A transcriptional complex composed of ER(α), GATA3, FOXA1 and ELL3 regulates IL-20 expression in breast cancer cells.

Interleukin-20 (IL-20) is a member of the IL-10 family. IL-20 expression is regulated by a transcription elongation factor, Ell3, in estrogen receptor-positive (ER(+)) breast cancer cells. In this study, we demonstrated that ER(α), GATA3 and FOXA1 form a transcriptional complex with Ell3 to regulate IL-20 expression in ER(+) breast cancer cells. We also determined that GATA3 and FOXA1 share a binding site with ER(α) in the interleukin-20 promoter. Furthermore, we found that FOXA1 represses IL-20 expression, whereas GATA3 and ER(α) activate it. In addition, we demonstrated that Ell3 associates with ER(α) to increase its binding affinity to the IL-20 promoter, which may prevent FOXA1 binding to the same region of this promoter. Our results expand upon the current understanding of the regulatory mechanism of IL-20 in cancer.