Reversion of chemoresistance in PXR2 by PXR shRNA. A, quantification of PXR expression by quantitative PCR (top) and western blot (bottom). * p < 0.05 (Mann and Whitney test), PXR expression in PXR2-Mock, PXR2-sh1334 and PXR2-sh2116 cells compared to pcDNA3-Mock cells. B, quantification of CYP3A4 mRNA expression after treatment by solvent (DMSO 0.1%) or 10 μM rifampicin for 24 h in serum-free medium. * p < 0.05 (Mann and Whitney test), CYP3A4 expression of cells treated by rifampicin compared to the vehicle treated groups. C, cell viability assay on pcDNA3-Mock, PXR2-Mock, PXR2-sh1334 and PXR2-sh2116 toward SN38. Columns, mean viability as a percentage of control (i.e., cells without chemotherapeutics treatment, 100%) from replicates (n = 6) from six separate experiments; bars, SEM. Student's t-test where performed between CTRL-mock cells to PXR2-Mock, PXR2-sh1334 and PXR2-sh2116: *** p < 0.001, ** p < 0.01, * p < 0.05.