title: Knockdown of Mad2 induces osteosarcoma cell apoptosis-involved Rad21 cleavage.
abstract: BACKGROUND
  Besides Mad2's role in carcinogenesis, recent study has shown that it is essential in cell survival. Here we found that knockdown of Mad2 causes osteosarcoma cell death through apoptosis, with the apoptotic signal resulting from Rad21 cleavage.
  
  
  METHODS
  U2OS and MG63 cells were divided into three groups: the Mad2 siRNA group, mock group and normal control group; the Mad2 siRNA group and mock group are transfected with Mad2 shRNA plasmid and mock plasmid, respectively. G418 was used to increase the transfection efficacy, which was evaluated by GFP fluorescence. Quantitative PCR and Western blotting analyses were used to detect the transcription and expression of Mad2, Rad21 and caspase-3, respectively. Flow cytometry assay using PE-labeled Annexin-V and PI, TUNEL assay and Hoechst 33258 staining were used to evaluate cell apoptosis.
  
  
  RESULTS
  We successfully achieved knockdown of Mad2 expression in cancer cells using RNA interference. We observed obvious apoptosis in the Mad2 siRNA group compared with the Mock and control group. We found that the apoptosis induced by Mad2 knockdown correlated with Rad21 cleavage.
  
  
  CONCLUSIONS
  These results confirmed that knockdown of Mad2 causes osteosarcoma cell death through apoptosis and provides evidence that the apoptotic signal resulted from Rad21 cleavage. This study suggested that Mad2 has potential to be a novel target for cancer therapy.
authors: Department of Orthopedics, Renmin Hospital, Wuhan University, Wuhan, Hubei, China.
authors: Ling
authors: L
authors: Yu
authors: Weichun
authors: W
authors: Guo
authors: Shenghao
authors: S
authors: Zhao
authors: Jin
authors: J
authors: Tang
authors: Jianhua
authors: J
authors: Liu
mesh_terms: D017209:Apoptosis; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D004268:DNA-Binding Proteins; D055785:Gene Knockdown Techniques; D006801:Humans; D064246:Mad2 Proteins; D009687:Nuclear Proteins / Q000502:physiology*; D012516:Osteosarcoma / Q000473:pathology*; D010750:Phosphoproteins / Q000502:physiology*; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000502:physiology*; D012097:Repressor Proteins / Q000235:genetics / Q000502:physiology*
chemical_list: D002135:Calcium-Binding Proteins; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; C577697:MAD2L1 protein, human; D064246:Mad2 Proteins; D009687:Nuclear Proteins; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; C429022:RAD21 protein, human; D012097:Repressor Proteins