Figure 4

Effects of dabrafenib and SR12813 on the proliferation of LS174T-hPXR cells. (A). LS174T control cells and LS174T hPXR cells were treated with 0.1% DMSO, 3 μM SPA70, 0.3 μM SR12813, 0.3 μM SR12813 + 3 μM SPA70, 0.3 μM dabrafenib and 0.3 μM dabrafenib + 3 μM SPA70 for 7 days. (B) LS174T hPXR cells were pretreated 24 h with SPA70 100 nM. This pretreatment was performed in order to reduce the basal proliferation of the cells, thus allowing a more sensitive detection of any PXR agonist activity that would result in growth induction. Then, medium was removed, cells were treated with increasing concentrations of SR12813 or dabrafenib for 7 days continuously, and cell growth was measured using MTT assay. Data are expressed as fold change in cell growth as compared to untreated cells and expressed as mean ± sd of three to six independent experiments, **** p < 0.0001, *** p < 0.001 (Student’s t-test) compared to DMSO-treated cells.