Lipid metabolism in colon cancer: Role of Liver X Receptor (LXR) and Stearoyl-CoA Desaturase 1 (SCD1).

Colorectal cancer (CRC) is one of the most commonly occurring cancers worldwide. Although several genetic alterations have been associated with CRC onset and progression, nowadays the reprogramming of cellular metabolism has been recognized as a fundamental step of the carcinogenic process. Intestinal tumor cells frequently display an aberrant activation of lipid metabolism. Indeed, to satisfy the growing needs of a continuous proliferation, cancer cells can either increase the uptake of exogenous lipids or upregulate the endogenous lipogenesis and cholesterol synthesis. Therefore, strategies aimed at limiting lipid accumulation are now under development in order to counteract malignancies. Two major players of lipids metabolism have been so far identified for their contribution to CRC development: the nuclear receptor Liver X Receptor (LXRs) and the enzyme Stearoyl-CoA Desaturase 1 (SCD1). Whereas LXR is mainly recognized for its role as a cholesterol sensor, finally promoting the loss of cellular cholesterol and whole-body homeostasis, SCD1 acts as the major regulator of new fatty acids, finely tuning the monounsaturated fatty acids (MUFA) to saturated fatty acids (SFA) ratio. Intriguingly, SCD1 is directly regulated by LXRs. Despite LXRs agonists have elicited great interest as a promising therapeutic target for cancer, LXR's ability to induce SCD1 and new fatty acids synthesis represent a major obstacle in the development of new effective treatments. Thus, further investigations are required to fully dissect the concomitant modulation of both players, to develop specific therapies aimed at blocking intestinal cancer cells proliferation, eventually counteracting CRC progression.