MTOR and colorectal carcinoma: Western blot assays showed that xCT knockdown significantly decreased the expression of MELK and the phosphorylation levels of AKT, mTOR, and important substrates of mTORC1 (S6K and 4E-BP1) in CRC cells, while there were no significant changes in the total expression of AKT, mTOR, S6K, and 4E-BP1 (Fig. 7I, J).