title: Bufalin induces apoptosis in human osteosarcoma U-2OS and U-2OS methotrexate300-resistant cell lines.
abstract: OBJECTIVE
  To investigate the antiproliferative activity and apoptosis-inducing effects of bufalin on human osteosarcoma cell lines.
  
  
  METHODS
  U-2OS and U-2OS methotrexate (MTX) 300-resistant cell lines were treated with bufalin. Cell viability was assessed using the MTT assay. Cell-cycle status, apoptosis-inducing effects, and the expression of apoptosis-related proteins were evaluated by flow cytometry, fluorescent staining, DNA fragmentation assays, and Western blotting. The effect of bufalin on dihydrofolate reductase (DHFR) expression was studied by RTPCR and Western blotting.
  
  
  RESULTS
  Bufalin inhibited cell growth in both U-2OS and U-2OS MTX300 cells. The induction of G2/M cell-cycle arrest was also seen in the cells treated with bufalin. The induction of apoptosis by bufalin was confirmed by increased expression of the tumor suppressor protein p53 and the increased ratio of the Bax/Bcl-2 proteins. Bufalin induced apoptosis to the same extent in both cell lines without regard to DHFR levels in the cells.
  
  
  CONCLUSIONS
  Bufalin inhibited the growth of and induced apoptosis in both MTX-sensitive and MTX-resistant human osteosarcoma U-2OS cells. The apoptosis-inducing effect of bufalin was not influenced by the presence of high levels of the DHFR protein.
authors: Department of Orthopaedic Oncology, First Affiliated Hospital of Sun Yat-Sen University, Guangzhou 510080, China.
authors: Jun-Qiang
authors: JQ
authors: Yin
authors: Jing-Nan
authors: JN
authors: Shen
authors: Wei-Wei
authors: WW
authors: Su
authors: Jin
authors: J
authors: Wang
authors: Gang
authors: G
authors: Huang
authors: Song
authors: S
authors: Jin
authors: Qian-Chen
authors: QC
authors: Guo
authors: Chang-Ye
authors: CY
authors: Zou
authors: Hao-Miao
authors: HM
authors: Li
authors: Fo-Bao
authors: FB
authors: Li
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002018:Bufanolides / Q000494:pharmacology*; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor / Q000187:drug effects*; D002470:Cell Survival / Q000187:drug effects; D053938:DNA Fragmentation; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D006801:Humans; D008727:Methotrexate / Q000494:pharmacology*; D012516:Osteosarcoma / Q000378:metabolism / Q000503:physiopathology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D002018:Bufanolides; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D013762:Tetrahydrofolate Dehydrogenase; C022777:bufalin; D008727:Methotrexate