OBJECTIVEThis paper aims to investigate the apoptotic effect of inactivated Sendai virus (hemagglutinating virus of Japan-enveloped, HVJ-E) on murine melanoma cells (B16F10) and the possible mechanisms involved in the putative apoptotic reactions.

METHODSB16F10 cells were treated with HVJ-E at various multiplicities of infection (MOI), and the reactive oxygen species (ROS), cell viability, and apoptosis were measured. Next, the roles of ROS in the regulation of Bcl-2/Bax and the activation of mitogen-activated protein kinase (MAPK) pathways in HVJ-E-treated B16F10 cells were analyzed. To further evaluate the cytotoxic effect of HVJ-E-generated ROS on B16F10 cells, HVJ-E was intratumorally injected, both with and without N-acetyl-L-cysteine (NAC), into melanoma tumors on BALB/c mice. Tumor volume was then monitored for 3 weeks, and the tumor proteins were separated for immunoblot assay.

RESULTSTreatment of B16F10 cells with HVJ-E resulted in a dose-dependent inhibition of cell-viability and an induction of apoptosis. The latter effect was associated with the generation of ROS. Inhibition of ROS generation by NAC resulted in a significant reduction of HVJ-E-induced Erk1/2, JNK, and p38 MAPK activation. Additionally, ROS inhibition caused a decrease in the Bcl-2/Bax ratio as well as promoting activation of apoptosis both in vitro and in vivo.

CONCLUSIONThese results suggest that HVJ-E possesses potential anticancer activity in B16F10 cells through ROS-mediated mitochondrial dysfunction involving the MAPK pathway.