ESTROGEN RECEPTOR ß ACTIVATION IMPAIRS MITOCHONDRIAL OXIDATIVE METABOLISM AND AFFECTS MALIGNANT MESOTHELIOMA CELL GROWTH IN VITRO AND IN VIVO

Estrogen receptor (ER) ß has been shown to possess a tumor suppressive effect and is a potential target for cancer therapy. Using gene-expression meta-analysis of human malignant pleural mesothelioma we identified an ESR2 (ERß coding gene) signature. High ESR2 expression was strongly associated with low SDHB (which encodes a mitochondrial respiratory chain complex II subunit) expression. We demonstrate that SDHB loss induced ESR2 expression and that activated ERß, by over-expression or by selective agonist stimulation, negatively affected oxidative phosphorylation compromising mitochondrial complex II and IV activity. This resulted in reduced mitochondrial ATP production, increased glycolysis dependence and impaired cell proliferation. The observed in vitro effects were phenocopied in vivo using a selective ERß agonist in a mesothelioma mouse model. On the whole, our data highlight an unforeseen interaction between ERß mediated tumor suppression and energy metabolism that may be exploited to improve on the therapy for clinical management of malignant mesothelioma.