Synthesis and biological evaluation of (3/4-(pyrimidin-2-ylamino)benzoyl)-based hydrazine-1-carboxamide/carbothioamide derivatives as novel RXRα antagonists

Abstract

Abnormal alterations in the expression and biological function of retinoid X receptor alpha (RXRα) have a key role in the development of cancer. Potential modulators of RXRα as anticancer agents are explored in growing numbers of studies. A series of (4/3-(pyrimidin-2-ylamino)benzoyl)hydrazine-1-carboxamide/carbothioamide derivatives are synthesised and evaluated for anticancer activity as RXRα antagonists in this study. Among all synthesised compounds, 6A shows strong antagonist activity (half maximal effective concentration (EC50) = 1.68 ± 0.22 µM), potent anti-proliferative activity against human cancer cell lines HepG2 and A549 cells (50% inhibition of cell viability (IC50) values < 10 µM), and low cytotoxic property in normal cells such as LO2 and MRC-5 cells (IC50 values > 100 µM). Further bioassays indicate that 6A inhibits 9-cis-RA-induced activity in a dose-dependent manner, and selectively binds to RXRα-=LΒD with submicromolar affinity (Kd = 1.20 × 10−7 M). 6A induces time-and dose-dependent cleavage of poly ADP-ribose polymerase, and significantly stimulates caspase-3 activity, leading to RXRα-dependent apoptosis. Finally, molecular docking studies predict the binding modes for RXRα-LBD and 6A.