INDUCTION BY 5-AZA-2'-DEOXYCYTIDINE, AN INHIBITOR OF DNA METHYLATION,OF LE(Y) ANTIGEN, APOPTOSIS AND DIFFERENTIATION IN HUMAN LUNG-CANCER CELLS

We recently developed a monoclonal antibody directed to carbohydrate a ntigen Le(y), BM-1/JIMRO, and found that expression of Le(y) antigen d efined by BM-1/JIMRO was associated with the process of apoptosis, but not with cell proliferation or necrosis. In the present experiments, we examined with BM-1/JIMRO the effects of various differentiation ind ucers on the growth and expression of Le(y) antigen in human lung canc er A549 cells. We found that a specific inhibitor of methylation of DN A, 5-aza-2' deoxycytidine (ADC), could markedly induce expression of L e(y) antigen in association with induction of apoptosis and differenti ation in the A549 cells. These results suggest that hypomethylation of DNA is involved in the molecular mechanisms of induction of Le(y) ant igen, apoptosis and differentiation in the cells.