title: Silencing of lysyl oxidase gene expression by RNA interference suppresses metastasis of breast cancer.
abstract: OBJECTIVE
  The aim of this study was to investigate possible mechanisms of LOX gene effects on invasion and metastasis of breast cancer cells by RNA interference.
  
  
  METHODS
  LOX-RNAi-LV was designed, synthesized, and then transfected into a breast cancer cell line (MDA-MB-231). Expression of LOX, MMP-2 and MMP-9 was determined by real-time PCR, and protein expression of LOX by Western blotting. Cell migration and invasiveness were assessed with Transwell chambers. A total of 111 cases of breast cancer tissues, cancer-adjacent normal breast tissues, and 20 cases of benign lesion tissues were assessed by immunohistochemistry.
  
  
  RESULTS
  Expression of LOX mRNA and protein was suppressed, and the expression of MMP-2 and MMP-9 was significantly lower in the RNAi group than the control group (P<0.05), after LOX-RNAi-LV was transfection into MDA-MB-231 cells. Migration and invasion abilities were obviously inhibited. The expression of LOX protein in breast cancer, cancer-adjacent normal breast tissues and benign breast tumor were 48.6% (54/111), 26.1% (29/111), 20.0% (4/20), respectively, associations being noted with clinical stage, lymph node metastasis, tumor size and ER, PR, HER2, but not age. LOX protein was positively correlated with MMP-2 and MMP-9.
  
  
  CONCLUSIONS
  LOX displayed an important role in invasion and metastasis of breast cancer by regulating MMP-2 and MMP-9 expression which probably exerted synergistic effects on the extracellular matrix (ECM).
authors.affiliation: Department of Breast Surgery, Cancer Hospital, Guangxi Medical University, Guangxi, China. jianlunliu@126.com
authors.forename: Jian-Lun
authors.initials: JL
authors.lastname: Liu
authors.forename: Wei
authors.initials: W
authors.lastname: Wei
authors.forename: Wei
authors.initials: W
authors.lastname: Tang
authors.forename: Yi
authors.initials: Y
authors.lastname: Jiang
authors.forename: Hua-Wei
authors.initials: HW
authors.lastname: Yang
authors.forename: Jing-Tao
authors.initials: JT
authors.lastname: Li
authors.forename: Xiao
authors.initials: X
authors.lastname: Zhou
mesh_terms: D001943:Breast Neoplasms / Q000201:enzymology* / Q000235:genetics / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D005260:Female; D020868:Gene Silencing; D006801:Humans; D008207:Lymphatic Metastasis; D020778:Matrix Metalloproteinase 2 / Q000235:genetics; D020780:Matrix Metalloproteinase 9 / Q000235:genetics; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D008249:Protein-Lysine 6-Oxidase / Q000096:biosynthesis* / Q000172:deficiency / Q000235:genetics*; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D014162:Transfection / Q000379:methods
chemical_list: D012333:RNA, Messenger; D008249:Protein-Lysine 6-Oxidase; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9