Overcoming vincristine resistance in cancer: computational design and discovery of piperine inspired P-glycoprotein inhibitors

P-glycoprotein (P-gp)/MDR-1 plays a major role in the development of multidrug resistance (MDR) by pumping the chemotherapeutic drugs out of the cancer cells and reducing their efficacy. A number of P-gp inhibitors were reported to reverse the MDR when co-administered with chemotherapeutic drugs. Unfortunately, none has approved for clinical use due to toxicity issues. Some of the P-gp inhibitors tested in the clinics are reported to have cross-reactivity with CYP450 drug metabolizing enzymes, resulting in unpredictable pharmacokinetics and toxicity of co-administered chemotherapeutic drugs. In this study, two piperine analogs (3 and 4) having lower cross-reactivity with CYP3A4 drug metabolizing enzyme are identified as P-glycoprotein (P-gp) inhibitors through computational design, followed by synthesis and testing in MDR cancer cell lines overexpressing P-gp (KB Ch^R 8-5, SW480-VCR and HCT-15). Both the analogs significantly increased the vincristine efficacy in MDR cancer cell lines at low micromole concentrations. Specifically, 3 caused complete reversal of vincristine resistance in KB Ch^R 8-5 cells and found to act as competitive inhibitor of P-gp as well as potentiated the vincristine induced NF-KB mediated apoptosis. Therefore, 3 ((2E,4E)-1-(6,7-dimethoxy-3,4-dihydroisoquinolin-2(1H)-yl)-5-(4-hydroxy-3-methoxyphenyl)penta-2,4-dien-1-one) can serve as a potential P-gp inhibitor for in vivo investigations, to reverse multi-drug resistance in cancer.

Keywords: P-glycoprotein; anti-cancer drug; computer-aided drug design; multi-drug resistance; piperine analogs and CYP3A4.