TY - JOUR T1 - Proteomic Analysis Reveals Aberrant <em>O</em>-GlcNAcylation of Extracellular Proteins from Breast Cancer Cell Secretion JF - Cancer Genomics - Proteomics JO - Cancer Genomics Proteomics SP - 201 LP - 209 VL - 12 IS - 4 AU - PUKKAVADEE NETSIRISAWAN AU - DARANEE CHOKCHAICHAMNANKIT AU - CHANTRAGAN SRISOMSAP AU - JISNUSON SVASTI AU - VORARATT CHAMPATTANACHAI Y1 - 2015/07/01 UR - http://cgp.iiarjournals.org/content/12/4/201.abstract N2 - Background: O-GlcNAcylation is a unique intracellular protein modification; however, few extracellular O-GlcNAc-modified proteins have been discovered. We have previously demonstrated that many cellular proteins were aberrant in O-GlcNAcylation in breast cancer tissues. In the present study, therefore, we investigated whether O-GlcNAc-modified proteins were abnormally secreted from breast cancer cells. Materials and Methods: Intracellular and extracellular proteins were prepared from cell lysates of breast cancer cells (MCF-7 and MDA-MB-231) and normal breast cells (HMEC) and from their serum-free media (SFM), respectively. O-GlcNAcylation level was examined by immunoblotting. O-GlcNAc-Modified proteins were identified using two-dimensional gel electrophoresis and Liquid Chromatography-tandem Mass Spectrometry. Results: O-GlcNAcylation level was significantly increased in the extracellular compartment of both types of cancer cells compared to normal cells. Interestingly, O-GlcNAc patterns differed between intracellular and extracellular proteins. Proteomic analysis revealed that many O-GlcNAc spots in MCF-7 secretions were abnormally increased in comparison to those in HMEC secretions. Among these, transitional endoplasmic reticulum ATPase (TER ATPase) and heat-shock 70 kDa (HSP70) were confirmed to be O-GlcNAc-modified. The levels of O-GlcNAc-HSP70 and O-GlcNAc-TER ATPase were higher in SFM from MCF-7 cells than in that from HMEC. Conclusion: O-GlcNAcomic study of the extracellular compartments reveals aberrant O-GlcNAc-secreted proteins, which may be of interest as potential biomarkers in breast cancer. ER -