黏蛋白是细胞表面的或分泌的、具有高度O-糖基化修饰的糖蛋白。黏蛋白型O-聚糖是由多肽:N-乙酰氨基半乳糖转移酶(ppGalNAc-T)家族催化起始合成的,在肿瘤中常常伴随着黏蛋白型O-聚糖结构和数量上的改变,形成肿瘤特异聚糖结构(cancer-associated glycans),如肿瘤Tn和T抗原等。肿瘤特异聚糖使肿瘤细胞的抗原性和黏附能力发生改变,促进肿瘤细胞的恶性增生与转移。而这些肿瘤特异聚糖结构,也为肿瘤的诊断与抗肿瘤药物或疫苗开发提供了理论基础。
Mucins are heavily O-glycosylated glycoproteins found in mucous secretions and as transmembrane glycoproteins of the cell surface with the glycan exposed to the external environment.In mucins,O-glycans are covalently α-linked via an N-acetylgalactosamine(GalNAc)moiety to serine or threonine,and the structures are named mucin-type O-glycans.Mucin-type O-glycans are initiated by UDP-GalNAc: polypeptide N-Acetylgalactosa minyltransferases,which enzymatic mechanism and structural features have been a hot topic of glycosyltransferases research.Mucin-type O-glycans of cancer cells are often changed,both in structure and in quantity,developing several cancer-associated glycans,such as T and Tn antigens.These structural changes can alter the function of the cancer cells,and its antigenic and adhesive properties,as well as its potential to invade and metastasize.These cancer-associated glycans can be exploited to tumor diagnosis,and in the development of anti-tumor drug or vaccine.