ERβ expression is suppressed by obesity-associated systemic factors in HER2-overexpressing breast cancer cells.

(A) ESR2 mRNA levels, measured by quantitative RT-PCR, in SKBR3 breast cancer cells and mammary carcinoma cells isolated from MMTV-neu mice following a 1-hour exposure to normal weight (N) or obese (OB) patient sera. (B) ERβ protein levels, measured by western blotting, in SKBR3 and MMTV-neu cells following a 2-hour exposure to N or OB patient sera. (C) ESR2 mRNA levels, measured by quantitative RT-PCR, in MCF-7, ZR75, and MDA-MB-231 breast cancer cells following a 1-hour exposure to N or OB patient sera. (D) ERβ protein levels, measured by western blotting, in MCF-7, ZR75, and MDA-MB-231 cells following a 2-hour exposure to N or OB patient sera. Data shown represents the average of at least three independent experiments. *, p<0.05; **, p<0.01 relative to OB