Abstract P3-04-04: Estrogen receptor β5 increases aggressiveness of the triple negative breast cancer cell line SUM159

Abstract

Abstract Recent clinical studies are indicating that the estrogen receptor β variant β5 (ERβ5) expression correlates to worse prognosis. We wanted to know if expression of ERβ5 is changing the growth behavior of the triple negative cell line SUM159. Estrogen receptor β5 is highly similar to estrogen receptor β1 except for a truncated C-terminus making the remaining ligand binding domain incapable of binding to estrogen. In addition a 4 amino acid unique peptide is added to the C-terminal end. Stably expressing ERβ5 using a transposon integrated tetracycline regulated expression system we find that expression of ERβ5 increases proliferation of the triple negative SUM159 cells especially in reduced serum condition compared to control cells. Since SUM159 have been shown to depend on autocrine stimulation for growth we are suggesting that expression of ERβ5 is affecting the production of autocrine growth factors. Citation Format: Faria M, Tin-U C, Dey P, Gustafsson J-A, Strom AM. Estrogen receptor β5 increases aggressiveness of the triple negative breast cancer cell line SUM159. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P3-04-04.