摘要
目的:构建含突变C-kit基因cDNA的真核表达质粒并行进一步的功能分析。方法:用RTPCR方法从人胎脑组织克隆野生型C-kit基因蛋白编码区cDNA。根据胃肠道间质瘤中检测出的Ckit基因突变序列,体外突变野生型CkitcDNA得到突变型CkitcDNA,与pcDNA3重组成真核表达质粒,并用脂质体法稳定转染人胚胎肾细胞(humanembryonickidneycell,HEK)293细胞系,G418加压筛选出阳性克隆;用Western印迹法检测转染细胞KIT蛋白表达,绘制细胞生长曲线,MTT法检测细胞增殖活性,流式细胞仪检测转染HEK细胞后细胞周期改变,并观察稳定转染突变型重组质粒人胚肾细胞在裸鼠内的成瘤性。分别设转染pcDNA3空白质粒和野生型的CkitcDNA真核表达质粒的HEK细胞做为对照。结果:构建了突变型C-kitcDNA与pcDNA3的真核表达质粒;功能检测分析表明:细胞生长曲线显示与对照组相比,实验组的生长速度明显增快;MTT比色显示,与对照组相比实验组细胞增殖活性显著增强;细胞周期检测结果显示,处于增殖期细胞(S+G2-M)比例显著高于对照组;体内结果显示转染突变型C-kit基因的HEK细胞在裸鼠体内成瘤。结论:C-kit原癌基因突变体可促使人类细胞生长加快,增殖活性明显增强,并可以使更多的细胞由静止期进入增殖期,并可使人胚胎肾细胞发生恶性转化,提示C-kit基因突变有可?
Objective:To construct the recombinant eukaryotic expression vector plasmids with mutant C-kit cDNA and to study the effect of the mutant C-kit gene on cell proliferation and cell cycle in gastrointestinal stromal tumor (GIST). Methods: Wild-type C-kit cDNA was cloned from human embryonic brain tissue by RT-PCR technique.Site-directed mutagenesis of the wild type C-kit cDNA was performed according to the C-kit mutations we cloned. Recombinant plasmids were stably transfected into human embryonic kidney cell line and the cells expressing mutant C-kit were selected by special cell culture medium containing G418.Expressions of C-kit protein of the transfectants were detected by Western blot.Cell proliferation and cell cycle of the transfectants were detected by MTT clolorimetic assay and flow cytometry,respectively.Whether HEK cell with mutated C-kit cDNA could grow autonomously in nude mice or not was also detected. pcDNA3 vector transfected and recombinant plasmids with wild-type C-kit cDNA transfected HEK cell were used as the control groups. Results: The mutant C-kit cDNA was obtained by site-directed mutagenesis of the wild type C-kit cDNA. Compared with the 2 control groups ,the growth rate and proliferative activity of the HEK cells with mutant C-kit cDNA were increased significantly.The analysis of cell cycle showed that more HEK cells with mutanted C-kit cDNA remained in proliferation phase (S+G 2-M)than the groups without mutated C-kit cDNA.HEK cells with the mutated C-kit also grew autonomously in nude mice.Conclusion: Mutation of C-kit gene can increase proliferation of human cells,causing malignant transformation of human normal cells,which may play an important role in the malignant transformation of GIST.
出处
《第二军医大学学报》
CAS
CSCD
北大核心
2005年第6期618-621,共4页
Academic Journal of Second Military Medical University
基金
国家自然科学基金(30070743).