目的：探讨沉默Bmi-1表达在逆转人肺癌顺铂耐药性的作用及机制。方法以siRNA沉默Bmi-1表达，MTT法检测细胞顺铂敏感性，流式细胞术检测细胞周期分布与凋亡，β-半乳糖酐酶染色法检测细胞的衰老，Western blot法检测Bmi-1、P14ARF、P16INK4a、P53、P21、Rb、ubi-H2AK119蛋白表达。结果肺癌顺铂耐药株A549/DDP细胞的Bmi-1表达明显高于A549细胞；沉默Bmi-1的表达显著增加耐药株对顺铂的敏感性（IC50从40.3±4.1μmol/L降到18.3±2.8μmol/L，P<0.01），细胞G0/G1期比值显著升高[从（48.9±2.3）%升到（78.7±7.6）%，P<0.01]；细胞β-半乳糖酐酶染色阳性，呈衰老特征。细胞衰老通路的P14ARF、P16INK4a、P53、P21、Rb表达上调，ubi-H2AK119表达下调。结论沉默Bmi-1表达能诱导A549/DDP细胞衰老，逆转对顺铂的耐药性，其作用机制可能与降低ubi-H2AK119表达、调节INK4a/ARF/Rb衰老通路有关。%Objective To investigate the effect of silencing Bmi-1 expression in reversing cisplatin resistance in human lung cancer cells and explore the possible mechanisms. Methods Cisplatin-resistant A549/DDP cells with small interference RNA (siRNA)-mediated Bmi-1 expression silencing were examined for cisplatin sensitivity using MTT assay and alterations in cell cycle distribution and apoptosis with flow cytometry, and the changes in cell senescence was assessed using β-galactosidase staining. The protein expressions of Bmi-1, P14ARF, P16INK4a, P53, P21, Rb and ubi-H2AK119 in the cells were determined with Western blotting. Results A549/DDP cells showed significantly higher Bmi-1 expression than A549 cells. After siRNA-mediated Bmi-1 silencing, A549/DDP cells showed significantly enhanced cisplatin sensitivity with an increased IC50 from 40.3± 4.1μmol/L to 18.3 ± 2.8μmol/L (P<0.01) and increased cell percentage in G0/G1 phase from (48.9 ± 2.3)%to (78.7 ± 7.6)%(P<0.01). Silencing Bmi-1 did not cause significant changes in the cell apoptosis rate but induced obvious senescence phenotype in A549/DDP cells with down-regulated expression of ubi-H2AK119 and up-regulated expressions of P14ARF, P16INK4a, P53,P21 and Rb. Conclusion Silencing Bmi-1 by RNA interference can induce cell senescence and resensitize A549/DDP cells to cisplatin possibly by regulating INK4a/ARF/Rb senescence pathway.
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