Antitumor Effect Of Combining TRAIL And MnSOD Mediated By CEA-controlled Oncolytic Adenovirus In Lung Cancer

Lung cancer is one of the leading causes of death in the world, of which the adenocarcinoma has been reported to be the most common subtype. In China, the incidence and mortality of lung cancer is the highest in human cancers, and the mortality of lung cancer in China is higher than that the world average. So it is imperative to find a safe and efficient method for lung cancer therapy.Recently, carcinoembryonic antigen(CEA), was acted as a superb non-small-cell lung cancer marker candidate, and it is important to diagnose and prognose in lung cancer. Furthermore, it is also a kind of effective marker for cancer treatment. In recent studies, CEA showed a beneficial effect in cancer therapy with oncolytic adenovirus mediated anticancer gene. However, the antitumor effect of oncolytic adenovirusmediated single gene is limited. To obtain the better antitumor effect, Cancer Targeting dual Gene-Virotherapy strategy, which deliver two therapeutic genes linked by a connexon, is expected to reach a synergy in anticancer reaserch.In this study, we constructed a tumor-specific oncolytic adenovirus, which deleted E1 B 55kDa gene, CD55-TRAIL-IETD-MnSOD. The virus has the fusion protein cDNAs for tumor necrosis factor-related apoptosis-inducing ligand(TRAIL) and for Manganese superoxide dismutase(MnSOD) cDNA linked through a 4-amino acid caspase-8 cleavage site(IETD), and use a CEA promoter to control virus E1 A express. Firstly, we used real-time PCR to screen the CEA positive cancer cell lines. After that, to verify its targeting cancer therapy effect and inducing apoptosis signaling pathway, the anticancer capacity was evaluated by MTT assay, CPE assay of crystal violet staining, Hoechst33342 staining, Flow cytometry and Western blotting in vitro. Finally, A549 tumor xenograft model in nude mice was used to explore its anti-tumor effect in vivo. The results indicated that CD55-TRAIL-IETD-MnSOD caused more cell apoptosis than CD55-TRAIL or CD55-MnSOD alone or their combination in vitro, but hardly cytotoxicity in normal cells. The reaserch in nude mice, data showed that CD55-TRAIL-IETD-MnSOD could effectively suppress tumor growth than other groups, with no histological damage in liver, spleen or kidney tissues.In conclusion, this is the first work to use a CEA promoter-regulated oncolytic adenovirus, CD55-TRAIL-IETD-MnSOD, for cancer research, which maybe an effective strategy for lung cancer clinical therapy.