Expression data from human hepatocellular carcinoma cell line HepG2

ABSTRACT: Drug-induced liver injury (DILI) is an important clinical problem. Here we used a genomics approach to establish the critical drug-induced toxicity pathways that act in synergy with the pro-inflammatory cytokine tumor necrosis factor (TNF) to cause cell death of liver HepG2 cells. Transcriptomics of the cell injury stress response pathways initiated by two hepatoxicants, diclofenac and carbamazepine, revealed the endoplasmic reticulum (ER) stress/translational initiation signaling and Nrf2 antioxidant signaling as two major affected pathways, which was similar to that observed for the majority of ~80 DILI compounds in primary human hepatocytes. The ER stress was primarily related to PERK and ATF4 activation and subsequent expression of CHOP, which was all independent of TNFα signaling. Identical ATF4 dependent transcriptional programs were observed in primary human hepatocytes as well as primary precision cut human liver slices. Targeted RNA interference studies revealed that while ER stress signaling through IRE1α and ATF6 acted cytoprotective, activation of the ER stress protein kinase PERK and subsequent expression of CHOP was pivotal for the onset of drug/TNF-induced apoptosis. While inhibition of the Nrf2-dependent adaptive oxidative stress response enhanced the drug/TNF cytotoxicity, Nrf2 signaling did not affect CHOP expression. Both hepatotoxic drugs enhanced expression of the translational initiation factor EIF4A1, which was essential for CHOP expression and drug/TNF-mediated cell killing. Our data support a model in which enhanced drug-induced translation initiates PERK-mediated CHOP signaling in an EIF4A1 dependent manner, thereby sensitizing towards caspase-8-dependent TNF induced apoptosis. We sought to determine the effect of co-exposure of certain drugs associated with idiosyncratic DILI with the cytokine TNFalpha to mimic drug exposure with inflammation signaling in HepG2 cells Human hepatoma HepG2 cells were obtained from American Type Culture Collection (ATCC, Wesel, Germany), cultured in DMEM supplemented with 10% (v/v) FBS, 25 U/mL penicillin and 25 µg/mL streptomycin and used for experiments between passage 5 and 20.

ORGANISM(S): Homo sapiens

SUBMITTER: Steven Wink 

PROVIDER: E-GEOD-54254 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress