| High mortality, low survival rate, and poor treatment effect make cancer threpay become the current challenge for medical and biology. Cancer has become the ahead cause of death in worldwide. Among of which hepatocellular carcinoma is one of the most common malignant tumors, and its incidence is very high in China and even in some areas with the highest mortality rates among cancers. Traditionally the therapeutic methods of cancer include surgery, radiotherapy and chemotherapy. However, due to the metastasis easily, invasion, and uncurability et al for above, people are now being explored safer and effective anti-cancer treatment strategies, including cancer gene therapy.The occurrence of cancer is fundamentally the cause of multiple gene mutation. Cancer gene therapy is expected to become a novel treatment strategy for cancer. Manganese superoxide dismutase gene (MnSOD) is a new tumor suppressor gene. Studies showed that MnSOD can prevent normal cells to transform into cancer cells, inhibit tumor cell growth and promote the rapid apoptosis of tumor cells, exhibiting the potent anti-tumor effects. In addition the choice of vector is very important for successful gene therapy. Recently adenovirus vector has been widely used because of the large packaging capacity, stability and security, unaffected virus replication after the insertion of foreign genes. The modified oncolytic adenovirus Ad.enAFP-E1A-â–³E1B55Kd was constructed by us through deleting adenovirus E1B55Kd region and displacing adenovirus E1A gene promoter with the hepatoma-specific alpha-fetoprotein ( AFP) promoter, which can greatly improve the targeting of viral infection and the hepatoma-specific of virus-carried MnSOD gene. In this study, the therapeutic virus Ad.enAFP-E1A-â–³E1B55Kd-MnSOD was constructed by the modified oncolytic adenovirus Ad.enAFP-E1A-â–³E1B55Kd as vectors to carry therapeutic genes MnSOD. Subsequently, the identification of correct virus construction by PCR, cell morphology changes and cell apoptosis after infected by virus by microscope, the tumor-specific killing effect by MTT assay, the evaluation of liver normal cell security by crystal violet staining , and the detection of apoptosis mechanism by western blot assay were performed. The results indicate the obvious pathological changes and growth inhibition of hepatoma cells after infection of therapeutic viruses, while little impact on the liver normal cells with high security. Moreover, the treatment of therapeutic virus Ad.enAFP-E1A-â–³E1B55Kd-MnSOD significantly induced apoptosis of hepatoma cells through carrying the MnSOD gene, indicating the good targeting ability and the effect of inhibition of tumor cell growth.In conclusion, oncolytic adenovirus Ad.enAFP-E1A-â–³E1B55Kd-MnSOD was constructed under the control of hepatoma-specific AFP promoter. The studies show that the Ad.enAFP-E1A-â–³E1B55Kd-MnSOD exhibited liver cancer-specific killing effect and the inducement of apoptosis in hepatoma cells, while not for liver normal cells, which laid the preliminary foundation for further in vivo antitumor researches and clinical liver cancer treatment. |
