环状 RNA（circRNA）-PGAM1 通过调控 miR-542-3p/CDC5L/PEAK1 通路促进上皮性卵巢癌的恶性进展。
Circ-PGAM1 promotes malignant progression of epithelial ovarian cancer through regulation of the miR-542-3p/CDC5L/PEAK1 pathway.
机构信息
Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, Shenyang, China.
出版信息
Cancer Med. 2020 May;9(10):3500-3521. doi: 10.1002/cam4.2929. Epub 2020 Mar 13.
BACKGROUND
Epithelial ovarian cancer (EOC) is the most common ovarian malignant cancer. Circular RNA is a type of endogenous noncoding RNA and is considered as a novel regulatory molecule in the development and progression of tumors. This study investigated the expression and functions of a circular RNA, circular-phosphoglycerate mutase 1 (circ-PGAM1), in EOC tissues and cells.
METHODS
The expression of circ-PGAM1 and miR-542-3p in EOC was analyzed using quantitative RT-PCR. Immunohistochemistry and western blot were performed to confirm the localization and expression of cell division cycle 5-like (CDC5L) and pseudopodium enriched atypical kinase 1 (PEAK1) in EOC tissues. Cell lines (CAOV3 and OVCAR3) overexpressing or silencingcirc-PGAM1 and miR-542-3p were established to explore the functions of circ-PGAM1 and miR-542-3p in ovarian cancer cells. Furthermore, dual-luciferase reporter assay was performed to study the interactions between circ-PGAM1 and miR-542-3p and between miR-542-3p and CDC5L. CCK-8, transwell, and flow cytometry were used to study the effect of circ-PGAM1 and miR-542-3p on cell biological behaviors including proliferation, migration, invasion, and apoptosis. The interaction between CDC5L and the PEAK1 gene promoter was confirmed using chromatin immunoprecipitation (ChIP).
RESULTS
Circ-PGAM1 was upregulated in EOC tissues, whereas linear PGAM1 was not deregulated in EOC tissues. Silencing of circ-PAGM1 inhibited proliferation, migration, and invasion of ovarian cancer cells and promoted cell apoptosis. MiR-542-3p was downregulated in EOC tissues, and miR-542-3p overexpression inhibited malignant progression of ovarian cancer cells. Circ-PGAM1 directly interacted with miR-542-3p, with mutual negative feedback between them. CDC5L was a direct target of miR-542-3p and played an oncogenic role in ovarian cancer cells. Furthermore, the CDC5L protein binds directly to the PEAK1 promoter to promote its transcription. PEAK1 overexpression activated ERK1/2 and JAK2 signaling pathways and promoted malignant biological behaviors of ovarian cancer cells. Circ-PAGM1 silencing combined with miR-542-3p overexpression played the greatest anticancer role in vivo.
CONCLUSION
The circ-PGAM1/miR-542-3p/CDC5L/PEAK1 pathway played an important role in the progression of ovarian cancer and might be a novel therapeutic target for ovarian cancer.
背景
上皮性卵巢癌（EOC）是最常见的卵巢恶性肿瘤。环状 RNA 是一种内源性非编码 RNA，被认为是肿瘤发生和发展中一种新的调节分子。本研究探讨了环状 RNA、磷酸甘油酸变位酶 1（circ-PGAM1）在上皮性卵巢癌组织和细胞中的表达和功能。
方法
采用定量 RT-PCR 分析 EOC 中 circ-PGAM1 和 miR-542-3p 的表达。免疫组织化学和 Western blot 用于证实细胞分裂周期 5 样蛋白（CDC5L）和假足富集的非典型激酶 1（PEAK1）在 EOC 组织中的定位和表达。建立过表达或沉默 circ-PGAM1 和 miR-542-3p 的卵巢癌细胞系（CAOV3 和 OVCAR3），以探讨 circ-PGAM1 和 miR-542-3p 在卵巢癌细胞中的功能。此外，还进行了双荧光素酶报告基因实验来研究 circ-PGAM1 和 miR-542-3p 之间以及 miR-542-3p 和 CDC5L 之间的相互作用。CCK-8、Transwell 和流式细胞术用于研究 circ-PGAM1 和 miR-542-3p 对细胞增殖、迁移、侵袭和凋亡等生物学行为的影响。利用染色质免疫沉淀（ChIP）实验证实了 CDC5L 与 PEAK1 基因启动子之间的相互作用。
结果
circ-PGAM1 在 EOC 组织中上调，而线性 PGAM1 在 EOC 组织中未失调。沉默 circ-PAGM1 抑制卵巢癌细胞的增殖、迁移和侵袭，并促进细胞凋亡。miR-542-3p 在 EOC 组织中下调，miR-542-3p 过表达抑制卵巢癌细胞的恶性进展。circ-PGAM1 与 miR-542-3p 直接相互作用，它们之间存在相互负反馈。CDC5L 是 miR-542-3p 的直接靶标，在卵巢癌细胞中发挥致癌作用。此外，CDC5L 蛋白直接结合到 PEAK1 启动子上，促进其转录。PEAK1 的过表达激活了 ERK1/2 和 JAK2 信号通路，并促进了卵巢癌细胞的恶性生物学行为。circ-PAGM1 沉默联合 miR-542-3p 过表达在体内发挥最大的抗癌作用。
结论
circ-PGAM1/miR-542-3p/CDC5L/PEAK1 通路在上皮性卵巢癌的进展中起重要作用，可能成为卵巢癌的一种新的治疗靶点。
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