Tumour growth in mice resistant to diet-induced obesity

Obesity is a chronic disease with associated increases in the incidence, and a reduction in survival, of many cancer types. Obesity results from an imbalance in calorie intake and calorie requirement. This study aimed to investigate the separate effects of high-fat diet and obesity on cancer in an animal model resistant to diet-induced obesity. Male BALB/c mice fed long-term on a high-fat, Western-style diet were implanted with syngeneic CT26 colon adenocarcinoma cells and compared to mice fed normal diet. BALB/c mice on high-fat diet were 10% heavier than mice fed normal diet, with no difference in tumour growth rates or tumour cell proliferation. Subgroups of mice that became obese on high-fat diet, however, showed increased tumour growth rates compared to mice fed normal diet, whereas mice that remained slim showed no difference in tumour growth. Protein arrays identified several adipokines that were expressed at different levels, including serum Tissue Inhibitors of Metallo-Proteinases (TIMP-1) and tumour C-Reactive Protein (CRP). In conclusion, tumour growth was enhanced in mice unable to resist obesity, and adipokine profiles were affected by the animals’ ability to resist obesity