[摘要] 目的：探讨miR-520a-3p 通过靶向卷曲受体8(FZD8)调控非小细胞肺癌（NSCLC）A549/TAX细胞对紫杉醇（TAX）的敏感性。方法：选用NSCLC A549 细胞、TAX抗性细胞株A549/TAX及人肺上皮细胞HLF-α，用qPCR检测A549 和A549/TAX细胞中miR-520a-3p 的表达水平。依据转染质粒的不同分为对照组、miR-520a-3p mimics 组、si-FZD8 组和si-FZD8+miR-520a-3p inhibitor组，用6 μmol/L的TAX处理各组A549/TAX细胞后，用CCK-8 检测A549/TAX细胞的增殖能力，用Annexin V-FITC/PI 染色流式细胞术检测A549/TAX细胞的凋亡水平，用WB检测A549/TAX细胞中FZD8 的表达水平。双荧光素酶报告基因系统检测miR-520a-3p 与FZD8 的靶向关系。结果：miR-520a-3p 在A549/TAX细胞中低表达（P<0.01），且TAX能够上调A549/TAX细胞中miR-520a-3p 的表达水平（P<0.01）。6 μmol/L TAX处理后，过表达miR-520a-3p 可显著抑制A549/TAX细胞的增殖并促进其凋亡（均P<0.01）。双荧光素酶报告基因证明miR-520a-3p 可靶向下调FZD8 的表达水平（P<0.01）。si-FZD8 可显著抑制A549/TAX细胞增殖、促进细胞凋亡，从而增强细胞对TAX的敏感性；同时敲降miR-520a-3p 和FZD8 可逆转敲降FZD8 对A549/TAX细胞TAX敏感性的增强作用（P<0.01）。结论：miR-520a-3p 可通过靶向下调FZD8 表达水平增强A549/TAX细胞TAX敏感性。

[Abstract] Objective: To investigate the influence of miR-520a-3p on paclitaxel (TAX) sensitivity of non-small cell lung cancer (NSCLC) A549/TAX cells via regulating frizzled class receptor 8 (FZD8). Methods: NSCLC A549 cells, TAX-resistant cell line A549/TAX and human lung epithelial HLF-α cells were selected. The expression level of miR-520a-3p in A549 and A549/TAX cells was detected by qPCR. According to different transfection plasmids, the experimental cells were divided into control group, miR-520a-3p mimics group, si-FZ8 group and si-FZD8+miR-520a-3p inhibitor group. After being treated with 6 μmol/L paclitaxel, the proliferation of A549/TAX cells was determined by CCK-8 assay. Flow cytometry with Annexin V-FLTC/PI staining was used to detect the apoptosis level of A549/TAX cells. The expression of FZD8 in A549/TAX cells was detected by WB. The targeting relationship between miR-520a-3p and FZD8 was verified by the dual-luciferase reporter gene system. Results: miR-520a-3p was poorly expressed in TAX-resistant A549/TAX cells (P<0.01), and TAX up-regulated the expression of miR-520a-3p in A549/TAX cells (P<0.01). After the treatment with 6 μmol/L TAX, over-expression of miR-520a-3p significantly inhibited the proliferation of A549/TAX cells and promoted apoptosis (all P<0.01). Dual luciferase reporter gene assay showed that miR-520a-3p targetedly down-regulated the expression of FZD8 (P<0.01). si-FZD8 could significantly inhibit the proliferation and promote cell apoptosis of A549 / TAX cells, thereby enhancing the TAX sensitivity of cells. At the same time, simultaneous knockdown of miR-520a-3p and FZD8 could reverse the enhancement of FZD8 knockdown on TAX sensitivity of A549/TAX cells (P<0.01). Conclusion: miR-520a-3p enhances the TAX sensitivity of A549/TAX cells by down-regulating the expression of FZD8.