The Protective Effect of INH<sub>2</sub>BP, a Novel PARP Inhibitor 5-Iodo-6-Amino-1,2-Benzopyrone, Against Hydrogen Peroxide-Induced Apoptosis Through ERK and p38 MAPK in H9c2 Cells

INH2BP (5-iodo-6-amino-1,2-benzopyrone), a poly-ADP ribose polymerase inhibitor, has been shown to possess anti-cancer, anti-viral, and anti-inflammation properties. The aim of this study was to investigate the protective effect of INH2BP against oxidative stress-induced apoptosis in H9c2 cardiomyoblast cells. While the treatment of H9c2 cardiomyoblasts cells with hydrogen peroxide (H2O2) caused a loss of cell viability and an increase in the number of apoptotic cells, INH2BP significantly protected the cells against H2O2-induced cell death without any cytotoxicity. Our data also shows that INH2BP significantly scavenged intracellular reactive oxygen species (ROS), and markedly enhanced the expression of antioxidant enzymes such as Mn-SOD (superoxide) and Cu/Zn-SOD, and heme oxygenase-1, which was accompanied by the concomitant activation of extracellular regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) phosphorylation in H9c2 cells. The effects of INH2BP on ERK1/2 and p38 MAPK phosphorylation were abrogated by PD98059, an ERK1/2 inhibitor, and SB203580, a p38 inhibitor. In addition, inhibition of ERK1/2 and p38 MAPK by these inhibitors significantly attenuated INH2BP-mediated H9c2 viability as well as cleaved caspases-3, Bax, and Bcl-2 activation. Taken together, these results demonstrate that INH2BP prevents H2O2-induced apoptosis in H9c2 cells by reducing the production of intracellular ROS, regulating apoptotic-related proteins, and the activation of the ERK1/2 and p38 MAPK.