Reversal of P-glycoprotein Mediated Multidrug Resistance in MCF-7/R Cancer Cells by Esculetin Derivatives: Experimental and MD Simulation Studies

Abstract

Coumarins of natural origin have been explored as potential inhibitors of P-glycoprotein (P-gp). Esculetin which belongs to the class of coumarin has been derivatized with known hydrazine pharmacophores viz; benzoyl hydrazine (BH), isonicotinyl hydrazine (INH), and hydrazino benzoic acid. The homology modeling approach was used to predict the three-dimensional structure of human P-gp. An <i>in-silico</i> study has been performed for the structural insight into the molecular mechanism of P-gp inhibition of the esculetin derivatives by molecular docking (MD) and simulation studies. The cell cytotoxic activities of the synthesized compounds were evaluated using in-vitro studies. The sublines resistant doxorubicin (MCF-7/R) were generated and the activities of P-gp proteins were estimated using fluorescent dye accumulation assays. The E-BH showed promising P-gp inhibitory activity and cell cytotoxicity against MCF7 and MCF7/R (resistant) breast cancer cell lines. In line with experimental observations, the E-BH (Esculetin benzoyl hydrazine) has yielded the lowest energy stable complex with P-gp and is stabilized by intermolecular hydrogen bonding and more hydrophobic interactions during 100 ns of simulation. This suggested that the activity of P-gp is probably controlled by hydrophobic interactions. Performed experimental and computational studies has helped to elucidate the mechanism of P-gp inhibition by E-BH. Thus, amongst the three derivatives; E-BH exhibits greater efficacy in blocking the efflux mechanism.