Downregulation of lncRNA X Inactive Specific Transcript (XIST) Suppresses Cell Proliferation and Enhances Radiosensitivity by Upregulating mir-29c in Nasopharyngeal Carcinoma Cells

作者：Qian Han, Liang Li, Hengpo Liang, Yaqiong Li, Jiacun Xie, Zhibin Wang · 发表于：Medical Science Monitor · 年份：2017 · DOI：10.12659/msm.905370 · 被引用次数：30 · 研究领域：Cancer-related molecular mechanisms research、RNA Research and Splicing、Circular RNAs in diseases

BACKGROUND LncRNA X inactive specific transcript (XIST) was reported to function as an oncogene in nasopharyngeal carcinoma cells (NPC) by sponging miR-34a-5p. However, the role of XIST in modulating the radiosensitivity of NPC cells and its mechanism still remain undefined. MATERIAL AND METHODS The expressions of XIST and miR-29c in NPC cells were evaluated by qRT-PCR. CNE1 and CNE2 cells were transfected with si-XIST, pcDNA-XIST, miR-29c mimics, anti-miR-29c, or respective controls by Lipofectamine 2000. The effects of XIST knockdown and miR-29c overexpression on cell proliferation, survival fraction, and γ-H2AX expression were investigated by CCK-8 assay, colony formation assay, immunofluorescence, and Western blot, respectively. Luciferase reporter assay and qRT-PCR analysis were performed to confirm whether XIST interacts with miR-29c and regulates its expression. RESULTS XIST was upregulated and miR-29c was downregulated in NPC cells. The expressions of XIST and miR-29c changed reversely in response to irradiation. Knockdown of XIST and miR-29c overexpression both resulted in a dramatic suppression of cell proliferation, a marked enhancement of radiosensitivity, and an obvious increase of γ-H2AX foci formation in NPC cells. Luciferase reporter assay and qRT-PCR analysis demonstrated that XIST interacts with miR-29c and negatively regulates its expression. Moreover, miR-29c inhibition abrogated XIST knockdown-induced cell proliferation inhibition and radiosensitivity inc...