Inactivated Sendai Virus Suppresses Murine Melanoma Growth by Inducing Host Immune Responses and Down-regulating β-catenin Expression

Abstract Objective This paper aims to investigate the anti-tumor mechanism of inactivated Sendai virus （Hemagglutinating virus of Japan envelope, HVJ-E） for murine melanoma （B16F10）. Methods The murine dendritic cells （DCs） were treated with HVJ-E, and then the cytokines secreted from DCs and costimulation-related molecules on DCs were measured. Meanwhile, the expression of 13-catenin in HVJ-E treated murine melanoma cells was detected. In addition, HVJ-E was intratumorally injected into the melanoma on C57BL/6 mice, and the immune cells, CTL response and tumor volume were analyzed. Results HVJ-E injected into B16F10 melanoma obviously inhibited the growth of the tumor and prolonged the survival time of the tumor-bearing mice. Profiles of cytokines secreted by dendritic cells （DCs） after HVJ-E stimulation showed that the number of cytokines released was significantly higher than that elicited by PBS （P〈O.05）. The co-stimulation-related molecules on DCs were comparable to those stimulated by LPS. Immunohistochemical examinations demonstrated the repression of 13-catenin in B16F10 melanoma cells after HVJ-E treatment. Meanwhile, real-time reverse transcription PCR revealed that HVJ-E induced a remarkable infiltration of CDllc positive cells, chemokine ligand 10 （CXCL10） molecules, interleukin-2 （IL-2） molecule, CD4^＋ and CD8^＋ T cells into HVJ-E injected tumors. Furthermore, the mRNA expression level of 13-catenin in the HVJ-E injected tumors was also down-regulated. In addition, B16F10-specific CTLs were induced significantly after HVJ-E was injected into the tumor-bearing mice. Conclusion This is the first report to show the effective inhibition of melanoma tumors by HVJ-E alone and the mechanism through which it induces antitumor immune responses and regulates important signal pathways for melanoma invasion. Therefore, HVJ-E shows its prospect as a novel therapeutic for melanoma therapy.

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.

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.