Deregulation of Cancer-Related Pathways in Primary Hepatocytes Derived from DNA Repair-Deficient Xpa−/−p53+/− Mice upon Exposure to Benzo[a]pyrene

Abstract

The current method to predict carcinogenicity of chemicals or drugs is the chronic 2-year rodent bioassay, which has disadvantages in duration, animal use, and specificity. An attractive alternative is the DNA repair-deficient Xpa(-/-)p53(+/-) mouse model that is sensitive to both genotoxic and nongenotoxic carcinogens. A next step in alternative carcinogenicity testing is the development of reliable in vitro systems. We investigated the use of primary hepatocytes, isolated from wild-type (WT) and Xpa(-/-)p53(+/-) mice, in combination with transcriptome analyses for their usefulness to predict carcinogenic features of compounds. As a proof of principle, we studied the response of hepatocytes to the genotoxic carcinogen benzo[a]pyrene (B[a]P). Upon treatment, both WT and Xpa(-/-)p53(+/-) hepatocytes appeared to be metabolically active. However, Xpa(-/-)p53(+/-) hepatocytes were more sensitive than WT hepatocytes to B[a]P treatment in terms of cell survival. In B[a]P-treated WT hepatocytes, DNA repair and cell cycle control genes were transcriptionally activated. Xpa(-/-)p53(+/-) hepatocytes were more responsive to B[a]P exposure, resulting in the downregulation of cancer-related pathways. Deregulation of mitogen-activated protein kinase signaling seems to play an essential role in this and might be the underlying reason for the increased susceptibility of Xpa(-/-)p53(+/-) mice toward carcinogens. Our conclusion is that primary hepatocytes combined with transcriptomics are promising to identify the carcinogenic features of chemicals. Furthermore, these cells seem suitable to gain further insight into the molecular mechanisms of the increased sensitivity of Xpa(-/-)p53(+/-) mice toward both genotoxic and nongenotoxic carcinogens.

Genome-Wide Functional and Stress Response Profiling Reveals Toxic Mechanism and Genes Required for Tolerance to Benzo[a]pyrene in S. cerevisiae

“…Similarly, LIG4 upregulation has been associated with tobacco-related cancers and not BaP specifically, though BaP is a component of tobacco smoke (Wu et al, 2004). In addition, rodent studies of rats and mice found ortholog upregulation of UBE2B and PRDX5 as well as downregulation of DTD1 (Chen et al, 2001; van Kesteren et al, 2011). While none of the genes in Table 7, with the exception of select solute carriers previously discussed and VDAC1, have been conclusively linked to adverse outcomes in human cells and BaP exposure, they represent candidate susceptibility loci as they are related to carcinogenesis pathways.…”

A roadmap for the development of alternative (non-animal) methods for systemic toxicity testing

“…For carcinogenicity, in vitro transcriptomics approaches are emerging (Guyton et al, 2009;Jacobs, 2009;van Kesteren et al, 2011;Vinken et al, 2008). These have been applied initially to genotoxic carcinogens , but the approach makes just as much sense for the non-genotoxic mechanisms, and there are early indications that genotoxic and non-genotoxic effects can be discriminated (Magkoufopoulou et al, 2011;Plant, 2008).…”

“…ITS are a consequence of REACH (van Leeuwen et al, 2007), which argues for the use of all available information and views use of the definitive animal experiment only as a last resort. However, the ITS suggested for reproductive toxicity (Fig.…”

Screening for Drug-Induced Hepatotoxicity in Primary Mouse Hepatocytes Using Acetaminophen, Amiodarone, and Cyclosporin A as Model Compounds: An Omics-Guided Approach

“…+/-mouse have been considered as a model for carcinogenicity screening (van Kesteren et al, 2011). As such, primary mouse hepatocytes seem a promising model for hepatic toxicity studies.…”