Polyamines, DNA Methylation and Cell Differentiation

Abstract
Cells that have become depleted of their putrescine and spermidine content, e. g. by treatment with 2-difluoromethyl-ornithine (DFMO), an enzyme-activated irreversible inhibitor of ornithine decarboxylase (Metcalf et al., 1978), grow slowly or not at all (Heby, 1981; Pegg, 1988). In addition to causing growth arrest, polyamine depletion has been found to induce or suppress cell differentiation (Heby et al., 1987). Teratocarci-noma stem cells belong to the category of cells that are induced to differentiate in response to putrescine and spermidine depletion (Heby et al., 1983; 1987; Schindler et al., 1983; Oredsson et al., 1985).