title: Up-regulation of miR-224 promotes cancer cell proliferation and invasion and predicts relapse of colorectal cancer.
abstract: BACKGROUND
  MicroRNAs (miRNAs) are small, non-coding RNAs that can function as oncogenes or tumor suppressors in human cancer. Abnormally expressed miR-224 was found to play a fundamental role in several types of cancer. The aim of this study was to investigate the prognostic and biological values of miR-224 in colorectal cancer (CRC).
  
  
  METHODS
  Quantitative RT-PCR (qRT-PCR) was used to evaluate expression levels of miR-224. The postoperative survival rate was analyzed with Kaplan-Meier method. The roles of miR-224 in cell proliferation, migration and invasion were analyzed with pre-miR-224 transfected cells. In addition, the regulation of SMAD4 by miR-224 was evaluated by qRT-PCR, Western blotting and luciferase reporter assays.
  
  
  RESULTS
  In the present study, we demonstrated that miR-224 was significantly up-regulated in CRC tissue samples and associated with disease relapse and a relative poorer disease-free survival rate. Moreover, ectopic expression of miR-224 potently promoted tumor cell proliferation, migration and invasion in vitro. Furthermore, the over-expression of miR-224 in CRC cell lines decreased SMAD4 expression at the translational level and decreased SMAD4-driven luciferase-reporter activity.
  
  
  CONCLUSIONS
  Our data suggest that miR-224 could play an oncogenic role in the cellular processes of CRC and represent a novel biomarker for tumor relapse of CRC patients.
authors.affiliation: The First Department of General Surgery, The Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China.|Institute of Hepatobiliary, Pancreas and Intestinal Disease, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China.
authors.forename: Guang-Jun
authors.initials: GJ
authors.lastname: Zhang
authors.affiliation: The First Department of General Surgery, The Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China.|Institute of Hepatobiliary, Pancreas and Intestinal Disease, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China.
authors.forename: He
authors.initials: H
authors.lastname: Zhou
authors.affiliation: Department of Pathology, The North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China.
authors.forename: Hua-Xu
authors.initials: HX
authors.lastname: Xiao
authors.affiliation: Department of Microbiology and Parasitology, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Li
authors.affiliation: The First Department of General Surgery, The Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China.|Institute of Hepatobiliary, Pancreas and Intestinal Disease, North Sichuan Medical College, Nanchong, Sichuan, People's Republic of China.
authors.forename: Tong
authors.initials: T
authors.lastname: Zhou