Table 2.

Elevation of cellular drug metabolism in relation to pregnane X receptor or steroid and xenobiotic receptor

Background on PXR/SXR research	Materials and methods	Results and discussion	Ref.
PXR can enhance detoxification of irinotecan in cancer cells	PXR cDNA-mediated expression in human colorectal cancer cell lines Human liver and colon biopsies	PXR cDNA-mediated overexpression led cell-resistance to irinotecan and SN38	Raynal et al.[25]
PXR/SXR is known to be involved in the upregulation of genes associated with the detoxification of irinotecan	ChIP with anti-PXR/SXR antibodies. PXR/SXR mediated induction of CYPs and ABC transporters after exposure of LS180 and HepG2 cells to irinotecan or SN-38	PXR enrichment induced by SN-38 treatment to CYP3A4 gene enhancer and promoter regions SN-38 induced CYP3A4/5 (6-13-fold) and UGT1A1 and MRP2 by 2-3-fold. PXR/SXR decreased irinotecan cytotoxicity in LS180	Basseville et al.[26]

ChIP: Chromatin-immunoprecipitation; PXR: pregnane X receptor; SXR: steroid and xenobiotic receptor; CYPs: cytochrome P-450; ABC: ATP-binding cassette.