Abstract 1825: Sustained aerobic exercise alone does not counteract the tumor-promoting effects of a westernized diet on prostate cancer progression in vivo

Abstract

Abstract Introduction: The influence of lifestyle behaviors on prostate cancer (PCa) is well established. Our lab has previously reported that diets high in both fat and carbohydrates – the “Westernized” diet – promote PCa tumor growth in vivo. Numerous studies have also found an inverse relationship between exercise and PCa progression. However, the exact relationships between diet, exercise and PCa, as well as their underlying mechanisms, are unclear. Herein we aim to investigate the effect of sustained aerobic exercise on PCa tumor growth in animals fed a “Westernized” diet or a normal diet. Methods: Athymic nude mice (n=46) were inoculated subcutaneously with LNCaP cells. Mice were fed ad libitum with either a high-fat/high-carbohydrate diet (HFHC) or a standard normal diet (Normal), and randomized into exercising (Ex) and non-exercising groups (No-Ex). Exercise was undertaken 3 days per week (3 × 15 mins; 2-min breaks between cycles; 2.0-7.0 m/min) for 8 weeks, using a forced exercise wheel. Body weights, tumor volumes, and food consumption were recorded tri-weekly. Comparisons between groups over time were performed using RANOVA Type 3 Tests of Fixed Effects. Results: There were no significant differences in body weight between the groups over time. The HFHC-Ex group (n=10) had the highest rate of tumor growth compared to all other groups (p<=0.0007). No significant differences were observed between the rate of tumor growth of the HFHC-No Ex group (n=11) and the Normal-No Ex group (n=12) or between the Normal-No Ex group and the Normal-Ex group (n=10). However, the rate of tumor growth of the Normal-Ex group was reduced compared to the HFHC-No Ex group (p<=0.0008). Food consumption analysis revealed significant differences (p<=0.012) in energy consumption (kcal) between each of the groups over time. Mice in HFHC-Ex group consumed the most energy compared to all other groups followed by HFHC-No Ex>Normal-Ex>Normal-No Ex groups. Conclusions: The results indicate that exercise stimulated an increase in food consumption. In mice fed a tumor-promoting “Westernized diet,” this enhanced the rate of tumor growth. However, in mice placed on a normal diet, this increase in energy consumption did not correspond with increased tumor growth over time, emphasizing the importance of both exercise and healthy diet in the progression of PCa. Further studies to examine the relationship between diet and exercise with respect to PCa progression are currently underway. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1825. doi:10.1158/1538-7445.AM2011-1825