microRNA-125b对人视网膜母细胞瘤多药耐药性影响的实验研究

目的 探讨microRNA-125b（miR-125b）在人视网膜母细胞瘤细胞中多药耐药的作用及其机制。设计 实验研究。 研究对象 人视网膜母细胞瘤SO-RB50细胞。方法 用RT-PCR方法检测miR-125b视网膜母细胞瘤细胞株SO-RB50和耐药细胞株SO-Rb50/VCR中的表达变化；化学合成的miR-125b过表达（miR-125mimic 组）和抑制载体（miR-125inhibitor组）转染SO-Rb50细胞株，用MTT法和Annexin V-FITC法检测在药物长春新碱、依托泊苷和卡铂，依次作用上述转染细胞后，细胞增生力和细胞凋亡的变化；用蛋白印迹法检测miR-125b过表达和抑制表达后细胞株SO-RB50中 MAGE-A/P53蛋白的表达变化。主要指标 细胞存活率和细胞凋亡率。结果 SO-Rb50/VCR组与SO-RB50组相比，miR-125b的表达显著增高（P=0.002）；长春新碱、依托泊苷和卡铂依次作用于转染后的SO-RB50细胞株后，miR-125mimic组与miR-125inhibitor组相比，细胞存活率显著增高（P=0.000），细胞凋亡率显著下降（P=0.000），P53蛋白表达水平显著下降（P=0.001），MAGE-A蛋白表达水平显著增高（P=0.004）。结论 在SO-RB50细胞中，下调miR-125b后提高肿瘤细胞对化疗药物敏感性，且miR-125b可能是通过MAGE-A/P53通路调控视网膜母细胞瘤多药耐药性。

Effects of microRNA-125b on multidrug resistance in human retinoblastoma

Objective To explore the effects of microRNA-125b (miR-125b) on the retinoblastoma multidrug resistance and to study its molecular mechanism of miR-125b on chemotherapy sensitivity. Design Experimental study. Participants The retinablastoma cell lines SO-RB50. Methods The expression of miR-125b was detected by real-time PCR in SO-RB50 cell line and SO-RB50/VCR cell line. The synthesized miR-125b mimic (miR-125mimic group) and miR-125b inhibitor (miR-125inhibitor group) was transfected into retinoblastoma SO-RB50 cell line. In addition, three chemotherapeutic drugs, including carboplatin, etoposide and vincristine, were used to treat the transfected SO-RB50 cell line respectively, in order to evaluate the sensitivity of RB cells. The cell proliferation and apoptosis were measured by MTT and Annexin V-FITC. The protein expression level of MGEA-A and P53 was detected in the transfected SO-RB50 cell line by Western blot. Main Outcome Measures The percentage of cell survival and the percentage of apoptotic cells to total cells. Results MiR-125b was significantly up-regulated （P=0.000）in the SO-RB50/VCR cell line compared to that in the SO-RB50 cell line (P=0.000). It apparently promotes RB cell proliferation and suppresses cell apoptosis（P=0.000） in the miR-125mimic group compared with that in the miR-125inhibitor group treated by carboplatin, etoposide and vincristine respectively （P=0.000）. The protein expression level of MAGE-A was higher significantly in the miR-125mimic group than in the miR-125inhibitor group（P=0.004）. Meanwhile, the protein expression level of P53 was lower significantly in the miR-125mimic group than in the miR-125inhibitor group (P=0.001). Conclusion The SO-RB50 cell line inhibited the expression of miR-125b was sensitive to carboplatin, etoposide and vincristine, and furthermore miR-125b/MAGE-A/p53 axis may be conducive to enhancing the efficacies of chemotherapeutic treatments for RB.