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, MTl--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.

Inactivated Sendai Virus Induces Apoptosis in Murine Melanoma Cells by IGF-1R Down-regulation

The mortality of cancer patients has considerably improved due to progress in surgery, chemotherapy and radiotherapy. However, some types of cancers, such as melanoma, remain refractory to conventional strategies. Although melanoma accounts for only 4% of all dermatological malignancies, it is responsible for 80% of mortalities from skin tumors[11. The reported survival rate of melanoma over 5 years is not yet encouraging due to its chemo-resistance and rapid metastasis. Therefore, it is necessary to develop new drugs with potent activity and weak side-effect against melanoma.

Inactivated Sendai Virus Induces Apoptosis Mediated by Reactive Oxygen Species in Murine Melanoma Cells

Objective This paper aims to investigate the apoptotic effect of inactivated Sendai virus （hemagglutinating virus of Japan-enveloped, HVJ-E） on routine melanoma cells （B16FlO） and the possible mechanisms involved in the putative apoptotic reactions. Methods B16F10 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 B16FlO cells, HVJ-E was intratumorally injected, both with and without N-acetyI-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. Results Treatment 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 Erkl/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. Conclusion These results suggest that HVJ-E possesses potential anticancer activity in B16F10 cells through ROS-mediated mitochondrial dysfunction involving the MAPK pathway.