2% of those tested) showed changes of comparable magnitude . The validity of the array results was confirmed for selected genes using Northern blots to assess messenger RNA levels . These results suggest that studies using antisense oligonucleotide technology to modulate gene expression need to be interpreted with caution. J Bacteriol, 2002 May, 184(9), 2543 - 5 Overexpression of the Escherichia coli sugE gene confers resistance to a narrow range of quaternary ammonium compounds; Chung YJ et al.; SugE of Escherichia coli, first identified as a suppressor of groEL mutations but a member of the small multidrug resistance family, has not previously been shown to confer a drug resistance phenotype . We show that high-level expression of sugE leads to resistance to a subset of toxic quaternary ammonium compounds. Clin Cancer Res, 2002 Apr, 8(4), 1068 - 74 Expression of the breast cancer resistance protein in breast cancer; Faneyte IF et al.; PURPOSE: The breast cancer resistance protein (BCRP) is involved in in vitro multidrug resistance and was first identified in the breast cancer cell line MCF7/AdrVp . The aim of this study was to investigate the role of BCRP in resistance of breast cancer to anthracycline treatment . EXPERIMENTAL DESIGN: BCRP mRNA was determined with real-time reverse transcription-PCR and immunostaining in nine breast cancer cell lines and in samples of 25 primary breast carcinomas and 27 patients who received preoperative anthracycline-based therapy . Tumor response to treatment and patient survival were recorded . RESULTS: In cell lines, only MCF7 and BT20 had BCRP mRNA levels coinciding with membrane-bound immunostaining . In clinical samples, BCRP expression varied widely (range, 0.01-0.86) . With immunohistochemistry, BCRP was detected in vessels and normal breast epithelium but not in tumor cells . There was no difference in BCRP expression between anthracycline-naive and treated tumor samples . BCRP expression was not associated with decreased response or survival . CONCLUSIONS: There is no indication that elevated BCRP expression in breast carcinomas confers resistance to anthracyclines . Expression was not detectable with immunohistochemistry. J Biol Chem, 2002 Jun 14, 277(24), 21254 - 60 Epub 2002 Apr 09. New regulators of drug sensitivity in the family of yeast zinc cluster proteins; Akache B et al.; The Gal4p family of yeast zinc cluster proteins comprises over 50 members that are putative transcriptional regulators . For example, Pdr1p and Pdr3p activate multidrug resistance genes by binding to pleiotropic drug response elements (PDREs) found in promoters of target genes such as PDR5, encoding a drug efflux pump involved in resistance to cycloheximide . However, the role of many zinc cluster proteins is unknown . We tested a panel of strains carrying deletions of zinc cluster genes in the presence of various drugs . One deletion strain (Deltardr1) was resistant to cycloheximide, whereas eight strains showed sensitivity to the antifungal ketoconazole or cycloheximide . Unnamed zinc cluster genes identified in our screen were called RDS for regulators of drug sensitivity . RNA levels of multidrug resistance genes such as PDR16, SNQ2, and PDR5 were decreased in many deletion strains . For example, cycloheximide sensitivity of a Deltastb5 strain was correlated with decreased RNA levels and promoter activity of the PDR5 gene . We tested if activation of PDR5 is mediated via a PDRE by inserting this DNA element in front of a minimal promoter linked to the lacZ gene . Strikingly, activity of the reporter was decreased in a Deltastb5 strain . The purified DNA binding domain of Stb5p bound to a PDRE in vitro . Mutations in the PDRE known to affect binding of Pdr1p/Pdr3p showed similar effects when assayed with Stb5p . These results strongly suggest that Stb5p is a transcriptional activator of multidrug resistance genes . Thus, we have identified new regulators of drug sensitivity in the family of zinc cluster proteins. Gene, 2002 Mar 20, 286(2), 299 - 306 cDNA cloning and genomic organization of the murine MRP7, a new ATP-binding cassette transporter; Kao HH et al.; Cellular resistance to cytotoxic drugs is a major obstacle to the treatment of disseminated cancers . Multidrug resistance protein (MRP) subfamily is a member of the ATP-binding cassette transporters which has been shown to cause multidrug resistance, except for P-glycoprotein . A new MRP subfamily gene, mrp7A (Abcc10), and its splicing variant, mrp7B, were isolated from mouse . The lengths of the open reading frames of mouse mrp7A and mrp7B are 4383 and 4506 bp, respectively . Estimated polypeptide sequences of mrp7A and mrp7B are 1460 and 1501 amino acids . The mouse mrp7 gene consists of at least 21 exons and 20 introns spanning around 20 kb that is almost the same as the one in human MRP7 gene, but different with the other MRP subfamily genes . The promoter region was isolated from the genomic clone and shown to support the luciferase activity seven fold over the promoterless negative control and two fold activity higher than the positive control of SV40 promoter . The analysis of tissue expression of mrp7A and mrp7B showed that these two transcripts express differentially in specific tissues. J Fr Ophtalmol, 2002 Feb, 25(2), 187 - 93 {New strategies in the management of retinoblastoma}; Balmer A et al.; It was rare that a child survived retinoblastoma at the beginning of the twentieth century . Today the survival rate is in the order of 95% in reference centers, with new strategies improving prognosis step by step . Systematic enucleation used to be the starting point of any true and structured management, until the advent of radiotherapy made it possible not only to save lives but also to retain some useful vision . Early diagnosis has enabled focal therapies such as photocoagulation, cryocoagulation, and radioactive applicators to open up a new era of targeted tumor treatment . However, the onset of nonocular tumors secondary to radiotherapy, the resistance of certain tumors to irradiation, and unsightly cosmetic consequences all justify research into alternative therapeutic strategies . New types of chemotherapy have shown spectacular results and are currently under study: chemoreduction to make large tumors more manageable and enable less aggressive treatment of tumors located in delicate sites, thermochemotherapy using the effect of heat on plasma membrane permeability to antimitotics, and chemotherapy associated with cyclosporine to reduce the multidrug resistance of certain tumors . The aim is to avoid primary enucleation and external beam radiation as far as possible . The future may lie in local chemotherapy, hyperthermia, and dynamic phototherapy, accelerated proton beam radiotherapy also has promising prospects. Med Clin (Barc), 2002 Mar 23, 118(10), 376 - 8 {Imported tuberculosis: an emerging disease in industrialised countries}; Valles X et al.; BACKGROUND: The aim of this study was to describe the characteristics of imported tuberculosis (TB) in Barcelona during 1999 and 2000 . MATERIAL AND METHOD: Epidemiological surveillance questionnaire . RESULTS: During 1999 and 2000, a 7.9% decrease in TB cases was observed among the native population in Barcelona, whereas cases among immigrants grew up to 47.2% . In 2000, 449 TB cases were detected among the native population (incidence, 29.5/100,000) and 121 among immigrants (incidence, 555.9/100,000) . Three outbreaks were identified, involving one Indian community (11 cases), two Dominican families (4 cases) and one city school (2 cases) whose index case was a cooperant . Isolated strains of Mycobacterium tuberculosis at the first, second and third outbreak were multisensitive, multidrug-resistant and isoniazid-resistant, respectively . CONCUSIONS: The emergence of imported TB cases in Barcelona over 1999 and 2000 suggests that current preventive guidelines must be reviewed. Chin Med J (Engl), 2002 Feb, 115(2), 238 - 41 Establishment of multidrug-resistance cell line C(6)/adr and reversal of drug-resistance; Liu F et al.; OBJECTIVE: To investigate the mechanism of multidrug resistance (MDR) in a human glioma cell and methods for overcoming multi-drug resistance . METHODS: MDR cell line C(6)/adr was established . The expression of the mdr-1 gene and its P-glycoprotein (P-gp) in the C(6)/adr cell line was observed by RT-PCR and flow cytometry . The reversal of MDR by verapamil, erythromycin, dihydropyridine, P-gp monoclonal antibody and Salvia miltiorrhiza (SM) was studied by microtiter tetrazolium (MTT) assay or by high performance liquid chromatographic assay . RESULTS: The mdr-1 gene of the C(6)/adr cell line was positive, over-expressing P-gp . The drug-resistance of the C(6)/adr cell lines could be partly reversed by 2 - 6 microg/ml of verapamil, 50 - 100 microg/ml of erythromycin, or 5 microg/ml of dihydropyridine . As concentration increased, they had a better effect . Among these drugs, 100 microg/ml of erythromycin had the best result of reversal . Dihydropyridine 1 microg/ml, P-gp monoclonal antibody and SM had no effect . CONCLUSION: The mdr-1 gene and its expression might be associated with the MDR of glioma cells . Verapamil, erythromycin and dihydropyridine could reverse the MDR of glioma cells. Zhonghua Nei Ke Za Zhi, 2002 Mar, 41(3), 183 - 5 {The relationship between expression of lung resistance-related protein gene or multidrug resistance-associated protein gene and prognosis in newly diagnosed acute leukemia}; Zhao Y et al.; OBJECTIVE: To evaluate the relationship between the expression of lung resistance-related protein (lrp) gene or multidrug resistance-associated protein (mrp) gene and prognosis in untreated acute leukemia (AL) patients . METHODS: Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to examine the expression of lrp and mrp gene in 58 newly diagnosed AL patients . RESULTS: The positive rate of lrp and mrp gene expression in newly diagnosed acute lymphocytic leukemia (ALL) group was 15.0% and 40.0% and it was 15.8% and 42.1% in newly diagnosed acute nonlymphocytic leukemia (ANLL) group . In both the ALL and ANLL groups, the difference of the first complete remission rate in lrp negative and in lrp positive patients was not significant (P > 0.05), the same results were found with mrp gene . The difference of the first complete remission rate between lrp(+)/mrp(+) and lrp(-)/mrp(-) patients was significant (P < 0.05) . There was no relationship between lrp and mrp gene . CONCLUSION: Neither lrp nor mrp gene as a single indicator to forecast original multidrug resistance is sensitive, but lrp combined with mrp as one indicator will be sensitive. Eur J Clin Microbiol Infect Dis, 2002 Feb, 21(2), 114 - 22 Two-year population-based molecular epidemiological study of tuberculosis transmission in the metropolitan area of Milan, Italy; Moro ML et al.; A 2-year, population-based, molecular epidemiological study was conducted in Milan, Italy, to determine the proportion of tuberculosis (TB) cases attributable to recent transmission . All strains were typed by restriction fragment length polymorphism (RFLP) analysis; clustering was considered indicative of recent transmission . Of the 581 cases, 239 (41.1%) belonged to clusters that consisted of 2 to 11 patients; 28.1% were attributable to recent transmission (number of clustered patients minus 1) . Clustering was associated with multidrug-resistant Mycobacterium tuberculosis strains (74.2% of cases), AIDS (60.2%), and a history of incarceration (67.4%) . The frequency of multidrug-resistant Mycobacterium tuberculosis was 5.3% overall (15.4% among AIDS patients) . Among AIDS patients, infection with a resistant strain was independently associated with clustering (odds ratio, 1.32; 95% confidence interval, 1.07-1.163), while among non-AIDS patients, three factors were associated with clustering: history of incarceration (odds ratio, 2.03; 95% confidence interval, 1.41-2.92), age <30 years (odds ratio, 1.43; 95% confidence interval, 1.05-1.94), and native-born Italian nationality (odds ratio, 1.44; 95% confidence interval, 1.08-1.92) . Of the 118 patients who belonged to either the smallest or the largest cluster, 19 (16.1%) reported an epidemiological link with another study patient . The results of this study highlight the need for control programs that focus on selected high-risk groups consisting primarily of HIV-infected individuals and persons with social and lifestyle risks for TB . These programs should be aimed at reducing the probability of transmission of drug-resistant TB through early identification of cases and provision of effective treatment until the individual is cured. Int J Hematol, 2002 Feb, 75(2), 154 - 60 Comparison of Pgp- and MRP-mediated multidrug resistance in leukemia cell lines; Gong YP et al.; Drug resistance is a major cause of the failure of anticancer chemotherapy . Multidrug resistance is often caused by overexpression of the P-glycoprotein (Pgp) or the multidrug resistance-related protein (MRP) . In the present study, we compared daunorubicin (DNR) accumulation, subcellular distribution, and the effect of modulators on drug accumulation and subcellular distribution in the Pgp-expressing K562 cell line and the MRP-expressing HL60 cell line using reverse-transcriptase polymerase chain reaction, MTT (3-{4, 5-dimethylthiazol-z-yl}-2,5-diphenyltetrazolium bromide) drug cytotoxicity assay, fluorocytometry, and confocal laser scanning microscopy . The 2 resistant cell lines exhibit similar levels of resistance to DNR and decreased drug accumulation . Altered drug subcellular distribution in the resistant cell lines compared to that in the sensitive cell lines was shown and, moreover, differences in drug distributions between the 2 resistant cell lines were found . DNR fluorescence in the resistant HL60 cell line was distributed into punctate regions in the cytoplasm; the nucleus and other cytoplasm were almost negative . In contrast, the resistant K562 cells showed a bright fluorescent signal located in the peripheral cytoplasm and perinuclear region; the nucleus and other cytoplasmic regions showed no signal . Use of the modulator verapamil increased drug accumulation and restored the altered subcellular distribution of the drug in the 2 resistant cell lines . The Golgi apparatus inhibitor brefeldin A had similar action in the resistant HL60 line but had little effect in the resistant K562 line . Therefore, our study suggested that there were differences between the 2 resistant cell lines in the compartments sequestering DNR. Saudi Med J, 2002 Mar, 23(3), 305 - 10 Risk factors for drug-resistant Mycobacterium tuberculosis in Saudi Arabia; Alrajhi AA et al.; OBJECTIVE: To identify rates of primary and secondary drug-resistant Mycobacterium tuberculosis and their risk factors from a tertiary-care center in the Kingdom of Saudi Arabia . METHODS: Review of microbiological and clinical data of all patients with positive isolates of Mycobacterium tuberculosis between 1995 and 2000 at King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia . RESULTS: Susceptibility to antituberculosis agents was tested in 320 isolates from 320 patients . The median age was 50 years . Pulmonary tuberculosis was diagnosed in 106 (33%) patients, extrapulmonary in 183 (57%), and both in 31 (10%) patients . Two hundred forty-six isolates were sensitive to all 5 first line agents . Resistance to at least one of the first line agents was documented in 36 (11.3%) isolates . For the year 2000, resistance rates increased to 17.6% . Monoresistance was noted in 20 isolates (6.3%) and polyresistance in 16 isolates (5.0%) including 9 multidrug-resistant Mycobacterium tuberculosis isolates (2.8%) . Resistance rates for antituberculosis agents are: Isoniazid, 9.1%; Rifampin, 2.8%; Ethambutol, 1.6%; Streptomycin, 5%; Pyrazinamide, 3.6% . Seventy-eight percent of the resistant isolates are considered primary resistance . History of antituberculosis therapy was the only risk factor associated with drug resistant Mycobacterium tuberculosis, odds ratio 19.9 (P< 0.00001) . The mean age of patients with resistant isolates was 42 years compared to 49 years in patients with susceptible isolates (P= 0.047) . CONCLUSION: In a population of mostly Saudi patients, primary and secondary drug-resistant Mycobacterium tuberculosis is relatively low but has increased lately . Previous history of antituberculosis chemotherapy and young age are risk factors identified. J Nucl Med, 2002 Apr, 43(4), 519 - 25 99mTc-sestamibi imaging in the assessment of toremifene as a modulator of multidrug resistance in patients with breast cancer; Mubashar M et al.; Multidrug resistance (MDR) due to expression of a membrane-associated permeability glycoprotein (P-glycoprotein {Pgp}) prevents successful cytotoxic chemotherapy for breast cancer . Identification of MDR would facilitate selection of chemotherapy regimens and MDR modulators . This study aimed to evaluate (99m)Tc-sestamibi imaging for predicting overexpression of Pgp in primary breast cancer and to measure the efficacy of toremifene, the MDR modulator, in vivo . METHODS: Twenty patients with untreated breast cancer had (99m)Tc-sestamibi imaging 20 and 120 min after tracer injection before and after a 3-d course of toremifene (780 mg/d) . Tumor samples were obtained during surgery for correlation of imaging and Pgp immunohistochemistry . RESULTS: Sixteen of 20 tumors were visualized with sestamibi . Before toremifene, there was a significant inverse correlation (Spearman rank correlation coefficient {R(S)}) between staining intensity, based on the anti-Pgp monoclonal antibodies C494 and C219, and the tumor-to-background ratio (T/B) at 120 min (R(S) = -0.85; P < 0.001 and R(S) = -0.71; P < 0.001, respectively) . However, the correlation between the T/B and immunohistochemistry at 20 min was significant only for C494 (R(S) = -0.57; P < 0.01) . Similarly, before toremifene, there was an inverse correlation between staining intensity and the change in the T/B between 20 and 120 min (R(S) = -0.77; P < 0.001 and -0.75; P < 0.001 for C494 and C219) . After toremifene, an inverse correlation between staining intensity and the T/B was seen only at 120 min and only with C494 (R(S) = -0.68; P < 0.01) . However, the change in the T/B between 20 and 120 min correlated significantly with staining intensity for C494 and C219 (R(S) = -0.68; P < 0.01 and -0.7; P < 0.01 for C494 and C219, respectively) . Toremifene did not significantly alter the overall T/B at either 20 or 120 min when data were compared before and after toremifene . Nevertheless, at 120 min, 8 of 8 tumors with low Pgp expression showed reduced uptake after toremifene, whereas 5 of 6 tumors with strong expression showed increased uptake (P < 0.003) . Moreover, there was a significant correlation between the change in the T/B and staining intensity with C494 (R(S) = 0.59; P < 0.05) and C219 (R(S) = 0.56; P < 0.05) at 120 min but not at 20 min . CONCLUSION: (99m)Tc-Sestamibi accumulation in breast cancer correlates with Pgp expression . Toremifene has a dual effect on this accumulation, increasing it through an inhibitory effect on Pgp while at the same time reducing it by a direct competition with sestamibi . The latter implies that in response to Pgp modulation the efflux of various agents may be affected differently. Lancet Infect Dis, 2002 Apr, 2(4), 209 - 18 Epidemiology of drug-resistant malaria; Wongsrichanalai C et al.; Since the first reports of chloroquine-resistant falciparum malaria in southeast Asia and South America almost half a century ago, drug-resistant malaria has posed a major problem in malaria control . By the late 1980s, resistance to sulfadoxine-pyrimethamine and to mefloquine was also prevalent on the Thai-Cambodian and Thai-Myanmar (Thai-Burmese) borders, rendering them established multidrug-resistant (MDR) areas . Chloroquine resistance spread across Africa during the 1980s, and severe resistance is especially found in east Africa . As a result, more than ten African countries have switched their first-line drug to sulfadoxine-pyrimethamine . Of great concern is the fact that the efficacy of this drug in Africa is progressively deteriorating, especially in foci in east Africa, which are classified as emerging MDR areas . Urgent efforts are needed to lengthen the lifespan of sulfadoxine-pyrimethamine and to identify effective, affordable, alternative antimalarial regimens . Molecular markers for antimalarial resistance have been identified, including pfcrt polymorphisms associated with chloroquine resistance and dhfr and dhps polymorphisms associated with sulfadoxine-pyrimethamine resistance . Polymorphisms in pfmdr1 may also be associated with resistance to chloroquine, mefloquine, quinine, and artemisinin . Use of such genetic information for the early detection of resistance foci and future monitoring of drug-resistant malaria is a potentially useful epidemiological tool, in conjunction with the conventional in-vivo and in-vitro drug-sensitivity assessments . This review describes the various features of drug resistance in Plasmodium falciparum, including its determinants, current status in diverse geographical areas, molecular markers, and their implications. Exp Hematol, 2002 Apr, 30(4), 340 - 5 Human T-cell lymphotropic virus type I Tax activates lung resistance-related protein expression in leukemic clones established from an adult T-cell leukemia patient; Sakaki Y et al.; OBJECTIVE: We examined the significance of human T-cell lymphotropic virus type I (HTLV-I) Tax protein-induced resistance to anticancer drugs and the relationship between Tax and multidrug resistance proteins . MATERIALS AND METHODS: S1T cell, a leukemic non-Tax-producing T-cell clone established from an adult T-cell leukemia (ATL) patient, S1TcTax05 and S1TcTax10 clones, transfected with Tax stably expressing cDNA, and S1Tneo, transfected with a neomycin-resistant gene, were examined for Tax-related anticancer drug resistance . Resistance of those cells to the anticancer drugs doxorubicin, etoposide, cisplatin, and vindesine was tested with the MTT method . Expression of multidrug resistance protein mRNAs (MDR1, MRP1, cMOAT/MRP2, and LRP) was analyzed with reverse transcriptase polymerase chain reaction (RT-PCR) . Doxorubicin subcellular distribution in those cells was examined by fluorescence microscopy . RESULTS: S1TcTax05 and S1TcTax10 showed resistance to doxorubicin, etoposide, and vindesine, but not to cisplatin as compared with S1T or S1Tneo . RT-PCR demonstrated that MRP1 mRNA was expressed, but MDR1, cMOAT, and LRP mRNAs were not in S1T or S1Tneo . Marked expression of LRP mRNA was detected, but no change of MDR1, MRP1, or cMOAT mRNA expression in Tax-expressing S1TcTax05 and S1TcTax10 . Fluorescence microscopy demonstrated that doxorubicin was distributed mainly in the cytoplasm of S1TcTax05 and S1TcTax10, and in the nucleus of S1T and S1Tneo . CONCLUSIONS: These findings suggest that Tax-related drug resistance of ATL cells is due to LRP and not MDR1, as reported previously . These findings in cells derived from an ATL patient suggest a novel mechanism for drug resistance in Tax-expressing ATL cells. Int J Tuberc Lung Dis, 2002 Apr, 6(4), 320 - 5 Treatment outcome of relapse and defaulter pulmonary tuberculosis patients; Sevim T et al.; SETTING: Tuberculosis clinic in a referral hospital . OBJECTIVE: To evaluate the effect of risk factors on the outcome of retreatment in relapse and defaulter pulmonary tuberculosis patients . DESIGN: A total of 57 retreatment tuberculosis patients treated and monitored in our centre between January 1997 and June 1999 were evaluated with respect to treatment outcome . Factors which have on effect on treatment outcome were investigated . RESULTS: Of 57 patients, 37 (64.9%) were classified as relapse cases and 20 (35.1%) as defaulters . The treatment success rate was 71.9% (68.4% cure rate and 3.5% completion rate) . Failure was encountered in 22.8% . Twenty-six patients (45.6%) exhibited resistance to at least one drug, namely rifampicin . The multidrug-resistance (MDR) rate was 18.5% . Treatment success rates were 100% and 50%, respectively, in patients in whom susceptibility to all drugs and resistance to at least one drug were detected . Successful outcome was possible in 68.8% of patients with any rifampicin resistance and in 20% of patients with MDR tuberculosis . Retreatment resulted in failure in 80% and 100%, respectively, of patients whose sputum cultures remained positive at the end of the second and third months . CONCLUSION: Drug resistance proved the most important factor affecting treatment outcome . Success rates in retreatment of patients with any rifampicin resistance or MDR tuberculosis are low . Conversion to negative sputum results at the end of the second and third months of retreatment seems to be a significant parameter for a successful outcome. Int J Tuberc Lung Dis, 2002 Apr, 6(4), 289 - 94 The nationwide tuberculosis drug resistance survey in Mongolia, 1999; Tsogt G et al.; SETTING: Mongolia, a country in the Western Pacific Region burdened with many cases of tuberculosis, with rapid expansion of DOTS over the last several years . OBJECTIVE: To determine the prevalence of resistance to major anti-tuberculosis drugs among tuberculosis patients who have never been treated previously . DESIGN: Sputum specimens were collected from all smear-positive tuberculosis patients identified from 1 November 1998 to 1 May 1999 . RESULTS: Resistance to any of the four major drugs (streptomycin, isoniazid, rifampicin, and ethambutol) was as high as 28.9% (95%CI 24.7-33.5), primarily due to high streptomycin resistance of 24.2% (95%CI 20.3-28.6) . Isoniazid resistance was also high, at 15.3% (95%CI 12.1-19.1) . Resistance levels to ethambutol and rifampicin were relatively low, at 1.7% (95%CI 0.8-3.5) and 1.2% (95%CI 0.5-2.9), presumably because these drugs were only recently introduced into Mongolia . Multidrug resistance was also rare, at 1.0% (95%CI 0.1-1.8) . Drug resistance rates were higher in middle-aged patients than in younger and older age groups combined (P = 0.006) . Males tended to have higher resistance than females, although this was of statistically marginal significance (P = 0.08) . No significant regional differences in drug resistance were found . CONCLUSION: While multidrug resistance was rare, isoniazid resistance was very common, which necessitates closer monitoring of the treatment outcomes of individual patients as well as long-term follow-up for drug resistance on a nationwide scale. Diagn Cytopathol, 2002 Apr, 26(4), 228 - 31 Nested PCR for diagnosis of tuberculous lymphadenitis and PCR-SSCP for identification of rifampicin resistance in fine-needle aspirates; Gong G et al.; An accurate diagnosis of tuberculosis and multidrug resistance is important for the control of tuberculosis, which remains a major public health problem . Fine-needle aspiration (FNA) has provided an alternative tool for bacterial examination . This study was performed to investigate the usefulness of one-step polymerase chain reaction (PCR) and PCR-SSCP as a routine test for the detection of Mycobacterium tuberculosis and rifampicin-resistant strain in FNA . Ziehl-Neelsen stain (Z-N) and PCR were processed using the aspirates of tuberculous lymphadenitis for the detection of M . tuberculosis . PCR-SSCP was done for the identification of rpoB mutation . M . tuberculosis was detected in 49/63 (77.8%) by PCR and 25/63 (39.7%) by Z-N . There were 26 cases with PCR(+)/Z-N(-) and two cases with PCR(-)/Z-N(+) . Twelve cases showed negativity against both . In 7/22 (31.8%), rpoB mutation was observed . In conclusion, PCR is more sensitive in the detection of M . tuberculosis in FNA than Z-N . PCR-SSCP could also be used in FNA in the prediction of multidrug resistance . Med Res Rev, 2002 May, 22(3), 305 - 28 Bioactive taxoids from the Japanese yew Taxus cuspidata; Kobayashi J et al.; A series of new taxoids, named taxuspines A-H and J-Z (1-25) and taxezopidines A-H and J-L (26-36), have been isolated together with 37 known taxoids (37-73) including paclitaxel (53) from the Japanese yew, Taxus cuspidata Sieb . et Zucc . (Taxaceae) . These new taxoids possess various skeletons containing 5/7/6, 6/10/6, 6/5/5/6, 6/8/6, or 6/12-membered ring systems . Among the new taxoids, some non-taxol-type compounds remarkably reduced CaCl(2)-induced depolymerization of microtubules, or increased cellular accumulation of vincristine in multidrug-resistant tumor cells as potent as verapamil . On the other hand, chemical derivatization of taxinine (37), one of major taxoids obtained from this yew, led to the discovery of unusual reactions of taxinine derivatives . Here we describe our recent results on the isolation, structure elucidation, and bioactivity of these new and known taxoids and the formation of unexpected products of the unusual reactions of taxinine . Biochem Pharmacol, 2002 Mar 15, 63(6), 1143 - 7 Characterization of anthracenediones and their photoaffinity analogs; Chou KM et al.; In an attempt to overcome the cardiotoxicity and cross-resistance problems caused by the anticancer drugs anthracyclines and anthracenediones during chemotherapy, we have developed a series of aza-anthracenedione compounds by modifying the chromophore and the side arms of anthracyclines and anthracenediones . One of these aza-anthracenediones, 6,9-bis{(2-aminoethyl)amino}benzo{g}isoquinoline-5,10-dione (BBR 2778), which is currently under phase II clinical trials, showed remarkable antitumor activity and appeared to lack a cardiotoxic effect in preclinical studies . However, it was still cross-resistant against multidrug resistance (MDR) cells expressing P-glycoprotein (P-gp) . In contrast, another aza-anthracenedione, 6,9-bis{{2-(dimethylamino)ethyl}amino}benzo{g}isoquinoline-5,10-dione, which has side arm structures different from those of BBR 2778, was highly active against MDR cells . In this study, BBR 2778, BBR 2378, and an anthracenedione compound, 1,4-bis{(2-aminoethyl)amino}-5,8-dimethyl-9,10-anthracenedione, were used to assess the relationship between the chemical structures of these drugs and their interactions with DNA and P-gp . In addition, the biological and pharmacological influences of photoaffinity labeling were also studied for BBR 2778 and DEH . As the results indicate, the photolabeled analogs of BBR 2778 and DEH were less DNA-reactive and less cytotoxic . The more lipophilic compound, BBR 2378, and the photolabeled analogs of BBR 2778 and DEH inhibited P-gp labeling by azidopine better than did the more hydrophilic parental compounds . These studies suggested that the DNA binding affinity of BBR 2778 and DEH could be important in determining their cytotoxicity, and that the chemical structure of the side arms and the lipophilicity of these drugs are critical in determining their cross-resistance. Int J Tuberc Lung Dis, 2002 Jan, 6(1), 32 - 8 Prevalence of resistance to anti-tuberculosis drugs: results of the 1998/99 national survey in Italy; Migliori GB et al.; OBJECTIVE: To determine the prevalence of resistance to the main anti-tuberculosis drugs in newly and previously treated tuberculosis patients in Italy and to evaluate the contribution of foreign-born and human immunodeficiency virus (HIV) positive cases to drug resistance . METHODS: Methods and definitions were derived from the WHO/IUATLD Global Project on Anti-tuberculosis Drug Resistance Surveillance . Univariate and multivariate analysis was used to study prevalence rates of drug resistance in risk groups . RESULTS: In a national survey in Italy, 810 initial isolates of Mycobacterium tuberculosis (683 from new cases, 115 from retreatment cases and 12 from patients whose treatment history was unknown/dubious) were analysed . Low prevalence of drug and multidrug resistance was found in the new cases (isoniazid 2.9%; rifampicin 0.8%; multidrug resistance 1.2%; any drug resistance 12.3%) . The prevalence of resistance to isoniazid and rifampicin was significantly higher in immigrants and HIV-positive subjects, respectively . A high prevalence of drug resistance was found in cases with previous treatment failure or default (isoniazid 5.2%; rifampicin 4.3%; multidrug resistance 36.5%; any drug resistance 61.7%) . RECOMMENDATIONS: Special efforts are necessary to monitor trends in drug resistance and to ensure favourable treatment outcomes among immigrants and HIV-positive tuberculosis cases. Zhonghua Fu Chan Ke Za Zhi, 2001 Nov, 36(11), 669 - 71 {Study on the reversion of drug resistance in human cervical cancer cell lines}; Chen H et al.; OBJECTIVE: To determine the resistance reversion of mitomycin (MMC) by 3'-Keto-bmt1-val2-cyclosporin (SDZ PSC 833) in human cervical cancer in vitro and in vivo . METHEDS: A xenografted mitomycin resistant mice model of cervical cancer was devolped . The reversion of mitomycin resistance by SDZ PSC 833 (1 or 3 mg/L) was detected from human cervical cancer cell (Hela) and its resistant subline Hela/MMC in vitro and in vivo . Studies in vitro include drug resistance reversion experiment and the changes of morphology . Studies in vivo including tumor volume and tumor related histopathological changes in the autopsied specimen were evaluated by comparing random sections of each group . RESULTS: Nontoxic doses of SDZ PSC 833 could result in almost partial reversion of MMC-resistance of Hela/MMC . In vivo studies also showed SDZ PSC 833 augmented the growth inhibitory effect of mitomycin on Hela/MMC xenografted in nude mice . CONCLUSION: SDZ PSC 833 can overcome mitomycin resistance of Hela/MMC in vitro and in vivo, so SDZ PSC 833 will be a better candidate clinically for reversing multidrug resistance. J Infect Dis, 2002 Apr 15, 185(8), 1197 - 202 Epub 2002 Apr 01. Worldwide incidence of multidrug-resistant tuberculosis; Dye C et al.; Planning for tuberculosis (TB) control requires an assessment of the number and distribution of drug-resistant cases . This study used results of resistance surveys from 64 countries, together with data predictive of resistance rates from 72 others, to estimate the number of new multidrug-resistant (MDR) TB cases that occurred in 2000 . By these methods, an estimated 273,000 (95% confidence limits, 185,000 and 414,000) new cases of MDR TB occurred worldwide in 2000, 3.2% of all new TB cases . The analysis provides the first comprehensive set of estimates of the MDR TB burden by country and globally. Sheng Li Xue Bao, 2002 Feb 25, 54(1), 1 - 6 The role of MDR1 gene in volume-activated chloride currents in pigmented ciliary epithelial cells; Chen LX et al.; The role of multidrug resistance (MDR1) gene in the activation of volume-activated chloride currents in bovine pigmented ciliary epithelial (PCE) cells was investigated by the patch-clamp technique, the antisense approach, the immunofluorescent technique and the confocal microscopy . PCE cells express P-glycoprotein (P-gp, the product of MDR1 gene) . An MDR1 antisense oligonucleotide suppressed MDR1 expression (93% reduction of P-gp immunofluorescence), delayed the activation of a volume-activated chloride current (latency prolonged by 109%), reduced the activation rate by 62% and decreased the peak value of the current by 56% . The transfection reagent lipofectin and the mismatch control oligonucle