Stephen D. Hursting, PhD, MPH
University of North Carolina
Chapel Hill, North Carolina
Chapel Hill, North Carolina
Titles and Affiliations
Professor, Department of Nutrition
Nutrition Research Institute and
Lineberger Comprehensive Cancer Center
University of North Carolina
Chapel Hill, North Carolina
Research area
To understand the drivers of obesity-related breast cancer and develop effective prevention interventions.
Impact
Obesity is an important risk and prognostic factor for several types of breast cancer, but relatively few studies examine whether the cancer-promoting effects of chronic obesity can be reversed. Dr. Hursting established that robust weight loss accomplished by bariatric surgery and various calorie-restricted diets can reverse obesity-associated metabolic, inflammatory, and pro-cancer effects. However, the expense and risks associated with bariatric surgery and the challenge in maintaining severe calorie restricted diets precludes the use of either method to reverse the effects of chronic obesity. Therefore, Dr. Hursting and his colleagues developed an easily adopted intermittent energy restricted diet regimen. When compared to weight loss surgery, this novel diet was more effective for reversing the adverse effects of obesity on breast cancer. It may thus provide a more affordable and feasible alternative strategy to reduce breast cancer risk than either bariatric surgery or severe diet restriction. Importantly, both weight loss methods reprogrammed the gut microbiome (the bacteria that inhabit the intestines) to be healthier—produce fewer inflammatory metabolites. Dr. Hursting and his colleagues will investigate these findings to break the obesity-breast cancer link and inform better treatment strategies for patients.
Progress Thus Far
Dr. Hursting’s team previously showed that one type of bacteria, called Akkermansia muciniphila (A. Muciniphilia), decreases with obesity but increases dramatically with bariatric surgery and the low calorie restricted diet. However, further studies assessing testing probiotic treatment with A. mucophila had little effect so they did not pursue it further.
Instead, the team discovered that the gut microbiota generated from high-fat diet-induced obesity alters pro-inflammatory, immune, and other cancer-related signatures.
What's next
These results drive the team’s next research question: do microbiome-dependent effects on inflammation, immunity and/or metabolism underlie the procancer effects of diet-induced obesity and the anticancer effects of intermittment calorie restriction? In the coming year, the team will test if either the microbiota generated by high-fat diet-induced obesity or from intermittent calorie affects tumor progression.
Biography
Dr. Stephen Hursting is Professor in the Department of Nutrition and the Lineberger Comprehensive Cancer Center at UNC-Chapel Hill and Professor at the UNC Nutrition Research Institute in Kannapolis, NC. He earned his PhD in nutritional biochemistry and MPH in nutritional epidemiology from the UNC-Chapel Hill, and he completed postdoctoral training in molecular carcinogenesis and cancer prevention at the National Cancer Institute (NCI). Prior to joining the UNC faculty in 2014, Dr. Hursting was Professor and Chair of the Department of Nutritional Sciences at the University of Texas at Austin and Professor of Molecular Carcinogenesis at the UT-MD Anderson Cancer Center (2005-14). He also served as Deputy Director of the NCI’s Office of Preventive Oncology and Chief of the NCI’s Nutrition and Molecular Carcinogenesis Laboratory Section (1999-2005). His research interests center on diet-gene interactions relevant to cancer prevention, particularly the molecular and metabolic mechanisms underlying obesity-breast cancer associations, and the interplay between obesity, diabetes and breast cancer risk and response to therapy. Primarily using specially engineered laboratory models of breast cancer in parallel with breast cancer prevention trials (in collaboration with Dr. Carol Fabian at the Kansas Cancer Center), he is currently focusing on the molecular and metabolic changes occurring in response to lifestyle-based (dietary and physical activity), or pharmacologic manipulation of energy metabolism and cell signaling pathways, with emphasis on the IGF-1/Akt/mTOR and Wnt signaling pathways as well as inflammation. He also has expertise in assessing diet-related serum and tissue biomarkers, including hormones/growth factors, cytokines and chemokines, and microRNA’s in tissue samples.
