PXR and NF-κB correlate with the inducing effects of IL-1β and TNF-α on ABCG2 expression in breast cancer cell lines.

In this study we aimed to evaluate PXR and ABCG2 gene expression patterns and NF-κB activity induced by proinflammatory cytokines in different breast normal and carcinoma cells. The effects of proinflammatory cytokines on ABCG2 and PXR mRNA expression were studied using real-time PCR. Western blot analysis used for evaluating the protein levels of ABCG2, PXR and the active form of NF-κB (p65 in nuclear protein extract). Significant inductions in the ABCG2 and PXR mRNA and protein levels and NF-κB activity, were observed in MCF7, BT-474, CAL51, 184A1 and HBL100 cells, upon treatment with 50 ng/ml of IL-1β and TNF-α. On the contrary significant reduction of the ABCG2 and PXR mRNA and protein levels and NF-κB activity, were observed in MDA-MB-435 cell line. In conclusion, IL-1β and TNF-α induced ABCG2 and PXR expression and NF-κB activity in some breast cancer and normal cell lines. Similar patterns of induction and reduction in PXR and ABCG2 genes and NF-κB activity suggest a probable relationship between ABCG2, PXR and NF-κB.