Acetaminophen cytotoxicity in HepG2 cells is associated with a decoupling of glycolysis from the TCA cycle, loss of NADPH production, and suppression of anabolism

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Title: Acetaminophen cytotoxicity in HepG2 cells is associated with a decoupling of glycolysis from the TCA cycle, loss of NADPH production, and suppression of anabolism
Authors: Behrends, V
Giskeodegard, GF
Bravo-Santano, N
Letek, M
Keun, HC
Item Type: Journal Article
Abstract: Acetaminophen (APAP) is one of the most commonly used analgesics worldwide, and overdoses are associated with lactic acidosis, hepatocyte toxicity, and acute liver failure due to oxidative stress and mitochondrial dysfunction. Hepatoma cell lines typically lack the CYP450 activity to generate the reactive metabolite of APAP observed in vivo, but are still subject to APAP cytotoxicity. In this study, we employed metabolic profiling and isotope labelling approaches to investigate the metabolic impact of acute exposure to cytotoxic doses of APAP on the widely used HepG2 cell model. We found that APAP exposure leads to limited cellular death and substantial growth inhibition. Metabolically, we observed an up-regulation of glycolysis and lactate production with a concomitant reduction in carbon from glucose entering the pentose-phosphate pathway and the TCA cycle. This was accompanied by a depletion of cellular NADPH and a reduction in the de novo synthesis of fatty acids and the amino acids serine and glycine. These events were not associated with lower reduced glutathione levels and no glutathione conjugates were seen in cell extracts. Co-treatment with a specific inhibitor of the lactate/H+ transporter MCT1, AZD3965, led to increased apoptosis in APAP-treated cells, suggesting that lactate accumulation could be a cause of cell death in this model. In conclusion, we show that APAP toxicity in HepG2 cells is largely independent of oxidative stress, and is linked instead to a decoupling of glycolysis from the TCA cycle, lactic acidosis, reduced NADPH production, and subsequent suppression of the anabolic pathways required for rapid growth.
Issue Date: 1-Feb-2019
Date of Acceptance: 4-Dec-2018
URI: http://hdl.handle.net/10044/1/69363
DOI: https://doi.org/10.1007/s00204-018-2371-0
ISSN: 0340-5761
Publisher: Springer
Start Page: 341
End Page: 353
Journal / Book Title: Archives of Toxicology
Volume: 93
Issue: 2
Copyright Statement: © 2018 The Authors. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativeco mmons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.
Sponsor/Funder: Commission of the European Communities
Funder's Grant Number: 602156
Keywords: Science & Technology
Life Sciences & Biomedicine
Toxicology
Acetaminophen
Metabolomics
GC-MS
NMR
Isotopomer spectral analysis
HepG2
N-ACETYLCYSTEINE
HEPARG CELLS
METABOLISM
HEPATOTOXICITY
MECHANISMS
SPECTROSCOPY
METABONOMICS
AZD3965
DRUGS
GC–MS
1115 Pharmacology and Pharmaceutical Sciences
Publication Status: Published
Online Publication Date: 2018-12-14
Appears in Collections:Division of Surgery
Division of Cancer



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