Genome-Wide Analysis of endometrial cancer Ishikawa cells: comparison to breast cancer T47D cells reveals cell-type specific mechanisms in response to progesterone and estradiol

LA GRECA A; SORONELLAS D; VALLEJO G; MERINO G; FRESNO C; VICENT GP; FERNÁNDEZ E; BEATO M; SARAGÜETA P

Trento

Simposio; 26th Pezcoller Symposium; 2014

Pezcoller Foundation

Progesterone (Pg) acting through the progesterone receptor (PR) is a major determinant in the development and progression of breast and endometrial pathologies. Though PR gene expression mechanisms are well described in breast cancer cells, it is still not fully understood how PR affects downstream signalling pathways and cross-talks with other intracellular signal transduction pathways in endometrial carcinoma cells. We aim to study the role of PR in cell-type specific response to Pg comparing human endometrial Ishikawa cells and the well characterized human breast cancer T47D cells. Genome-wide ChIP-seq analysis of untreated (T0) and 5 (R5), 30 (R30) and 60 (R60) min R5020 10 nM-treated Ishikawa cells revealed 256 PR binding sites (PRbs) of which the majority were located in proximal promoter regions (>=1 kb) of both treated and untreated cells. Strikingly, recent work in T47D cells (Ballaré et.al., 2013) show substantially more PRbs than Ishikawa cells. Of the 256 sites, 181 sites were already present in untreated cells and only 55 sites uniquely occurred in treated cells (14 in R30, 17 in R60 and 24 in both). Although none of the PRbs contained PREs, DNA motif analysis evinced binding sites for many transcription factors (GATA, SP and ELF). Global gene expression analysis in response to 12hs R5020 or estradiol (E2) was performed with RNA-seq technology to identify 1287 genes regulated by R5020 and 506 genes by E2. Remarkably, R5020 modulates 2.5 times more genes than E2 and nearly 55% of E2-regulated genes are also responsive to R5020. Taken together, these results suggest that the genomic role of PR in regulating chromatin remodeling and gene expression takes place mostly through sites occupied by the receptor beforehand and that R5020 would have a stronger impact on gene regulation than E2 in Ishikawa cells. Tissue-specific and common patterns of genome-wide PR binding and gene regulation may determine the therapeutic effects of antiprogestins in uterine pathologies and breast cancer.