EFFECT OF ALL-TRANS-RETINOIC ACID AND PHORBOL 12-MYRISTATE 13-ACETATEON THE ACTIVITY OF HUMAN HEPATOCELLULAR-CARCINOMA CELL-SURFACE BETA-1,4-GALACTOSYLTRANSFERASE

A human hepatocellular carcinoma cell line, SMMC-7721, was treated wit h all-trans-retinoic acid (RA) and phorbol 12-myristate 13-acetate (PM A) to induce its differentiation and proliferation respectively. A bia ntennary sugar chain fluorescently labelled with 2-aminopyridine (PA), GlcNAc beta 1-2Man alpha 1-6(GlcNAc beta 1-2Man alpha 1-3)Man beta 1- beta 1-2Man alpha 1-34GlcNAc beta 1-4GlcNAc-PA, was used to detect the activity of beta-1,4-galactosyltransferase on the cell surface by HPL C. The results show that the activity of beta-1,4-galactosyltransferas e on the cell surface increases when the cell is treated with RA, but decreases when it is treated with PMA, whereas the activities of the w hole cell remain stable during the treatments.