Abstract:

Objective To investigate the inhibitory effect of X-linked inhibitor of apoptosis associated factor-1 (XAF1) on xenograft growth in nude mice with hepatocellular carcinoma. Methods The models of xenografted nude mice with human hepatocellular carcinoma cell line SMMC7721 were established. Intratumor injection was performed on three tumor sites in each group of mice （n=5） with recombinant adenovirus Ad5/F35-XAF1, control virus Ad5/F35-Null at the same infective titre or PBS of the same volume every two days for two weeks. The volumes of xenografts in all nude mice were measured every three days, and the differences between Ad5/F35-XAF1 group and the other two groups were compared. The apoptosis of tumor cells was determined by in situ end-labeling TUNEL method, the expression of XAF1 protein and microvessel density (MVD) were detected by immunohistochemistry. Results Intratumoral injection of Ad5/F35-XAF1 significantly inhibited the growth of tumor xenografts with smaller tumor size, less tumor weight and lower MVD compared with those injected with control virus Ad5/F35-Null and PBS (P<0.05 or P<0.01). However, the apoptosis index and expression of XAF1 protein in Ad5/F35-XAF1 group were significantly increased compared with the other two groups (P<0.01). Conclusion Ad5/F35-XAF1 significantly inhibits xenograft growth in nude mice with hepatocellular carcinoma, which is probably associated with the effects of XAF1 inducing hepatocellular carcinoma cell apoptosis and suppressing tumor angiogenesis.

Key words: X-linked inhibitor of apoptosis-associated factor 1, hepatocellular carcinoma, adenovirus, xenograft, apoptosis, angiogenesis