南蛇藤总萜通过LIMK1和SSH通路靶向丝切蛋白1(cofilin1)抑制胃癌转移的机制

Epithelial-to-mesenchymal transition (EMT), the process of cells losing their epithelial phenotype and acquiring a migratory mesenchymal phenotype, has been accepted to play an important role in cancer metastasis in several human malignancies including gastric cancer. Previous studies was performed to investigate the inhibitory effects of Celastrus orbiculatus (COE) on the invasion and migration of human gastric cancer cells in vitro. Recently, using a comparative proteomics approach, the target-specific proteins were identified as differently expressed, with cofilin1 being one of the most significantly down-regulated proteins induced by COE (2.5-fold down-regulation). Therefore, we selected cofilin1 for further study. In this study, we investigated the role of cofilin1 in COE-mediated inhibition of EMT and tumor metastasis in vivo. We also investigated the interaction between Rac1-Rho kinase (ROCK)1/p21-activated kinase (PAK)1-LIM kinase (LIMK)1 and Slingshot (SSH) signaling pathway in controlling metastatic potential of gastric cancer cells and explored the underlying molecular mechanism by which COE modulates the EMT-mediated alteration of human gastric cancer cells. These findings reveal that application of COE in treating metastatic gastric cancer boasts promising prospect and will become potential therapy all over the world.

上皮间质转化（EMT）是胃癌远端转移的重要生物学过程。前期研究发现，中药提取物南蛇藤总萜可明显抑制胃癌细胞EMT进程，从而抑制胃癌侵袭、迁移的发生。经蛋白质组学分析，EMT上游的关键调控蛋白丝切蛋白1（cofilin 1）在南蛇藤总萜作用前后的表达差异性最为显著，但cofilin 1参与南蛇藤总萜抑制胃癌EMT发生的分子机制尚不清楚。本项目拟结合体内外研究，探讨南蛇藤总萜靶向cofilin 1蛋白，通过Rac1 - ROCK1/ PAK1 - LIMK1及SSH信号通路抑制胃癌细胞侵袭和迁移的分子机制，为开发生物利用度高的抗癌新药奠定基础。

侵袭转移是胃癌治疗和术后复发的关键事件，而上皮间质转化（EMT）又是胃癌远端转移的重要生物学过程，是胃癌发生、发展和远处转移的关键事件。前期研究发现，中药提取物南蛇藤总萜可明显抑制胃癌细胞EMT进程，从而抑制胃癌侵袭、迁移的发生。经蛋白质组学分析，EMT上游的关键调控蛋白丝切蛋白1（cofilin 1，CFL1）在南蛇藤总萜作用前后的表达差异性最为显著，但CFL1参与南蛇藤总萜抑制胃癌EMT发生的分子机制尚不清楚。基与此，本项目拟结合体内外研究，探讨南蛇藤总萜靶向CFL1蛋白，通过 LIMK1及SSH信号通路抑制胃癌细胞侵袭和迁移的分子机制，探讨CFL1在南蛇藤总萜抑制胃癌侵袭转移过程中的作用；揭示南蛇藤总萜如何通过LIMK1/SSH调控CFL1信号通路的效应与机制；阐明南蛇藤总萜对胃癌动物模型中肿瘤生长、转移的影响及作用机制。 经过课题组的研究，我们发现南蛇藤总萜能够明显抑制TGF-β1诱导的人胃癌细胞侵袭转移的发生，其作用机制可能是南蛇藤总萜对HSP27、 Prohibitin、CFL1、Annexin A5等多个靶点蛋白共同作用的结果。回顾相关的文献，我们发现CFL1在胃癌细胞侵袭转移的过程中扮演了重要的角色。因此，我们在后续实验中，选择CFL1作为研究的切入点，从CFL1如何参与南蛇藤总萜对胃癌侵袭转移抑制过程的角度，深入探讨南蛇藤总萜抑制胃癌侵袭转移的分子机制。后期实验研究发现，南蛇藤总萜能够明显抑制CFL1磷酸化酶和去磷酸化酶LIMK/SSH的表达，而LIMK和SHH调控CFL1的磷酸化状态，从而影响细胞骨架的重塑。因此，南蛇藤总萜主要通过调控LIMK和SSH这两个CFL1的磷酸化和去磷酸化酶来调控CFL1的.抑制CFL1以后，细胞骨架重塑受到抑制，从而抑制胃癌细胞侵袭转移。然而南蛇藤总萜如何作用于CFL1的磷酸化和去磷酸化酶的，细胞骨架重塑又是如何影响胃癌细胞侵袭转移的还有待进一步研究。