Fig. 1.

PHHs cultured in 3D spheroids resemble freshly isolated cells regarding expression patterns of drug-metabolizing enzymes, drug transporters, and hepatic markers. (A) Expression of phase I (CYP2C8, CYP2C9, CYP2D6, and CYP3A4) and phase II (GSTT1 and UGTA1) metabolic enzymes, drug transporters (SLCO1B1 and ABCB11), ligand-activated nuclear receptors (CAR, PXR, and PPARA) as well as the critical hepatic transcription factor HNF4A and the main hepatocyte secretory product, albumin (ALB), were quantified in PHH spheroids by quantitative polymerase chain reaction and normalized to expression in freshly isolated cells of the same donors (n = 3 to 4 donors; donor demographics are shown in Table 1). Importantly, with the exception of CYP2C8 (33% of expression of freshly isolated cells, P = 0.001) and CYP2C9 (40%, P = 0.004), no significant differences in expression levels between freshly isolated cells and PHH spheroids were detected. Error bars indicate S.E.M. **P < 0.01 (heteroscedastic two-tailed t test). (B) Expression levels of genes analyzed in (A) were elevated up to 1834-fold in the 3D spheroids compared with 2D cultured PHHs from the same donors after 7 days in culture. FC, Fold change; n.s., not significant (P > 0.05).