Elevation of alpha2-->6 sialyltransferase and alpha1-->2 fucosyltransferase activities in human choriocarcinoma.
Structures of N-linked sugar chains are species and tissue specific and change in the course of tumorigenesis. Sialyl linkages of human placental glycoproteins are exclusively Neu5Ac alpha2-->3Gal, whereas Fuc alpha1-->2Gal and Neu5Ac alpha2-->6Gal residues are expressed in human chorionic gonadotropin and alkaline phosphatase, which are produced in human choriocarcinoma JEG-3 and BeWo cells. In the present study, to elucidate the enzymological and molecular biological basis of the structural changes that occur in the course of tumorigenesis, alpha1-->2 fucosyltransferase, alpha2-->3 and alpha2-->6 sialyltransferase activities, and the expression levels of the corresponding mRNAs were measured. The alpha2-->3 sialyltransferase activity did not change as a result of tumorigenesis; however, the alpha2-->6 siayltransferase activity and alpha1-->2 fucosyltransferase activity in JEG-3 and BeWo cells increased to levels several times higher than those in placenta Competitive PCR analysis showed that the expression levels of mRNA encoding alpha1-->2 fucosyltransferase and mRNA encoding alpha2-->6 sialyltransferase increased significantly as a result of tumorigenesis, indicating that such structural changes are regulated at the level of transcription of these glycosyltransferase genes.
Department of Biochemistry, Sasaki Institute, Tokyo, Japan.
K
K
Fukushima
S
S
Hara-Kuge
A
A
Seko
Y
Y
Ikehara
K
K
Yamashita
D002240:Carbohydrate Sequence; D002822:Choriocarcinoma / Q000097:blood / Q000201:enzymology*; D017931:DNA Primers; D005260:Female; D005647:Fucosyltransferases / Q000235:genetics / Q000378:metabolism*; D006023:Glycoproteins / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000737:chemistry; D010920:Placenta / Q000201:enzymology*; D011247:Pregnancy; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012799:Sialyltransferases / Q000235:genetics / Q000378:metabolism*; D013379:Substrate Specificity; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured; D014594:Uterine Neoplasms / Q000097:blood / Q000201:enzymology*; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase; D000097631:Galactoside 2-alpha-L-fucosyltransferase
D017931:DNA Primers; D005647:Fucosyltransferases; D006023:Glycoproteins; D009844:Oligosaccharides; D012333:RNA, Messenger; D012799:Sialyltransferases; D000094802:beta-D-Galactoside alpha 2-6-Sialyltransferase; D000097631:Galactoside 2-alpha-L-fucosyltransferase