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Updated: Apr 20, 2026

Co-immunoprecipitation Assay Using Endogenous Nuclear Proteins from Cells Cultured Under Hypoxic Conditions
Published on: August 2, 2018
Reactive oxygen species increase HEPN1 expression via activation of the XBP1 transcription factor
1Department of Biological Sciences, Seoul National University, Seoul 151-742, Republic of Korea.
Abstract:
Hepatocellular carcinoma downregulated 1 (HEPN1), a cell growth arrest- and apoptosis-related gene, is suppressed in hepatocellular carcinoma (HCC). However, transcriptional control of HEPN1 has not been characterized. Here, we show that exposure to reactive oxygen species (ROS) leads to upregulation of the mRNA expression of HEPN1 in HCC cell lines. Mechanistically, ROS increase production of an alternately spliced form of X-box binding protein 1 (XBP1s) and XBP1s increases HEPN1 expression by binding to the HEPN1 promoter, thereby acting as a transcriptional activator. Finally, HEPN1 overexpression increases the expression of p53, p21, and Bax, all of which are ROS-upregulated proteins.
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