Abstract 1258: Lifestyle improvements delay cancer onset and progression by adapting endocrine and immune signaling in mouse models
Authors: Foglesong Grant D. , Bergin Stephen M. , Huang Wei , Caligiuri Michael A. , Cao Lei 
Published: July 2017

Metabolic syndromes instigate substantial morbidity and mortality worldwide via its negative effects of many diseases including cancer. Obesity in particular has been deemed a causative factor for breast cancer in post-menopausal women, while worsening prognosis regardless of menopausal status. Importantly, progression of many metabolic syndromes can largely be slowed or reversed with aggressive lifestyle changes, thus also having the potential to mitigate cancer onset. A mouse model of environmental enrichment (EE) to improve motosensory, cognitive, and social stimulation by increasing physical engagement and social interaction triggers vast improvements in overall health. These include boosting mental health, reducing adiposity, prevention of diet-induced obesity (DIO), promoting the white to brown fat transition, enhancing insulin sensitivity, improving immune function, limiting inflammation, and inhibition of cancer growth. We have elucidated the central mechanism of EE to be the activation of the hypothalamic-sympathoneural-adipocyte (HSA) axis, a specific neuroendocrine route in which the brain communicates with adipose tissue via the sympathetic nervous system. Once activated, norepinephrine (NE) is released directly onto adipose tissue which induces the observed metabolic improvements. Breast cancer is uniquely exposed to this adipose-NE so we sought to explore this distinctive microenvironment in the context of both local and systemic endocrine and immune signaling in varied body mass states and menopausal statuses. Our data showed that EE diminished leptin levels and delayed cancer onset in the MMTV-PyMT spontaneous mouse model of breast cancer and slowed growth in a DIO allograft model. In contrast, EE failed to attenuate tumor progression in ob/ob mice in the absence of leptin, but rather enhanced tumor growth, suggesting that the leptin-NE relationship is one of the key peripheral mediators of the EE anti-breast cancer effects. We also observed significant immune cell modulation in the adipose tissue following EE. Initial characterization revealed a decrease in the proportion of tumor-associated macrophages (TAMs) and an overall anti-inflammatory response which together with the drop in leptin may contribute to the observed anti-cancer effects. We plan to further elucidate this EE-induced adipose and immune cell modulation with the ultimate goal of developing therapeutic strategies to treat both metabolic syndromes as well as associated and possibly independent cancer types.

Citation Format: Grant D. Foglesong, Stephen M. Bergin, Wei Huang, Michael A. Caligiuri, Lei Cao. Lifestyle improvements delay cancer onset and progression by adapting endocrine and immune signaling in mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1258. doi:10.1158/1538-7445.AM2017-1258