Metabolic Activation of Cholestatic Drug-Induced Bile Acid-Dependent Toxicity in Human Sandwich-Cultured Hepatocytes

Abstract We previously reported a cell-based toxicity assay using sandwich-cultured hepatocytes in combination with a titrated amount of human bile acid (BA) species. In this assay, test compound-induced inhibition of BA efflux from sandwich-cultured hepatocytes leads to BA-dependent cell toxicity (BA tox , i.e., cell death due to the accumulation of BAs). Using this assay, we investigated whether 1-aminobenzotriazole (1-ABT; a nonselective cytochrome P450 inhibitor) enhanced or suppressed test compound-induced BA tox . There was a tendency that BA tox of many compounds was enhanced by 1-ABT in human hepatocytes; in contrast, such a tendency was not observed in rat hepatocytes. In particular, 1-ABT tended to enhance BA tox of several compounds (clopidogrel, ticlopidine, everolimus, etc.) in human, whereas 1-ABT tended to enhance BA tox of only ticlopidine in rat. These results indicate that this system can be used to evaluate BA tox while taking into account drug metabolism and the existence of an interspecies difference in the effect of 1-ABT treatment on BA tox .