Malignant manipulaTORs of metabolism: suppressing BCAA catabolism to enhance mTORC1 activity

The mammalian target of rapamycin complex 1 (mTORC1) plays an important role in the development and progression of multiple cancers. Its activity is regulated by both growth factor and nutrient signals, and the branched-chain amino acid (BCAA) leucine plays an important and unique role in this process. Recently we found that cancers of the liver and multiple other tissues suppress the catabolism of BCAAs, thereby facilitating the chronic activation of mTORC1. Our results unveil how mTORC1's nutrient-sensing arm can be manipulated by tumors, and suggest that restoring BCAA catabolism may help control mTORC1 activity in cancer cells.