Estrogen Receptor Beta Impacts Hormone-Induced Alternative mRNA Splicing in Breast Cancer Cells

Estrogens play an important role in breast cancer (BC) development and progression, where the two isoforms of the estrogen receptor (ERa and ERß) are generally co-expressed and mediate the effects of these hormones in cancer cells. ERß has been suggested to exert an antagonist role toward the oncogenic activities of ERa, and for this reason it is considered an oncosuppressor. As clinical evidence regarding a prognostic role for this receptor subtype in hormone-responsive BC is still limited and conflicting, more knowledge is required on the biological functions of ERß in cancer cells. We described previously the ERß and ERa interactomes of BC cells, identifying specific and distinct patterns of protein interactions for the two receptors. In particular, we identified factors involved in mRNA splicing and maturation as important components of both ERa and ERß pathways. Guided by these findings, we investigated here in depth the differences in the early transcriptional events and RNA splicing patterns induced in ERa vs ERa+ERß cells, by expressing ERß in ERa+ human BC MCF-7 cells. High-throughput mRNA sequencing was then performed in both cell lines after stimulation with 17b-estradiol, and the results obtained were compared. Overall design: We investigated here in depth the differences in the early transcriptional events and RNA splicing patterns induced in ERa vs ERa+ERß cells, by expressing ERß in ERa+ human BC MCF-7 cells. High-throughput mRNA sequencing was then performed in both cell lines after stimulation with 17b-estradiol, and the results obtained were compared.

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Dago DN, Scafoglio C, Rinaldi A, Memoli D, Giurato G, Nassa G, Ravo M, Rizzo F, Tarallo R, Weisz A