目的：探讨Tg737基因过表达对人肝癌细胞株细胞周期和凋亡的影响及可能的机制。方法：将肝癌HepG2和MHCC97-H细胞分别用脂质体法转染pcDNA3.1-Tg737质粒（Tg737过表达组）或pcDNA3.1空载体（空载体组），或单纯脂质体孵育（脂质体组），以各自未处理的细胞为空白对照。48 h后分别用流式细胞仪检测细胞周期与凋亡，Hoechst33342染料法检测细胞核形态，Western blot法检测cyclin A、Bax、Bcl-2表达。结果：与各自的空白对照组比较，Tg737过表达组HepG2和MHCC97-H细胞的S期细胞数量与细胞凋亡率均明显增加（均P<0.05），且细胞核均出现明显凋亡形态学改变，同时伴随cyclin A、Bax的表达上调和Bcl-2的下调（均P<0.05）；空载体组、脂质体组HepG2和MHCC97-H细胞镜下未见明显的凋亡形态学变化，且上述指标差异均无统计学意义（均P>0.05）。结论：Tg737基因过表达可以抑制肝癌细胞周期进程、促进其凋亡，机制可能与Tg737参与调节cyclin A、Bax、Bcl-2有关的信号通路有关。
Influence of Tg737 gene overexpression on cell cycle and apoptosis of hepatocellular carcinoma cells
Objective: To investigate the influence of Tg737 gene overexpression on cell cycle and apoptosis in human hepatocellular carcinoma cell lines and the possible mechanism. Methods: Human hepatocellular carcinoma HepG2 and MHCC97-H cells were transfected with pcDNA3.1-Tg737 plasmid (Tg737 overexpression group) or empty pcDNA3.1 vector (empty vector group) mediated by liposome delivery, or cultured with liposomes alone (liposome group), respectively, with corresponding untreated cells as blank controls. Forty-eight hours later, the cell cycle status and apoptosis were analyzed by flow cytometry, nuclear morphological changes were examined by Hoechst 33342 assay, and the expression levels of cyclin A, Bax and Bcl-2 were detected by Western blot analysis. Results: Compared with corresponding blank controls, in Tg737 overexpression group of either HepG2 or MHCC97-H cells, the number of cells in the S stage and apoptosis rate were significantly increased (all P<0.05), and presented with the typical nuclear morphological changes of apoptosis, with significant upregulation of cyclin A and Bax and downregulation of Bcl-2 (all P<0.05); both HepG2 or MHCC97-H cells in empty vector group or liposome group showed no evident morphological changes of apoptosis, and the difference in all above indexes showed no statistical significance (all P>0.05). Conclusion: Tg737 gene overexpression can inhibit the cell-cycle progression and promote apoptosis of hepatocellular carcinoma cells, and the mechanism may be associated with the participation of Tg737 in regulating the signaling pathways involving cyclin A, Bax and Bcl-2.