lncRNA-MIR99AHG与PTBP1相互作用调控TKS5的选择性剪接促进结直肠癌细胞侵袭性伪足形成的分子机制研究

侵袭性伪足在肿瘤转移早期发挥重要作用，但调控机制尚不清楚。申请人通过比对高低转移潜能的结直肠癌细胞系的lncRNA表达谱，发现lncRNA分子MIR99AHG在高转移细胞和患者转移灶中显著升高，过表达MIR99AHG能促进转移和侵袭性伪足形成，并改变伪足关键效应分子TKS5不同剪接异构体的组成性表达，这一效应与MIR99AHG的相互作用分子即选择性剪接调控因子PTBP1相关，高度提示MIR99AHG可能通过PTBP1调控TKS5的选择性剪接，从而促进侵袭性伪足形成和肿瘤转移。本项目拟通过临床标本和队列数据，明确MIR99AHG在结直肠癌的表达模式；通过体内外功能实验，明确MIR99AHG在结直肠癌转移中的生物学功能；通过分子间相互作用研究，阐明MIR99AHG通过PTBP1调控TKS5选择性剪接的作用机制。本项目将揭示非编码RNA调控侵袭性伪足的新机制，为结直肠癌转移的临床诊疗提供新策略。

The formation of invadopodia by cancer cells plays an important role in the early stage of metastasis. However, the underlying regulatory mechanisms remain unclear. By comparing the lncRNA expression profiles between a pair of colorectal cancer cell lines with high and low metastatic potential, we found that MIR99AHG was significantly increased in high metastatic cancer cells and tissues from patients. Overexpression of MIR99AHG could significantly promote cell migration and invasion. MIR99AHG could interact with PTBP1, which is an important regulator of alternative splicing, and change the isoform expression ratio of the key effector molecule TKS5 of invadopodia. Our results highly suggest that MIR99AHG regulates the alternative splicing of TKS5 through PTBP1, affects the formation of invadopodia and promotes metastasis. This project intends to clarify the expression pattern of MIR99AHG in colorectal cancer through clinical specimens and cohort data, and to evaluate its clinical usages as a predictor and diagnostic biomarker in metastasis. Through in vivo and in vitro functional experiments, the biological functions of MIR99AHG in colorectal cancer will be determined. Through study of the interaction between molecules, the mechanisms of MIR99AHG in promoting the alternative splicing of TKS5 through PTBP1 will be elucidated. This project will deepen our understanding of lncRNA regulation in invadopodia formation and metastasis, and help to provide new strategies for the diagnosis and treatment of metastatic colorectal cancer.