MiR-329 Regulates Cell Proliferation And Apoptosis By Targeting GRB2 In Pancreatic Cancer

Objective:This study was intended to uncover the miR-329 expression level in tumor tissue of pancreatic cancer patients and find the correlation between miR-329 expression level and pancreatic cancer clinicopatholoic variables and prognosis.Also,we aimed to determine the exact relationship between miR-329 and the biological features of pancreatic cancer.Furthermore,the mechanisms study was designed to demonstrate the function and potential target of miR-329 mediated pancreatic tumor developmentMethods:The expression level of miR-329 in 34 paired pancreatic cancer tissues was confirmed by qRT-PCR,and the relationship between miR-329 expression and clinicopatholoic variables was explored.Then,expression of miR-329 in pancreatic cancer cell lines,primary pancreatic cancer cell and immortalized pancreatic ductal epithelial cell line(HPDE)was explored.The specific miR-329 mimics/inhibitor were transfected into pancreatic cancer cell lines to up-regulate/down-regulate miR-329 expression to investigate its biological effects(proliferation,apoptosis and tumorigenicity)in vitro and in vivo.Results:Using qRT-PCR,it was found that miR-329 expression was downregulated in the pancreatic cancer patients who demonstrated significantly shorter overall survival than the patients having upregulated expression.Also,more advanced pT stage cases were observed in the low miR-329 expression group of patients.In addition,we demonstrate a general decrease in pancreatic cancer cell lines compared with HPDE.Interestingly,our studies uncovered that miR-329 overexpression inhibited proliferation and induced apoptosis of pancreatic cancer cells,in contrast the miR-329 inhibitor reversed this phenomenon dramatically.Additionally,overexpression of miR-329 significantly limited tumor growth in the xenograft model.In the mechanism study,we identified GRB2 as a direct target of miR-329 in pancreatic cancer cells,and expression of GRB2 was inversely correlated with miR-329 expression in pancreatic cancer patients.Furthermore,GRB2 overexpression in cell line and xenograft model dramatically diminished miR-329 mediated anti-proliferation and apoptosis induction,indicating that GRB2/pERK pathway was mainly downregulated by miR-329 expressionConclusions:miR-329 expression was downregulated in the pancreatic cancer patients who demonstrated significantly shorter overall survival than the patients having upregulated expression.Overexpression of miR-329 in pancreatic cancer cells dramatically suppressed cell proliferation and induced cell apoptosis both in vitro and in vivo.And it was confirmed that GRB2 is a direct target of miR-329.In general,our study has shed light on miR-329 regulated mechanism,and miR-329/GRB2/pERK is potential to be targeted for pancreatic cancer management.