Figure 2. PXR expression is increased in colorectal ALDH^br CSCs.

a. Aldefluor assay and gates used for CRC1 cell-sorting. The ALDH inhibitor DEAB was added to identify ALDH-positive (ALDH^br) cells. b. Percentage of sphere-forming cells of the ALDH^br and ALDH^lo populations. c. Percentage of surviving cells, 72 hours after exposure of ALDH^br and ALDH^lo cells to the indicated concentrations of Firi (1X=50μM 5-FU + 500nM SN38). Data are expressed as mean ± SEM of 3 experiments, and half maximal effective concentrations (EC₅₀) are indicated. d. RT-qPCR analyses of mRNA expression for PXR, PXR targets and CSC marker genes in the ALDH^br compared to the ALDH^lo population (F.I., Fold Induction). e. RT-qPCR quantification of PXR mRNA in ALDH^br and ALDH^lo cells from CRC cell lines. d,e: Data are expressed as mean ± SEM (n=3) and reported as fold change compared to ALDH^lo cells. f. ALDH1A1, PXR, GAPDH and β-ACTIN protein expression in unsorted (NS), ALDH^lo and ALDH^br CRC1 cells. g. PXR transcriptional activity was determined in ALDH^lo and ALDH^br CRC1 cells 24 hours after transfection with luciferase reporter plasmids. Data are expressed as mean ± SEM (n=3) of luciferase/β-Galactosidase ratio. *, p<0.05; **, p<0.005.