Enhancement Of Cytotoxicity And Specificity Of Vaccinia Virus Armed With GM-CSF And SMAC Linked By F2A In Cancer Therapy

Generally, cancer can resist the chemotherapeutic drugs and cell death, which make itintractable to eradicate tumors. GM-CSF is an immune stimulating factor inproliferation of granulocyte and macrophage concerning innate immunity andregulates the switch of monocyte to dendritic cell involving antigen presentation inadaptive immunity. SMAC/DIABLO plays a critical role in activating of caspases andmoderating of IAPs inhibition. Since cancer generation attributes to multiple genes,single durative gene is insufficient for caring cancer. We used F2A as a linkerbetween GM-CSF and SMAC to construct expression cassette of dual genes. In thisstudy, we engineered tumor-targeted vaccinia carrying GM-CSF and SMAC/DIABLOwith disputing the viral TK gene. Hence, because of the animal model foundationissue, we focused on studying in VV-SMAC.Our results showed that VV-SMAC specifically and efficiently infected anddestroyed HCC cells by triggering both caspase-dependent apoptosis neutralizingIAPs and necroptosis induced by RIP1kinase activity. Moreover, ripoptosome, aprerequisite complex depending on the RIP1activity, was assembled whileVV-SMAC was infecting cells. In addition, the combination of VV-SMAC andvinblastine had a synergistic effect on HCC cells. In summary, our data suggests thatVV-SMAC is a promising candidate for gene therapy through enhancement ofapoptosis and necroptosis.In addition, the impaction of viral infection in combination of therapy strategies isfully unclear although the novel strategies are usually combined with traditionalchemotherapy. In this study, we found that among6chemotherapeutic drugsdoxorubicin performed an effective cytotoxicity in HCC. Nonetheless, genotoxicdrugs didn’t synergize vaccinia virus and even decreased the viral propagation. Moreover, the similar phenomenon was appeared in combining vaccinia withresveratrol and thioridazine at early stage could be attenuated later. Accordingly, ourresults suggested that doxorubicin, resveratrol and thioridazine displayed efficientcytotoxicity in HCC whereas in normal liver cell and genotoxic drugs were notappropriate to associate with vaccinia in liver cancer treatment.