Elevation of an?(1,3) fucosyltransferase activity correlated with apoptosis in the human colon adenocarcinoma cell line, HT-29

Abstract

We studied changes in the carbohydrate expression following apoptotic cell death induced by treatment with interferon (IFN)-γ and anti-Fas antibody using human colon adenocarcinoma HT-29 cells. An apoptotic cell death of HT-29 accompanied with typical DNA fragmentation was observed when the cells were cultured sequentially with IFN-γ and anti-Fas antibody. In flow cytometric analyses, the expression of Le^x and Le^y antigen was strongly and slightly enhanced, respectively, on the cell surface in accordance with the apoptosis. When the fucosyltransferase (Fuc-T) activities of the lysates from the treated cells were examined relative to those from untreated cells, a 2.5-fold increase of α(1,3)-Fuc-T activities and a slight increase of α(1,2)-Fuc-T activities were observed, but little or no increase of α(1,4)-Fuc-T activity was detected. In Northern blot analyses using probes for Fuc-T III, IV, V, VI and VII genes, strong RNA messages for Fuc-T III, V and/or VI and a weak RNA message for Fuc-T IV were detected in the untreated HT-29 cells. On the other hand, in the treated cells, the messages for Fuc-T III, V and/or VI were found to almost disappear and the 2.3 kb message for Fuc-T IV was observed to elevate 2.8-fold. Therefore, we suggest that the strongly increased expression of Le^x antigen found on the HT-29 cell surface might be involved in the process of apoptosis, and that the enhancement of the antigen expression seems to result from the increased activity of α(1,3)-Fuc-T encoded mainly by the Fuc-T IV gene.