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Differential transcriptional regulation of hypoxia-inducible factor-1α by arsenite under normoxia and hypoxia: involvement of Nrf2.
- Source :
-
Journal of molecular medicine (Berlin, Germany) [J Mol Med (Berl)] 2016 Oct; Vol. 94 (10), pp. 1153-1166. Date of Electronic Publication: 2016 Jun 10. - Publication Year :
- 2016
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Abstract
- Arsenite (As(III)) is widely distributed in nature and can be found in water, food, and air. There is significant evidence that exposure to As(III) is associated with human cancers originated from liver, lung, skin, bladder, kidney, and prostate. Hypoxia plays a role in tumor growth and aggressiveness; adaptation to it is, at least to a large extent, mediated by hypoxia-inducible factor-1α (HIF-1α). In the current study, we investigated As(III) effects on HIF-1α under normoxia and hypoxia in the hepatoma cell line HepG2. We found that As(III) increased HIF-1α protein levels under normoxia while the hypoxia-mediated induction of HIF1α was reduced. Thereby, the As(III) effects on HIF-1α were dependent on both, transcriptional regulation via the transcription factor Nrf2 mediated by NOX4, PI3K/Akt, and ERK1/2 as well as by modulation of HIF-1α protein stability. In line, the different effects of As(III) via participation of HIF-1α and Nrf2 were also seen in tube formation assays with endothelial cells where knockdown of Nrf2 and HIF-1α abolished As(III) effects. Overall, the present study shows that As(III) is a potent inducer of HIF-1α under normoxia but not under hypoxia which may explain, in part, its carcinogenic as well as anti-carcinogenic actions.<br />Key Message: As(III) increased HIF-1α under normoxia but reduced its hypoxia-dependent induction. The As(III) effects on HIF-1α were dependent on ROS, NOX4, PI3K/Akt, and ERK1/2. The As(III) effects under normoxia involved transcriptional regulation via Nrf2. Knockdown of Nrf2 and HIF-1α abolished As(III) effects in tube formation assays. The data may partially explain As(III)'s carcinogenic and anti-carcinogenic actions.<br />Competing Interests: The authors declare that they have no conflict of interest.
- Subjects :
- Animals
Antineoplastic Agents pharmacology
Carcinogens pharmacology
Cell Hypoxia physiology
Cell Line
Cells, Cultured
Extracellular Signal-Regulated MAP Kinases
Fibroblasts drug effects
Fibroblasts metabolism
Heme Oxygenase-1 genetics
Hep G2 Cells
Humans
Hypoxia-Inducible Factor 1, alpha Subunit metabolism
Mice
NADPH Oxidase 4
NADPH Oxidases
NF-E2-Related Factor 2
Phosphatidylinositol 3-Kinases
Plasminogen Activator Inhibitor 1 genetics
Proto-Oncogene Proteins c-akt
Reactive Oxygen Species metabolism
Arsenites pharmacology
Cell Hypoxia genetics
Gene Expression Regulation drug effects
Hypoxia-Inducible Factor 1, alpha Subunit genetics
Subjects
Details
- Language :
- English
- ISSN :
- 1432-1440
- Volume :
- 94
- Issue :
- 10
- Database :
- MEDLINE
- Journal :
- Journal of molecular medicine (Berlin, Germany)
- Publication Type :
- Academic Journal
- Accession number :
- 27286880
- Full Text :
- https://doi.org/10.1007/s00109-016-1439-7