OGT and breast carcinoma: For example, the mTORC1 pharmacological activator (MHY1485) induced the increase of total cellular O-GlcNAcylation and OGT levels in colon cell lines, while mTORC1 inhibition by rapamycin had the opposite effect, reducing total cellular O-GlcNAcylation and OGT levels in colon cells and various breast cancer cell lines (46, 65).