Induction of apoptosis in hormone-resistant human prostate cancer PC3 cells by inactivated Sendai virus.

Objective: Inactivated Sendai virus particle [hemagglutinating virus of Japan envelope (HVJ-E)] has a potential oncolytic effect due to its ability to induce apoptosis in tumor cells. However, the molecular mechanism of apoptosis induction in cancer cells mediated by HVJ-E has not been fully elucidated. This paper aims to investigate the underlying mechanism of apoptosis induction by HVJ-E in prostate cancer cells (PC3).

Methods: PC3 cells were treated with HVJ-E at various MOI, and then interferon-β (IFN-β) production, and the cell viability and apoptosis were detected by ELISA, MTT-based assay and flow cytometry, respectively. Next, the roles of Jak-Stat, MAPK and Akt pathways played in HVJ-E-induced apoptosis in PC3 cells were analyzed by immunoblot assay. To further evaluate the cytotoxic effect of HVJ-E on PC3 cells, HVJ-E was intratumorally injected into prostate cancers on BALB/c-nude mice, and the tumor volume was monitored for 36 days.

Results: HVJ-E induced IFN-β production and activated Jak-Stat signaling pathway, which resulted in the activation of caspase-8, caspase-3, and PARP in PC3 prostate cancer cells post HVJ-E treatment. Furthermore, we observed for the first time that p38 and Jnk MAPKs in PC3 cells contributed to HVJ-E-induced apoptosis. In addition, intratumoral HVJ-E treatment displayed a direct inhibitory effect in an in vivo BALB/c nude mouse prostate cancer model.

Conclusion: Our findings have provided novel insights into the underlying mechanisms by which HVJ-E induces apoptosis in tumor cells.