MiR-21會誘發miR-184抑制CDC25A和c-MYC之表現促進非小細胞肺癌腫瘤惡化

MiR-184 Deregulated by the MiR-21 Promotes Tumor Malignancy and Poor Outcomes in Non-small Cell Lung Cancer via Targeting CDC25A and c-Myc

林倉祺(Tsang-Chi Lin)

指導教授 ： 周明智 ； 李輝

中山醫學大學/醫學院/醫學研究所/博士(2016年)

摘要

景. 已知微小RNA-184 (miR-184)在人類癌症之發展具有雙重角色。但miR-184在非小細胞肺癌(Non-small cell lung cancer, SCLC)之角色仍不清楚。
方法. 分別構築wild-type和mutant CDC25A報導基因質體以驗證miR-184是否在後轉錄層次影響CDC25A表現，以及利用 Boyden chamber分析miR-184是否透過CDC25A 和c-Myc而影響細胞侵襲能力。以定量PCR方式分析124個非小細胞肺癌檢體中miR-184、miR-21、PDCD4、c-Myc、CDC25A mRNA之表現，以Kaplan-Meier和Cox regression統計分析這些基因表現對臨床肺癌病人存活率(Overall survival, OS)和無復發存活率(Relapse-free survival, RFS)之影響。
結果. MiR-184 會結合CDC25A 編碼區(coding region)造成CDC25A mRNA不穩定而抑制其表現，反之，降低miR-184會使CDC25A表現量和細胞侵襲能力增強。MiR-21/PDCD4會引起miR-184表現量降低，造成CDC25A和c-Myc表現增加，而促進肺癌細胞之侵襲能力。肺癌患者miR-184表現量和miR-21、CDC25A、 c-Myc mRNA負相關性，但和PDCD4 mRNA呈現正相關性。肺癌病患High-CDC25A或high-c-Myc mRNA 相較於對照組 (Low-CDC25A或Low-c-Myc)，有較短存活率(OS)和無復發存活率(RFS)。患者具有low-miR-184/high-CDC25A/high-c-Myc 腫瘤有最差的存活率，其次依序為low-miR-184 /high-CDC25A、low-miR-184/high-c-Myc、high-c-Myc、high-CDC25A。
結論. MiR-184在非小細胞肺癌扮演抑癌角色，會經由抑制 CDC25A和c-Myc表現，而抑制腫瘤細胞之增生和侵襲，因此miR-184表現量低的非小細胞肺癌患者可能有較差的臨床預後。

關鍵字

非小細胞肺癌 ； 微小RNA-184 ； 微小RNA-21 ； 細胞侵襲

並列摘要

Background. MicroRNA (miR)-184 has been reported to have a dual role in human cancers. However, the role of miR-184 in non-small cell lung cancer (NSCLC) remains unclear.
Methods. Wild-type or mutant CDC25A promoters were constructed by PCR and site-directed mutagenesis to verify whether miR-184 could inhibit CDC25A expression at post-transcription level. Boyden chamber assay was used to assess whether miR-184 could modulate cell invasiveness via targeting CDC25A and c-Myc. We utilized 124 tumors from NSCLC patients to determine miR-184, miR-21, PDCD4 mRNA, c-Myc mRNA, and CDC25A mRNA expression levels by means of real-time PCR analysis. The prognostic value of CDC25A, c-Myc, and miR-184 on overall survival (OS) and relapse-free survival (RFS) was evaluated by Kaplan–Meier and Cox regression analysis.
Results. MiR-184 suppressed CDC25A expression by enhancing the instability of its mRNA as a result of miR-184 binding to its coding region. An increase in CDC25Aexpression by means of a reduction in miR-184 promotes cell invasiveness. Moreover, a concomitant increase in CDC25A and c-Myc expression as a result of decreased miR-184 via the miR-21-mediated PDCD4 reduction is responsible for cell invasiveness. Among patients, miR-184 expression in lung tumors was found to correlate negatively with CDC25A mRNA, c-Myc mRNA, and miR-21 expression, but was positively related to PDCD4 mRNA expression. High-CDC25A, or high-c-Myc mRNA tumors exhibited shorter OS and RFS periods than their counterparts. The worst OS and RFS were observed in low-miR-184/high-CDC25A/high-c-Myc tumors, followed by low-miR-184 /high-CDC25A, low-miR-184/high-c-Myc, high-c-Myc, and high-CDC25A tumors.
Conclusions. MiR-184 as a tumor suppressor miR inhibits cell proliferation and invasion capability via targeting CDC25A and c-Myc. Low miR-184 level may predict worse prognosis in NSCLC patients.

並列關鍵字

NSCLC ； micro-RNA-184 ； micro-RNA-21 ； Invasion

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