Silencing gtse1 gene expression induces apoptosis of hepatocarcinoma cells through p53 pathway / 肿瘤

ABSTRACT

Objective: To validate the high-expression of G2 and S phase-expressed protein 1 (GTSE1) gene expression in primary liver cancer tissues and cell lines, and further to study the effect of GTSE1 gene silencing on the apoptosis of liver cancer cells. Methods: The expression matrix data of 4 individual clinical studies on primary liver cancer from Gene Expression Omnibus (GEO) database were analyzed using R software, and the differentially expressed genes between liver cancer and adjacent tissues were screened. The high expression of GTSE 1, one of the up-regulated genes, was validated in 3 cases of liver cancer tissues and 3 stains of liver cancer cell lines by Western blotting. Hep-G2 and Bel-7402 cells were transfected with the specific siRNA targeting GTSE 1 gene, then the effects of GSTE1 gene expression down-regulation on the proliferation, apoptosis and 5-fluorouracil (5-FU) sensitivity of liver cancer cells were measured by CCK-8 and FCM, respectively. Furthermore, the content and sub-cellular localization of p53 as well as the expression alteration of Bcl-2 family members were detected by Western blotting. Results: 51 up-regulated and 146 down-regulated genes were found in all 4 studies. Among them, the up-regulation of GTSE1 gene expression was further verified in 3 clinical liver cancer tissue samples and 3 liver cancer cell lines Hep-G2, Bel-7402 and SMMC-7721 (all P < 0.001). The silencing efficiency of GTSE1 gene in Hep-G2 and Bel-7402 cells transfected with the specific siRNA was more than 70%. After the down-regulation of GTSE1 expression, the proliferation of Hep-G2 and Bel-7402 cells was significantly inhibited in a time-dependent manner (all P < 0.05), the cell cycle was arrested in G1 phase, the apoptotic rate was significantly increased, and the cell sensitivity to 5-FU was significantly enhanced (all P < 0.01). In GTSE1 expression down-regulated Hep-G2 and Bel-7402 cells, the levels of total p53 and phosphorylated p53 were up-regulated (all P < 0.05), and the nuclear portion of p53 was increased (both P < 0.01); while the expression levels of Bcl-2 family pro-apoptotic members Bak and Bax were significantly raised, and the anti-apoptotic member Bcl-2 expression were reduced (all P < 0.05), respectively. Conclusion: The down-regulation of GTSE1 expression promotes the apoptosis of liver cancer cells by activating p53 pathway, and enhances the response to anti-tumor drugs.