Altered N-Glycan expression profile in epithelial-to-mesenchymal transition of NMuMG cells revealed by an integrated strategy using mass spectrometry and glycogene and lectin microarray analysis.

Epithelial-to-mesenchymal transition (EMT) is an essential biological process that occurs in embryonic development, metastatic diseases, and cancer progression. Altered expression of glycans is known to be associated with cancer progression. No studies to date have presented global analysis of the precise variation of N-glycans in EMT. We describe here the profile of N-glycans and glycogene expression in the EMT process induced by transforming growth factor-β1 (TGFβ1) in a normal mouse mammary gland epithelial (NMuMG) cell model. An integrated strategy with a combination of mass spectrometry, glycogene microarray analysis, and lectin microarray analysis was applied, and results were confirmed by lectin histochemistry and quantitative real-time PCR. In TGFβ-induced EMT, levels of high-mannose-type N-glycans were enhanced, antennary N-glycans, and fucosylation were suppressed, and bisecting GlcNAc N-glycans were greatly suppressed. The expression of seven N-glycan-related genes was significantly changed. The products of glycogenes ALG9, MGAT3, and MGAT4B appeared to contribute to the observed alteration of N-glycans. The findings indicate that dysregulation of N-glycan synthesis plays a role in the EMT process. Systematic glycomic analysis based on the combination of techniques described here is expected to facilitate the discovery of the aberrant N-glycosylation in tumor progression and provide essential information in systems glycobiology.