293FT is a highly suitable mammalian cell line for the in vitro enzymatic activity analysis of typical P450 proteins.

Mammalian cells have been widely used for the in vitro evaluation of the functional effect of allelic variants of cytochrome P450 (CYP). The aim of this study was to determine the most suitable mammalian cell line for the in vitro drug metabolism analysis of CYP variants. Three reported cell lines (COS-7, HepG2, 293T) and one fast-growing variant of the 293 cell line 293FT were transfected with vectors expressing green fluorescent protein or typical variants of CYP2C9, CYP2C19 or CYP2D6 to investigate the protein expression levels and the catalytic activity of expressed CYP allelic variants. The transfected 293FT cells had the highest protein expression level and exhibited the highest enzymatic activity, while HepG2 cells showed the lowest activity among the four tested cell lines. Simultaneously, 293FT cells still maintained the similar relative enzymatic ratio among three typical CYP2C9 variants to that of the commonly used COS-7 cells. In addition, 293FT cells could also be used for the in vitro functional evaluation of two other typical P450 proteins, CYP2C19 and CYP2D6. Therefore, the 293FT cell line is more suitable for the in vitro enzymatic activity analysis of typical P450 proteins than any other reported mammalian cell lines.