Metabolic and hormonal remodeling of colorectal cancer cell signaling by diabetes

Abstract

The existence of molecular links that facilitate colorectal cancer (CRC) development in the population with type 2 diabetes (T2D) is supported by substantial epidemiological evidence. This review summarizes how the systemic metabolic and hormonal imbalances from T2D alter CRC cell metabolism, signaling and gene expression as well as their reciprocal meshing, with an overview of CRC molecular subtypes and animal models to study the diabetes-CRC cancer links. Metabolic and growth factor checkpoints ensure a physiological cell proliferation rate compatible with limited nutrient supply. Hyperinsulinemia and hyperleptinemia in prediabetes and excess circulating glucose and lipids in T2D, overcome formidable barriers for tumor development. Increased nutrient availability favours metabolic reprogramming, alters signaling and generate mutations and epigenetic modifications, through increased reactive oxygen species and oncometabolites. The reciprocal control between metabolism and hormone signaling is lost in diabetes. Excess adipose tissue at the origin of T2D, unbalances adipokine (leptin / adiponectin) secretion ratios and function and disrupts the Insulin/IGF axes. Leptin/adiponectin imbalances in T2D are believed to promote proliferation and invasion of CRC cancer cells and contribute to inflammation, an important component of CRC tumorigenesis. Disruption of the Insulin/IGF axes in T2D targets systemic and CRC cell metabolic reprogramming, survival and proliferation. Future research to clarify the molecular diabetes-CRC links will help to prevent CRC and reduce its incidence in the diabetic population and must guide therapeutic decisions.