Leucine and Its Importance for Cell Signalling Pathways in Cancer Cachexia-Induced Muscle Wasting

The anabolic effects of a supplemented diet with branched-chain amino acids, especially leucine, on skeletal muscle wasting and as a co-adjuvant in cancer treatment have been well-studied. Leucine is a precursor of protein synthesis and acts as a nutritional signal, affecting multiple metabolic processes (e.g., satiety, thermo-genesis, energy efficiency, and body composition). Previous studies related to nutritional therapy have mainly focused on myopenia, which is the loss of skeletal muscle mass in some pathologies, including cancer. Leucine plays a role in the maintenance and even increase of lean body mass in healthy individuals as well as the prevention of disease states that culminate in myopenia. Herein, we review the available data addressing the mechanisms by which leucine acts as a cellular signal, thereby stimulating muscle protein synthesis, leading to the inhibition of muscle catabolism, especially in an experimental model of cancer cachexia. We also show differences found in the metabolomic and proteomic analyses, including the use of leucine in maternal diets as a preventative for muscle wasting as supported by our experimental data.