环状RNA circRhoC内源性竞争micRNA185/302/1249调控其靶基因VEGF影响卵巢癌发生、发展的分子机制解析

Ovarian cancer is a malignant tumor with serious threaten to women health, studies have shown that circRNAs could sponge adsorpt miRNAs to relieve its inhibition to the downstream proteins, and involved in the tumorigenesis and progression of cancer. Our previous studies have shown that RhoC promoted ovarian carcinogenesis, invasion and metastasis, and could form the circular structure circRhoC (circ_0013549), which was overexpressed in ovarian cancer tissue. Knocking down circRhoC in ovarian cancer cells could inhibit cell proliferation, migration and invasive ability, while promote apoptosis. Bioinformatics analysis demonstrated that there were binding sites for miR-185, miR-302, miR-1249 near the splice sites of circRhoC, and the three miRNAs also had binding sites in the 3'UTR region of VEGF. Therefore, we suggest that circRhoC may endogenously competitively inhibit miR-185/302/1249, relieves their inhibition to VEGF gene and promote the occurrence and development of ovarian cancer. This study intends to use a variety of biological techniques and methods to comprehensive verificat this hypothesis from the histology, cytology, and animal model, and study the molecular mechanism of tumorigenesis and progression of ovarian cancer in-depth.

卵巢癌是严重威胁女性健康的恶性肿瘤，研究表明环状RNA能够海绵吸附miRNA，解除其对下游蛋白的抑制，参与癌症发生发展。我们前期研究发现RhoC促进卵巢癌的发生及侵袭转移，并且能够反向剪切形成环状结构circRhoC（circ_0013549），其在卵巢癌组织中高表达，在卵巢癌细胞中敲低circRhoC，能抑制细胞增殖、迁移和侵袭能力，促进凋亡。生物信息学分析circRhoC的剪接位点处存在miR-185、miR-302、miR-1249结合位点，而上述三种miRNA在VEGF的3’UTR区均存在结合位点。因此我们提出假说： circRhoC能够内源竞争抑制miR-185/302/1249，解除其对VEGF基因的抑制，促进卵巢癌的发生和发展。本研究拟运用多种生物学技术和方法，从组织学，细胞学，动物模型进行多角度多层次全面验证此假说，深入探讨卵巢癌发生发展的分子机制。

卵巢癌是女性生殖系统常见的恶性肿瘤，其致死率居妇科恶性肿瘤首位。近年来多项研究发现环状RNA在包括卵巢癌在内的多种恶性肿瘤发生发展进程中发挥重要作用。本研究发现RhoC基因通过反向剪切形成的环状结构circRhoC在卵巢癌组织中表达水平显著高于正常组织，且其表达与卵巢癌的分期及分化相关。在卵巢癌细胞CAOV3中，circRhoC过表达可促进细胞增殖、迁移、侵袭。而在细胞系A2780中沉默circRhoC后结果相反。通过裸鼠腹腔注射实验，我们发现circRhoC的下调减弱了卵巢癌细胞在腹膜内的传播。此外，本研究证实circRhoC主要通过海绵吸附miR-302e，减少miR-302e对VEGFA的抑制作用，以及直接与VEGFA结合并调控其表达，进而促进卵巢癌的发生发展。除此之外，本研究还发现了其他在卵巢癌发生发展过程中起调控作用的环状RNA，如：circ-CSPP1、circ-WHSC1、circPUM1及circ-NOLC1。本研究的顺利实施，将丰富卵巢癌发生发展的理论研究，并可能为其阻断治疗提供新的靶点。