title: MiR-300 regulate the malignancy of breast cancer by targeting p53.
abstract: OBJECTIVE
  In this study, we investigated the role of miR-300 in regulating cell proliferation and invasion of breast cancer (BC) cells.
  
  
  METHODS
  MicroRNA and protein expression patterns were compared between breast cancer tissue and normal tissue and between two different prognostic groups. The up-regulation of miR-300 was confirmed by real-time reverse transcription polymerase chain reaction and its expression was analyzed in MCF-7 breast cancer cells.
  
  
  RESULTS
  We observed that miR-300 expression was frequently and dramatically up-regulated in human breast cancer tissues and cell lines compared with the matched adjacent normal tissues and cells. We further showed that transient and stable over-expression of miR-300 could promote cell proliferation and cell cycle progression. Moreover, p53, a key inhibitor of cell cycle, was verified as a direct target of miR-300, suggesting that miR-300 might promote breast cancer cell proliferation and invasion by regulating p53 expression.
  
  
  CONCLUSIONS
  Our findings indicated that miR-300 up-regulation might exert some sort of antagonistic function by targeting p53 in breast cancer cell proliferation during breast tumorigenesis.
authors.affiliation: Cancer Center, The First Hospital of Jilin University, Changchun Jilin P. R. China.
authors.forename: Xiao-Heng
authors.initials: XH
authors.lastname: Xu
authors.affiliation: Department of Neurology, Affiliated Hospital of Beihua University Jilin, P. R. China.
authors.forename: Da-Wei
authors.initials: DW
authors.lastname: Li
authors.affiliation: Cancer Center, The First Hospital of Jilin University, Changchun Jilin P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Feng
authors.affiliation: Cancer Center, The First Hospital of Jilin University, Changchun Jilin P. R. China.
authors.forename: Hong-Mei
authors.initials: HM
authors.lastname: Chen
authors.affiliation: Cancer Center, The First Hospital of Jilin University, Changchun Jilin P. R. China.
authors.forename: Yan-Qiu
authors.initials: YQ
authors.lastname: Song
keywords: MCF-7; MiR-300; breast cancer; p53; target therapy