Journal Article

In vitro Biologic Activities of the Antimicrobials Triclocarban, Its Analogs, and Triclosan in Bioassay Screens: Receptor-Based Bioassay Screens

Cherednichenko, Gennady, Pessah, Isaac N., Gee, Shirley J., Sanmarti, Enio, Chen, Jiangang, Ahn, Ki Chang, Denison, Michael S., Chang, Daniel P. Y., Zhao, Bin, Lasley, Bill, Hammock, Bruce D., Kültz, Dietmar

2008

Overview

Background: Concerns have been raised about the biological and toxicologic effects of the anti-microbials triclocarban (TCC) and triclosan (TCS) in personal care products. Few studies have evaluated their biological activities in mammalian cells to assess their potential for adverse effects. Objectives: In this study, we assessed the activity of TCC, its analogs, and TCS in in vitro nuclear-receptor-responsive and calcium signaling bioassays. Materials and methods: We determined the biological activities of the compounds in in vitro, cell-based, and nuclear-receptor-responsive bioassays for receptors for aryl hydrocarbon (AhR), estrogen (ER), androgen (AR), and ryanodine (RyR1). Results: Some carbanilide compounds, including TCC (1-10 μM), enhanced estradiol (E₂)-dependent or testosterone-dependent activation of ER- and AR-responsive gene expression up to 2.5-fold but exhibited little or no agonistic activity alone. Some carbanilides and TCS exhibited weak agonistic and/or antagonistic activity in the AhR-responsive bioassay. TCS exhibited antagonistic activity in both ER- and AR-responsive bioassays. TCS (0.1-10 μM) significantly enhanced the binding of [³H]ryanodine to RyR1 and caused elevation of resting cytosolic [Ca²⁺] in primary skeletal myotubes, but carbanilides had no effect. Conclusions: Carbanilides, including TCC, enhanced hormone-dependent induction of ER- and AR-dependent gene expression but had little agonist activity, suggesting a new mechanism of action of endocrine-disrupting compounds. TCS, structurally similar to noncoplanar ortho-substituted polychlorinated biphenyls, exhibited weak AhR activity but interacted with RyR1 and stimulated Ca²⁺ mobilization. These observations have potential implications for human and animal health. Further investigations are needed into the biological and toxicologic effects of TCC, its analogs, and TCS.

• Publisher: National Institute of Environmental Health Sciences. National Institutes of Health. Department of Health, Education and Welfare,National Institute of Environmental Health Sciences
• Subject: Activation / Analogs / Animal health / Animals / Anti-Bacterial Agents - pharmacology / Antimicrobial agents / Antimicrobials / Aromatic compounds / Bills / Binding / Bioassay / Bioassays / Biological / Biological Assay / Calcium / Carbanilides / Carbanilides - pharmacology / Cell lines / Consumer products / Copyrights / Drugs / Elevation / Environmental health / Estrogens / Gene expression / Health / Health aspects / Human / Humans / Hydrocarbons / In Vitro Techniques / In vitro testing / Measurement / Methods / Models, Molecular / Receptors / Receptors, Cell Surface - drug effects / Reporter genes / Screens / Testosterone / Transitional cell carcinoma / Triclocarban / Triclosan / Triclosan - pharmacology / Tumor Cells, Cultured