Effects of Chronic and Intermittent Calorie Restriction on Adropin Levels in Breast Cancer

ABSTRACT

Adropin is a peptide hormone that has been implicated in insulin resistance and as a potential regulator of growth. The aim of this study is to determine the effect of calorie restriction on circulating levels of adropin in the MMTV-TGFα breast cancer mouse model and investigate the effects of adropin peptide on the viability of MCF-7 and MDA-231 breast cancer cells in culture. Ten-week-old mice were assigned to either ad libitum-fed (AL), chronic calorie-restricted, or intermittent calorie-restricted groups. Concentrations of serum adropin were measured using an enzyme-linked immunosorbent assay. Results showed an inverse correlation between serum adropin levels and mouse age that was attenuated by calorie restriction. In the AL group the level of adropin was significantly lower at week 50 compared to levels at week 10. However, among the calorie-restricted groups, serum levels of adropin remained high at week 50. The cell-line-specific effects were observed after treatment of cancer cell lines with a series of adropin concentrations (5, 10, 25, 50 ng/mL). Flow cytometry analysis showed that MCF-7 cells entered the early phase of apoptosis after treatment with 50 ng/mL for 24 h. Adropin may be involved in the protective effects that calorie restriction has on breast cancer risk.

Acknowledgments

We thank Dr. Margot P. Cleary for generously donating the breeding colony of the MMTV-TGFα transgenic mice and Dr. Kathleen Arcaro and Christopher Bergweiler for kindly editing the manuscript. This research was funded by the Scientific and Technological Research Council of Turkey (TUBITAK, 114S429). We also thank Yeditepe University Animal Facility Employees and student assistants Ilker Coban, Burcu Cicekdal, and Goktug Karabiyik for their help for handling and taking care of animals.

Declaration of Interest

No financial or other interests are or may be construed as a conflict of interest.