CASC2 的上调通过海绵吸附 miR-193a-5p 和调节 mTOR 表达来抑制自噬，从而使神经胶质瘤对替莫唑胺的细胞毒性敏感。

Upregulation of CASC2 sensitized glioma to temozolomide cytotoxicity through autophagy inhibition by sponging miR-193a-5p and regulating mTOR expression.

机构信息

Department of Pediatrics, Hangzhou First People's Hospital, Nanjing Medical University, the Fourth Clinical Medical College of Zhejiang Chinese Medicine University, Hangzhou 310003, Zhejiang, PR China.

Department of Psychiatry, Tongde Hospital of Zhejiang Province, Hangzhou 310012, Zhejiang, PR China.

出版信息

Biomed Pharmacother. 2018 Jan;97:844-850. doi: 10.1016/j.biopha.2017.10.146. Epub 2017 Nov 7.

DOI:10.1016/j.biopha.2017.10.146

PMID:29136760

Abstract

OBJECTIVE

Numerous studies suggested autophagy was involved in temozolomide (TMZ) resistance in glioma. Long non-coding RNA (lncRNA) CASC2 was shown to be downregulated in glioma tissues and cell lines, and was related to the TMZ resistance. However, whether CASC2 affects TMZ resistance through regulating autophagy is unknown. The aim of this study was to assess the role and mechanism of CASC2 in TMZ-induced drug resistance in glioma cells.

METHODS

Glioma and the adjacent non-cancerous tissues from 32 patients were collected. The expressions of CASC2 and miR-193a-5p were determined by PCR, and their correlation was analyzed. The correlation between CASC2 expression and the clinical characteristics of patients was also studied. Glioma cells were treated with TMZ to acquire the TMZ-resistant cell lines in which the expressions of CASC2, miR-193a-5p, and mTOR were measured. The regulatory roles of CASC2, miR-193a-5p, and mTOR were defined through the loss of function and luciferase reporter assays. Autophagy was inhibited by autophagy inhibitor 3-MA, CASC2 and mTOR overexpression, or miR-193a-5p inhibitor, and the effect of which on cell viability, apoptosis, and migration of TMZ-resistant glioma cells was evaluated.

RESULTS

CASC2 downregulation and miR-193a-5p upregulation was found to be associated with advanced clinical stage and TMZ response in patients with glioma. CASC2 negatively regulates miR-193a-5p expression by direct interaction in glioma cells. Overexpression of CASC2 or inhibition of miR-193a-5p reduced TMZ-induced autophagy via mTOR upregulation, which makes the glioma cells become sensitive to TMZ cytotoxicity.

CONCLUSION

CASC2 is downregulated in gliomas, resulting in increased miR-193a-5p level and a decrease in mTOR expression, which further induces protective autophagy, leading to TMZ resistance. Inhibition of autophagy helps to increase the efficacy of TMZ.

摘要

目的

许多研究表明自噬参与了胶质瘤中替莫唑胺（TMZ）耐药。长链非编码 RNA（lncRNA）CASC2 在胶质瘤组织和细胞系中表达下调，与 TMZ 耐药有关。然而，CASC2 是否通过调节自噬来影响 TMZ 耐药尚不清楚。本研究旨在评估 CASC2 在 TMZ 诱导的胶质瘤细胞药物耐药中的作用和机制。

方法

收集 32 例患者的胶质瘤和相邻非癌组织。通过 PCR 测定 CASC2 和 miR-193a-5p 的表达，并分析其相关性。还研究了 CASC2 表达与患者临床特征的相关性。用 TMZ 处理胶质瘤细胞，获得 TMZ 耐药细胞系，测定 CASC2、miR-193a-5p 和 mTOR 的表达。通过功能丧失和荧光素酶报告基因检测确定 CASC2、miR-193a-5p 和 mTOR 的调节作用。通过自噬抑制剂 3-MA、CASC2 和 mTOR 过表达或 miR-193a-5p 抑制剂抑制自噬，评估其对 TMZ 耐药胶质瘤细胞活力、凋亡和迁移的影响。

结果

发现 CASC2 下调和 miR-193a-5p 上调与胶质瘤患者的晚期临床分期和 TMZ 反应有关。CASC2 通过直接相互作用在胶质瘤细胞中负调控 miR-193a-5p 的表达。CASC2 的过表达或 miR-193a-5p 的抑制通过上调 mTOR 减少 TMZ 诱导的自噬，使胶质瘤细胞对 TMZ 的细胞毒性敏感。