title: miR-340 inhibition of breast cancer cell migration and invasion through targeting of oncoprotein c-Met.
abstract: BACKGROUND
  Different microRNAs have been shown to have oncogenic and tumor-suppressive functions in human cancers. Detection of their expression may lead to identifying novel markers for breast cancer.
  
  
  METHODS
  The authors detected miR-340 expression in 4 human breast cell lines and then focused on its role in regulation of tumor cell growth, migration, and invasion and target gene expression. They then analyzed miR-340 expression in benign and cancerous breast tissue specimens.
  
  
  RESULTS
  Endogenous miR-340 expression was down-regulated in the more aggressive breast cancer cell lines, which was confirmed in breast cancer tissue specimens by using quantitative real-time polymerase chain reaction. Further studies showed that induction of miR-340 expression was able to suppress tumor cell migration and invasion, whereas knockdown of miR-340 expression induced breast cancer cell migration and invasion. At the gene level, the authors identified c-Met as a direct miR-340 target to mediate cell migration and invasion through regulation of MMP-2 and MMP-9 expression. Ex vivo, loss of miR-340 expression was associated with lymph node metastasis, high tumor histological grade, clinical stage, and shorter overall survival of breast cancer as well as increased c-Met expression in breast cancer tissue specimens.
  
  
  CONCLUSIONS
  miR-340 may play an important role in breast cancer progression, suggesting that miR-340 should be further evaluated as a novel biomarker for breast cancer metastasis and prognosis, and potentially a therapeutic target.
authors.affiliation: Department of Pathology, Shanghai Medical College, Fudan University, Shanghai, People's Republic of China.
authors.forename: Zheng-sheng
authors.initials: ZS
authors.lastname: Wu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Wu
authors.forename: Chao-qun
authors.initials: CQ
authors.lastname: Wang
authors.forename: Xiao-nan
authors.initials: XN
authors.lastname: Wang
authors.forename: Jing
authors.initials: J
authors.lastname: Huang
authors.forename: Jing-jing
authors.initials: JJ
authors.lastname: Zhao
authors.forename: Shan-shan
authors.initials: SS
authors.lastname: Mao
authors.forename: Gui-hong
authors.initials: GH
authors.lastname: Zhang
authors.forename: Xiao-chun
authors.initials: XC
authors.lastname: Xu
authors.forename: Nong
authors.initials: N
authors.lastname: Zhang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017403:In Situ Hybridization; D008207:Lymphatic Metastasis / Q000235:genetics; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis / Q000235:genetics; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D016133:Polymerase Chain Reaction; D019859:Proto-Oncogene Proteins c-met / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering; D017978:Receptors, Growth Factor / Q000235:genetics / Q000378:metabolism*; D015996:Survival Rate
chemical_list: D034741:RNA, Small Interfering; D017978:Receptors, Growth Factor; C491743:MET protein, human; D019859:Proto-Oncogene Proteins c-met; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9