Background: O-GlcNAcylation is a single sugar attachment of serine and/or threonine residues on intracellular proteins. Recent reports reveal that it can modify several secretory proteins; however, the underlying mechanisms are largely unexplored.
Materials and methods: To investigate whether extracellular vesicles (EVs) carry secretory O-GlcNAc-modified proteins that were isolated from colorectal cancer (CRC) cells, two-dimensional gel electrophoresis followed with O-GlcNAc immunoblotting and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were applied.
Results: It was revealed that the O-GlcNAc modification of many EV proteins was increased in metastatic cells. Among these, transitional endoplasmic reticulum ATPase (TER ATPase) and RuVB-like1 were successfully confirmed for the O-GlcNAc modification in which the levels were significantly higher in EVs of metastatic CRC cell line.
Conclusion: These data, demonstrate that proteins carried by EVs are O-GlcNAc-modified. Importantly, elevated aberrant O-GlcNAcylation of EV proteins might serve as a potential biomarker of metastatic CRC.
Keywords: Colorectal cancer; O-GlcNAcylation; RuVB-like1; extracellular vesicles; metastasis; transitional endoplasmic reticulum ATPase.
Copyright© 2016, International Institute of Anticancer Research (Dr. John G. Delinasios), All rights reserved.