siRNA沉默P21表达对细胞周期解偶联和细胞凋亡的影响

目的： 利用RNAi技术探讨P21蛋白表达对HeLa 细胞周期解耦联和细胞凋亡的影响。方法： 丝裂霉素刺激HeLa细胞后可诱导P21蛋白高表达，采用脂质体转染技术将p21 siRNA 载体转染至HeLa细胞48 h后给予MMC刺激，利用流式细胞术检测HeLa细胞的P21蛋白表达、 细胞倍体的形成和细胞凋亡的改变。结果： p21 siRNA 载体可有效干扰经MMC诱导的HeLa细胞中P21蛋白表达, MMC刺激后24 h和48 h细胞2倍体百分数明显少于对照组(P<0.01)，4倍体和8倍体细胞百分数明显多于对照组(P<0.01)。p21 siRNA沉默HeLa细胞p21后，凋亡细胞百分率明显高于空质粒对照组(P<0.01)。结论： p21 siRNA可有效沉默HeLa细胞P21蛋白表达，在P21蛋白低表达的情况下，HeLa细胞可通过p53非依赖途径诱导细胞死亡，可能与细胞周期解偶联和p53非依赖的细胞凋亡有关。

Effects of p21siRNA on cell cycle uncoupling and apoptosis

AIM:To investigate the effects of P21 protein on cell cycle uncoupling and cell apoptosis with RNA interference assay.METHODS: The expression of P21 protein in HeLa cells was induced by mitomycin(MMC).Lipofect transfection assay was used to take the p21 siRNA into HeLa cells and MMC was given 48 h after transfection.FCM assay was applied to detect the expression of P21 and ratio of polyploid cells and apoptosis.RESULTS: p21 siRNA plasmid interfered the expression of P21 protein in HeLa cells.The number of 2 haploid cells was decreased obviously(P<0.01).The number of 4 haploid and 8 haploid cells was increased significantly(P<0.01) compared with control plasmid 24 and 48 h after MMC was given.CONCLUSION: p21 siRNA silenced the P21 protein and cell death in HeLa cells was induced by p53-independent pathway in the condition of lower expression of P21 protein.The mechanism may be related to cell cycle uncoupling and apoptosis by p53-independent pathway.