The Function And Molecular Mechanism(s) Of Formin-like 1 (FMNL1) In Pancreatic Cancer Development

Objective: This study was intended to uncover the FMNL1 expression level in tumor tissue of pancreatic cancer patients.Also,this thesis aimed to find the correlation between FMNL1 expression level and pancreatic cancer prognosis.Furthermore,the mechinistic study of this thesis was designed to demonstrate the function and mechanism of FMNL1 mediated pancreatic tumor development.Methods: FMNL1 protein expression in tumor tissues of 39 pancreatic adenocarcinoma patients were evaluated by immuno-histochemistry(IHC).The relevance between the FMNL1 expression level and patient survival time was analyzed by SPSS 22.0.FMNL1 protein expression in pancreatic cancer cell lines was quantified by western blot,then sh RNA and lenti-virus transfection was used to knock down the expression of FMNL1 in pancreatic cancer cell line sw1990 and Bxpc3 which showed elevated level of FMNL1.The growth,wound healing,migration,invasion and endothelial cell tube formation were evaluated in FMNL1 downregulated sw1990 and Bxpc3 cells by cck-8 growth assay,wound healing assays,migration assays,invasion assays and tube formation assays,respectively.Furthermore,the migration of different pancreatic cancer cell lines based on their expression level of FMNL1 was evaluated by migration assay.The role of FMNL1 that play in tumor cells metastasis was investigated by peritoneal xenograft metastasis model in nude mice.The RNA-sequence,protein assay and western blot were utilized to explore the FMNL1 mediated signaling pathway in pancreatic cancer cells.Results: The FMNL1 protein level in pancreatic cancer tissue was significantly elevated in 9 out of 39 patients.The patients showing high expression level of FMNL1 demonstrated poor prognosis(median survival time: 12.5 Month VS 26 Month,p<0.05).Downregulation of FMNL1 in sw1990 and Bxpc3 remarkably deminished the migration and invation efficiency of cells when compared to control,whereas the FMNL1knock-down did not affect cell growth.Interestingly,we found a positive correlation between migration efficiency and FMNL1 expression level of several pancreatic cancer cell lines.In peritoneal xenograft metastasis model,less peritoneal spreading was observed in the FMNL1 knocked down group compared with control group.In the mechanistic study,within Westerm Blot,RNA-seq and protein assays,some Epithelial-Mesenchymal Transition(EMT)markers,like E-cadherin,ZO-1,?-catenin,Snail,Slug,Vimentin,Claudin,were found regulated,revealing the blocking of EMT progressConclusion: High level of FMNL1 expression was correlated with poor prognosis in pancreatic cancer.FMNL1 facilitate metastasis of pancreatic cancer cells by promoting EMT pathway.