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 antigen Le(y), BM-1/JIMRO, and found that expression of Le(y) antigen defined 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 inducers on the growth and expression of Le(y) antigen in human lung cancer A549 cells. We found that a specific inhibitor of methylation of DNA, 5-aza-2' deoxycytidine (ADC), could markedly induce expression of Le(y) antigen in association with induction of apoptosis and differentiation in the A549 cells. These results suggest that hypomethylation of DNA is involved in the molecular mechanisms of induction of Le(y) antigen, apoptosis and differentiation in the cells.