title: [8-Chloro-adenosine increases the activity of transcription factor CREB by modification of phosphorylation].
abstract: OBJECTIVE
  8-Chloro-adenosine(8-Cl-Ado) is an anti-tumor drug,which has been investigated and developed recently in China. The molecular mechanism of 8-Cl-Ado is now unclear. This study was conducted to investigate the effect of 8-Cl-Ado on the activity of transcription factor cAMP-response-element-binding protein(CREB) and its correlative mechanism in human promyelocytic leukemia cell line HL-60.
  
  
  METHODS
  MTT method was used to determine IC(50) (the concentration showing 50% of inhibition rate) of 8-Cl-Ado to HL-60. The protein levels and phosphorylated levels of CREB at different time following 8-Cl-Ado stimulation were examined using Western blot analysis. Gel shift assay was performed to examine DNA binding levels of CREB at different time following 8-Cl-Ado stimulation.
  
  
  RESULTS
  (1)The IC(50) of 8-Cl-Ado to HL-60 was about 0.42 micromol/L. (2)8-Cl-Ado increased phosphorylated level of CREB rapidly, which was maximal at 30 minutes, and returned to basal level in 6 hours. The protein level of CREB was constant during 8-Cl-Ado stimulation. (3)8-Cl-Ado did not influence binding level of DNA and CREB.
  
  
  CONCLUSIONS
  The increase of transcriptional activity of CREB induced by 8-Cl-Ado depends on the increased level of phosphorylated CREB, but is not associated with the protein level and DNA binging level of CREB.
authors.affiliation: Department of Cell Biology, Beijing Institute for Cancer Research,School of Oncology, Peking University, Beijing, PRChina. changxiaoyan2002@yahoo.com.cn
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Chang
authors.forename: Jia-Chun
authors.initials: JC
authors.lastname: Fang
authors.forename: Nai-Qin
authors.initials: NQ
authors.lastname: Wang
authors.forename: Tong
authors.initials: T
authors.lastname: Liu
authors.forename: Hong
authors.initials: H
authors.lastname: Su
mesh_terms: D015762:2-Chloroadenosine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D017362:Cyclic AMP Response Element-Binding Protein / Q000187:drug effects / Q000378:metabolism*; D018922:HL-60 Cells; D006801:Humans; D010766:Phosphorylation / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D017362:Cyclic AMP Response Element-Binding Protein; D014157:Transcription Factors; D015762:2-Chloroadenosine; C075440:8-chloroadenosine