title: [Changes in the biological behaviors of colon cancer cells under simulated hypoxia in vitro].
abstract: OBJECTIVE
  To investigate the reactivity of colon cancer cell line SW480 and CD133(+) SW480 subsets to hypoxia in vitro and the changes in the expressions of anti-apoptosis and angiogenesis genes.
  
  
  METHODS
  SW480 cells was subjected to CoCl(2) exposure at varying concentrations and for different time lengths to induce hypoxia, and the protein expression of hypoxia induced factor 1α (HIF-1α) was detected by Western blotting. The CD133(+) SW480 cells were sorted by magnetic activated cell sorting (MACS) and their proportion was assayed by flow cytometry (FCM). The CD133(+) SW480 subsets were exposed to CoCl(2) at the optimal concentration with exposure time selected in terms of HIF-1α level, and their tumor stem cell sphere formation ability was evaluated. Real-time PCR was used to compare the mRNA expression levels of the surface markers of colon cancer stem cells (CD133 and PROM1), survivin, and vascular endothelial growth factor (VEGF).
  
  
  RESULTS
  Exposure to 200 µmol/L CoCl(2) for 8 h resulted in the highest HIF-1α expression in SW480 cells, but the same exposure failed to induce HIF-1α expression in CD133(+) SW480 subsets. The CD133(+) SW480 subsets, after CoCl(2)-induced hypoxia, showed significantly enhanced ability of cell sphere formation. Hypoxia of SW480 cells caused significant increases in CD133, survivin and VEGF mRNA levels by 1.607∓0.103, 2.745∓0.370 and 3.798∓0.091 folds, respectively (P<0.05).
  
  
  CONCLUSIONS
  CoCl(2) can simulate hypoxia in colon cancer cells in vitro to induce stable HIF-1α expression, which is concentration- and time-dependent. The hypoxia-stimulated tumor stem sells show an enhanced sphere formation and anti-apoptotic and anti-angiogenic abilities.
authors.affiliation: Department of Gastroenterology, Southern Medical University, Guangzhou, 510515, China. qingqing1961@126.com
authors.forename: Qing
authors.initials: Q
authors.lastname: Qing
authors.forename: Yuan-yuan
authors.initials: YY
authors.lastname: Wang
authors.forename: Shao-heng
authors.initials: SH
authors.lastname: Zhang
authors.forename: Hai-tao
authors.initials: HT
authors.lastname: Qing
authors.forename: Ya-dong
authors.initials: YD
authors.lastname: Wang
authors.forename: Chu-di
authors.initials: CD
authors.lastname: Chen
authors.forename: Bing
authors.initials: B
authors.lastname: Xiao
mesh_terms: D017209:Apoptosis / Q000502:physiology*; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000473:pathology*; D003198:Computer Simulation; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000473:pathology*; D009389:Neovascularization, Pathologic / Q000503:physiopathology*
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit