缺氧诱导Hif-3α转录调控RhoC/ROCK1-LIMK1-CFL1信号通路增强胰腺癌的侵袭转移

It’s still a hard work to cure the pancreatic cancer with high invasive and metastatic characteristics. That the mesenchymal–amoeboid transition of tumor cell can contribute to its high-speed migration and metastasis is commonly believed, and that’s dependented on Rho / ROCK signaling pathway for the regulation of F-actin. Our preliminary study confirms that the newly discovered hypoxia-inducible HIF-3α has caused a lot of F-actin to gather on the inside of the cell membrane and significantly enhanced the invasion and metastasis of pancreatic cancer cells . Bioinformatics analysis suggests that RhoC, ROCK1 and CFL1 promoter regions contain HIF-3α transcription binding sites HREs. Pre-experiments suggest HIF3α can increase RhoC expression and activity. Therefore, we propose hypotheses that transcriptional regulation of hypoxia-inducible HIF-3α targeted the key genes from RhoC / ROCK1-LIMK1-CFL1 signaling pathway and significantly enhanced the invasion and metastasis of pancreatic cancer cells. In order to prove this hypothesis, a set of assay of cell biology, animal and clinic were planed to investigate the expression and activity of RhoC, ROCK1 and CFL1 which were regulated by HIF-3α,and to investigate the role of HIF-3α in the activation of the signaling pathway.The molecular mechanism that HIF-3α enhanced invasion and metastasis of pancreatic cancer cells by activation of the signaling pathway RhoC / ROCK1-LIMK1-CFL1 was ultimately clarified.

胰腺癌的高侵袭转移性仍然是临床治疗的难点，普遍观点认为肿瘤细胞的间充质-阿米巴样移动方式转变有助于其以“极高”的速度迁移并转移，这依赖于Rho/ROCK信号通路对F-actin的调控。我们的前期研究证实：缺氧诱导新近发现的HIF-3α通过引起F-actin在细胞膜内侧聚集，显著地增强了胰腺癌细胞侵袭转移能力。生物信息学分析提示RhoC、ROCK1、CFL1的启动子区域均含有HIF-3α转录结合位点HREs，预实验提示HIF3α能上调RhoC的表达和活性。因此，我们提出研究假设：缺氧诱导HIF-3α靶向转录调控RhoC/ROCK1-LIMK1 -CFL1信号通路增强胰腺癌的侵袭转移。为此，本项目将从细胞学和动物实验以及临床标本检验等验证HIF-3α转录调控RhoC、ROCK1和CFL1的表达与活性，探讨HIF-3α在激活该信号通路中的作用，最终阐明HIF-3α增强胰腺癌侵袭转移的分子机制。

研究背景：肿瘤细胞内缺氧是导致其高侵袭转移的主要原因之一，缺氧和高侵袭转移是胰腺癌的重要特征。转录因子HIF3α作为新近发现的HIF家族成员，其在胰腺癌细胞中的生物学功能与转录调控机制目前还不清楚。研究内容：①HIF-3α与胰腺癌侵袭转移能力的相关性，②HIF-3α转录调控RhoC/ROCK1/CFL信号通路蛋白的表达与活性，③HIF-3α与F-actin聚集相关性，④ HIF-3α以及和HNRNPH相互作用与自噬依赖的侵袭转移能力的相关性，⑤HIF-3α/HNRNPH转录调控自噬相关基因TP53INP2和DRAM1的表达。研究结果：证实了HIF3α在胰腺癌中高表达，转录调控RhoC/ROCK1/CFL信号通路蛋白的表达与活性，促进了F-actin在细胞内膜侧的聚集，增强了胰腺癌细胞的收缩力和侵袭转移能力；证实了HIF-3α和HNRNPH相互作用，通过上调胰腺癌细胞自噬水平和自噬依赖的侵袭转移能力；证实了HIF-3α转录调控自噬相关基因TP53INP2和DRAM1的表达。科学意义：阐明了胰腺癌高表达HIF3α增强胰腺癌细胞侵袭转移能力的部分分子机制，为寻找胰腺癌分子治疗靶点奠定了理论基础。