1.Adenoviral Vector For Hepatocellular Carcinoma Gene Therapy 2.Conditionally Replicating Adenovirus-mediated ShRNA Targeting Apollon Induces Apoptosis And Inhibits Tumor Cell Growth In Vitro And In Vivo

Conditionally replicating adenovirus (CRAd) i.e. oncolytic adenovirus can selectively replicate in cancer cells. CRAds can be used in their own right as oncolytic agents because they lyse infected cancer cells to allow their progeny to spread to neighboring cells. Their ability to amplify and spread through a tumor mass also makes CRAds useful in cancer gene therapy as an efficient delivery vehicle for therapeutic genes. Apart from causing a direct anticancer effect, the therapeutic transgene product expressed by a CRAd can also enhance the oncolytic potency of the CRAd. In this regard, we initiated a strategy, designated as Targeting Gene-Virotherapy of Cancer, by taking the advantage of both gene therapy and virotherapy. Hepatocellular carcinoma (HCC) displays a high resistance to TRAIL-mediated cell death because HCC cells express high levels of inhibitor of apoptosis proteins (IAPs). we have constructed an oncolytic adenoviral vector (ZD55) and used this vector to deliver Smac gene (ZD55-Smac) and TRAIL gene (ZD55-TRAIL) into HCC cells. The combined treatment of ZD55-Smac and ZD55-TRAIL resulted in significant reduction of XIAP expression level. Complete tumor regression was observed by combination of ZD55-Smac and ZD55-TRAIL in all treated animals in vivo. The combination of Smac and TRAIL delivered via the oncolytic adenoviral vector would provide a useful strategy for therapy of HCC and might also be applied to other IAPs abundant cancers. The activation of NF- B induced by TRAIL renders HCC cells resistant to TRAIL-mediated cell apoptosis. Here we described that the adenoviral vector expressing CYLD (Ad/hTERT-CYLD) augmented the cytotoxicity of TRAIL in HCC cells by negatively regulating NF- B activity since CYLD could reverse the ubiquitination of TNF receptor-associated factor 2 (TRAF2) and interact with the I B kinaseγ(IKKγ). The combined treatment of Ad/hTERT-CYLD and ZD55-TRAIL induced rapid and potent apoptosis in HCC cells and eradicated the BEL7404 xenograft tumors. This may be a new useful strategy for HCC or other tumor cells with enhanced NF- B activity. Apollon, a membrane-associated inhibitor of apoptosis protein (IAP), protects cells against apoptosis and is upregulated in certain tumor cells. In this study, we examined the effects of Apollon protein knockdown by RNA interference on the growth of human Hela, HT-1080 and MCF-7 cells in vitro and in vivo. We constructed an oncolytic adenovirus (ZD55) containing the RNA polymerase III-dependent U6 promoter to express short hairpin RNA (shRNA) directed against Apollon (ZD55-siApollon). Our data showed that ZD55-siApollon successfully exerted a gene knockdown effect and resulted in the growth inhibition of tumor cells both in culture and in athymic mice in vivo. Cell cycle analysis, DAPI staining and western blot analysis revealed that ZD55-siApollon-mediated suppression of Apollon induced apoptosis. Intratumoral injection of ZD55-siApollon significantly inhibited tumor growth in the HT-1080 xenograft mice models. Furthermore, ZD55-siApollon showed a synergistic antitumor effect with the chemotherapeutic agent 5-fluorouracil. In conclusion, these results suggest that depletion of Apollon by oncolytic adenovirus-shRNA delivery system may be a promising strategy for cancer therapy.