[Security of dual cancer-specific targeting vector and its cytotoxic effect when harbored].

Background & Objective: The xenograft tumor mass in nude mice could be completely eliminated using the targeting dual gene-virotherapy strategy. Now, the most important point is to improve its security. This study was to construct dual cancer-specific targeting adenovirus called TD55 to evaluate its security, and construct TD55-TRAIL to explore its antitumor effect.

Methods: Plasmid pTD55 was constructed through replacing E1A promoter with promoter of human telomerase reverse transcriptase and deleting E1B 55KD gene, and plasmid pTD55-TRAIL was constructed by inserting TRAIL gene into pTD55. Adenoviruses TD55 and TD55-TRAIL were obtained through homologous recombination in 293 cells. Cytotoxic effects of TD55 and TD55-TRAIL on human colon cancer cell lines SW620 and HCT116, human lung cancer cell line A549, and human embryonic lung cell lines MRC5 and WI38 were detected by crystal violet staining and MTT assay. Tumor cell apoptosis was detected by flow cytometry.

Results: Cytotoxic effects of TD55-TRAIL on MRC5 and WI38 cells were weaker than those of ZD55-TRAIL. The virus proliferation ability of ZD55-TRAIL in normal cells is 3-5 times stronger than those of TD55 and TD55-TRAIL. The apoptosis rate of TD55-TRAIL-infected SW620 cells was 3.3 times as high as that of TD55-infected SW620 cells.

Conclusions: TD55-TRAIL has better security than ZD55-TRAIL in normal cells. So, the security of medication will be improved with dual targeting vector TD55. TD55-harbored gene as TD55-TRAIL has stronger effect than TD55 in inducing apoptosis of tumor cells.