Large amounts of long non-coding RNAs (lncRNAs) have been annotated whereas most of them have not been functionally characterized. Here we identified lncRNA ENST00000441932 as an oncogenic lncRNA in esophageal squamous cell carcinoma (ESCC) and named lnc-MCEI (lncRNA mediated the chemosensitivity of ESCC by regulating IGF2). What's more, the effect of lnc-MCEI on the chemosensitivity of ESCC was further evaluated. Bioinformatics analysis demonstrated that lnc-MCEI was involved in the tumorigenesis of ESCC and lnc-MCEI levels were significantly increased in ESCC cells and tissues. Additionally, lnc-MCEI knockdown retarded cell proliferation, colony formation of ESCC cells, but induced cell apoptosis. Moreover, lnc-MCEI knockdown significantly improved the chemosensitivity of ESCC to cisplatin (DDP) both in vivo and in vitro. Further mechanisms disclosed that lnc-MCEI functioned as a competing endogenous RNA (ceRNA) via sponging miR-6759-5p and IGF2 was a target of miR-6759-5p. Meanwhile, we found that IGF2 suppressed chemosensitivity of ESCC cells via PI3K/AKT pathway. These data suggested that lnc-MCEI was an oncogenic lncRNA and lnc-MCEI knockdown enhanced chemosensitivity of ESCC cells to cisplatin by targeting miR-6759-5p /IGF2/PI3K/AKT axis.

中文翻译：

---

Lnc-MCEI通过miR-6759-5p介导食管鳞状细胞癌的化学敏感性以竞争性调节IGF2

大量长链非编码 RNA (lncRNA) 已被注释，而其中大多数尚未进行功能表征。在这里，我们将 lncRNA ENST00000441932 鉴定为食管鳞状细胞癌 (ESCC) 中的致癌 lncRNA，并命名为lnc - MCEI （lnc RNA通过调节IGF2)。此外，进一步评估了lnc-MCEI对ESCC化疗敏感性的影响。生物信息学分析表明，lnc-MCEI参与了ESCC的肿瘤发生，并且在ESCC细胞和组织中lnc-MCEI水平显着升高。此外，lnc-MCEI 敲低延缓了细胞增殖和 ESCC 细胞的集落形成，但诱导了细胞凋亡。此外，lnc-MCEI 敲低显着提高了 ESCC在体内和体外对顺铂 (DDP) 的化学敏感性. 进一步的机制表明，lnc-MCEI 通过海绵化 miR-6759-5p 发挥竞争性内源性 RNA (ceRNA) 的作用，而 IGF2 是 miR-6759-5p 的靶标。同时，我们发现IGF2通过PI3K/AKT通路抑制ESCC细胞的化学敏感性。这些数据表明lnc-MCEI是一种致癌lncRNA，lnc-MCEI敲低通过靶向miR-6759-5p/IGF2/PI3K/AKT轴增强了ESCC细胞对顺铂的化学敏感性。