Synergistic Inhibition Of Liver Cancer Cell Growth In Vitro And Xenografted Tumor Growth In Vivo Mechanism Research Of The Ad-XAF-1&TNF-α Adenovirus Vector Of Primary Hepatocellular Carcinoma

OBJECTIVES: This study investigated the expression of XAF-1 and TNF-α effect on HCC cell growth, and analysis of its molecular mechanism.METHODS: We examined the expression of XAF-1 in both mRNA and protein levels in the HCC intratumor specimens. Then we investigated the tumor suppressive role of a recombinant adenovirus which co-expressed XAF-1 and TFN-α, on the tumor growth of HCC cells.In order to evaluating the therapeutic effect of Ad-XAF-1&TNF-αadenovirus vector on the Hep G2 97 h M people hepatocellular carcinoma(HCC) cells in nude mice transplantation tumor model, we selected the intratumor injection methods through Ad-XAF-1&TNF-αadenovirus vector. And then the control was injected by an equal volume of saline solution.RESULTS: demonstrated that the XAF-1 expression was significantly reduced in HCC intratumor specimens than in HCC peritumor specimens, with an association with the tumor malignance. And the XAF-1 reduction was reconfirmed in such HCC cell lines as MHCC97 L, HepG2 and MHCC97 H. Moreover, we constructed a recombinant adenovirus, Ad-XAF-1&TNF-α, which co-expressed XAF-1 and TNF-α efficiently via a 2A peptide coding sequence, and both mRNA and protein levels of XAF-1 and TFN-α were significantly promoted by the Ad-XAF-1&TNF-α infection in HCC MHCC97 L cells, almost with a ratio of 1:1. Furthermore, we confirmed that the Ad-XAF-1&TNF-α infection reduced more significantly the growth of HCC MHCC97 L cells than the infection with the infection with the Ad-XAF-1 or Ad-TNF-α virus. Compared with the PBS injection of nude mouse tumors,Ad- XAF-1 & TNF alpha and Ad- con group of nude mouse tumors had accumulated growth trend of decline with the speeding up of the experimental process(P<0.05). Ad- XAF- 1 & TNF alpha treatment group nude mice tumors grow slowly and the difference was statistically significant Compared with the Ad- con group of nude mouse tumors(P < 0.05). After the 7 day of treatment of Ad- XAF- 1 & TNF alpha, tumor inhibition rate had the highest(65.87%).but then with the passage of time, the inhibitory rate fell, and the tumor inhibition rate was 60.78% at the28 day. The immunohistochemical staining and RT-PCR experimental results showed that with Ad- con group and PBS group nude mice tumor tissue XAF-1, compared to the positive expression rate of TNF alpha(6.11%±1.73%, 6.42% ±2.59%),XAF-1, increased the positive expression of TNF alpha in the Ad- XAF- 1 & TNF alpha treatment group nude mice tumor tissue(16.39%±1.39%)(P<0.05). Meanwhile, mRNA expression levels of Ad-XAF- 1 & TNF alpha treatment group nude mice tumor tissue increased compared with Ad-con and PBS group..CONCLUSIONS: Thus, for the first time, we have constructed an adenovirus, which co-expressed XAF-1 and TNF-α in same ORF and expressed them proportionally. What’s more the co-expressive Ad-XAF-1&TNF-α virus inhibited the proliferation of HCC cells more efficiently, induced the expression of the XAF-1, TNF-α in the Nude mice xenograft, reduced the tumors volume and maintained the higher tumor inhibition rate,promoting the mRNA expression.It implyed that co-expressive Ad-XAF-1&TNF-α virus had a promising anti-tumor effect against HCC,and potential clinical value for further study.