Effects of Endurance Exercise on Tumor Growth in... | 2020 LAUNCH UGR Expo
Effects of endurance exercise on tumor growth in a rodent model of postmenopausal breast cancer Background: Obesity and physical inactivity have been linked to an increase risk for postmenopausal breast cancer. With more than 70% of the US population overweight or obese and more than half of the population not attaining recommended physical activity levels, exercise is a lifestyle change that could decrease cancer risk or improved cancer outcomes in postmenopausal women. Despite the known health benefits of exercise, the optimal exercise “prescription” (type, intensity, frequency, duration) for cancer prevention are not known. The goal of this study is to determine the mechanisms by which endurance exercise decreases tumor growth. Methods: Female Wistar rats were injected with the carcinogen (MNU) to induce mammary tumor formation, and fed a diet (46% kcal fat) to promote obesity. Tumor development and growth was measured weekly using digital calipers. At 18 wks of age, obese (OB) and lean (L) rats were selected based on percent body fat (qMR; EchoMRI). Tumor bearing rats were ovariectomized (OVX) to model menopause when a tumor reached 1cm3. At the time of OVX, rats were randomized to an 8-wk exercise intervention (EX; treadmill exercise) or sedentary (SED) controls. Results: OB rats had significantly higher body weight and % body fat than L at all time points measured. OVX induced weight gain and fat deposition in all animals. Exercise suppressed food intake in the OB, but this was not sufficient to prevent the weight gain or fat accumulation that occurs after OVX. Plasma metabolites were not different between EX and SED rats (glucose, insulin, triglycerides, non-esterified free fatty), likely because all rats were in positive energy balance and consuming a high fat diet. Preliminary analysis suggests that the tumor response to exercise was heterogeneous, with exercise decreasing tumor growth in some, but not all, animals. Conclusion: Regular exercise did not affect body composition or whole body metabolic health, but decreased the growth of tumors in some animals. Ongoing analysis will determine additional whole body and tumor-specific factors that predict tumor response to exercise. This knowledge will be used to delineate the mechanisms by which exercise alters tumor growth, and to determine the optimal exercise prescription for cancer prevention. --- The 2020 Virtual LAUNCH Undergraduate Research Expo is four virtual days of synchronous, asynchronous, and static learning activities. We welcome all undergraduates, graduates, faculty, and staff to learn how to engage in undergraduate research at Texas A&M. This year's Expo will help connect undergraduates to university settings, research communities, and experiences that are unique to the research enterprise at our R1 institution. LAUNCH: Undergraduate Research is committed to highlighting opportunities and programs across all disciplines. Event website: https://tx.ag/UGRexpo LAUNCH Undergraduate Research: https://ugr.tamu.edu Instagram: https://instagram.com/tamu_ugr Facebook: https://facebook.com/tamuugr Twitter: https://twitter.com/TAMU_UGR Aggie Research Program: https://aggieresearch.tamu.edu Twitter: https://twitter.com/AggieResearch ---- Graphics and Video Editing: Dillon Jones
Effects of endurance exercise on tumor growth in a rodent model of postmenopausal breast cancer Background: Obesity and physical inactivity have been linked to an increase risk for postmenopausal breast cancer. With more than 70% of the US population overweight or obese and more than half of the population not attaining recommended physical activity levels, exercise is a lifestyle change that could decrease cancer risk or improved cancer outcomes in postmenopausal women. Despite the known health benefits of exercise, the optimal exercise “prescription” (type, intensity, frequency, duration) for cancer prevention are not known. The goal of this study is to determine the mechanisms by which endurance exercise decreases tumor growth. Methods: Female Wistar rats were injected with the carcinogen (MNU) to induce mammary tumor formation, and fed a diet (46% kcal fat) to promote obesity. Tumor development and growth was measured weekly using digital calipers. At 18 wks of age, obese (OB) and lean (L) rats were selected based on percent body fat (qMR; EchoMRI). Tumor bearing rats were ovariectomized (OVX) to model menopause when a tumor reached 1cm3. At the time of OVX, rats were randomized to an 8-wk exercise intervention (EX; treadmill exercise) or sedentary (SED) controls. Results: OB rats had significantly higher body weight and % body fat than L at all time points measured. OVX induced weight gain and fat deposition in all animals. Exercise suppressed food intake in the OB, but this was not sufficient to prevent the weight gain or fat accumulation that occurs after OVX. Plasma metabolites were not different between EX and SED rats (glucose, insulin, triglycerides, non-esterified free fatty), likely because all rats were in positive energy balance and consuming a high fat diet. Preliminary analysis suggests that the tumor response to exercise was heterogeneous, with exercise decreasing tumor growth in some, but not all, animals. Conclusion: Regular exercise did not affect body composition or whole body metabolic health, but decreased the growth of tumors in some animals. Ongoing analysis will determine additional whole body and tumor-specific factors that predict tumor response to exercise. This knowledge will be used to delineate the mechanisms by which exercise alters tumor growth, and to determine the optimal exercise prescription for cancer prevention. --- The 2020 Virtual LAUNCH Undergraduate Research Expo is four virtual days of synchronous, asynchronous, and static learning activities. We welcome all undergraduates, graduates, faculty, and staff to learn how to engage in undergraduate research at Texas A&M. This year's Expo will help connect undergraduates to university settings, research communities, and experiences that are unique to the research enterprise at our R1 institution. LAUNCH: Undergraduate Research is committed to highlighting opportunities and programs across all disciplines. Event website: https://tx.ag/UGRexpo LAUNCH Undergraduate Research: https://ugr.tamu.edu Instagram: https://instagram.com/tamu_ugr Facebook: https://facebook.com/tamuugr Twitter: https://twitter.com/TAMU_UGR Aggie Research Program: https://aggieresearch.tamu.edu Twitter: https://twitter.com/AggieResearch ---- Graphics and Video Editing: Dillon Jones