The redox state of glutathione regulates the hypoxic induction of HIF-1.
Hypoxia inducible factor 1 (HIF-1) regulates the transcription of vascular endothelial growth factor (VEGF), which plays important roles in angiogenesis. We investigated the redox effect of glutathione (GSH) on the hypoxic induction of HIF-1 in a human oral squamous cell carcinoma (HSC-2) cell line. The maximal induction of HIF-1 in HSC-2 cells was observed 30 h after hypoxia, and VEGF mRNA was expressed after 36 h under hypoxia. GSH ethyl ester (GSHee, a membrane permeable analog of GSH) and N-acetyl-L-cysteine (NAC, a membrane permeable precursor of GSH) reduced HIF-1 binding activity in a dose-dependent manner. Further, HIF-1 dependent promoter activity was similarly reduced by GSHee and NAC. However, ebselen, which increases glutathione peroxidase activity and oxidizes GSH, negated the effect of GSHee on HIF-1 dependent promoter activity. The inhibitory effect of GSHee and NAC on HIF-1 binding activity was reversed by bis (2-chlorethyl)-nitrosourea, an oxidized glutathione (GSSG) reductase inhibitor which increases the concentration of GSSG. GSSG methyl ester (GSSGme), a membrane permeable analog of GSSG, enhanced HIF-1 dependent promoter activity and exhibited a bell-shaped concentration-dependant activity curve. The increasing effect of GSSGme on HIF-1 induction was also observed under chemically-induced hypoxia obtained using cobalt chloride. These results suggest that changes in the intracellular GSSG/GSH ratio may regulate HIF-1 induction during hypoxia.
Department of Diagnostic and Therapeutic Sciences, Division of Pharmacology, Meikai University School of Dentistry, Sakado, Saitama, Japan. mtajima@dent.meikai.ac.jp
Masamichi
M
Tajima
Yukiko
Y
Kurashima
Kenji
K
Sugiyama
Tsutomu
T
Ogura
Hiroshi
H
Sakagami
D000111:Acetylcysteine / Q000494:pharmacology; D000818:Animals; D001393:Azoles / Q000494:pharmacology; D045744:Cell Line, Tumor; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology*; D019803:Glutathione Disulfide / Q000494:pharmacology; D005980:Glutathione Reductase / Q000037:antagonists & inhibitors / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000378:metabolism*; D051793:Hypoxia-Inducible Factor 1 / Q000378:metabolism*; D054833:Isoindoles; D016566:Organoselenium Compounds / Q000494:pharmacology; D010084:Oxidation-Reduction; D012333:RNA, Messenger / Q000235:genetics; D015533:Transcriptional Activation / Q000187:drug effects*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics
D001393:Azoles; D004791:Enzyme Inhibitors; D051793:Hypoxia-Inducible Factor 1; D054833:Isoindoles; D016566:Organoselenium Compounds; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C042986:ebselen; C042431:S-ethyl glutathione; D005980:Glutathione Reductase; D005978:Glutathione; D019803:Glutathione Disulfide; D000111:Acetylcysteine