Transforming growth factor-β challenge alters the N-, O-, and glycosphingolipid glycomes in PaTu-S pancreatic adenocarcinoma cells

Pancreatic ductal adenocarcinoma (PDAC) is characterized by poor prognosis and high mortality. Transforming growth factor-beta (TGF-beta) plays a key role in PDAC tumor progression, which is often associated with aberrant glycosylation. However, how PDAC cells respond to TGF-beta and the role of glycosylation therein is not well known. Here, we investigated the TGF-beta-mediated response and glycosylation changes in the PaTu-8955S (PaTu-S) cell line deficient in SMA-related and MAD-related protein 4 (SMAD4), a signal transducer of the TGF-beta signaling. PaTu-S cells responded to TGF-beta by upregulating SMAD2 phosphorylation and target gene expression. We found that TGF-beta induced expression of the mesenchymal marker N-cadherin but did not significantly affect epithelial marker E-cadherin expression. We also examined differences in N-glycans, O-glycans, and glycosphingolipid-linked glycans in PaTu-S cells upon TGF-beta stimulation. TGF-beta treatment primarily induced N-glycome aberrations involving elevated levels of branching, core fucosylation, and sialylation in PaTu-S cells, in agreement with TGF-beta-induced changes in the expression of glycosylation-associated genes. In addition, we observed differences in O glycosylation and glycosphingolipid glycosylation profiles after TGF-beta treatment, including lower levels of sialylated Tn antigen and neoexpression of globosides. Furthermore, the expression of transcription factor sex-determining region Y-related high-mobility group box 4 was upregulated upon TGF-beta stimulation, and its depletion blocked TGF-beta-induced N-glycomic changes. Thus, TGF-beta-induced N-glycosylation changes can occur in a sex-determining region Y-related high-mobility group box 4-dependent and SMAD4-independent manner in the pancreatic PaTu-S cancer cell line. Our results open up avenues to study the relevance of glycosylation in TGF-beta signaling in SMAD4-inactivated PDAC.

Automated summary

Transforming growth factor-beta (TGF-beta) plays a key role in pancreatic ductal adenocarcinoma (PDAC) progression, and glycosylation is associated with it. The study found that PDAC cells deficient in the signal transducer of TGF-beta signaling, SMAD4, exhibit glycosylation changes upon TGF-beta stimulation, including elevated N-glycome aberrations and alterations in O-glycosylation and glycosphingolipid glycosylation profiles.