Hybrid Molecule from <i>O</i>²‑(2,4-Dinitrophenyl)diazeniumdiolate and Oleanolic Acid: A Glutathione <i>S</i>‑Transferase π‑Activated Nitric Oxide Prodrug with Selective Anti-Human Hepatocellular Carcinoma Activity and Improved Stability

Abstract

A series of hybrids from <i>O</i>²-(2,4-dinitrophenyl)­diazeniumdiolate and oleanolic acid (OA) were designed, synthesized, and biologically evaluated as novel nitric oxide (NO)-releasing prodrugs that could be activated by glutathione <i>S</i>-transferase π (GSTπ) overexpressed in a number of cancer cells. It was discovered that the most active compound, <b>21</b>, released high levels of NO selectively in HCC cells but not in the normal cells and exhibited potent antiproliferative activity in vitro as well as remarkable tumor-retarding effects in vivo. Compared with the reported GSTπ-activated prodrugs JS-K and PABA/NO, <b>21</b> exhibited remarkably improved stability in the absence of GSTπ. Importantly, the decomposition of <b>21</b> occurred in the presence of GSTπ and was much more effective than in glutathione <i>S</i>-transferase α. Additionally, <b>21</b> induced apoptosis in HepG2 cells by arresting the cell cycle at the G2/M phase, activating both the mitochondrion-mediated pathway and the MAPK pathway and enhancing the intracellular production of ROS