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MDR1 Gene (mdr1 + gene)
Selected AbstractsFunctional C3435T polymorphism of MDR1 gene: an impact on genetic susceptibility and clinical outcome of childhood acute lymphoblastic leukemiaEUROPEAN JOURNAL OF HAEMATOLOGY, Issue 5 2004Krzysztof Jamroziak Abstract: The significance of genetic background in childhood acute lymphoblastic leukemia (ALL) is not well understood. Polymorphisms of genes encoding for xenobiotics and drug transporters are potential factors, which can influence the risk of developing ALL and its clinical outcome. P-glycoprotein (P-gp) is an adenosine triphosphate-binding cassette (ABC)-family transporter involved in protection against xenobiotics and multi-drug resistance. Recently, the single-nucleotide polymorphism C3435T of MDR1 gene has been found to be associated with altered tissue expression and function of P-gp. To evaluate whether C3435T MDR1 polymorphism is associated with the occurrence and outcome of ALL, 113 children with ALL (median age 5.1 yr) and 175 healthy individuals of Polish Caucasian origin were studied by polymerase chain reaction-restriction fragment-length polymorhism (PCR-RFLP) assay. The mutant homozygous TT genotype was found to be associated with occurrence of ALL (OR, 95% CI; 1.8, 1.1,3.1; P = 0.037). Besides, the analysis of factors influencing clinical outcome of our ALL patient cohort showed that CC genotype carriers had significantly lower event-free survival probability (pEFS) (0.62 vs. 0.87; P = 0.007) and overall survival probability (pOS) (0.72 vs. 0.91; P = 0.006). The Cox proportional hazards model-based analysis revealed that the hazard ratios for lower pEFS and lower pOS among CC homozygous subjects were 3.9 (P = 0.008) and 3.3 (P = 0.02), respectively. In conclusion, the results of the present study provide evidence that C3435T MDR1 polymorphism may involve both the susceptibility to and the clinical outcome of childhood ALL. Carriers of the TT genotype are more at risk of developing ALL than other individuals, whereas CC genotype carriers are supposed to have worse prognosis. [source] Multidrug resistance 1 gene polymorphism and susceptibility to inflammatory bowel diseaseINFLAMMATORY BOWEL DISEASES, Issue 5 2007S. Ardizzone MD Abstract Background: Several studies have evaluated the role of the multidrug resistance 1 gene (MDR1) polymorphism, which encodes the membrane-bound efflux transporter P-glycoprotein 170, in determining susceptibility to and disease behavior in inflammatory bowel disease (IBD), but with conflicting results. Methods: A total of 211 patients with Crohn's disease (CD), 97 patients with ulcerative colitis (UC), and 212 control subjects were investigated for the presence of MDR1 G2677T/A and C3435T polymorphisms. Genotype frequencies of CD and UC patients were compared to those observed in a control population. Genotype,phenotype correlations with major clinical features were also established and estimated risks (odds ratio [OR] with 95% confidence interval [CI]) for the mutations were calculated by a logistic regression analysis and multiple correspondent analysis. Results: No significant difference was observed for genotype frequencies for both MDR1 G2677T/A and C3435T polymorphisms on overall disease susceptibility for either CD or UC patients compared with control subjects. A significant association was found between the MDR1 C3435T polymorphism and patients with ileo-colonic CD (OR = 3.34; 95% CI: 1.34,8.27). Interestingly, a negative association was found between MDR1 C3435T polymorphism in patients with a positive family history for IBD (OR = 0.44; 95% CI: 0.20,0.95) and articular manifestations (OR = 0.29; 95% CI: 0.13,0.68). Both susceptible and protective effects were identified. No significant association between G2677T/A polymorphism and any specific subphenotypes was found, nor was there any association with subphenotypic categories of UC and both single nucleotide polymorphisms. Conclusions: The results of our study suggest that MDR1 gene polymorphism could have a role in determining susceptibility to IBD. The variability of this possible effect in the several studies reported so far may be the indirect expression of the complex role played by the MDR1 gene and its product, P-glycoprotein 170, in the regulation of host,bacteria interactions and in the pathogenesis of IBD. (Inflamm Bowel Dis 2007) [source] Postmortem Blood Concentrations of R - and S -Enantiomers of Methadone and EDDP in Drug Users: Influence of Co-Medication and P-glycoprotein GenotypeJOURNAL OF FORENSIC SCIENCES, Issue 2 2010Anders Buchard M.Sc. Abstract:, We investigated toxicological and pharmacogenetic factors that could influence methadone toxicity using postmortem samples. R - and S -methadone were measured in femoral blood from 90 postmortem cases, mainly drug users. The R -enantiomer concentrations significantly exceeded that of the S -enantiomers (Wilcoxon's test, p < 0.001). The samples were divided into four groups according to other drugs detected (methadone only, methadone and strong analgesics, methadone and benzodiazepines, or methadone and other drugs). There was no significant difference in any of the R -methadone/total methadone ratios among the four groups. The median R/S ratio was 1.38, which tends to be higher than that reported for the plasma of living subjects. In addition, we investigated whether small nucleotide polymorphisms in the MDR1 gene that encode the drug transporter P-glycoprotein were associated with the concentrations of R - and S -methadone and its metabolite 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine. No significant association was detected. [source] Reversal of cancer multidrug resistance by green tea polyphenolsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2004Yuying Mei The aim of this study was to examine the effect and mechanism of green tea polyphenols (TP) on reversal of multidrug resistance (MDR) in a carcinoma cell line. Using the MTT assay, TP was examined for its modulating effects on the drug-resistant KB-A-1 cells and drug-sensitive KB-3,1 cells. When 10 ,g mL,1 (-)-epigallocatechin gallate (EGCG) or 40 ,g mL,1 TP were present simultaneously with doxorubicin (DOX), the IC50 of DOX on KB-A-1 cells decreased from 10.3 ± 0.9 ,g mL,1 to 4.2 ± 0.2 and 2.0 ± 0.1 ,g mL,1, respectively. TP and EGCG enhanced the DOX cytotoxicity on KB-A-1 cells by 5.2-and 2.5-times, respectively, but did not show a modulating effect on KB-3,1 cells. This indicated that both TP and EGCG had reversal effects on the MDR phenotype in-vitro. A KB-A-1 cell xenograft model was established, and the effect of TP on reversing MDR in-vivo was determined. Mechanistic experiments were conducted to examine the uptake, efflux and accumulation of DOX. Cloning and expression of the nucleotide binding domain of the human MDR1 gene in Escherichia coli was established, and by using colorimetry to examine the activity of ATPase to hydrolyse ATP, the ATPase activity of target nucleotide binding domain protein was determined. TP exerted its reversal effects through the inhibition of ATPase activity, influencing the function of P-glycoprotein, and causing a decreased extrusion of anticancer drug and an increased accumulation of anticancer drug in drug resistant cells. Using reverse transcription-polymerase chain reaction, the inhibitory effect of TP on MDR1 gene expression was investigated. Down-regulation of MDR1 gene expression was the main effect, which resulted in the reversal effect of TP on the MDR phenotype. TP is a potent MDR modulator with potential in the treatment of P-glycoprotein mediated MDR cancers. [source] The basic and clinical implications of ABC transporters, Y-box-binding protein-1 (YB-1) and angiogenesis-related factors in human malignanciesCANCER SCIENCE, Issue 1 2003Michihiko Kuwano In our laboratories, we have been studying molecular targets which might be advantageous for novel cancer therapeutics. In this review, we focus on how ATP-binding cassette (ABC) transporter superfamily genes, Y-box-binding protein-1 (YB-1), and tumor angiogenesis-associated factors could contribute to the development of novel strategies for molecular cancer therapeutics. ABC transporters such as P-glycoprotein/MDR1 and several MRP family proteins function to protect cells from xenobiotics, drugs and poisons, suggesting that ABC transporters are a double-edged sword. In this regard, P-glycoprotein/MDR1 is a representative ABC transporter which plays a critical role in the efflux of a wide range of drugs. We have reported that gene amplification, gene rearrangements, transcription factor YB-1 and CpG methylation on the promoter are involved in MDR1 gene overexpression in cultured cancer cells. Among them, two mechanisms appear to be relevant to the up-regulation of MDR1 gene in human malignancies. We first reported that MDR1 gene promoter is activated in response to environmental stimuli, and is modulated by methylation/demethylation of CpG sites on the MDR1 promoter. We also demonstrated that YB-1 modulates not only transcription of various genes associated with cell growth, drug resistance and DNA synthesis, but also translation, mRNA stabilization and DNA repair/self-defense processes. Angiogene-sis is also involved in tumor growth, invasion and metastasis of various malignancies, and so angiogenesis-related molecules also offer novel molecular targets for anticancer therapeutics. (Cancer Sci 2003; 94: 9,14) [source] | ||||||||||