title: MiR-145 functions as a tumor suppressor via regulating angiopoietin-2 in pancreatic cancer cells.
abstract: BACKGROUND
  Pancreatic cancer is currently one of the leading causes of cancer deaths without any effective therapies. Mir-145 has been found to be tumor-suppressive in various types of cancers. The aim of this study is to investigate the role of miR-145 in pancreatic cancer cells and explore its underlying mechanism.
  
  
  METHODS
  Quantitative real time PCR was used to determine the expression level of miR-145 and angiopoietin-2 (Ang-2) mNRA, and the expression level of Ang-2 protein was measured by western blotting. The anti-cancer activities of miR-145 were tested both in in vitro by using cell invasion and colony formation assay and in vivo by using xenograft assay. The direct action of miR-145 on Ang-2 was predicted by TargetScan and confirmed by luciferase report assay. The vascularization of xenografts were performed by immunohistochemical analysis.
  
  
  RESULTS
  The expression level of miR-145 was significantly lower and the expression levels of Ang-2 mRNA and protein was significantly higher in the more aggressive pancreatic cancer cells (MiaPaCa-2 and Panc-1) when compared to that in BxPC3 cells. Overexpression of miR-145 in the BxPC3, MiaPaCa-2 and Panc-1 cells suppressed the cell invasion and colony formation ability, and the expression level of Ang-2 protein in MiaPaCa-2 and Panc-1 cells was also suppressed after pre-miR-145 transfection. Intratumoral delivery of miR-145 inhibited the growth of pancreatic cancer xenografts and angiogenesis in vivo, and also suppressed the expression level of angiopoietin-2 protein. Luciferase report assay showed that Ang-2 is a direct target of miR-145, and down-regulation of angiopoietin-2 by treatment with Ang-2 siRNA in the BxPC3, MiaPaCa-2 and Panc-1 cells suppressed cell invasion and colony formation ability. The reverse transcription PCR results also showed that Tie1 and Tie2 were expressed in BxPC3, MiaPaCa-2 and Panc-1 cells.
  
  
  CONCLUSIONS
  MiR-145 functions as a tumor suppressor in pancreatic cancer cells by targeting Ang-2 for translation repression and thus suppresses pancreatic cancer cell invasion and growth, which suggests that restoring of miR-145 may be a potential therapeutic target for pancreatic cancer.
authors: Department of General Surgery, DrumTower Clinical Medical College of Nanjing Medical University, Nanjing, 210008 Jiangsu Province China.
authors: Hao
authors: H
authors: Wang
authors: Department of Gastroenterology, The First People's Hospital of Taicang, Suzhou, 215400 Jiangsu Province China.
authors: Cheng
authors: C
authors: Hang
authors: Department of Gastroenterology, Zhongda Hospital, Southeast University, Nanjing, 210009 Jiangsu Province China.
authors: Xi-Long
authors: XL
authors: Ou
authors: Department of Gastroenterology, The First People's Hospital of Taicang, Suzhou, 215400 Jiangsu Province China.
authors: Jin-Shan
authors: JS
authors: Nie
authors: Department of General Surgery, DrumTower Clinical Medical College of Nanjing Medical University, Nanjing, 210008 Jiangsu Province China.
authors: Yi-Tao
authors: YT
authors: Ding
authors: Department of Gastroenterology, The First People's Hospital of Taicang, Suzhou, 215400 Jiangsu Province China.
authors: Shi-Gui
authors: SG
authors: Xue
authors: Department of Gastroenterology, The First People's Hospital of Taicang, Suzhou, 215400 Jiangsu Province China.
authors: Hua
authors: H
authors: Gao
authors: Department of Gastroenterology, The First People's Hospital of Taicang, Suzhou, 215400 Jiangsu Province China.
authors: Jian-Xin
authors: JX
authors: Zhu
keywords: Ang-2; Angiogenesis; Pancreatic cancer; miR-145