title: [Effects of arsenic trioxide on the methylation of TMS1 gene in K562 cells].
abstract: OBJECTIVE
  To detect the methylation status of TMS1 gene and its demethylation by arsenic trioxide (As₂O₃) in K562 cells.
  
  
  METHODS
  K562 cells were treated with different concentrations of As₂O₃ for 48 hours. Methylation-specific PCR (MSP) was used to determine the methylation status of TMS1. RT-PCR and Western blot were used to detect the levels of TMS1 mRNA and protein. TMS1 associated apoptosis proteins Bcl-2/Bax were also analyzed by Western blot. Apoptosis were evaluated by flow cytometry using Annexin V/propium iodide (PI) double staining.
  
  
  RESULTS
  TMS1 gene was completely methylated in K562 cells and the levels of TMS1 mRNA and protein were low (0.01±0.01, 0.09±0.02), which could be reversed (mRNA: 0.72±0.04; protein: 1.30±0.06; P<0.01) by 2 μmol/L As2O3 via overt demethylation of TMS1 gene. Apoptosis in experiment group (12.24±1.06) was significantly higher than that in control group (2.05±0.16, P<0.05). In experiment group, the down-expression of antiapoptotic protein Bcl-2 and up-expression of pro-apoptotic protein Bax led to an obvious decline ratio of Bcl-2/Bax (0.56±0.12), as compared to the control group (1.94±0.14, P<0.01).
  
  
  CONCLUSIONS
  As₂O₃ could up-regulate TMS1 gene expression by reversing its hypermethylation and induced apoptosis by down-regulation of Bcl-2/Bax ratio in K562 cells.
authors.affiliation: Department of Hematology, Qian Foshan Hospital, Shandong University, Jinan 250014, China.
authors.forename: Hongli
authors.initials: H
authors.lastname: Li
authors.affiliation: Department of Hematology, Qian Foshan Hospital, Shandong University, Jinan 250014, China.
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Dong
authors.affiliation: Department of Hematology, Qian Foshan Hospital, Shandong University, Jinan 250014, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Hematology, Qian Foshan Hospital, Shandong University, Jinan 250014, China.
authors.forename: Wenwei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Department of Hematology, Qian Foshan Hospital, Shandong University, Jinan 250014, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Dong
authors.affiliation: Department of Hematology, Qian Foshan Hospital, Shandong University, Jinan 250014, China.
authors.forename: Kehong
authors.initials: K
authors.lastname: Bi
authors.affiliation: Department of Hematology, Qian Foshan Hospital, Shandong University, Jinan 250014, China.
authors.forename: Chuansheng
authors.initials: C
authors.lastname: Zhu
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D000077237:Arsenic Trioxide; D001152:Arsenicals / Q000494:pharmacology*; D053468:CARD Signaling Adaptor Proteins; D003598:Cytoskeletal Proteins / Q000378:metabolism*; D019175:DNA Methylation / Q000187:drug effects*; D015536:Down-Regulation; D015973:Gene Expression Regulation, Leukemic; D006801:Humans; D020014:K562 Cells; D010087:Oxides / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D001152:Arsenicals; C494826:BAX protein, human; D053468:CARD Signaling Adaptor Proteins; D003598:Cytoskeletal Proteins; D010087:Oxides; C402202:PYCARD protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D000077237:Arsenic Trioxide