E₂ differentially down regulates IFN-γ signaling and IFN-γ induced proteins in endogenous ER⁺ breast cancer cell lines.

Abstract

<p>(A) MCF-7, (B) BT-474, (C) T47D, (G) MDA-MD-231, and (H) SK-BR-3 were cultured in E₂-depleted media, transfected with 8 X GAS binding sequence construct, then treated with vehicle (ethanol), E₂ (10⁻⁹ M) and stimulated or not with IFN-γ (100 U/ml) for 6 hours. Firefly luciferase activities in samples were normalized to Renilla luciferase activities in the same samples and expressed as fold induction over the un-stimulated mock. (D) MCF-7, (E) BT-474, (F) T47D, (I) MDA-MB-231 and (J) SK-BR-3 were cultured in E₂-depleted media, treated with vehicle (ethanol), or E₂ (10⁻⁹ M) and stimulated or not with IFN-γ (100 U/ml) for 96 hours. Western blot analysis of cytoplasmic extracts was performed for expression of IFN-γ inducible proteins: STAT1 (06-501), IRF1 (BD-20), IRF9 (C-20), GILT (T-18). Each figure represents one of three independent experiments.</p