| 1. |
- Boiso, Samuel, et al.
(författare)
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ABCB1 gene polymorphisms are associated with suicide in forensic autopsies
- 2013
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Ingår i: Pharmacogenetics & Genomics. - : Lippincott, Williams and Wilkins. - 1744-6872 .- 1744-6880. ; 23:9, s. 463-469
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Tidskriftsartikel (refereegranskat)abstract
- Background Polymorphisms in ABCB1 have the ability to affect both the function and the expression of the transporter protein P-glycoprotein and may lead to an altered response for many drugs including some antidepressants and antipsychotics.Objective The aim of this study was to examine the impact of the ABCB1 polymorphisms 1199Gandgt;A, 1236Candgt;T, 2677Gandgt;T/A, and 3435Candgt;T in deaths by suicide.Patients and methods A total of 998 consecutive Swedish forensic autopsies performed in 2008 in individuals 18 years of age or older, where femoral blood was available and a toxicological screening had been performed, were investigated. Genotypes were assessed with pyrosequencing and information on the cause and manner of each death was obtained from the forensic pathology and toxicology databases.Results There was a significantly higher frequency of the T allele at positions 1236, 2677, and 3435 among the suicide cases compared with the nonsuicide cases.Conclusion Our result from forensic cases suggests that ABCB1 polymorphisms are associated with an increased risk for completed suicides. The biological mechanisms involved and the clinical implications for these findings are largely unknown and need to be examined further.
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| 2. |
- Coulthard, Sally A, et al.
(författare)
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Increased Sensitivity to Thiopurines in Methylthioadenosine Phosphorylase-Deleted Cancers
- 2011
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Ingår i: MOLECULAR CANCER THERAPEUTICS. - : AMER ASSOC CANCER RESEARCH, 615 CHESTNUT ST, 17TH FLOOR, PHILADELPHIA, PA 19106-4404 USA. - 1535-7163. ; 10:3, s. 495-504
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Tidskriftsartikel (refereegranskat)abstract
- The thiopurines, 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG), are used in the treatment of leukemia. Incorporation of deoxythioguanosine nucleotides (dG(s)) into the DNA of thiopurine-treated cells causes cell death, but there is also evidence that thiopurine metabolites, particularly the 6-MP metabolite methylthioinosine monophosphate (MeTIMP), inhibit de novo purine synthesis (DNPS). The toxicity of DNPS inhibitors is influenced by methylthioadenosine phosphorylase (MTAP), a gene frequently deleted in cancers. Because the growth of MTAP-deleted tumor cells is dependent on DNPS or hypoxanthine salvage, we would predict such cells to show differential sensitivity to 6-MP and 6-TG. To test this hypothesis, sensitivity to 6-MP and 6-TG was compared in relation to MTAP status using cytotoxicity assays in two MTAP-deficient cell lines transfected to express MTAP: the T-cell acute lymphoblastic leukemic cell line, Jurkat, transfected with MTAP cDNA under the control of a tetracycline-inducible promoter, and a lung cancer cell line (A549-MTAP(-)) transfected to express MTAP constitutively (A549-MTAP(+)). Sensitivity to 6-MP or methyl mercaptopurine riboside, which is converted intracellularly to MeTIMP, was markedly higher in both cell lines under MTAP(-) conditions. Measurement of thiopurine metabolites support the hypothesis that DNPS inhibition is a major cause of cell death with 6-MP, whereas dG(s) incorporation is the main cause of cytotoxicity with 6-TG. These data suggest that thiopurines, particularly 6-MP, may be more effective in patients with deleted MTAP.
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| 3. |
- Coulthard, Sally, et al.
(författare)
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Increased sensitivity to thiopurines in methylthioadenosine phosphorylase-deleted cancers in PURINERGIC SIGNALLING, vol 6, issue , pp 33-33
- 2010
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Ingår i: PURINERGIC SIGNALLING. - : Springer Science Business Media. ; , s. 33-33
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Konferensbidrag (refereegranskat)abstract
- The thiopurines, 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG) are used in the treatment of leukaemia. Incorporation of deoxythioguanosine nucleotides (dGs) into the DNA of thiopurine-treated cells causes cell death but there is also evidence that thiopurine metabolites, particularly the 6-MP metabolite methylthioinosine monophosphate (MeTIMP), inhibit de novo purine synthesis (DNPS). The toxicity of DNPS inhibitors is influenced by methylthioadenosine phosphorylase (MTAP), a gene frequently deleted in cancers. Since the growth of MTAP-deleted tumour cells is dependent on DNPS or hypoxanthine salvage, we would predict such cells to show differential sensitivity to 6-MP and 6-TG. To test this hypothesis, sensitivity to 6-MP and 6-TG was compared in relation to MTAP status using cytotoxicity assays in two MTAP-deficient cell lines transfected to express MTAP: the T-cell acute lymphoblastic leukaemic cell line, Jurkat, transfected with MTAP cDNA under the control of a tetracycline-inducible promoter, and a lung cancer cell line (A549-MTAP-ve) transfected to express MTAP constitutively (A549-MTAP+ve). Sensitivity to 6-MP or methyl mercaptopurine riboside, which is converted intra-cellularly to MeTIMP, was markedly higher in both cell lines under MTAP-ve conditions. Measurement of thiopurine metabolites support the hypothesis that DNPS inhibition is a major cause of cell death with 6-MP, whereas dGs incorporation is the main cause of cytotoxicity with 6-TG. These data suggest that thiopurines, particularly 6-MP, may be more effective in patients with deleted MTAP.
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| 4. |
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| 5. |
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| 6. |
- Green, Henrik, et al.
(författare)
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Association of ABCB1 polymorphisms with survival and in vitro cytotoxicty in de novo acute myeloid leukemia with normal karyotype
- 2012
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Ingår i: The Pharmacogenomics Journal. - : Nature Publishing Group. - 1470-269X .- 1473-1150. ; 12:2, s. 111-118
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Tidskriftsartikel (refereegranskat)abstract
- Overexpression of the multi-drug transporter P-glycoprotein, encoded by the ABCB1 gene, is a clinically relevant problem in acute myeloid leukemia (AML). Polymorphisms in ABCB1 might contribute to cancer risk and therapeutic response. We therefore investigated the influence of polymorphisms G1199A, C1236T, G2677T/A and C3435T on cancer susceptibility, in vitro cytotoxicity and overall survival in 100 de novo AML patients with normal karyotype. Patients with 1236C/C or 2677G/G genotypes showed poorer survival than patients with other genotypes (P = 0.03 and P = 0.02, respectively). Both these genotypes were significant factors for survival in multivariate analysis, along with age, NPM1 and FLT3 mutation status. In vitro cytotoxicity studies demonstrated that leukemic cells from 1236T/T and 2677T/T patients were significantly more susceptible to mitoxantrone (P 0.02), and tended to be more susceptible to etoposide and daunorubicin (P = 0.07-0.09), but not to cytarabine. No significant difference in allele frequencies was found between patients and healthy volunteers (n = 400).
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| 7. |
- Green, Henrik, et al.
(författare)
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Impact of CYP3A5(*)3 and CYP2C8-HapC on Paclitaxel/Carboplatin-Induced Myelosuppression in Patients with Ovarian Cancer
- 2011
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Ingår i: Journal of Pharmaceutical Sciences. - : Elsevier. - 0022-3549 .- 1520-6017. ; 100:10, s. 4205-4209
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Tidskriftsartikel (refereegranskat)abstract
- The influence of genetic variants on paclitaxel-induced toxicity is of considerable interest for reducing adverse drug reactions. Recently, the genetic variants CYP2C8(*)3, CYP2C8-HapC, and CYP3A5(*)3 were associated with paclitaxel-induced neurotoxicity. We, therefore, investigated the impact of CYP2C8-HapC and CYP3A5(*)3 on paclitaxel/carboplatin-induced myelosuppression and neurotoxicity. Thirty-three patients from a prospective pharmacokinetics study were genotyped using pyrosequencing. Patients with variant alleles of CYP2C8-HapC were found to have significantly lower nadir values of both leukocytes and neutrophils (p andlt; 0.05) than patients with the wild-type genotype. CYP3A5(*)3/(*)1 patients were shown to have borderline, significantly lower nadir values of leukocytes (p = 0.07) than (*)3/(*)3 patients. Combining the two genotypes resulted in a significant correlation with both leukopenia and neutropenia (p = 0.01). No effect of these genetic variants on neurotoxicity could be shown in this rather small study, but their importance for paclitaxel-induced toxicity could be confirmed.
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| 8. |
- Jakobsen Falk, Ingrid, et al.
(författare)
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Association of CYP2B6 Genotype with Survival and Progression Free Survival in Cyclophosphamide Treated Multiple Myeloma
- 2012
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Ingår i: Journal of Cancer Therapy. - : Scientific Research Publishing. - 2151-1934 .- 2151-1942. ; 3:1, s. 20-27
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Cyclophosphamide is a conventional pro-drug used in Multiple Myeloma (MM) and other malignancies. The highly polymorphic CYP2B6 is suggested as a major contributor in cyclophosphamide bioactivation, and GST en-zymes are involved in detoxification. Polymorphisms of these enzymes may affect enzyme expression and function as well as treatment outcome. The aim of this study was to investigate the impact of the CYP2B6 SNPs G516T, A785G and C1459T, GSTP1 SNP Ile105Val, and GSTM1 and GSTT1 null variants, on the outcome for cyclophosphamide treated MM patients, in order to find markers of value for individualised therapy. Methods: We used allele specific PCR and Pyrosequencing to investigate the impact of CYP2B6 SNPs G516T, A785G and C1459T, GSTP1 Ile105Val, and GSTM1 and GSTT1 variants, on the outcome for 26 cyclophosphamide treated multiple myeloma patients. Results and Major Conclusion: The CYP2B6 785G carriers had significantly shorter progression free survival (p = 0.048*) and overall survival (p = 0.037*) with 785G/G patients having the worst outcome compared to patients carrying the wild type. A shorter progression free survival was also indicated in patients carrying both CYP2B6 516T & 785G (p = 0.068). These results indicate a predictive role of CYP2B6 SNPs, particularly A785G, in cyclophosphamide treatment.
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| 9. |
- Jakobsen Falk, Ingrid, et al.
(författare)
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Decreased survival in normal karyotype AML with single-nucleotide polymorphisms in genes encoding the AraC metabolizing enzymes cytidine deaminase and 5'-nucleotidase
- 2013
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Ingår i: American Journal of Hematology. - : John Wiley & Sons. - 0361-8609 .- 1096-8652. ; 88:12, s. 1001-1006
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Tidskriftsartikel (refereegranskat)abstract
- De novo acute myeloid leukemia with normal karyotype (NK-AML) comprises a large group of patients with no common cytogenetic alterations and with a large variation in treatment response. Single-nucleotide polymorphisms (SNPs) in genes related to the metabolism of the nucleoside analogue AraC, the backbone in AML treatment, might affect drug sensitivity and treatment outcome. Therefore, SNPs may serve as prognostic biomarkers aiding clinicians in individualized treatment decisions, with the aim of improving patient outcomes. We analyzed polymorphisms in genes encoding cytidine deaminase (CDA 79A>C rs2072671 and −451C>T rs532545), 5′-nucleotidase (cN-II 7A>G rs10883841), and deoxycytidine kinase (DCK 3′UTR 948T>C rs4643786) in 205 de novo NK-AML patients. In FLT3-internal tandem duplication (ITD)-positive patients, the CDA 79C/C and −451T/T genotypes were associated with shorter overall survival compared to other genotypes (5 vs. 24 months, P < 0.001 and 5 vs. 23 months, P = 0.015, respectively), and this was most pronounced in FLT3-ITD-positive/NPM1-positive patients. We observed altered in vitro sensitivity to topoisomerase inhibitory drugs, but not to nucleoside analogues, and a decrease in global DNA methylation in cells carrying both CDA variant alleles. A shorter survival was also observed for the cN-II variant allele, but only in FLT3-ITD-negative patients (25 vs. 31 months, P = 0.075). Our results indicate that polymorphisms in genes related to nucleoside analog drug metabolism may serve as prognostic markers in de novo NK-AML
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| 10. |
- Jakobsen Falk, Ingrid, et al.
(författare)
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Impact of ABCB1 single nucleotide polymorphisms 1236C>T and 2677G>T on overall survival in FLT3 wild-type de novo AML patients with normal karyotype
- 2014
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Ingår i: British Journal of Haematology. - : Wiley. - 0007-1048 .- 1365-2141. ; 167:5, s. 671-680
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Tidskriftsartikel (refereegranskat)abstract
- Drug resistance is a clinically relevant problem in the treatment of acute myeloid leukaemia (AML). We have previously reported a relationship between single nucleotide polymorphisms (SNPs) of ABCB1, encoding the multi-drug transporter P-glycoprotein, and overall survival (OS) in normal karyotype (NK)-AML. Here we extended this material, enabling subgroup analysis based on FLT3 and NPM1 status, to further elucidate the influence of ABCB1 SNPs. De novo NK-AML patients (n = 201) were analysed for 1199G>A, 1236C>T, 2677G>T/A and 3435C>T, and correlations to outcome were investigated. FLT3 wild-type 1236C/C patients have significantly shorter OS compared to patients carrying the variant allele; medians 20 vs. 49 months, respectively, P = 0.017. There was also an inferior outcome in FLT3 wild-type 2677G/G patients compared to patients carrying the variant allele, median OS 20 vs. 35 months, respectively, P = 0.039. This was confirmed in Cox regression analysis. Our results indicate that ABCB1 1236C>T and 2677G>T may be used as prognostic markers to distinguish relatively high risk patients in the intermediate risk FLT3 wild-type group, which may contribute to future individualizing of treatment strategies.
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