Epigenetic memory of obesity predisposes to colorectal cancer. Mus musculus

Colorectal cancer (CRC) is the third most common cancer worldwide. Obesity is a major risk factor with long-lasting effects on the predisposition to CRC even after weight loss; however, the mechanistic underpinnings remain poorly understood. Using a diet-induced obesity mouse model, we profiled cell-intrinsic alterations in colonic epithelium from young and aged obese mice compared with their age-matched controls, to gain insights into the progression of obesity-associated dysregulations in colonic cellular states. Cellular metabolic reprogramming occurred at early stage, boosting the number and function of stem/stem-like cells; while cell-intrinsic rewiring of signal transduction networks happened at later stage, promoting growth factor-independent proliferation. Strikingly, colonic DNA methylome was pre-programmed by obesity at young age priming for a tumor-prone gene signature after aging. Furthermore, obesity-related changes were substantially preserved after weight loss, potentially contributing to long-term predisposition to CRC. These findings broadened our perspectives on how obesity shapes the predisposition to CRC. Overall design: Ribo-zero RNA-Seq was performed in colonic epithelium from mice on three different dietary regimens as follows: 1) low-fat diet for 43 weeks; 2) high-fat diet for 43 weeks; 3) high-fat diet for an initial 15 weeks then switched to low-fat diet for another 28 weeks.