Aberrant <i>α</i>1→2Fucosyltransferases Found in Human Colorectal Carcinoma Involved in the Accumulation of Le^b and Y Antigens in Colorectal Tumors

Abstract

Evidence indicates that the presence of aberrant alpha 1-->2fucosylation pathways is responsible for the accumulation of large quantities of Le(b) and Y antigens in human colorectal carcinoma. Significantly higher activities of alpha 1-->2 as well as alpha 1-->3 and alpha 1-->4fucosyltransferases were found in most of the tissues from carcinoma than in the adjacent normal tissues and in healthy subjects. alpha 1-->2Fucosyltransferases associated with the synthesis of Le(b) (Fuc alpha 1-->2Gal beta 1-->3[Fuc alpha 1-->4]GlcNAc beta) and Y (Fuc alpha 1-->2Gal beta 1-->4[Fuc alpha 1-->3]GlcNAc beta) structures from Le(a) (Gal beta 1-->3[Fuc alpha 1-->4]GlcNAc beta) and X (Gal beta 1-->4[Fuc alpha 1-->3]GlcNAc beta) ones, respectively, were demonstrated in colorectal carcinomas and in colorectal carcinoma cell lines (COLO201, LS174T and SW1116). The activation of alpha 1-->2fucosyltransferase with such new substrate specificities in colorectal carcinoma might result in the preferential synthesis of Le(b) and Y structures from Le(a) and X rather than from H type 1 and H type 2 structures.