title: Disulfiram deregulates HIF-α subunits and blunts tumor adaptation to hypoxia in hepatoma cells.
abstract: OBJECTIVE
  Disulfiram is an aldehyde dehydrogenase inhibitor that was used to treat alcoholism and showed anticancer activity, but its anticancer mechanism remains unclear. The aim of this study was to investigate the effects of disulfiram on the hypoxia-inducible factor (HIF)-driven tumor adaptation to hypoxia in vitro.
  
  
  METHODS
  Hep3B, Huh7 and HepG2 hepatoma cells were incubated under normoxic (20% O2) or hypoxic (1% O2) conditions for 16 h. The expression and activity of HIF-1α and HIF-2α proteins were evaluated using immunoblotting and luciferase reporter assay, respectively. Semi-quantitative RT-PCR was used to analyze HIF-mediated gene expression. Endothelial tubule formation assay was used to evaluate the anti-angiogenic effect.
  
  
  RESULTS
  Hypoxia caused marked expression of HIF-1α and HIF-1α in the 3 hepatoma cell lines, dramatically increased HIF activity and induced the expression of HIF downstream genes (EPO, CA9, VEGF-A and PDK1) in Hep3B cells. HIF-2α expression was positively correlated with the induction of hypoxic genes (CA9, VEGF-A and PDK1). Moreover, hypoxia markedly increased VEGF production and angiogenic potential of Hep3B cells. Disulfiram (0.3 to 2 μmol/L) inhibited hypoxia-induced gene expression and HIF activity in a dose-dependent manner. Disulfiram more effectively suppressed the viability of Hep3B cells under hypoxia, but it did not affect the cell cycle. Overexpression of HIF-2α in Hep3B cells reversed the inhibitory effects of disulfiram on hypoxia-induced gene expression and cell survival under hypoxia.
  
  
  CONCLUSIONS
  Disulfiram deregulates the HIF-mediated hypoxic signaling pathway in hepatoma cells, which may contribute to its anticancer effect. Thus, disulfiram could be used to treat solid tumors that grow in a HIF-dependent manner.
authors.affiliation: Sehwa Girls' High School, 56-7 Sinbanpo-ro, Seocho-gu, Seoul 137-040, Korea.
authors.forename: Hye-joon
authors.initials: HJ
authors.lastname: Park
authors.forename: Min-sung
authors.initials: MS
authors.lastname: Kim
authors.forename: Kumsun
authors.initials: K
authors.lastname: Cho
authors.forename: Jang-hyuk
authors.initials: JH
authors.lastname: Yun
authors.forename: Yong-joon
authors.initials: YJ
authors.lastname: Choi
authors.forename: Chung-hyun
authors.initials: CH
authors.lastname: Cho
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000502:physiology; D051792:Basic Helix-Loop-Helix Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy / Q000378:metabolism*; D015687:Cell Hypoxia / Q000187:drug effects / Q000502:physiology; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D004221:Disulfiram / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D056945:Hep G2 Cells; D061307:Human Umbilical Vein Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D021122:Protein Subunits / Q000037:antagonists & inhibitors / Q000096:biosynthesis; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D004221:Disulfiram; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D021122:Protein Subunits; D000099162:Endothelial PAS Domain-Containing Protein 1; C497442:HIF1A protein, human