p53反义RNA对人肺癌细胞表型和顺铂敏感性的影响

目的 研究外源p53反义RNA对有p53基因 2 4 8密码点突变的人肺癌细胞系恶性表型和顺铂敏感性的影响。方法 构建p53反义RNA真核细胞表达载体PEGFP p53(AS) ,经酶切图证明反向联结质粒。Lipofectin介导转染有p53基因 2 4 8密码点突变的人肺癌细胞系 80 1D ,经G41 8筛选获耐受克隆。稀释法建立单细胞克隆系 ,应用PCR检测外源基因 ,荧光显微镜检测细胞绿色荧光蛋白表达 ,p53单抗免疫组化染色检测p53突变蛋白表达 ,体外集落形成实验检测细胞生长 ,流式细胞仪检测细胞周期 ,MTT法检测细胞对顺铂药物敏感性。结果 酶切图证明了p53 cDNA反向联结于质粒 ,构建了PEGFP p53(AS) ,并建立了转染单细胞克隆系PEGFP p53(AS) 80 1D及空载细胞系PEGFP 80 1D。PCR检测外源p53基因和neo基因存在于转染细胞系 ,而荧光显微镜下发现其胞浆有绿荧光蛋白表达。免疫组化染色p53突变蛋白在 80 1D细胞系为阳性 ,而PEGFP p53(AS) 80 1D为阴性 ,证明外源反义p53在转染细胞稳定表达并封闭内源突变蛋白表达。与母系相比 ,PEG FP p53(AS) 80 1D集落形成抑制率为 61 % (P <0 .0 1 ) ,流式细胞仪检测该细胞系G1期细胞数明显增加 ,出现G1期阻滞的表现。MTT检测PEGFP p53(AS) 80 1D对顺铂比母系更为敏感。结论 有p53基因 2 4 8密码点?

Experimental research for specific down-regulated expression of p53 gene by individual antisense RNA in vitro

Objective： To investigate the specific blockage effect of individual antisense RNA on mutant p53 gene in vitro. Methods： The single strand antisense transcription system containing mt-p53 exon 8 sequence （pGEM3zf（＋/-）p53exon8） was constructed. The ligation of antisense RNAwith mt-p53 gene was confirmed by in situ hybridization; MDA-MB-231 human breast cancer cells were transfected with ASp53exon8＇RNA cotionic liposome-mediated. Expression of mt-p53 protein was examined by immunocytochemical staining and Western blot. Cell proliferation was evaluated by MTT assay; Cell cycle distribution was determined by flow cytometry （FCM）; Apoptosis was observed by TUNEL. Results： In transfected MDA-MB-231 cells, hybridization signals were observed in cytoplasm. ASp53exon8＇RNA transfection induced inhibition of cell proliferation, G2/M phase arrest and increasing apoptotic rates. In addition, expression of p53 protein was down-regulated. Conclusion： pGEM3zf（＋/-）p53exon8 was well constructed and ASp53exon8＇RNA can block mt-p53 gene expression specifically and then inhibit MDA-MB-231 cell proliferation in vitro, which may serve as therapeutic means for human malignancy.