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Pharmacogenetic prediction of tamoxifen efficiacy and adverse effects in hormonal dependent breast karcinoma patients.
Argalácsová, Soňa ; Slanař, Ondřej (advisor) ; Vrána, David (referee) ; Paluch, Zoltán (referee)
ABSTRACT/SUMMARY Background: The clinical efficacy of tamoxifen therapy may be modified by the drug-metabolizing enzymes and transporting molecules involved into the pharmacokinetics of tamoxifen. The aim of this study was to evaluate the association of CYP2D6, ABCB1 polymorhisms and comedication with efficacy and safety of tamoxifen treatment. Methods: Totally 258 women with hormonal positive breast carcinoma were retrospectively evaluated in relation to CYP2D6, ABCB1 polymorphisms and comedication. Results: CYP2D6 polymorphisms or co-medication affecting CYP2D6 activity demonstrated no statistically significant effect on the efficacy of tamoxifen therapy or adverse event incidence; there was only a trend towards shortening the time to event (TTE) in CYP2D6 poor metabolizers. ABCB1 polymorphism rs2032582 was not associated with clinical outcomes, while a trend towards an increase of TTE in variant allele carriers was noted. The ABCB1 polymorphism rs1045642 demonstrated statistical significance in premenopausal patients (p = 0.0012, HR 0.69 (95% CI 0.21 to 2.31), and its significant association was noted with gynaecological /vasomotor adverse events (p = 0.0221, HR = 1.0588), with no evidence of the influence on the incidence and onset of venous complications. Conclusions: Although this work did not show...
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Study of effects of prolonged administration of emtricitabine on expression of ABC efflux transporters in maternal and fetal organs
Havlová, Ivana ; Červený, Lukáš (advisor) ; Hofman, Jakub (referee)
Charles University in Prague Faculty of Pharmacy in Hradec Králové Department of Pharmacology & Toxicology Student: Ivana Havlová Supervisor: PharmDr. Lukáš Červený, Ph.D. Title of diploma thesis: Study of effects of prolonged administration of emtricitabine on expression of ABC efflux transporters in maternal and fetal organs The aim of this thesis was to evaluate the effect of chronic administration of antiretroviral substance emtricitabine (FTC) on expression of drug efflux ABC-binding cassette (ABC) transporters in the placenta, maternal and fetal organs (brain, liver, kidney, small intestine) of pregnant rats. We focused on two most important representatives of drug efflux ABC transporters, P-glycoprotein (MDR1) and Breast Cancer Resistance Protein (BCRP). Knowledge of FTC effects on gene expression of these transporters is crucial especially when using FTC in combination therapy, known as Highly Active Antiretroviral Therapy (HAART). Changes in MDR1/BCRP expression may lead to significantly altered pharmacokinetics of concomitantly administered drugs. First, bioavailability was analyzed. AUC of FTC (3,5 mg/kg) following i.m. administration was comparable to that one after i.v. administration allowing us to use i.m. application as a route of FTC administration to rats. Subsequently,...
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Monitoring the effect of medically important drugs on activity of human P-glycoprotein using fluorescent probes
Veľas, Lukáš ; Gášková, Dana (advisor) ; Sigler, Karel (referee)
One of the main causes of failure in cancer treatment when using chemotherapy is the phenomenon of multidrug resistance - MDR. The most important protein mediating MDR in human cells is P-glycoprotein. The main goal of this thesis was the modification of fluorescent method - developed for studying yeast MDR pumps at the Department of Biophysics at the Institute of Physics of Charles University - to study the activity of P-glycoprotein in human tumor cells. The fluorescent method is based on the use of redistribution potentiometric probe diS-C3(3) which we found to be a substrate of P-glycoprotein. The optimalization of the method (experimental window) allowed sensitive monitoring of changes in the activity of P-glycoprotein caused by the effect of its several known inhibitors/substrates: oligomycin, amiodarone, verapamil, vinblastine, ketoconazole, itraconazole and FK506. New important results regarding the effect of these medically significant drugs on human cells were obtained. The developed method will undoubtedly be of great benefit in the search for new effective inhibitors and the study of their mechanisms in the future.
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Frequency of occurrence of selected single nucleotide polymorphisms of CYP2C8 and MDR1 in the Czech population and their influence on the effect of amiodarone
Pechandová, Kristina ; Perlík, František (advisor) ; Král, Jiří (referee) ; Anzenbacher, Pavel (referee)
Frequency of occurrence of selected single nucleotide polymorphisms of CYP2C8 and MDR1 in the Czech population and their influence on the effect of amiodarone Introduction: Variability in drug response is sometimes conditioned by genetic differences in the metabolism and the transport of drugs. Interindividual differences are often caused by polymorphisms affecting biotransformation activity of enzymes and expression of transporters. In the thesis we paid attention to the cytochrome P450 CYP2C8 and MDR1. First, we described the frequency of occurrence of selected variant alleles CYP2C8 * 2, CYP2C8 * 3 (2 substitution in exon 3 and 8, CYP2C8 and CYP2C8 * 3G416A * 3A1196G), CYP2C8 * 4, CYP2C8 P404A in the healthy Czech population and MDR1 variant alleles in these exons: 26 C3435T, 21 G2677A/T, 12 C1236T a 17 T-76A. Subsequently, we studied the influence of these polymorphisms on effects of amiodarone in the selected group of patients. Methods: We determined genotypes MDR1 a CYP2C8 by PCR-RFLP by using restriction enzymes and specific primers. We determined the frequency of MDR1 genotypes in 189 healthy volunteers and CYP2C8 in 161 healthy subjects. Further we included into the study 63 patients treated with amiodarone for longer than two months. Their treatment was assessed from medical records and...
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Frequency of occurrence of selected single nucleotide polymorphisms of CYP2C8 and MDR1 in the Czech population and their influence on the effect of amiodarone
Pechandová, Kristina ; Perlík, František (advisor) ; Král, Jiří (referee) ; Anzenbacher, Pavel (referee)
Frekvence výskytu vybraných bodových polymorfismů CYP2C8 a MDR1 v české populaci a jejich vliv na působení amiodaronu Úvod: Variabilita lékové odpovědi je někdy podmíněna genetickými rozdíly v metabolismu a transportu léčiv. Interindividuální rozdíly jsou často způsobeny polymorfismy, které ovlivňují biotransformační aktivitu enzymů a expresi transportérů. V disertační práci jsme věnovali pozornost cytochromu P450 izoenzymu CYP2C8 a MDR1. Nejprve jsme popsali frekvenci výskytu vybraných variantních alel CYP2C8*2, CYP2C8*3 (2 substituce v exonu 3 a 8, CYP2C8*3G416A a CYP2C8*3A1196G), CYP2C8*4, CYP2C8 P404A u zdravé české populace a variantních alel MDR1 v exonech: 26 C3435T, 21 G2677A/T, 12 C1236T a 17 T-76A. Následně jsme sledovali vliv těchto polymorfismů na působení amiodaronu u vybraného souboru pacientů. Metody: Genotyp MDR1 a CYP2C8 jsme stanovili pomocí PCR-RFLP za využití specifických restrikčních enzymů a primerů. Frekvence genotypů MDR1jsme určili u 189 zdravých dobrovolníků a CYP2C8 u 161 zdravých osob. Do sledování jsme dále zařadili 63 pacientů užívajících amiodaron déle než dva měsíce. Jejich léčbu jsme posuzovali ze záznamů lékařské dokumentace, s využitím standardních biochemických a hematologických vyšetření a záznamů EKG. Koncentrace amiodaronu a jeho metabolitu N-...
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