6-diazo-5-oxonorleucine and Urinary-Bladder-Neoplasms

High levels of the post-translational modification O-GlcNAcylation (O-GlcNAc) are found in multiple cancers, including bladder cancer. Autophagy, which can be induced by stress from post-translational modifications, plays a critical role in maintaining cellular homeostasis and regulating tumorigenesis. The impact of O-GlcNAcylation on autophagy in bladder cancer remains unclear. Here, we evaluate the change in autophagic activity in response to O-GlcNAcylation and explore the potential mechanisms.. O-GlcNAcylation levels in bladder cancer cells were altered through pharmacological or genetic manipulations: treating with 6-diazo-5-oxo-norleucine (DON) or thiamet-G (TG) or up- and downregulation of O-GlcNAc transferase (OGT) or O-GlcNAcase (OGA). Autophagy was determined using fluorescence microscopy and western blotting. Co-immunoprecipitation (Co-IP) assays were performed to evaluate whether the autophagy regulator AMP-activated protein kinase (AMPK) was O-GlcNAc modified.. Cellular autophagic flux was strikingly enhanced as a result of O-GlcNAcylation suppression, whereas it decreased at high O-GlcNAcylation levels. Phosphorylation of AMPK increased after the suppression of O-GlcNAcylation. We found that O-GlcNAcylation of AMPK suppressed the activity of this regulator, thereby inhibiting ULK1 activity and autophagy.. We characterized a new function of O-GlcNAcylation in the suppression of autophagy via regulation of AMPK.. Blockage of O-linked GlcNAcylation induces AMPK dependent autophagy in bladder cancer cells.

Topics: Acylation; AMP-Activated Protein Kinases; Autophagy; Autophagy-Related Protein-1 Homolog; Azo Compounds; beta-N-Acetylhexosaminidases; Cell Line, Tumor; Humans; Intracellular Signaling Peptides and Proteins; N-Acetylglucosaminyltransferases; Norleucine; Phosphorylation; Protein Processing, Post-Translational; Pyrans; RNA, Small Interfering; Thiazoles; Urinary Bladder Neoplasms