p53及p21^wafl蛋白表达与人舌癌细胞多药耐药性的关系

目的 探讨p53及p21^wafl蛋白表达与人舌癌细胞系Tca8113多药耐药性（MDR）的关系。方法 采用脂质体介导的转染技术，将野生型p53（wt-p53）基因导入人舌癌耐药细胞系Tca8113／BLM；分子信标（Molecular Beacon）法检测人舌癌细胞系Tca8113及其耐药细胞系Tca8113／BLM中p53基因的mRNA水平；Western blot检测亲本、耐药细胞和转染细胞中p53、p21^wafl、P-gp和MRP蛋白的表达变化；MTT法检测不同细胞的药物敏感性，流式细胞仪检测细胞周期的改变，激光共聚焦显微镜观察细胞凋亡。结果 在人舌癌耐药细胞系Tca8113／BLM中p53基因的表达明显下调，并且未检测到p21^wafl蛋白的表达；转染了wt—p53的耐药细胞Tca8113／BLM／p53中p53和p21^wafl蛋白表达均显著上调，而P-gP和MRP的蛋白表达则明显下调，其对药物BLM的敏感性增加10．1倍（P〈0．01）；转染细胞的周期也发生改变，G2期细胞增加，G1和S期细胞减少，转染细胞明显出现凋亡。结论 人舌癌耐药细胞系Tca8113／BLM多药耐药性的产生，可能通过p53和p21^wafl的表达下调使得多药耐药性相关蛋白P—gp和MRP表达上调来实现。

Relationship between the expression of p53 and its downstream effecter p21^wafl proteins and multi-drug resistance of human tongue cancer cell line

Objective To study the relationship between the expression of p53 and its downstream effecter p21~(waf1)protein and multi-drug resistance(MDR) of Tca8113/BLM cell line.Methods The cDNA of wildtype p53 gene was introduced into the drug-resistance cell line Tca8113/BLM by Lipofectamine-mediated transfection.The expression of p53 mRNA in Tca8113/BLM and its parental counterpart Tca8113 cell lines were analyzed using molecular beacons.The expression of p53,p21~(waf1),P-gp,and MRP proteins in Tca8113/BLM cell line transfected by wt-p53 cDNA,the untransfected control Tca8113/BLM cell line,its parental counterpart Tca8113 were analyzed by Western blotting.MTT assay was used to determine the drug-sensitivity of different cell lines.The cell cycle distribution and apotosis of different cell lines were also observed by flow cytometery(FCM) and laser confocus microscope(LCM),respectively.Results The expression of p53 protein was significantly lower,and no p21~(waf1) protein was detected in Tca8113/BLM cells.The protein expression of P-gp and MRP were significantly higher in Tca8113/BLM cells than in Tca8113 cells.By Western Blotting,the expression of p53 and p21~(waf1)proteins was significantly increased,while the expression of P-gp and MRP proteins was significantly decreased in Tca8113/BLM/p53 cells.Comparing to Tca8113/BLM cells,the sensitivity of BLM treatment in Tca8113/BLM/p53 cells was 10.1 fold increased.Tca8113/BLM/p53 cells decreased at G1 and S phase,and increased at G2 phase.LCM results showed that the apoptosis of Tca8113/BLM/p53 cells was more obvious than Tca8113/BLM cells when treated with the drug BLM.Conclusion The multi-drug resistance in Tca8113/BLM cell line is involved in down-regulation of p53 and p21~(waf1) protein levels,and up-regulation of P-gp and MRP protein levels.