upcyte® Hepatocytes express functional Phase I and II enzyme activities that are stable in long-term cultures. Therefore these cells represent a reliable model with which to determine clearance and metabolite profiles in drug metabolism studies.
upcyte® Hepatocytes exhibit basal CYP1A2, CYP2B6, CYP2C9 and CYP3A4 which are all induced by prototypical inducers (Figure 1). As with primary human hepatocytes, the induction response is donor-dependent; therefore, we offer a panel of different donors with a range of induction responses to choose from. The CYP induction responses in upcyte® Hepatocytes are reproducible across different stages of their growth - from the freshly "upcyted" cells to the final product. In addition, upcyte technologies has generated the upcyte® Hepatocyte cell strain 653-03-2D6, which stably expresses CYP2D6 (information & data see below).
Figure 1: Basal and induced activities in 2 different Lots of upcyte® Hepatocytes.
Figure 2: RIS calibration curve for upcyte® Hepatocytes from Donor 422A-03.
Known potent, mild and non- CYP3A4 inducers were used to create a calibration curve, correlating the "Relative Induction Score" (RIS, Fahmi et al., Drug Metab Dispos. 2008, 36(9):1971-4.) with known in vivo induction effects (% decrease in the AUC of ethinyl estradiol). Using this calibration curve, upcyte® Hepatocytes can be used to predict the in vivo CYP3A4 induction potential of test compounds.
CYP2D6 is responsible for metabolism and elimination of approximately 25% of clinically used drugs. This enzyme metabolizes several endogenous substances such as hydroxytryptamines and neurosteroids. There is considerable variation in efficiency and amount of CYP2D6 among individuals. Some people will eliminate certain drugs quickly (ultrarapid metabolizers), others slowly (poor metabolizers). The upcyte® Hepatocyte cell strain from donor 653-03 expresses a number of endogenous CYP enzymes but merely low levels (5 pmol/mL) of CYP2D6 (see figure below). In the 653-03-2D6 cell strain on the other hand, recombinant CYP2D6 is stably expressed with a basal activity of over 1600 pmol/mL in 0.1% DMSO. In comparison, HepaRG cells almost completely lack CYP2D6 activity with less than 1 pmol/mL. Due to their long viability in culture, CYP2D6 competent upcyte® Hepatocytes are ideal for long term clearance studies in early drug discovery.
Figure 3: Basal activities of upcyte® Hepatocytes from Donor 653-03-2D6..