Phorbol ester treatment of HL 60 leukemia cells results in increase of β-(1→4)-galactosyltransferase Original Research Article

We previously showed that HL 60 leukemia cells exhibit various changes in their cellular glycans after phorbol 12-myristate 13-acetate (PMA) treatment. These changes could originate largely from changes in one or several glycosyltransferases. In this report, we show using enzymatic measures, fluorescence microscopy, immunoblotting and Northern blot that β-(1→4)-galactosyltransferase I (GalT I) activity was higher (>×2) in PMA-treated compared with untreated HL 60 cells. Immunoblotting showed an increased intensity of the GalT I band at 49 kDa and Northern blot a weak increase of the GalT I transcript band, after PMA treatment. Moreover, Northern blot performed after actinomycin-D treatment of the cells, which inhibits transcription, suggests that the observed increase of GalT I expression could originate, in part, from increase of the stability of GalT I transcripts.