Targeted next-generation sequencing of genes involved in Warfarin Pharmacodynamics and pharmacokinetics pathways using the Saudi Warfarin Pharmacogenetic study (SWAP).

BACKGROUND: Warfarin is an oral anticoagulant commonly used for treatment and prophylaxis against thromboembolic events. Warfarins's narrow therapeutic index window is one of the main challenges in clinical practice; thus, it requires frequent monitoring and dose adjustment to maintain patients' therapeutic range. Warfarin dose variation and response are attributed to several inter-and intra-individuals factors, including genetic variants in enzymes involved in warfarin pharmacokinetics (PK) and pharmacodynamics (PD) pathways. Thus, we aim to utilize the next-generation sequencing (NGS) approach to identify rare and common genetic variants that might be associated with warfarin responsiveness. METHOD AND RESULTS: A predesigned NGS panel that included 16 genes involved in Warfarin PK/PD pathways was used to sequence 786 patients from the Saudi Warfarin Pharmacogenetic Cohort (SWAP). Identified variants were annotated using several annotation tools to identify the pathogenicity and allele frequencies of these variants. We conducted variants-level association tests with warfarin dose. We identified 710 variants within the sequenced genes; 19% were novel variants, with the vast majority being scarce variants. The genetic association tests showed that VKORC1 (rs9923231, and rs61742245), CYP2C9 (rs98332238, rs9332172, rs1057910, rs9332230, rs1799853, rs1057911, and rs9332119), CYP2C19 (rs28399511, and rs3758581), and CYP2C8 (rs11572080 and rs10509681) were significantly associated with warfarin weekly dose. Our model included genetics, and non-genetic factors explained 40.1% of warfarin dose variation. CONCLUSION: The study identifies novel variants associated with warfarin dose in the Saudi population. These variants are more likely to be population-specific variants, suggesting that population-specific studies should be conducted before adopting a universal warfarin genotype-guided dosing algorithm.

In vitro assessment of the efficiency of the PIM-1 kinase pharmacological inhibitor as a potential treatment for Burkitt's lymphoma.

Burkitt's lymphoma is an aggressive form of lymphoma affecting B lymphocytes. It occurs endemically in Africa and sporadically in the rest of the world. Due to the high proliferation rate of this tumor, intensive multi-drug treatment is required; however, the risk of tumor syndrome lysis is high. Overexpression of the proto-oncogene proviral integration of the Moloney murine leukemia virus (PIM-1) kinase is associated with the development of hematological abnormalities, including Burkitt's lymphoma (BL). PIM-1 primarily exerts anti-apoptotic activities through BAD phosphorylation. The aim of the present study was to investigate the in vitro efficiency of a PIM-1 kinase pharmacological inhibitor (PIM1-1) in BL. The impact of PIM1-1 was evaluated in terms of the viability and apoptosis status of the BL B cell lines, Raji and Daudi, compared with K562 leukemia cells, which highly express PIM-1. Cell viability and apoptotic status were assessed with western blotting, and PIM-1 gene expression was assessed with reverse transcription-quantitative PCR. After 48 h of treatment, PIM1-1 inhibited the Daudi, Raji and K562 cell viability with a half-maximal inhibitory concentration corresponding to 10, 20 and 30 µM PIM1-1, respectively. A significant decrease of ERK phosphorylation was detected in PIM1-1-treated Daudi cells, confirming the antiproliferative effect. The addition of 10 µM PIM1-1 significantly decreased the PIM-1 protein and gene expression in Daudi cells. An inhibition of the pro-apoptotic BAD phosphorylation was observed in the Daudi cells treated with 0.1-1 µM PIM1-1 and 10 µM PIM1-1 decreased BAD phosphorylation in the Raji cells. The apoptotic status of both PIM1-1-treated cells lines were confirmed with the detection of cleaved capase-3. However, no change in cell viability and PIM-1 protein expression was observed in the 10 µM PIM1-1-treated K562 cells. In conclusion, the findings indicated that the PIM1-1 pharmacological inhibitor may have therapeutic potential in BL, but with lower efficiency in leukemia.

The effect of the VKORC1 promoter variant on warfarin responsiveness in the Saudi WArfarin Pharmacogenetic (SWAP) cohort.

Warfarin is a frequently prescribed oral anticoagulant with a narrow therapeutic index, requiring careful dosing and monitoring. However, patients respond with significant inter-individual variability in terms of the dose and responsiveness of warfarin, attributed to genetic polymorphisms within the genes responsible for the pharmacokinetics and pharmacodynamics of warfarin. Extensive warfarin pharmacogenetic studies have been conducted, including studies resulting in genotype-guided dosing guidelines, but few large scale studies have been conducted with the Saudi population. In this study, we report the study design and baseline characteristics of the Saudi WArfarin Pharmacogenomics (SWAP) cohort, as well as the association of the VKORC1 promoter variants with the warfarin dose and the time to a stable INR. In the 936 Saudi patients recruited in the SWAP study, the minor allele C of rs9923231 was significantly associated with a 8.45 mg higher weekly warfarin dose (p value = 4.0 × 10-46), as well as with a significant delay in achieving a stable INR level. The addition of the rs9923231 status to the model, containing all the significant clinical variables, doubled the warfarin dose explained variance to 31%. The SWAP cohort represents a valuable resource for future research with the objective of identifying rare and prevalent genetic variants, which can be incorporated in personalized anticoagulation therapy for the Saudi population.