D,L-alpha-difluoromethylornithine, an irreversible inhibitor of ornithine decarboxylase, induces differentiation in MEL cells.

In the present study, the effect of D,L-alpha-difluoromethylornithine (DFMO), an irreversible inhibitor of ornithine decarboxylase (ODC), on Friend's murine erythroleukemia (MEL) cell differentiation is investigated. DFMO was able to induce differentiation of MEL cells in culture as determined by haemoglobin (Hb) content and percentage of cells synthesizing Hb detected by benzidine staining. DFMO at a concentration of 2 mM resulted in about 70% benzidine-positive cells on the fifth day. There was a time-dependent increase in the percentage of benzidine-positive cells starting from day three. However, only a 24 h presence of DFMO in the medium was required to induce differentiation suggesting that DFMO switches on a pathway during this period leading to terminal differentiation of MEL cells. DFMO induced differentiation of MEL cells was sensitive to dexamethasone and 5-bromo-2'-deoxyuridine.