miR-223在MEF2A调控下通过FBXO8和Akt/mTOR信号通路参与结直肠癌侵袭和转移的分子机制

预实验中我们筛选出miR-223为一个结直肠癌转移候选miRNA，发现miR-223能促进结直肠癌细胞的体外侵袭能力；根据生物信息学分析及预实验结果，我们提出了一个新的miR-223调控机制：即miR-223在MEF2A转录调控下，通过靶基因FBXO8及Akt/mTOR信号通路促进结直肠癌侵袭和转移。本项目拟验证这一机制，利用miRNA转染、干扰、荧光素酶报告系统、体内外侵袭及转移实验等进行（1）确认MEF2A是miR-223的上游转录因子，miR-223调控靶基因FBXO8及Akt/mTOR信号通路；（2）检测FBXO8及Akt/mTOR通路在miR-223诱导结直肠癌侵袭和转移中的作用；（3）证实FBXO8是miR-223的功能靶基因。旨在揭示一个新的miR-223表达调控机制，阐明miR-223在结直肠癌演进中的作用机制，为临床抗结直肠癌侵袭、转移提供新的miRNA和基因靶点。

Our previous study showed that miR-223 was a metastasis associated miRNA of colorectal carcinoma. miR-223 promoted cancer cell invasion in vitro. Based on the bioinformatic analyses and preliminary experiments, we proposed a novel regulatory mechanism of miR-223, that miR-223, transcriptionally regulated by MEF2A, promotes invasion and metastasis of colorectal carcinoma by targeting FBXO8 and Akt/mTOR signaling pathway. To validate this mechanism, miRNA transfection, interference, luciferase reporter system and experiments in vitro and in vivo are performed (1) To confirm that miR-223 is targeted by transcription factor MEF2A, and miR-223 regulates FBXO8 and Akt/mTOR signaling pathway; (2) To detect the effects of FBXO8 and Akt/mTOR pathway on the invasion and metastasis of colorectal carcinoma induced by miR-223; (3) To confirm that FBXO8 is a functional targeted gene of miR-223. Our study aims to reveal a novel regulatory mechanism of miR-223, to illustrate the molecular mechanism of miR-223 in the progression of colorectal carcinoma, and to provide the novel miRNA or gene target for clinical intervention of invasion and metastasis of colorectal carcinoma.