The expression of Phase II drug-metabolizing enzymes in human B-lymphoblastoid TK6 cells

Abstract

In vitro genotoxicity testing plays an important role in chemical risk assessment. The human B-lymphoblastoid cell line TK6 is widely used as a standard cell line for regulatory safety evaluations. Like many other mammalian cell lines, TK6 cells have limited metabolic capacity; therefore, usually require a source of exogenous metabolic activation for use in genotoxicity testing. Previously, we developed a set of TK6-derived cell lines that individually express one of fourteen cytochrome P450s (CYPs). In the present study, we surveyed a panel of major Phase II drug-metabolizing enzymes to characterize their baseline expression in TK6 cells. These results may serve as a reference enzymatic profile of this commonly used cell line.

Keywords:

• Human TK6 cells
• genotoxicity testing
• biotransformation
• Phase II drug-metabolizing enzymes

Acknowledgments

This manuscript reflects the views of the authors and does not necessarily reflect those of the U.S. FDA. We thank Drs. Dayton M. Petibone and Baitang Ning for their critical review of this manuscript.

Additional information

Funding

XL and YL were supported by an appointment to the Postgraduate Research Program at the National Center for Toxicological Research (NCTR), and KGN was supported by an appointment to the Summer Student Research Program; both programs are administered by the Oak Ridge Institute for Science Education through an interagency agreement between the U.S. Department of Energy and the U.S. Food and Drug Administration (FDA).