title: RNAi-mediated knockdown of relaxin decreases in vitro proliferation and invasiveness of osteosarcoma MG-63 cells by inhibition of MMP-9.
abstract: OBJECTIVE
  The purpose of this study is to determine the role of relaxin knowdown by siRNA transfection in cellular growth and invasion of osteosarcoma MG-63 cells, and discusses the molecular mechanisms of this action.
  
  
  METHODS
  The expression of relaxin in MG-63 cell was examined by western blot or RT-PCR. To evaluate the biological role of relaxin, proliferation assay (MTT) and invasion assay (BD Matrigel™), apoptosis assay (TUNEL and ELISA) and cell cycle analysis (flow cytometer) were performed after silencing relaxin using siRNA. MMP-9 expressions were analyzed using RT-PCR, western blot and zymography after silencing relaxin.
  
  
  RESULTS
  Results showed that the downregulation of relaxin expression by siRNA in human osteosarcoma MG-63 cells significantly inhibited cell proliferation and invasion in vitro. Furthermore, relaxin knockdown led to cell arrest in the G1/G0 phase of the cell cycle, and eventual apoptosis enhancement in MG-63 cells. We provide evidence in our cell model that the relaxin siRNA down-regulated the expression of MMP-9 and the MMP-9 activity, suggesting that relaxin may promote the proliferation, invasion and metastasis of osteosarcoma cells by regulating the expression of MMP-9 and facilitating ECM degradation.
  
  
  CONCLUSIONS
  Therefore, siRNA-directed knockdown of relaxin may represent a viable clinical therapy for osteosarcoma.
authors: Department of Spine, the Affiliated Hospital of Qingdao Medical College, Qingdao University, Qingdao, R.P. China. qyfymjf@126.com
authors: J-F
authors: JF
authors: Ma
authors: L
authors: L
authors: Liu
authors: W-J
authors: WJ
authors: Yang
authors: L N
authors: LN
authors: Zang
authors: Y-M
authors: YM
authors: Xi
mesh_terms: D001859:Bone Neoplasms / Q000473:pathology* / Q000628:therapy; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D006801:Humans; D020780:Matrix Metalloproteinase 9 / Q000235:genetics / Q000502:physiology*; D009361:Neoplasm Invasiveness; D012516:Osteosarcoma / Q000473:pathology* / Q000628:therapy; D034622:RNA Interference; D012065:Relaxin / Q000037:antagonists & inhibitors / Q000502:physiology*
chemical_list: D012065:Relaxin; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9