Glycan Structure of Blood Group-A Antigen in Hamster Normal Tissues and Pancreatic Cancers

Pancreatic cancers induced by N-nitrosobis(2-oxopropyl)amine in Syrian hamsters produce blood group A antigen. The glycan structure of the blood group A antigen-bearing glycoproteins purified from pancreatic cancer cells has been shown previously to be bound to Asn-linked complex oligosaccharides. Because blood group A antigen has usually been described as being on Ser/Thr-linked glycans, the distribution and glycan-protein linkage of the antigen were examined in normal hamster tissues in comparison with the findings on pancreatic cancer cells. The gastrointestinal tract, excluding the small intestine, expressed blood group A antigen. The liver, pancreas, and gallbladder did not show blood group A reactivity. Blood group A antigen in the proximal gastrointestinal tract was resistant to peptide N-glycosidase F digestion, which cleaves Asn-linked glycans from core proteins. Blood group A antigen was peptide N-glycosidase F sensitive in membrane preparations from pancreatic cancers. In the colon, this antigen was only partially removed by peptide-N-glycosidase F. These results demonstrate a difference in the structure of blood group A antigen-associated glycan between pancreatic cancers and normal hamster gastrointestinal tissues.