Membrane transporters are important determinants of drug bioavailability. Their expression and activity affect the intracellular drug concentration in leukemic cells impacting response to therapy. Pharmacogenomics represents genetic markers that reflect allele arrangement of genes encoding drug transporters associated with treatment response. In previous work, we identified SNP rs460089 located in the promotor of SLC22A4 gene encoding imatinib transporter OCTN1 as influential on response of patients with chronic myeloid leukemia treated with imatinib. Patients with rs460089-GC pharmacogenotype had significantly superior response to first-line imatinib treatment compared to patients with rs460089-GG. This study investigated whether pharmacogenotypes of rs460089 are associated with sustainability of treatment-free remission (TFR) in patients from the EUROpean Stop Kinase Inhibitor (EURO-SKI) trial. In the learning sample, 176 patients showed a significantly higher 6-month probability of molecular relapse free survival (MRFS) in patients with GC genotype (73%, 95% CI: 60-82%) compared to patients with GG (51%, 95% CI: 41-61%). Also over time, patients with GC genotype had significantly higher MRFS probabilities compared with patients with GG (HR: 0.474, 95% CI: 0.280-0.802, p = 0.0054). Both results were validated with data on 93 patients from the Polish STOP imatinib study. In multiple regression models, in addition to the investigated genotype, duration of TKI therapy (EURO-SKI trial) and duration of deep molecular response (Polish study) were identified as independent prognostic factors. The SNP rs460089 was found as an independent predictor of TFR.

• MeSH
• chronická myeloidní leukemie * farmakoterapie   genetika   MeSH
• imatinib mesylát terapeutické užití   MeSH
• inhibitory proteinkinas terapeutické užití   MeSH
• lidé MeSH
• membránové transportní proteiny terapeutické užití   MeSH
• prognóza MeSH
• protinádorové látky * škodlivé účinky   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• imatinib mesylát MeSH
• inhibitory proteinkinas MeSH
• membránové transportní proteiny MeSH
• protinádorové látky * MeSH

BACKGROUND: Through high-throughput next-generation sequencing of promoters of solute carrier and ATP-binding cassette genes, which encode drug transporters, we aimed to identify SNPs associated with the response to imatinib administered for first-line treatment of patients with chronic myeloid leukemia. METHODS: In silico analysis using publicly available databases was done to select the SLC and ABC genes and their promoters for the next-generation sequencing. SNPs associated with the imatinib response were identified using Fisher's exact probability tests and subjected to the linkage disequilibrium analyses with regulatory loci of concerned genes. We analyzed cumulative achievement of major molecular response and probability of event free survival in relation to identified SNP genotypes in 129 CML patients and performed multivariate analysis for determination of genotypes as independent predictors of outcome. Gene expression analysis of eight cell lines naturally carrying different genotypes was performed to outline an impact of genotypes on the gene expression. RESULTS: We observed significant differences in the frequencies of the rs460089-GC and rs460089-GG (SLC22A4) genotypes among rs2631365-TC (SLC22A5) genotype carriers that were associated with optimal and non-optimal responses, respectively. Loci rs460089 and rs2631365 were in highly significant linkage disequilibrium with 12 regulatory loci in introns of SLC22A4 and SLC22A5 encoding imatinib transporters. Genotype association analysis with the response to imatinib indicated that rs460089-GC carriers had a significantly higher probability of achieving a stable major molecular response (BCR-ABL1 transcript level below or equal to 0.1% in the international scale). In contrast, the rs460089-GG represented a risk factor for imatinib failure, which was significantly higher in rs460089-GG_rs2631365-TC carriers. CONCLUSIONS: This exploratory study depicted potentially important genetic markers predicting outcome of imatinib treatment, which may be helpful for tailoring therapy in clinical practice.

• Klíčová slova
• CML, Imatinib, Response, SLC,
• MeSH
• buňky K562 MeSH
• chronická myeloidní leukemie farmakoterapie   genetika   MeSH
• genotyp MeSH
• imatinib mesylát aplikace a dávkování   terapeutické užití   MeSH
• jednonukleotidový polymorfismus * MeSH
• lidé MeSH
• mutační rychlost MeSH
• nádorové buněčné linie MeSH
• promotorové oblasti (genetika) MeSH
• proteiny přenášející organické kationty genetika   MeSH
• protinádorové látky aplikace a dávkování   terapeutické užití   MeSH
• rodina nosičů rozpuštěných látek 22, člen 5 genetika   MeSH
• sekvenční analýza DNA metody   MeSH
• symportéry MeSH
• vazebná nerovnováha MeSH
• výsledek terapie MeSH
• vysoce účinné nukleotidové sekvenování metody   MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• imatinib mesylát MeSH
• proteiny přenášející organické kationty MeSH
• protinádorové látky MeSH
• rodina nosičů rozpuštěných látek 22, člen 5 MeSH
• SLC22A4 protein, human MeSH Prohlížeč
• SLC22A5 protein, human MeSH Prohlížeč
• symportéry MeSH