Glycogene Expression Alterations Associated with Pancreatic Cancer Epithelial-Mesenchymal Transition in Complementary Model Systems

Abstract

BackgroundThe ability to selectively detect and target cancer cells that have undergone an epithelial-mesenchymal transition (EMT) may lead to improved methods to treat cancers such as pancreatic cancer. The remodeling of cellular glycosylation previously has been associated with cell differentiation and may represent a valuable class of molecular targets for EMT.Methodology/Principal FindingsAs a first step toward investigating the nature of glycosylation alterations in EMT, we characterized the expression of glycan-related genes in three in-vitro model systems that each represented a complementary aspect of pancreatic cancer EMT. These models included: 1) TGFβ-induced EMT, which provided a look at the active transition between states; 2) a panel of 22 pancreatic cancer cell lines, which represented terminal differentiation states of either epithelial-like or mesenchymal-like; and 3) actively-migrating and stationary cells, which provided a look at the mechanism of migration. We analyzed expression data from a list of 587 genes involved in glycosylation (biosynthesis, sugar transport, glycan-binding, etc.) or EMT. Glycogenes were altered at a higher prevalence than all other genes in the first two models (p<0.05 and <0.005, respectively) but not in the migration model. Several functional themes were shared between the induced-EMT model and the cell line panel, including alterations to matrix components and proteoglycans, the sulfation of glycosaminoglycans; mannose receptor family members; initiation of O-glycosylation; and certain forms of sialylation. Protein-level changes were confirmed by Western blot for the mannose receptor MRC2 and the O-glycosylation enzyme GALNT3, and cell-surface sulfation changes were confirmed using Alcian Blue staining.Conclusions/SignificanceAlterations to glycogenes are a major component of cancer EMT and are characterized by changes to matrix components, the sulfation of GAGs, mannose receptors, O-glycosylation, and specific sialylated structures. These results provide leads for targeting aggressive and drug resistant forms of pancreatic cancer cells.

Sialic Acids Sweeten a Tumor's Life

“…In another comprehensive study, Maupin and colleagues analyzed gene expression in a model of TGF-b-induced EMT. Here, EMT induction caused upregulation of the enzymes ST3Gal II, ST6GalNAc IV, and ST8Sia IV, which are involved in the synthesis of the adhesion molecules GD1a and PSA (30). These studies indicate that the upregulation of sialyltransferases and subsequent expression of sialoglycans during EMT represent an important step underlying the migratory phenotype of metastasizing cancer cells.…”

Surprisal analysis characterizes the free energy time course of cancer cells undergoing epithelial-to-mesenchymal transition

“…GO analysis was conducted as described previously (ref. 27 and http://cbl-gorilla.cs.technion.ac.il). Threshold P value was 10…”

“…Surprisal analysis also was applied to microarray data for cultured Panc-1 epithelial cells 48 h after TGF-β1 treatment, when the cells attained a mesenchymal state (27). The balance state of Panc-1 cells, like that of A549 cells, was unaffected by TGF-β1 treatment (Fig.…”

β-Galactoside α2,6-Sialyltranferase 1 Promotes Transforming Growth Factor-β-mediated Epithelial-Mesenchymal Transition

“…The phosphorylated Smad proteins then form a trimer with Smad4 and translocate into the nucleus, where they associate and cooperate with other transcription factors to precisely regulate the target gene transcription (10). These reorchestrated target genes, as recently evidenced in several types of cancer cell lines undergoing EMT by mass spectrometry and microarray analysis, at least include the glycogenes involved in N-glycosylation, O-glycosylation, and sialylation (11)(12)(13), indicating the importance of cellular glycosylation pattern in both the transition to and the maintenance of the mesenchymal state.…”