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Updated: Jun 21, 2026
09:17
Co-immunoprecipitation Assay Using Endogenous Nuclear Proteins from Cells Cultured Under Hypoxic Conditions
Published on: August 2, 2018
STAT1 represses hypoxia-inducible factor-1-mediated transcription
Miki Hiroi1, Kazumasa Mori, Yoshiichi Sakaeda
1Department of Oral Biology and Tissue Engineering, Meikai University of School of Dentistry, Sakado, Saitama, Japan.
Biochemical and Biophysical Research Communications
|August 4, 2009
Summary
Interferon-gamma (IFNgamma) inhibits hypoxia-induced CXCR4 gene expression in glioblastoma cells. This inhibition is mediated by signal transducer and activator of transcription 1 (STAT1), acting as a negative regulator of hypoxia-inducible factor 1 (HIF-1) transcription.
Area of Science:
- Molecular Biology
- Cancer Research
- Immunology
Background:
- Tumor hypoxia promotes cancer progression and therapy resistance.
- Hypoxia induces genes like CXCR4 via hypoxia-inducible factor 1 (HIF-1).
- Interferon-gamma (IFNgamma) has anti-tumor effects, but its impact on HIF-1 is unclear.
Purpose of the Study:
- To investigate IFNgamma's effect on hypoxia-induced CXCR4 expression in glioblastoma.
- To elucidate the mechanism behind IFNgamma's potential inhibitory action.
- To determine the role of signal transducer and activator of transcription 1 (STAT1) in this process.
Main Methods:
- Human glioblastoma cell lines (A172, T98G) were exposed to hypoxia or deferoxamine (DFX).
- CXCR4 mRNA levels, HIF-1alpha protein, and DNA-binding activity were assessed.
- Luciferase reporter assays and RNA interference (RNAi) for STAT1 were employed.
Main Results:
- Hypoxia and DFX increased CXCR4 mRNA, HIF-1alpha, and HIF-1 DNA-binding activity.
- IFNgamma inhibited hypoxia-induced CXCR4 mRNA expression but not HIF-1alpha levels or DNA-binding.
- IFNgamma suppressed hypoxia-induced reporter gene activity, dependent on STAT1 activation.
Conclusions:
- IFNgamma inhibits hypoxia-induced CXCR4 gene expression in glioblastoma.
- STAT1 activation by IFNgamma acts as a negative regulator of HIF-1-dependent transcription.
- This pathway offers potential therapeutic targets for glioblastoma.
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