miR-499-5p-FOXO4-miR-185轴调控结肠癌EMT和转移的机制研究

Metastasis is a critical problem which Leads to poor prognosis of colorectal cancer (CRC). Epithelial mesenchymal transition (EMT) is recently viewed as an essential early step in tumor metastasis and the dominant program in human colon cancer. Most recently, several microRNAs(miRNAs) were found to be important modulators of tumor metastasis by targeting EMT-related pathway. Our previous study showed that miR-499-5p and miR-185 regulated metastasis in CRC by promoting or resisting EMT respectively,and they may, respectively, function through the regulation of FOXO4 and STIM1.Bioinformatics analysis found that FOXO4 is the potential transcription factor of miR-185. The project intends to use EMT chips and iTRAQ technology to comprehensively screen other important target genes of miR-499-5p and miR-185, and apply CHIP, EMSA and other technologies to study the transcriptional regulation mechanism. The purpose of this project is to clarify the specific molecular mechanism of miR-499-5p and miR-185 in regulating EMT and metastasis of CRC, and to provide new targets for the intervention of CRC metastasis.

转移是导致结肠癌预后不良的关键问题。上皮间质转化（EMT）是肿瘤转移的关键启动步骤，其在结肠癌进展中起主导作用。新近研究表明，miRNA在肿瘤EMT发生中发挥重要作用。本项目前期发现miR-499-5p和miR-185可以分别促进和抑制结肠癌EMT表型，肿瘤EMT相关重要分子FOXO4是miR-499-5p的靶基因，同时也是miR-185的潜在转录因子，钙信号关键分子STIM1是miR-185的潜在靶基因。为明确miR-499-5p-FOXO4-miR-185轴调控结肠癌EMT的具体生物学功能及其分子机制，本项目拟进一步采用EMT芯片和iTRAQ蛋白组学技术全面筛选和验证miR-499-5p-FOXO4-miR-185轴下游的其他重要靶基因，为逆转结肠癌EMT、干预结肠癌转移提供新的分子靶点和新的策略。

结肠癌转移的具体分子机制仍不清楚。本项目旨在研究miR-499-5p-FOXO4-miR-185分子轴在结肠癌转移及EMT中的功能及分子机制。STIM1是该信号相关的关键分子，在肿瘤发生发展中起重要作用。STIM1是本项目前期预测到的miR-499-5p-FOXO4-miR-185分子轴的潜在靶基因，它是细胞内介导钙信号的关键分子，与肿瘤生物学行为密切相关，其在结肠癌转移中的分子机制尚不明确。本项目中，我们研究发现STIM1在结肠癌高转移细胞系及组织中相对高表达，其可以显著促进结肠癌细胞的侵袭与转移，正向调控EMT，并与结肠癌的转移与预后密切相关。本项目进一步筛选发现肿瘤相关重要分子YWHAZ是miR-499-5p-FOXO4-miR-185分子轴的关键下游靶基因，其部分介导了该分子轴在结肠癌转移与EMT中的功能。本项目的研究成果有望为结肠癌防治提供新的分子靶点及分子标志物。