Wang Pei, Chen Dong, Ma Hongbing, Li Yong
Department of Cardiothoracic Surgery, Huaihe Hospital of Henan University, Kaifeng, People's Republic of China.
Onco Targets Ther. 2017 Oct 25;10:5137-5149. doi: 10.2147/OTT.S146423. eCollection 2017.
Long noncoding RNAs (lncRNAs) have been revealed to play essential role in drug resistance of multiple cancers. LncRNA MEG3 was previously reported to be associated with cisplatin (DDP) resistance in non-small cell lung cancer (NSCLC) cells. However, the molecular mechanism of MEG3 affecting DDP resistance in NSCLC remains to be further illustrated. In this study, we attempted to discuss whether MEG3 also could function as a competing endogenous RNA to regulate DDP resistance in NSCLC.
The expression of MEG3, miR-21-5p, and sex-determining region Y-box 7 (SOX7) in NSCLC tissues or cells was examined by quantitative real-time polymerase chain reaction (qRT-PCR). 3-(4,5-Dimethylthazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), flow cytometry, and caspase-3 activity analysis were applied to assess the DDP sensitivity of NSCLC cells. The interaction between MEG3, miR-21-5p, and SOX7 was explored by luciferase reporter assay, RNA immunoprecipitation (RIP) assay, qRT-PCR, and Western blot. Mouse NSCLC transplanted tumor was established to verify the functional role of MEG3 in DDP resistance in vivo.
MEG3 was downregulated in DDP-resistant NSCLC cells. Overexpression of MEG3 enhanced DDP sensitivity of NSCLC cells in vitro. MEG3 directly interacted with miR-21-5p and suppressed its expression. miR-21-5p significantly abolished the effects of MEG3 on DDP resistance via modulating cell proliferation and apoptosis. SOX7 was identified as a direct target of miR-21-5p and MEG3 positively regulated SOX7 expression by suppressing miR-21-5p. Moreover, MEG3 knockdown-induced pro-proliferative and anti-apoptotic effects were reversed in DDP-resistant NSCLC cells by upregulating SOX7. Furthermore, upregulation of MEG3 induced sensitivity of NSCLC cells to DDP in vivo.
MEG3 overexpression induced DDP sensitivity of NSCLC cells by regulating miR-21-5p/SOX7 axis, shedding light on the molecular mechanism of MEG3 involved in the development of DDP resistance of NSCLC cells.
长链非编码RNA（lncRNA）已被揭示在多种癌症的耐药性中发挥重要作用。先前有报道称lncRNA MEG3与非小细胞肺癌（NSCLC）细胞中的顺铂（DDP）耐药性有关。然而，MEG3影响NSCLC中DDP耐药性的分子机制仍有待进一步阐明。在本研究中，我们试图探讨MEG3是否也可作为竞争性内源性RNA来调节NSCLC中的DDP耐药性。
通过定量实时聚合酶链反应（qRT-PCR）检测NSCLC组织或细胞中MEG3、miR-21-5p和性别决定区Y框7（SOX7）的表达。应用3-(4,5-二甲基噻唑-2-基)-2,5-二苯基四氮唑溴盐（MTT）、流式细胞术和半胱天冬酶-3活性分析来评估NSCLC细胞对DDP的敏感性。通过荧光素酶报告基因检测、RNA免疫沉淀（RIP）检测、qRT-PCR和蛋白质免疫印迹法探索MEG3、miR-21-5p和SOX7之间的相互作用。建立小鼠NSCLC移植瘤以验证MEG3在体内对DDP耐药性的功能作用。
MEG3在DDP耐药的NSCLC细胞中表达下调。MEG3过表达增强了NSCLC细胞在体外对DDP的敏感性。MEG3直接与miR-21-5p相互作用并抑制其表达。miR-21-5p通过调节细胞增殖和凋亡显著消除了MEG3对DDP耐药性的影响。SOX7被鉴定为miR-21-5p的直接靶标，MEG3通过抑制miR-21-5p正向调节SOX7的表达。此外，通过上调SOX7，在DDP耐药的NSCLC细胞中，MEG3敲低诱导的促增殖和抗凋亡作用被逆转。此外，MEG3的上调在体内诱导了NSCLC细胞对DDP的敏感性。
MEG3过表达通过调节miR-21-5p/SOX7轴诱导NSCLC细胞对DDP的敏感性，为MEG3参与NSCLC细胞DDP耐药性发展的分子机制提供了线索。
