XPD/P44亚复合物对人肝癌细胞的生物学影响

目的:应用P44反义寡核苷酸转染人肝癌细胞SMMC-7721,探讨XPD/P44亚复合物对人肝癌细胞的生物学影响。方法:应用P44反义寡核苷酸转染人肝癌细胞SMMC-7721,同时用未做处理的SMMC-7721作为空白对照。用RT-PCR、Western blot法检测转染P44反义寡核苷酸后细胞内P44,XPD以及cdk7、cdk2、c-myc和cdc25A表达量的变化,并用四甲基偶氮唑盐(MTT)和流式细胞仪检测细胞增殖及其细胞周期的变化。结果:P44基因反义寡核苷酸转染人肝癌细胞SMMC-7721后,人剪切修复基因XPD mRNA及其蛋白的表达量显著减少,同时细胞周期调控基因cdk7、cdk2、c-myc和cdc25A mRNAs及其蛋白的表达量上调,肝癌细胞增殖明显。结论:XPD基因的表达受其分子伴侣P44的调节,XPD的作用需要有P44的参与;XPD/P44亚复合物可能是通过DNA损伤检控点来调控细胞周期的。

Biological Effects of Antisense P44 on XPD/P44 Subcomplex and Hepatoma Cell Behavior in Vitro

Objective:To investigate the effects of P44 on the cell cycle and its interaction with XPD,cdk7,cdk2,c-myc and cdc25A.Methods:Antisense oligonucleotides of P44 gene were transfected into SMMC-7721 cells.Cell lines for com-parison were matched on the same genetic background and passage.The expression of wild-type XPD,cdk7,cdk2,c-myc and cdc25A were detected by RT-PCR and Western blot.The cell growth and the cell cycle were examined by MTT and flow cy-tometry.Results:After transfection of SMMC-7721 with antisense oligonucleotides of P44,the expression of XPD mRNA was decreased significantly.The expressions of cell cycle regulatory genes including cdk7,cdk2,c-myc and cdc25A were en-hanced,and the inhibitory effects of XPD on cell growth were decreased and the hepatoma cells grew fast.Conclusion:XPD gene is regulated by its upstream regulatory gene P44,and its function requires the interaction of XPD with P44,which can re-sult in the changes of cdk7,cdk2,c-myc and cdc25A genes expression.XPD/P44 subcomplex is involved in the regulation of DNA damage checkpoint.