Objective: To investigate the mechanism mediating the regulatory effect of lncRNA MAGI2-AS3 on cisplatin (DDP) resistance in non-small cell lung cancer (NSCLC).
Methods: MAGI2-AS3 and miR-1269a expression levels were detected by qRT-PCR in DDP-sensitive lung cancer cell lines (A549 and H1299) and their resistant counterparts (A549/DDP and H1299/DDP). In A549 and H1299 cells with MAGI2-AS3 silencing and A549/DDP and H1299/DDP cells overexpressing MAGI2-AS3, the effects of 20 μmol/L DDP on cell viability and apoptosis were examined with CCK-8 assay, colony formation assay, flow cytometry and Western blotting, and the changes in epithelial-mesenchymal transition (EMT) were assessed with wound healing and Transwell assays. The interaction between MAGI2-AS3, miR-1269a and PTEN was predicted using GEPIA, StarBase and miRDB and verified with luciferase reporter gene assay and radioimmunoprecipitation (RIP) assay. A miR-1269a mimic and pcDNA3.1-PTEN plasmid were used to perform the rescue assay.
Results: MAGI2-AS3 expression was significantly downregulated in lung cancer tissues (P < 0.05) in association with a poor prognosis (P < 0.05). In the two DDP-resistant lung cancer cell lines, MAGI2-AS3 expression was significantly lowered as compared with the sensitive cells. Silencing MAGI2-AS3 significantly enhanced cell viability and promoted EMT of A549 and H1299 cells irrespective of DDP treatment, and also decreased DDP-induced apoptosis of the cells. In A549/DDP and H1299/DDP cells, MAGI2-AS3 overexpression strongly repressed cell viability and EMT irrespective of DDP treatment and promoted DDP-induced cell apoptosis. Luciferase reporter gene and RIP assays confirmed the binding of MAGI2-AS3 with miR-1269a and the binding of miR-1269a with 3 '-UTR domain of PTEN. The rescue assay demonstrated that MAGI2-AS3 acted as a sponge for miR-1269a to promote PTEN expression and downregulate AKT phosphorylation, thus inhibiting EMT and promoting DDP-induced apoptosis of A549/DDP cells.
Conclusion: MAGI2-AS3 enhances DDP sensitivity of NSCLC by targeted regulation of the miR-1269a/PTEN/AKT signaling axis.
目的: 研究lncRNA MAGI2-AS3对非小细胞肺癌顺铂耐药的影响及其分子机制。
方法: 采用qRT-PCR 检测MAGI2-AS3和miR-1269a在顺铂敏感细胞（A549，H1299）和顺铂耐药细胞（A549/DDP，H1299/DDP）中的表达差异。采用慢病毒敲低A549和H1299中的MAGI2-AS3的表达，过表达A549/DDP和H1299/DDP中的MAGI2-AS3并加入20 μmol/L顺铂（DDP）处理。A549/DDP和H1299/DDP细胞实验分组为：OE-NC组，OE-MAGI2-AS3组，OE-NC+DDP组，OE-MAGI2-AS3+DDP组，A549和H1299细胞实验分组为：sh-NC组，sh-MAGI2-AS3组，sh-NC+DDP组，sh-MAGI2-AS3+DDP组。CCK-8和细胞克隆形成实验检测细胞存活率，流式细胞术和Western blotting分别检测细胞凋亡率和蛋白表达量，划痕实验和Transwell检测细胞EMT变化。通过网站GEPIA 、StarBase和miRDB预测MAGI2-AS3、miR-1269a和PTEN之间的靶向关系，并采用荧光素酶报告基因实验和RIP实验验证。采用miR-1269a mimic和pcDNA3.1-PTEN进行Rescue实验。
结果: MAGI2-AS3在肺癌组织中的表达显著低于正常癌旁组织（P<0.05）且与患者不良预后相关（P<0.05）。A549/DDP和H1299/DDP中的MAGI2-AS3表达量显著低于A549和H1299（P<0.01）。干扰MAGI2-AS3可以显著促进顺铂处理前、后A549和H1299细胞的存活及EMT进程（P<0.01），同时降低顺铂诱导的细胞凋亡（P<0.005）。过表达MAGI2-AS3可以显著抑制顺铂处理前、后A549/DDP和H1299/DDP细胞存活与EMT进程（P<0.01），同时提升顺铂诱导的细胞凋亡（P<0.005）。MAGI2-AS3与miR-1269a结合在一起，miR-1269a与PTEN 3'UTR结合。在A549/DDP细胞内MAGI2-AS3通过靶向吸附miR-1269a促进PTEN的表达并下调AKT磷酸化从而抑制顺铂刺激下细胞的EMT进程（P<0.01）、促进顺铂诱导的A549/DDP细胞凋亡（P<0.01）。
结论: LncRNA MAGI2-AS3通过靶向调控miR-1269a/PTEN/AKT信号轴增强非小细胞肺癌对顺铂化疗的敏感性。
Keywords: cisplatin resistance; long noncoding RNA MAGI2-AS3; miR-1269a; non-small cell lung cancer.