脂肪酸结合蛋白5结合Vimentin蛋白在肝癌中的作用机制

Study on the mechanism of fatty acid binding protein 5 binding Vimentin protein in the Hepatocellular Carcinoma cells

目的 筛选和验证与脂肪酸结合蛋白5(FABP5)结合的互作蛋白,同时研究FABP5与候选蛋白的调控关系,进一步探讨FABP5在肝癌中的作用机制。方法 采用免疫沉淀联合串联质谱分析方法(IP-MS)筛选出与FABP5相互结合的蛋白;通过免疫共沉淀实验(Co-IP)从外源性和内源性层面验证FABP5与候选互作蛋白的结合关系;利用RT-qPCR、Western blot和免疫荧光法观察敲低FABP5对肝癌细胞中波形蛋白(Vimentin)转录和翻译水平的影响;通过鬼笔环肽染色实验观察过表达FABP5对肝癌细胞骨架的影响。结果 IP-MS鉴定出336个与FABP5相互结合的潜在靶蛋白,结合文献,挑选出5个与肿瘤相关的候选蛋白,分别为PRDX1、PRSS3、PKM、HSP90AA1和Vimentin蛋白。通过外源性和内源性Co-IP实验证实FABP5与Vimentin蛋白存在结合关系。敲低FABP5对肝癌细胞中Vimentin mRNA的表达没有显著作用,但可抑制Vimentin蛋白的表达,而过表达FABP5会影响肝癌细胞的骨架。结论 FABP5促进肝癌细胞的迁移和侵袭,其机制可能与FABP5结合调控Vimentin蛋白和影响细胞骨架重塑有关,有望成为抗肝癌的潜在靶点,为肝癌的治疗提供新的思路。

Objective The aim of this study was to screen and verify the proteins interacting with Vimentin,investigate the regulatory relationship between FABP5 and candidate proteins,and further explore the mechanism of FABP5 in hepatocellular carcinoma.Methods Immunoprecipitation combined with tandem mass spectrometry(IP-MS)was used to screen the proteins that bind to FABP5.The binding relationship between FABP5 and candi-date interacting proteins was verified from the exogenous and endogenous levels by Co-immune precipitation assay(Co-IP).RT-qPCR,Western blot and immunofluorescence were used to observe the effect of knockdown FABP5 on the transcription and translation of Vimentin in HCC cells.The effect of overexpressing FABP5 on the cytoskeleton of HCC cell was observed by phalloidin staining.Results 336 potential target proteins that bind to FABP5 were identi-fied through IP-MS.Based on literature,five candidate proteins related to tumors were selected,namely PRDX1,PRSS3,PKM,HSP90AA1,and Vimentin.The binding relationship between FABP5 and Vimentin protein was con-firmed through both exogenous and endogenous Co-IP.Knockdown FABP5 has no significant effect on the expression of Vimentin mRNA,but it can inhibit the expression of Vimentin protein,and overexpression of FABP5 can affect the cytoskeleton of HCC cell.Conclusions FABP5 promotes the migration and invasion of HCC cells by the regula-tion of Vimentin and the influence of cytoskeletal remodeling,and thus it is expected to be a potential target for anti-HCC and provide new ideas for the treatment of HCC.