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Toxicol Sci. 2016 Feb;149(2):372-84. doi: 10.1093/toxsci/kfv249. Epub 2015 Nov 24.

Calcium Contributes to the Cytotoxic Interaction Between Diclofenac and Cytokines.

Author information

1
Department of Pharmacology and Toxicology, Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824 rothr@msu.edu.
2
Department of Pharmacology and Toxicology, Institute for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824.

Abstract

Diclofenac (DCLF) is a widely used non-steroidal anti-inflammatory drug that is associated with idiosyncratic, drug-induced liver injury (IDILI) in humans. The mechanisms of DCLF-induced liver injury are unknown; however, patients with certain inflammatory diseases have an increased risk of developing IDILI, which raises the possibility that immune mediators play a role in the pathogenesis. DCLF synergizes with the cytokines tumor necrosis factor-alpha (TNF) and interferon-gamma (IFN) to cause hepatocellular apoptosis in vitro by a mechanism that involves activation of the endoplasmic reticulum (ER) stress response pathway and of the mitogen-activated protein kinases, c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinase (ERK). DCLF also causes an increase in intracellular calcium (Ca(++)) in hepatocytes, but the role of this in the cytotoxic synergy between DCLF and cytokines is unknown. We tested the hypothesis that Ca(++) contributes to DCLF/cytokine-induced cytotoxic synergy. Treatment of HepG2 cells with DCLF led to an increase in intracellular Ca(++) at 6 and 12 h, and this response was augmented in the presence of TNF and IFN at 12 h. The intracellular Ca(++) chelator BAPTA/AM reduced cytotoxicity and caspase-3 activation caused by DCLF/cytokine cotreatment. BAPTA/AM also significantly reduced DCLF-induced activation of the ER stress sensor, protein kinase RNA-like ER kinase (PERK), as well as activation of JNK and ERK. Treatment of cells with an inositol trisphosphate receptor antagonist almost completely eliminated DCLF/cytokine-induced cytotoxicity and decreased DCLF-induced activation of PERK, JNK, and ERK. These findings indicate that Ca(++) contributes to DCLF/cytokine-induced cytotoxic synergy by promoting activation of the ER stress-response pathway and JNK and ERK.

KEYWORDS:

BAPTA/AM; ER stress; MAPK; calcium; caspase; diclofenac; idiosyncratic drug-induced liver injury; interferon-gamma; non-steroidal anti-inflammatory drugs; tumor necrosis factor

PMID:
26609140
PMCID:
PMC4900219
DOI:
10.1093/toxsci/kfv249
[Indexed for MEDLINE]
Free PMC Article

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