Antitumor Activity of D-Mannosamine In Vitro: Cytotoxic Effect Produced by Mannosamine in Combination with Free Fatty Acids on Human Leukemia T-Cell Lines

Cytotoxic effects of mannosamine and free fatty acids on humanmalignant T-lymphoid cell lines derived from patients with T-cellleukemia were investigated. The combination of mannosamine andan unsaturated fatty acid (oleate or linoleate) produced morestriking cytotoxic effects on malignant lymphoid cells thanon normal human lymphocytes. The amino sugars glucosamine ormannosamine in the combination caused a synergistic cytotoxiceffect, while the other carbohydrates (N-acetylmannosamine,N-acetylglucosamine, or mannose) had little effect. On the otherhand, the effect of saturated fatty acids (palmitate or stearate)in the same system was nil. An unsaturated fatty acid (oleate)caused an increase in lipid fluidity of the surface membranein MOLT-4 lymphoid cells, which possess higher lipid fluidityin combination with mannosamine, while saturated fatty acidshad no effect on the fluidity properties of the membrane lipids(even in the presence of mannosamine). The relationship betweenmannosamine and unsaturated fatty acids in cytolysis was discussed.