Antitumor activity of D-mannosamine in vitro: different sensitivities among human leukemia cell lines possessing T-cell properties.

D-Mannosamine is toxic to human malignant T-lymphoid cell lines derived from patients with T-cell leukemia. We observed heterogeneity of mannosamine susceptibility among those cell lines. The leukemic T-cell lines, subgrouped according to the degree of mannosamine inhibition on nucleic acid biosyntheses, were: Subgroup 1, HPB-MLT cells; Subgroup 2, CCRF-HSB-2 and HPB-ALL cells; and Subgroup 3, MOLT-4 cells. The most sensitive line, HPB-MLT, originated from the patient with adult T-cell leukemia. The cytotoxicity of mannosamine was potentiated by a fatty acid, sodium oleate, at concentrations that were noncytolytic, and the interaction between the two drugs was synergistic. These results would suggest that mannosamine induces changes in the membrane structure of the leukemia cells. Thus, the primary target of the tumoricidal activity of mannosamine may also be the cellular membranes.