miR-34c 下调导致鼻咽癌细胞中 SOX4 过表达和顺铂耐药。
MiR-34c downregulation leads to SOX4 overexpression and cisplatin resistance in nasopharyngeal carcinoma.
机构信息
Princess Margaret Cancer Centre, University Health Network, Toronto, Canada.
Department of Medical Biophysics, University of Toronto, Toronto, Canada.
出版信息
BMC Cancer. 2020 Jun 26;20(1):597. doi: 10.1186/s12885-020-07081-z.
BACKGROUND
A major cause of disease-related death in nasopharyngeal carcinoma (NPC) is the development of distant metastasis (DM) despite combination chemoradiotherapy treatment. We previously identified and validated a four microRNA (miRNA) signature that is prognostic for DM. In this study, characterization of a key component of this signature, miR-34c, revealed its role in chemotherapy resistance.
METHODS
Two hundred forty-six NPC patient biopsy samples were subject to comprehensive miRNA profiling and immunohistochemistry (IHC). Two human normal nasopharyngeal cell lines (immortalized; NP69 and NP460), as well as the NPC cell line C666-1, were used for miR-34c gain-of-function and loss-of-function experiments. Signaling pathways were assessed using quantitative real-time PCR (qRT-PCR) and Western blot. Cell viability was measured using the ATPlite assay.
RESULTS
MiR-34c was downregulated in NPC patient samples, and confirmed in vitro to directly target SOX4, a master regulator of epithelial-to-mesenchymal transition (EMT). MiR-34c downregulation triggered EMT-representative changes in NP69 and NP460 whereby Snail, ZEB1, CDH2, and SOX2 were upregulated, while Claudin-1 and CDH1 were downregulated. Phenotypically, inhibition of miR-34c led to cisplatin resistance, whereas miR-34c over-expression sensitized NPC cells to cisplatin. TGFβ1 decreased miR-34c and increased SOX4 expression in vitro. The TGFβ receptor 1 inhibitor SB431542 reduced SOX4 expression and increased cisplatin sensitivity. Finally, IHC revealed that lower SOX4 expression was associated with improved overall survival in chemotherapy-treated NPC patients.
CONCLUSION
miR-34c is downregulated in NPC. Repression of miR-34c was shown to increase SOX4 expression, which leads to cisplatin resistance, while TGFβ1 was found to repress miR-34c expression. Taken together, our study demonstrates that inhibition of the TGFβ1 pathway could be a strategy to restore cisplatin sensitivity in NPC.
背景
尽管采用了联合放化疗治疗，鼻咽癌（NPC）患者疾病相关死亡的一个主要原因仍是远处转移（DM）的发生。我们之前已经确定并验证了一个与 DM 预后相关的四 miRNA（miRNA）特征。在这项研究中，对该特征的一个关键组成部分miR-34c 进行了表征，揭示了其在化疗耐药中的作用。
方法
对 246 例 NPC 患者活检样本进行了全面 miRNA 谱分析和免疫组织化学（IHC）检测。使用了 2 个人类正常鼻咽细胞系（永生化；NP69 和 NP460）以及 NPC 细胞系 C666-1 进行 miR-34c 的功能获得和功能丧失实验。使用定量实时 PCR（qRT-PCR）和 Western blot 检测信号通路。通过 ATP 荧光检测法测量细胞活力。
结果
miR-34c 在 NPC 患者样本中下调，并在体外证实其直接靶向 SOX4，后者是上皮间质转化（EMT）的主要调节因子。miR-34c 的下调导致 NP69 和 NP460 中 EMT 代表性变化，从而上调 Snail、ZEB1、CDH2 和 SOX2，而下调 Claudin-1 和 CDH1。表型上，抑制 miR-34c 导致顺铂耐药，而过表达 miR-34c 则使 NPC 细胞对顺铂敏感。TGFβ1 在体外降低 miR-34c 的表达并增加 SOX4 的表达。TGFβ 受体 1 抑制剂 SB431542 降低 SOX4 的表达并增加顺铂敏感性。最后，IHC 显示，化疗治疗的 NPC 患者中 SOX4 表达较低与总体生存改善相关。
结论
miR-34c 在 NPC 中下调。抑制 miR-34c 被证明可增加 SOX4 的表达，从而导致顺铂耐药，而 TGFβ1 被发现可抑制 miR-34c 的表达。综上所述，我们的研究表明，抑制 TGFβ1 通路可能是恢复 NPC 中顺铂敏感性的一种策略。
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