摘要
目的研究HER2/neu基因过表达通过磷脂酰肌醇3激酶(PI3K)通路对乳腺癌细胞MCF7野生型p53基因表达、细胞增殖及对γ射线照射敏感性的影响。方法以脂质体介导的HER2/neu基因转染MCF7细胞,用G418筛选阳性克隆。通过Westernblot鉴定HER2/neu蛋白的表达,并检测p53、信号转导分子Akt和pAkt蛋白含量的变化及PI3K通路抑制剂LY294002对上述蛋白表达水平的影响。以MTT法检测细胞增殖以及细胞对γ射线照射的敏感性。结果共获得18个稳定转染HER2/neu基因的阳性克隆,其中1个克隆有HER2/neu基因过表达。过表达HER2/neu的MCF7细胞pAkt蛋白含量升高,p53蛋白含量低于对照组细胞,LY294002能够抑制pAkt蛋白和p53蛋白的变化。同时,过表达HER2/neu基因的MCF7细胞生长速度高于对照组细胞,对γ射线照射治疗的敏感性降低,而LY294002能够抑制细胞生长并增强放射治疗的敏感性。结论MCF7细胞中HER2/neu基因的过表达,能够通过激活PI3K通路导致野生型p53蛋白含量减少、细胞增殖加快及放疗的敏感性降低,这可能是某些p53蛋白为野生型的肿瘤患者对治疗产生抗性的原因。
Objective To investigate the effect of HER2/neu overexpression on the wild p53 gene expression, cell proliferation and sensitivity to γ irradiation via phosphatidylinositol 3 kinase (PI3K) pathway in human breast cancer cell MCF7. Methods Lipofectin mediated gene transfection method was used to transfer HER2/neu into MCF7 cells. Expression of HER2/neu, p53, Akt and p Akt protein after PI3K pathway inhibitor LY294002 treatment was determined by Western blot. Cell proliferation and cell surviving fraction after γ irradiation treatment were assayed by MTT. Results Eighteen of HER2/neu stably transfected MCF7 cell clones were established, one of them was HER2/neu overexpressing. HER2/neu overexpressing MCF7 cells showed higher p Akt expression and lower p53 expression than those of parental MCF7 cells, which could be abrogated by LY294002. HER2/neu overexpressing MCF7 cells had higher proliferation rate and lower sensitivity to γ irradiation than those of parental MCF7 cells, which could be opposed by LY294002. Conclusion Overexpression of HER2/neu induces reduced expression of wild type p53 protein,relatively high cell proliferation and low sensitivity to γ irradiation in breast cancer cell MCF7 by activating PI3K/Akt pathway, which may contribute to therapeutic resistance in some breast cancer patients with wild type p53 gene status.
出处
《中华肿瘤杂志》
CAS
CSCD
北大核心
2004年第10期594-597,共4页
Chinese Journal of Oncology
