Abstract 5414: AMPK regulates HER2/EGFR activity in HER2-positive breast cancer.

Abstract

The AMP-activated Protein Kinase (AMPK) is a master regulator of cell metabolism, controlling fatty acid synthesis, protein synthesis and carbohydrate metabolism. Physiological states with increased AMPK activity are associated with decreased cancer incidence, leading to interest in AMPK as a potential target for cancer therapy and prevention. To explore a possible role of AMPK modulation in breast cancer therapy, we investigated how activation of AMPK affects breast cancer cell signaling and survival. Initial experiments found that breast cancer cell lines with amplification and over-expression of HER2 (BT474, HCC1419, and SKBR3) are 2-fold to 5-fold more sensitive to cytotoxic effects of AICAR, a canonical pharmacological activator of AMPK, than breast cancer cell lines that lack HER2 amplification (MCF7 and MDA231). In parallel to this activation of AMPK, we observed dose- and time-dependent inhibitory effects on phosphorylation and activity of HER2 and EGFR in these AICAR-treated, HER2-amplified breast cancer cells, with activation of AMPK and suppression of HER2/ EGFR activity preceding commitment to cell death. To further explore how AMPK activity affects HER2/ EGFR, we stably transfected HER2-amplified breast cancer cells with constitutively active AMPKα and observed that AMPK activated by this genetic manipulation also leads to decreased HER2 and EGFR phosphorylation and associated downstream signaling as well as reduced cell growth. Finally, we found that morin, a flavinoid compound previously found to inhibit fatty acid synthesis, also activates AMPK and inhibits HER2 and EGFR signaling in parallel, further supporting the link across these pathways. Our results lead us to postulate that AMPK regulates HER2 and EGFR activity in HER2-amplified breast cancer cells, and activation of AMPK might provide therapeutic benefit in such cancers. Citation Format: Teraneh Jhaveri, Ju Hyung Woo, Edward Gabrielson. AMPK regulates HER2/EGFR activity in HER2-positive breast cancer. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5414. doi:10.1158/1538-7445.AM2013-5414