Figure 4. Inhibition of the PXR effects on OATP1A2 using a specific PXR inhibitor.
Cell based reporter gene assays in HepG2 cells using the reporter vector containing the −5120 to −6600 fragment of the OATP1A2 gene was performed to determine the ability of A-792611 (10 μM) to inhibit the rifampin (10 μM) associated PXR mediated transactivation (4A). T47-D cells were treated with rifampin (10 μM) in the presence of different concentrations of A-792611 to determine the modulation of OATP1A2 expression using real-time RT-PCR (4B). Western Blot analysis was performed to evaluate the effect of rifampin (1μM) in the presence and absence of the PXR inhibitor A-792611 (1μM) on OATP1A2 expression in T47-D cells (4C). Cell lysates of HeLa cells transfected with OATP1A2-pEF6 or pEF6-vector only were used as positive and negative controls. Actin expression was assessed in the same blot to visualize equivalent sample loading for the cell lysates (4C).