title: Inhibitory effects of extracellular adenosine triphosphate on growth of esophageal carcinoma cells.
abstract: OBJECTIVE
  To study the growth inhibitory effects of ATP on TE-13 human squamous esophageal carcinoma cells in vitro.
  
  
  METHODS
  MTT assay was used to determine the inhibition of proliferation of ATP or adenosine (ADO) on TE-13 cell line. The morphological changes of TE-13 cells induced by ATP or ADO were observed under fluorescence light microscope by acridine orange (AO)/ethidium bromide (EB) double stained cells. The internucleosomal fragmentation of genomic DNA was detected by agarose gel electrophoresis. The apoptotic rate and cell cycle after treatment with ATP or ADO were determined by flow cytometry.
  
  
  RESULTS
  ATP and ADO produced inhibitory effects on TE-13 cells at the concentration between 0.01 and 1.0 mmol/L. The IC(50) of TE-13 cells exposed to ATP or ADO for 48 and 72 h was 0.71 or 1.05, and 0.21 or 0.19 mmol/L, respectively. The distribution of cell cycle phase and proliferation index (PI) value of TE-13 cells changed, when being exposed to ATP or ADO at the concentrations of 0.01, 0.1, and 1 mmol/L for 48 h. ATP and ADO inhibited the cell proliferation by changing the distribution of cell cycle phase via either G(0)/G(1) phase (ATP or ADO, 1 mmol/L) or S phase (ATP, 0.1 mmol/L) arrest. Under light microscope, the tumor cells exposed to 0.3 mmol/L ATP or ADO displayed morphological changes of apoptosis. A ladder-like pattern of DNA fragmentation was obtained from TE-13 cells treated with 0.1-1 mmol/L ATP or ADO in agarose gel electrophoresis. ATP and ADO induced apoptosis of TE-13 cells in a dose-dependent manner at the concentration between 0.03 and 1 mmol/L. The maximum apoptotic rate of TE-13 cells exposed to ATP or ADO for 48 h was 16.63% or 16.9%, respectively.
  
  
  CONCLUSIONS
  ATP and ADO inhibit cell proliferation, arrest cell cycle, and induce apoptosis of TE-13 cell line.
authors.affiliation: School of Pharmacy, Hebei Medical University, Shijiazhuang 050017, Hebei Province, China.
authors.forename: Ming-Xia
authors.initials: MX
authors.lastname: Wang
authors.forename: Lei-Ming
authors.initials: LM
authors.lastname: Ren
authors.forename: Bao-En
authors.initials: BE
authors.lastname: Shan
mesh_terms: D000241:Adenosine / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D053938:DNA Fragmentation / Q000187:drug effects; D004938:Esophageal Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D006801:Humans
chemical_list: D000255:Adenosine Triphosphate; D000241:Adenosine