VKORC1 pharmacogenetics and pharmacoproteomics in patients on warfarin anticoagulant therapy: transthyretin precursor as a potential biomarker.

BACKGROUND: Recognizing specific protein changes in response to drug administration in humans has the potential for the development of personalized medicine. Such changes can be identified by pharmacoproteomics approach based on proteomic technologies. It can also be helpful in matching a particular target-based therapy to a particular marker in a subgroup of patients, in addition to the profile of genetic polymorphism. Warfarin is a commonly prescribed oral anticoagulant in patients with prosthetic valve disease, venous thromboembolism and stroke. METHODS AND FINDING: We used a combined pharmacogenetics and iTRAQ-coupled LC-MS/MS pharmacoproteomics approach to analyze plasma protein profiles of 53 patients, and identified significantly upregulated level of transthyretin precursor in patients receiving low dose of warfarin but not in those on high dose of warfarin. In addition, real-time RT-PCR, western blotting, human IL-6 ELISA assay were done for the results validation. CONCLUSION: This combined pharmacogenomics and pharmacoproteomics approach may be applied for other target-based therapies, in matching a particular marker in a subgroup of patients, in addition to the profile of genetic polymorphism.

A comparative proteomic analysis of HepG2 cells incubated by S(-) and R(+) enantiomers of anti-coagulating drug warfarin.

Warfarin is a commonly prescribed oral anti-coagulant with narrow therapeutic index. It interferes with vitamin K cycle to achieve anti-coagulating effects. Warfarin has two enantiomers, S(-) and R(+) and undergoes stereoselective metabolism, with the S(-) enantiomer being more effective. We reported that the intracellular protein profile in HepG2 cells incubated with S(-) and R(+) warfarin, using iTRAQ-coupled 2-D LC-MS/MS. In samples incubated with S(-) and R(+) warfarin alone, the multi-task protein Protein SET showed significant elevation in cells incubated with S(-) warfarin but not in those incubated with R(+) warfarin. In cells incubated with individual enantiomers of warfarin in the presence of vitamin K, protein disulfide isomerase A3 which is known as a glucose-regulated protein, in cells incubated with S(-) warfarin was found to be down-regulated compared to those incubated with R(+) warfarin. In addition, Protein DJ-1 and 14-3-3 Proteinsigma were down-regulated in cells incubated with either S(-) or R(+) warfarin regardless of the presence of vitamin K. Our results indicated that Protein DJ-1 may act as an enzyme for expression of essential enzymes in vitamin K cycle. Taken together, our findings provided molecular evidence on a comprehensive protein profile on warfarin-cell interaction, which may shed new lights on future improvement of warfarin therapy.