Suppression of sialyl Lewis X expression and E-selectin-mediated cell adhesion in cultured human lymphoid cells by transfection of antisense cDNA of an alpha1-->3 fucosyltransferase (Fuc-T VII).
The antisense cDNA approach was used to identify the endogenous fucosyltransferase species responsible for synthesis of the sialyl Lewis X (NeuAcalpha2-->3 Galbeta1-->4[Fucalpha1-->3]GlcNAcbeta1-->R) determinant in human lymphoid cells. The cultured human adult T-cell leukemia cell line, ED40515-N, expressed the message of alpha1-->3 fucosyltransferase (Fuc-T) IV and VII, with a low level of the Fuc-T III and VI message, and manifested the sialyl Lewis X as well as Lewis X (Galbeta1-->4 [Fucalpha1-->3]GlcNAcbeta1-->R) determinant at the cell surface. Transfection of this cell line with the pRc/CMV vector containing an antisense human Fuc-T VII construct (pRc/CMV/5'FT7AS) resulted in a significant decrease of endogenous Fuc-T VII message and a marked reduction in the cell surface expression of sialyl Lewis X determinant as well as a reduction in the enzymatic activity of alpha1-->3 fucosyltransferase against sialylated type 2 chain substrate. This was accompanied by diminution of cell adhesive activity toward E-selectin on interleukin-1beta-treated endothelial cells. These results indicated that the synthesis of the sialyl Lewis X determinants that were functionally active as E-selectin ligands was mainly mediated by Fuc-T VII in these lymphoid cells. On the other hand, the message of Fuc-T IV showed no significant change in the transfectant clones, and the surface expression of the Lewis X antigen as well as the enzymatic activity of alpha1-->3 fucosyltransferase against non-sialylated type 2 chain substrate was well preserved. The clear contrast between the diminished expression of sialyl Lewis X and the conserved manifestation of Lewis X in the transfectant clones suggested that the synthesis of sialyl Lewis X and that of Lewis X are independently regulated by different fucosyltransferases in human lymphoid cells. Fuc-T VII must be involved in the synthesis of sialyl Lewis X, while the synthesis of Lewis X is mediated by an enzyme other than Fuc-T VII, most probably Fuc-T IV.
Hiraiwa
N
N
Program of Experimental Pathology, Research Institute, Aichi Cancer Center, Nagoya 464, Japan. rkannagi@aichi-cc.pref.aichi.jp
Dohi
T
T
Kawakami-Kimura
N
N
Yumen
M
M
Ohmori
K
K
Maeda
M
M
Kannagi
R
R
D000328:Adult; D015152:Blotting, Northern; D002448:Cell Adhesion; D002478:Cells, Cultured; D018076:DNA, Complementary / Q000378:metabolism; D019040:E-Selectin / Q000378:metabolism*; D005434:Flow Cytometry; D005647:Fucosyltransferases / Q000235:genetics*; D006801:Humans; D007945:Leukemia, Lymphoid / Q000378:metabolism; D007983:Lewis Blood Group Antigens; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D009844:Oligosaccharides / Q000096:biosynthesis*; D012333:RNA, Messenger / Q000378:metabolism; D000080506:Sialyl Lewis X Antigen; D014162:Transfection; D014407:Tumor Cells, Cultured
D018076:DNA, Complementary; D019040:E-Selectin; D007983:Lewis Blood Group Antigens; D016376:Oligonucleotides, Antisense; D009844:Oligosaccharides; D012333:RNA, Messenger; D000080506:Sialyl Lewis X Antigen; D005647:Fucosyltransferases; C031692:galactoside 3-fucosyltransferase