Abstract 377: Time-restricted feeding: A dietary intervention to treat breast cancer in postmenopausal obese mice

Background: Abundant evidence indicates that obesity increases risk for breast cancer and the incidence further increases by 40% in obese postmenopausal women. Therefore it is envisioned by diverse research groups that the risk of breast cancer in obese postmenopausal women is an ever-increasing menace that needs to be curbed soon with effective practical strategies that could have a far-reaching impact. In this setting, time-restricted feeding (TRF), the practice of consuming ad libitum energy during the normal active phase, has been demonstrated to reinforce normal metabolic regulation, thereby attenuating obesity-driven metabolic deregulation. Although studies have assessed the effect of TRF on metabolism, no investigations have been carried out in human or mouse exploring TRF in cancer remission. Therefore, the present work is to understand the efficacy of TRF for improved breast cancer remission in postmenopausal obese female mice. Further, the work explores the mechanistic link of TRF for reduced tumor growth. Methods: Ovariectomized and 4-vinylcyclohexene diepoxide (VCD) treated mice were used as a postmenopausal model. Both ovariectomized and VCD mice were made obese by feeding them with 60% high-fat diet (HFD) and then grouped into ad libitum group (24 h access to food) and TRF group (8 hr access to food at night) to assess metabolic and tumor growth effect of TRF. To develop breast tumor, mice were injected with py230 breast cancer cell line into the mammary fat pad. The metabolic effect of TRF was assessed by glucose tolerance test, insulin tolerance test, body weight measurement, food intake, lipid accumulation in liver by HE staining and measurement of different tissue weight. Measuring the tumor volume over time and tumor weight assessed TRF effect on tumor growth. Performing a tumor growth study in mice fed with HFD and HFD containing diazoxide assessed insulin dependency of tumor growth in ad libitum group. Insulin-dependent tumor growth was validated by tumor growth study in normal chow-fed mice implanted with insulin pump or without pump (control). Results: The preliminary studies in ovariectomized and VCD-treated postmenopausal mice suggest that restricting access to Western-style HFD in active night phase improves insulin resistance, glucose tolerance, and hepatic steatosis. Further, TRF exhibited reduced tumor growth compared to ad libitum group. More importantly, the results from tumor growth study in mice fed with HFD with/without diazoxide or normal chow mice with/without insulin pump, suggest that the tumor growth is insulin dependent and TRF may be acting through attenuating insulin signaling. Conclusion: Experimental and animal model data corroborate that TRF improves metabolic deregulation and reduces breast tumor growth in HFD-fed obese mice. The results suggest putative application of such therapeutic intervention for breast cancer therapy. Citation Format: Manasi Das, Emilie Gross, Deepak Kumar, Consuelo Sauceda, Hyun-Tae Park, Dorothy D. Sears, Lesley Ellies, Nicholas Webster. Time-restricted feeding: A dietary intervention to treat breast cancer in postmenopausal obese mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 377.