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Cancer Lett. 2019 Aug 28;458:46-55. doi: 10.1016/j.canlet.2019.05.031. Epub 2019 May 24.

NRF2 antioxidant response protects against acidic bile salts-induced oxidative stress and DNA damage in esophageal cells.

Author information

1
Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA; Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA.
2
Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA.
3
Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Surgical Oncology, the First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China.
4
Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA; Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Veterans Affairs, Miami Healthcare System, Miami, FL, USA.
5
Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA; Sylvester Comprehensive Cancer Center, University of Miami Miller School of Medicine, Miami, FL, USA; Department of Veterans Affairs, Miami Healthcare System, Miami, FL, USA. Electronic address: welrifai@med.miami.edu.

Abstract

Gastroesophageal reflux disease (GERD) is the main risk factor for Barrett's tumorigenesis. In this study, we investigated the role of NRF2 in response to exposure to acidic bile salts (ABS), in conditions that mimic GERD, using Barrett's esophagus cell models. We detected an increase in NRF2 protein levels, following exposure to ABS. We found oxidization of cysteines (cysteines with oxidized thiol groups) in KEAP1 protein with a weaker interaction between NRF2 and KEAP1, following ABS exposure. Treatment with bile salts increased nuclear NRF2 levels, enhancing its transcription activity, as measured by an ARE (antioxidant response element) luciferase reporter assay. The mRNA expression levels of NRF2 target genes, HO-1 and GR, were increased in response to ABS exposure. Using genetic overexpression and knockdown of NRF2, we found that NRF2 has a critical role in suppressing ABS-induced ROS levels, oxidative DNA damage, DNA double strand breaks, and apoptosis. Collectively, our results suggest that transient induction of NRF2 in response to ABS plays a pivotal role in protecting esophageal cells by maintaining the levels of oxidative stress and DNA damage below lethal levels under GERD conditions.

KEYWORDS:

Barrett's; DNA damage; Oxidative stress

PMID:
31132430
PMCID:
PMC6571054
[Available on 2020-08-28]
DOI:
10.1016/j.canlet.2019.05.031

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