title: Stable knockdown of clusterin by vectorbased RNA interference in a human breast cancer cell line inhibits tumour cell invasion and metastasis.
abstract: OBJECTIVE
  Overexpression of the clusterin (CLU) gene occurs in breast cancer and is associated with lymph node metastasis. The present study explored the effect of CLU silencing on invasion and metastasis, and the relationship between CLU expression and the extracellular  signal-regulated kinase (ERK) / matrix metalloproteinase-9 (MMP) signalling pathway in human breast cancer cells.
  
  
  METHODS
  A pcDNA3.1-based RNA interference approach was used to knockdown the CLU gene in MDA-231 cells (MDA-231-CLUi); control MDA-231 cells were transfected with  an empty vector (MDA-231-Vec). Reverse transcription-polymerase chain reaction was used to assess CLU and MMP-9 mRNA levels, and Western blotting was used to analyse CLU, MMP-9 and ERK protein levels. Metastatic potential was evaluated using in vitro and in vivo models  of invasion and metastasis.
  
  
  RESULTS
  Compared with MDA-231-Vec cells, the MDA-231-CLUi cells demonstrated reduced migration and invasion in vitro and decreased metastatic potential in vivo. Reintroduction and reexpression of the CLU gene into the MDA-231-CLUi  cells restored the invasive phenotype. MMP-9 mRNA and protein levels were reduced in MDA-231-CLUi cells, and there was a correlation between activated ERK and CLU and MMP-9 protein levels.
  
  
  CONCLUSIONS
  CLU may regulate the aggressive behaviour of human breast cancer cells through  modulation of ERK signalling and MMP9 expression.
authors.affiliation: Centre of Breast Disease, The Affiliated Hospital of QingDao University Medical College, QingDao University, QingDao, China.
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: L
authors.initials: L
authors.lastname: Jia
authors.forename: P
authors.initials: P
authors.lastname: Zhao
authors.forename: Y
authors.initials: Y
authors.lastname: Jiang
authors.forename: S
authors.initials: S
authors.lastname: Zhong
authors.forename: D
authors.initials: D
authors.lastname: Chen
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D051152:Clusterin / Q000235:genetics* / Q000378:metabolism*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D005419:Flavonoids / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D020935:MAP Kinase Signaling System; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D009361:Neoplasm Invasiveness; D009362:Neoplasm Metastasis; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D034741:RNA, Small Interfering
chemical_list: D051152:Clusterin; D005419:Flavonoids; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D048049:Extracellular Signal-Regulated MAP Kinases; D020780:Matrix Metalloproteinase 9; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one