The Effect Of CD109 In The Development Of Pancreatic Cancer

Research background:Pancreatic cancer is one of the most malignant tumors due to its concealed characteristics.The vast majority of patients receiving their first treatment were already at advanced stages with local invasion or metastasis,leading to a poor median survival of 3 to 6 months.Therefore,identification of biomarkers for prognosis prediction and as new therapeutic targets has become one of the hot topics in pancreatic cancer research.Our previous studies have shown that the high expression of PRSS3 was negatively correlated with the survival of pancreatic cancer patients and that PRSS3 secreted into extracellular space cleaved cell membrane protein CD109.However,the mechanism of cleavage products in the development of pancreatic cancer has not been reported.Objective:The aim of this study was to analyze the PRSS3-mediated cleavage sites on CD109,investigate the mechanism underlining the action of cleavage products in pancreatic cancer pathogenesis.What is more,the function of CD109 might be another way for diagnosis and prognosis prediction of pancreatic cancer.The result about CD109 might be lay an important molecular basis for targeted therapy in pancreatic cancer.Methods:The expression level of CD109 protein was determined by Western blotting in 8 human pancreatic cancer cell lines.After biotin-labeled cells from pancreatic cancer cell line Patu8988 s were incubated with active PRSS3,the tCD109 fragments were collected from the supernatant and used for N-terminal amino acid sequence analysis using nanoLC-MS / MS.According to identified cleavage site,vector pSec-tCD109 was then constructed expressing secretory type of tCD109 from animal cells.We transfected pSec-tCD109 in Patu8988 t or Miapac-2 cells and determined the effect of tCD109 on tumor cell proliferation,migration and infiltration.Co-immunoprecipitation was employed to study the interaction between tCD109 and TGF-β receptors and signal transduction pathways that regulated cell behaviors.Results:1.In pancreatic cancer cells,BxPC-3、PANC-1、Patu8988s and Suit-2 express the high level of protein CD109.However,CFPAC-1、Capan-1、Miapaca-2 and Patu8988 t have not be detected the expression of protein CD109.2.In Patu8988 s cancer cells,PRSS3 can cleave membrane protein CD109 at the cleavage site R663-F664.3.The cleavage fragment V22-R663,tCD109,can promote the proliferation of pancreatic cancer cells.The number of cells in Patu8988t-tCD109 group(1.967±0.056)was significantly higher than that in group Patu8988t-pcDNA3.1(1.224±0.051)(p<0.05)by MTT.Similarly,the number of cells in Miapac-2-tCD109 group(2.266±0.027)was also significantly higher than that in group Miapac-2-pcDNA 3.1(1.409±0.06)(p<0.05).4.The cleavage fragment V22-R663,tCD109,can promote the invasion and metastasis of pancreatic cancer cells.tCD109.The results of Transwell showed that the number of Patu8988t-tCD109 through Matrigel and membrane(42.54±3.21)was significantly higher than that in control group(10.10±2.30)(p<0.05).5.tCD109 competed with TGF-β1 in binding to TGF-β receptors,inhibiting its downstream signal transduction.Conclusion:1.The cleavage fragment V22-R663,tCD109,competed with TGF-β1 in binding to TGF-β receptors,inhibiting its downstream signal transduction.As a result,tCD109 can promote the proliferation and invasion and metastasis of pancreatic cancer cells.2.The function of CD109 might be lay an important molecular basis for targeted therapy in pancreatic cancer.