EPA Science Inventory

Metabolic Disruption Early in Life is Associated With Latent Carcinogenic Activity of Dichloroacetic Acid in Mice

Citation:

Wehmas, L., A. Deangelo, S. Hester, B. Chorley, G. Carswell, G. Olson, M. George, J. Carter, S. Eldridge, A. Fisher, B. Vallanat, AND C. Wood. Metabolic Disruption Early in Life is Associated With Latent Carcinogenic Activity of Dichloroacetic Acid in Mice. TOXICOLOGICAL SCIENCES. Society of Toxicology, 159(2):354-365, (2017).

Description:

Early-life environmental factors can influence later-life susceptibility to cancer. Recent evidence suggests that metabolic pathways may mediate this type of latency effect. Previously, we reported that short-term exposure to dichloroacetic acid (DCA) increased liver cancer in mice 84 weeks after exposure was stopped. Here, we evaluated time course dynamics for key events related to this effect. This study followed a stop-exposure design in which 28-day-old male B6C3F1 mice were given the following treatments in drinking water for up to 93 weeks: deionized water (dH2O, control); 3.5 g/l DCA continuously; or 3.5 g/l DCA for 4–52 weeks followed by dH2O. Effects were evaluated at eight interim time points. A short-term biomarker study was used to evaluate DCA effects at 6, 15, and 30 days. Liver tumor incidence was higher in all DCA treatment groups, including carcinomas in 82% of mice previously treated with DCA for only 4 weeks. Direct effects of DCA in the short-term study included decreased liver cell proliferation and marked mRNA changes related to mitochondrial dysfunction and altered cell metabolism. However, all observed short-term effects of DCA were ultimately reversible, and prior DCA treatment did not affect liver cell proliferation, apoptosis, necrosis, or DNA sequence variants with age. Key intermediate events resulting from transient DCA exposure do not fit classical cytotoxic, mitogenic, or genotoxic modes of action for carcinogenesis, suggesting a distinct mechanism associated with early-life metabolic disruption..

Purpose/Objective:

This study supports goals of the Adverse Outcome Pathway Discovery and Development (AOPDD) Project Cancer AOP Task (CSS 17.01.1g). One of the primary aims of this task is to identify biomarkers of susceptibility based on early events in AOPs for cancer. This study was conducted to examine non-genetic pathways driving latent cancer risk. This work supports FY17 Key Product 1 (Putative AOPs and their Applications) by developing a novel AOP for cancer incorporating metabolic programming and life stage susceptibility.

URLs/Downloads:

https://doi.org/10.1093/toxsci/kfx146   Exit

Record Details:

Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Start Date: 07/20/2017
Completion Date: 07/20/2017
Record Last Revised: 12/07/2017
Record Created: 12/07/2017
Record Released: 12/07/2017
OMB Category: Other
Record ID: 338617

Organization:

U.S. ENVIRONMENTAL PROTECTION AGENCY

OFFICE OF RESEARCH AND DEVELOPMENT

NATIONAL HEALTH AND ENVIRONMENTAL EFFECTS RESEARCH LABORATORY

INTEGRATED SYSTEMS TOXICOLOGY DIVISION

CARCINOGENESIS BRANCH