Galectin-1 gene expression and methylation state in human T leukemia cell lines.

Galectin-1 has been demonstrated to be a mediator of T-cell apoptosis acting on activated T-cells and, in a selective manner, on different T leukemia cell lines. Here we show that the sensitivity to galectin-1 is associated with repression of the endogenous galectin-1 gene whereas non-sensitive cells express high levels of galectin-1. Repression of galectin-1 gene in sensitive cells is associated with hyper-methylation of the promoter region. Transient treatment of non-expressing cells with the demethylating agent 5-azacytidine led to irreversible demethylation and subsequent reactivation of galectin-1 gene.