转人肝刺激物质基因的肝癌细胞增殖状态研究

Increased cellular proliferation in BEL-7402 hepatoma cells transfected by human hepatic stimulator substance gene

本文通过研究转染人肝刺激物质 (hepaticstimulatorsubstance ,HSS)的肝癌细胞增殖状态 ,进一步探讨了该基因的生物学功能。将人HSS基因导入BEL 740 2肝癌细胞 ,用Northern和Southern杂交法证实该基因在靶细胞中有稳定表达。并通过测定细胞生长曲线、细胞S期比例和细胞MAPK活性 ,观察到转HSS基因BEL 740 2细胞增殖发生了改变。实验结果提示 ,HSS表达的肝癌细胞DNA合成增加、增殖速度加快 ,可能与MAPK激活有关。HSS基因表达可促进细胞增殖。

A hepatotropic factor originally identified in weanling or regenerating rat livers, known as hepatic stimulator substance (HSS), is characterized by promoting markedly liver regeneration after partial hepatectomy. Although HSS gene and the gene product have been described recently, the cellular mechanism of HSS and its genetic function remain obscure. In our previous studies, human HSS (hHSS) was demonstrated to promote the growth of hepatoma cells and phosphorylate the mitogen-activated protein kinase (MAPK). In this study, we reported the growth features of human hepatoma cells response to hHSS gene transfection. The hHSS eukaryotic vector was transfected to BEL-7402 hepatoma cells and the expression of hHSS was analyzed with Northern and Southern blot. The results showed that the HSS recombinant construct was functionally expressed in the target cells as analyzed with Northern blot and reverse transcriptase polymerase chain reaction (RT-PCR). The growth potential of HSS-transfected hepatoma cells was markedly enhanced as compared with the non-transfected cells. The S-phase of the hHSS-transfected cells increased by 61 5% than that of the non-transfected cells as shown by flow cytometry. Moreover, MAPK phosphorylation, one of the most important mitogenic indexes of growth signal cascade, was profoundly activated at sites of Thr202/Tyr204 due to HSS gene transfer. Based on these results, it is concluded that the introduction of HSS gene into hepatoma cells might be able to stimulate directly the cellular growth in vitro, allowing a possibility of reevaluation of HSS mechanism in intact cells.