p53基因对人胃癌细胞生长及致瘤性的抑制作用

Suppression of Growth and Tumorigcnicity in Human Gastric Cancer Cells by the Introduction of Exogenous p53 Gene

p53基因异常是人类肿瘤中最常见的基因变异之一,是最有希望用于肿瘤基因治疗的目的基因。在人胃癌组织中有较高频率的p53基因缺失和突变,为探讨p53基因用于胃癌治疗的可行性,我们采用脂质体介导方法将外源性野生型p53基因转染一株p53基因有部分缺失的人胃癌BGC823细胞,获得较高的转染效率,对转染后细胞DNA,RNA和蛋白进行分析,结果表明外源性p53基因已整合入细胞并获稳定表达,表达有外源性野生型p53基因的细胞生长速度、软琼脂集落形成率及裸鼠致瘤性均有部分抑制。这一结果进一步证明p53基因在胃癌发生发展过程中起重要作用,本研究为采用野生型p53基因转染进行胃癌基因治疗提供了细胞学实验依据。

The p53 gene is one of the most common targets for genetic abnormalities in human tumors. Restoring wild - type p53 gene (wt-p53) into cancer cells which have p53 deletion is a strategy in cancer gene therapy. In order to explore the feasibility of this hypothesis, we selected a gastric cancer cell line BGC823 which was confirmed having deletion of chromosome 17pl3 and decreased expression level of p53 mRNA . We transfected construct pC53SN3 containing wt - p53 into BGC823 cell line with lipofectin mediated gene transferration, and G418 resistant colonies were characterized by using analysis of PCR, Southern blot hybridization, Northern blot hybridization and Western blot hybridization. These data showed that exogenous wt-p53 had successfully transferred into BGC823 cells and obtained high expression. The cell growth rates in regular medium and soft agar were inhibited from 30 to 40 percent in the BGC823 cells transfected with wt - p53. The tumorigenicity in nude mice showed that one of four mice failed to form tumor and three of them delayed to form tumor from 7 to 14 days comparing with monk and parent BGC823 cells. These results suggested that exogenous wt -p53 could suppress the growth ability and tumorigenicity of human gastric cancer cells. The method of using lipofectin mediated wt-p53 gene transfection may have a potentially therapeutic effect on human gastric cancer.