Obesity-associated systemic interleukin-6 promotes pre-adipocyte aromatase expression via increased breast cancer cell prostaglandin E2 production

Laura W. Bowers, Andrew J. Brenner, Stephen D. Hursting, Rajeshwar R. Tekmal, Linda A. deGraffenried

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

Obesity is associated with a worse breast cancer prognosis, particularly in estrogen receptor alpha (ERα) positive, postmenopausal patients. We hypothesized that this is mediated in part by an elevation in breast cancer cell cyclooxygenase-2 (COX-2) expression and prostaglandin E2 (PGE2) production that results in greater local pre-adipocyte aromatase expression. We utilized an in vitro model of the obese patient’s tumor microenvironment in which cultured MCF-7 breast cancer cells and pre-adipocytes were exposed to pooled serum from obese (OB; BMI ≥ 30.0 kg/m2) or normal weight (N; BMI 18.5–24.9 kg/m2) postmenopausal women. Exposure to OB versus N sera significantly increased MCF-7 cell COX-2 expression and PGE2 production. Pre-adipocyte aromatase expression was 89 % greater following culture in conditioned media (CM) from MCF-7 cells exposed to OB versus N sera (OB-CM and N-CM, respectively), a difference nullified by MCF-7 cell treatment with the COX-2 inhibitor celecoxib. Previous analysis of the sera revealed significantly higher interleukin-6 (IL-6) concentrations in the OB versus N samples. Depletion of IL-6 from the sera neutralized the difference in pre-adipocyte aromatase expression stimulated by OB-CM versus N-CM. Finally, CM from pre-adipocyte/MCF-7 cell co-cultures exposed to OB sera stimulated greater MCF-7 and T47D breast cancer cell ERα activity and proliferation in comparison to N sera. This study indicates that obesity-associated systemic IL-6 indirectly enhances pre-adipocyte aromatase expression via increased breast cancer cell PGE2 production. Investigation regarding the efficacy of a COX-2 inhibitor/aromatase inhibitor combination therapy in the obese postmenopausal patient population is warranted.

Original languageEnglish (US)
Pages (from-to)49-57
Number of pages9
JournalBreast Cancer Research and Treatment
Volume149
Issue number1
DOIs
StatePublished - 2015

Keywords

  • Aromatase
  • Cyclooxygenase-2
  • Interleukin-6
  • Obesity
  • Prostaglandin E2

ASJC Scopus subject areas

  • Oncology
  • Cancer Research

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