Involvement of O-glycosylation defining oncofetal fibronectin in epithelial-mesenchymal transition process.

Abstract

The process termed "epithelial-mesenchymal transition" (EMT) was originally discovered in ontogenic development, and has been shown to be one of the key steps in tumor cell progression and metastasis. Recently, we showed that the expression of some glycosphingolipids (GSLs) is down-regulated during EMT in human and mouse cell lines. Here, we demonstrate the involvement of GalNAc-type (or mucin-type) O-glycosylation in EMT process, induced with transforming growth factor β (TGF-β) in human prostate epithelial cell lines. We found that: (i) TGF-β treatment caused up-regulation of oncofetal fibronectin (onfFN), which is defined by mAb FDC6, and expressed in cancer or fetal cells/tissues, but not in normal adult cells/tissues. The reactivity of mAb FDC6 requires the addition of an O-glycan at a specific threonine, inside the type III homology connective segment (IIICS) domain of FN. (ii) This change is associated with typical EMT characteristics; i.e., change from epithelial to fibroblastic morphology, enhanced cell motility, decreased expression of a typical epithelial cell marker, E-cadherin, and enhanced expression of mesenchymal markers. (iii) TGF-β treatment up-regulated mRNA level of FN containing the IIICS domain and GalNAc-T activity for the IIICS domain peptide substrate containing the FDC6 onfFN epitope. (iv) Knockdown of GalNAc-T6 and T3 inhibited TGF-β-induced up-regulation of onfFN and EMT process. (v) Involvement of GSLs was not detectable with the EMT process in these cell lines. These findings indicate the important functional role of expression of onfFN, defined by site-specific O-glycosylation at IIICS domain, in the EMT process.

• Authors: Leonardo Freire-de-Lima, Kirill Gelfenbeyn, Yao Ding, Ulla Mandel, Henrik Clausen, Kazuko Handa, Sen-Itiroh Hakomori
• Journal: Proceedings of the National Academy of Sciences of the United States of America (Proc Natl Acad Sci U S A) Vol. 108 Issue 43 Pg. 17690-5 (Oct 25 2011) ISSN: 1091-6490 [Electronic] United States
• PMID: 22006308 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Antibodies, Monoclonal
• Cadherins
• DNA Primers
• Fibronectins
• RNA, Messenger
• RNA, Small Interfering
• Transforming Growth Factor beta
• oncofetal fibronectin
• N-Acetylgalactosaminyltransferases
• UDP-N-acetylgalactosamine polypeptide N-acetylgalactosaminyltransferase 6
• polypeptide N-acetylgalactosaminyltransferase

Topics

• Animals
• Antibodies, Monoclonal
• Blotting, Western
• Cadherins
• Cell Line
• DNA Primers (genetics)
• Epithelial Cells
• Epithelial-Mesenchymal Transition (physiology)
• Fibronectins (metabolism)
• Gene Expression Regulation, Neoplastic (physiology)
• Gene Knockdown Techniques
• Glycosylation
• Humans
• Mice
• N-Acetylgalactosaminyltransferases (genetics)
• RNA, Messenger (metabolism)
• RNA, Small Interfering (genetics)
• Reverse Transcriptase Polymerase Chain Reaction
• Transforming Growth Factor beta (pharmacology)