环状RNA circ_000926介导的TR4促进肾细胞癌侵袭转移的机制研究

The metastatic renal cell carcinoma (RCC) resists to both radio- and chemo-therapy and has become a major obstacle in the treatment of RCC, thus its metastatic mechanism becomes a research focus of the present study. Our previous work suggest that high expression of the testicular nuclear receptor 4 (TR4) may promote the migration and invasion of RCC. Through circRNA chip screening of TR4 differentially expressed cells, we found that circ_000926 decreased in TR4 knocked-down cells and circ_000926 was involved in RCC metastasis. Thus we speculate that TR4 may promote RCC metastasis through upregulating circ_000926 expression. Our study aims to probe the role of TR4/circ_000926 signaling pathway in migration and invasion of RCC, to explore its possible mechanism from the molecular, cellular, creatural and clinical fields. Insight in to the molecular mechanism of RCC metastasis may provide novel ideas and theoretical basis of therapeutic targets for kidney cancer.

转移性肾癌对放化疗均不敏感，是目前肾癌治疗中的难点，因此肾癌转移的机制已成为当下研究的焦点。我们前期研究发现：睾丸孤核受体4（TR4）高表达促进肾细胞癌侵袭转移；TR4差异表达肾癌细胞circRNA芯片筛选表明circ_000926在TR4敲低细胞中低表达；体外实验提示circ_000926与肾癌细胞的侵袭转移相关。因此，我们认为TR4可能通过上调circ_000926的表达从而促进肾癌的转移。本课题拟通过一系列体内外实验，综合运用CRISPR、RNA-IP、circRNA敲低与过表达、裸鼠原位肾癌移植模型、双荧光素酶报告基因等技术，从细胞、动物、临床多个层次研究TR4在肾癌转移中的作用，阐明TR4调控circ_000926影响肾癌转移的具体分子机制，为转移性肾癌的诊治提供新的思路和理论依据。

转移性肾癌是目前肾癌治疗中的难点，深入研究肾癌转移的机制，寻求更好的转移性肾癌的治疗方法显得尤为重要。环状RNA (circRNA)是一种特殊的选择性剪接产生的环状内源性RNA，参与多种疾病的进展。然而，circRNA在透明细胞肾细胞癌(ccRCC)中的作用至今鲜有报道。我们采用环状RNA芯片检测筛选ccRCC中异常表达的circRNA，发现circ-AKT3在ccRCC癌组织低表达。随后大样本组织RT-qPCR验证显示circ-AKT3在ccRCC组织呈低表达，且circ-AKT3在ccRCC细胞株中的表达水平显著低于人正常肾细胞(HK-2)。Circ-AKT3表达水平与临床病理的相关性分析显示circ-AKT3与ccRCC的恶性程度负相关。体外和体内研究显示circ-AKT3可抑制ccRCC转移，暨敲低circ-AKT3可促进ccRCC的迁移和侵袭，而过表达circ-AKT3可抑制ccRCC的转移。进一步机制研究表明Circ-AKT3通过竞争性结合miR-296-3p，增强E-cadherin表达，从而抑制ccRCC转移。因此，Circ-AKT3是ccRCC恶性程度的潜在标记物，并有望作为一种新的治疗手段更好地抑制ccRCC转移。