沉默CXCR4的表达逆转肺癌细胞顺铂耐药

目的:探讨沉默CXCR4对肺癌细胞顺铂耐药的影响，并研究其分子作用机制。方法:利用RT-qPCR测定肺癌耐药（A549/DDP）及药物敏感细胞株（A549）中CXCR4 mRNA的表达水平；利用LipofectamineTM 2000将siRNA-CXCR4转染至肺癌耐药细胞株中，RT-qPCR及蛋白质印迹法（Western blot）验证siRNA对CXCR4基因的靶向沉默效率；利用CCK-8法检测沉默CXCR4后肺癌耐药细胞的增殖活性；利用流式细胞仪测定沉默CXCR4后肺癌耐药细胞的凋亡率；利用MTT法测定沉默CXCR4后肺癌耐药细胞对顺铂的敏感性；利用Western blot实验测定沉默CXCR4后CYP1B1蛋白的表达水平。结果:RT-qPCR实验结果显示，肺癌耐药细胞株A549/DDP中CXCR4 mRNA的表达量显著高于药物敏感细胞株（P＜0.01）；体外转染siRNA-CXCR4可明显下调A549/DDP细胞株中CXCR4的表达（P＜0.001）；CCK-8实验结果显示，沉默CXCR4的表达抑制了A549/DDP细胞的增殖活性（P＜0.01）；流式细胞仪实验结果显示，沉默CXCR4的表达促进了A549/DDP细胞凋亡（P＜0.01）；MTT实验结果显示，沉默CXCR4的表达增加了A549/DDP细胞对顺铂的敏感性（P＜0.01）；Western blot实验结果显示，沉默CXCR4后CYP1B1蛋白的表达水平显著降低（P＜0.05）。结论:沉默CXCR4的表达抑制肺癌耐药细胞增殖、促进凋亡，逆转肺癌细胞顺铂耐药，CXCR4正向调控CYP1B1的表达，可能是CXCR4逆转肺癌细胞顺铂耐药的作用机制。

Silencing CXCR4 expression reverses cisplatin resistance in lung cancer cells

Objective:To investigate the effect of silencing CXCR4 on cisplatin resistance in lung cancer cells and its molecular mechanism.Methods:RT-qPCR was used to determine the expression of CXCR4 mRNA in lung cancer drug resistance (A549/DDP) and drug sensitive cell line (A549).siRNA-CXCR4 was transferred into lung cancer drug-resistant cell line by LipofectamineTM 2000.CCK-8 assay was used to detect the proliferation activity of lung cancer drug-resistant cells after silencing CXCR4.Flow cytometry was used to detect the apoptosis rate of lung cancer drug-resistant cells after silencing CXCR4.MTT assay was used to determine the sensitivity of lung cancer drug-resistant cells to cisplatin after silencing CXCR4,and Western blot assay was used to detect the expression of CYP1B1 protein after silencing CXCR4.Results:The results of RT-qPCR assay showed that the expression of CXCR4 mRNA in lung cancer drug-resistant cell line A549/DDP was significantly higher than that in drug-sensitive cell line (P＜0.01).In vitro transfection of siRNA-CXCR4 significantly down-regulated CXCR4 expression in A549/DDP cell lines (P＜0.001).The results of CCK-8 assay showed that the expression of silencing CXCR4 inhibited the proliferation of A549/DDP cells (P＜0.01).The results of flow cytometry showed that the expression of silencing CXCR4 promoted cell apoptosis of A549/DDP cells (P＜0.01).The results of MTT assay showed that the expression of silencing CXCR4 increased the sensitivity of A549/DDP cells to cisplatin (P＜0.01).The results of Western blot showed that the expression level of CYP1B1 protein was significantly decreased after silencing CXCR4 (P＜0.05).Conclusion:Silencing the expression of CXCR4 can inhibit the proliferation,promote apoptosis of lung cancer drug-resistant cells,reverse the resistance of lung cancer cells to cisplatin,and CXCR4 positively modulates the expression of CYP1B1,which may be the mechanism of CXCR4 to reverse the resistance of lung cancer cells to cisplatin.