Obesity-associated systemic factors inhibit <i>ESR2</i> gene transcription via HER2 signaling.

<p>(A) <i>ESR2</i> mRNA levels in parental SKBR3 cells and SKBR3 cells stably transfected with an empty pGFP vector (SKBR3-GFP) or a GFP-tagged <i>ESR2</i> overexpression plasmid (SKBR3-ERB#3 and #5). Quantitative RT-PCR was used to assess <i>ESR2</i> mRNA levels following exposure to normal weight (N) or obese (OB) patient sera for 1 hour. (B) <i>ESR2</i> mRNA levels, measured by quantitative RT-PCR, in SKBR3 cells exposed to N or OB patient sera for 1 hour +/- 1.0 ug/ml Herceptin (H). (C) <i>ERBB2</i> expression, measured by quantitative RT-PCR, in SKBR3 cells without transfection (No siR) or following transfection with negative control siRNA (Neg siR) or siRNA to <i>ERBB2</i> (ERBB2 siR). (D) <i>ESR2</i> expression, measured by quantitative RT-PCR, after a 1-hour exposure to OB or N patient sera, in SKBR3 cells transfected with No siR, Neg siR, or ERBB2 siR. Data shown represents the average of at least three independent experiments. Different letters indicate statistically significant differences, p<0.05.</p

Breast cancer cell viability and growth are increased by the obesity-associated inhibition of <i>ESR2</i> expression.

<p>(A) Cell viability, measured by MTT assay, in SKBR3 cells without transfection (No siR) or with transfection of a negative control siRNA (Neg siR) or siRNA to <i>ESR2</i> (ESR2 siR) and following exposure to normal weight (N) or obese (OB) patient sera for 7 days. (B) Following 10 days of exposure to N or OB patient sera, colony formation was assessed in No siR, Neg siR, and ESR2 siR SKBR3 cells. (C) Viability of parental SKBR3 cells and SKBR3 cells stably transfected with an empty pGFP vector (SKBR3-GFP) or a GFP-tagged <i>ESR2</i> overexpression plasmid (SKBR3-ERB#3 and #5) was measured by MTT assay after the cells were cultured in N or OB patient sera for 7 days. (B) Following 10 days of exposure to N or OB patient sera, colony formation was assessed in parental SKBR3, SKBR3-GFP, and SKBR3-ERB#3 and #5 cell lines. Data shown represents the average of at least three independent experiments. Different letters indicate statistically significant differences, p<0.05.</p

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

<p>(A) <i>ESR2</i> 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) <i>ESR2</i> 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</p

Obesity-associated systemic factors modulate expression of the ERβ target genes <i>BCL2</i> and <i>CCND1</i>.

<p>(A) <i>ESR2</i> mRNA and ERβ protein levels, measured by quantitative RT-PCR and western blotting respectively, in SKBR3 cells without transfection (No siR) or following transfection with a negative control siRNA (Neg siR) or siRNA to <i>ESR2</i> (ESR2 siR). (B) <i>BCL2</i> mRNA levels, measured by quantitative RT-PCR, in SKBR3 cells transfected with No siR, Neg siR, or ESR2 siR and exposed to 2% normal weight (N) or obese (OB) patient sera for 24 hours. (C) <i>CCND1</i> mRNA levels, measured by quantitative RT-PCR, in SKBR3 cells and transfected with No siR, Neg siR, or ESR2 siR and exposed to 2% N or OB patient sera for 24 hours. Data shown represents the average of at least three independent experiments. Different letters indicate statistically significant differences, p<0.05.</p