Chemical Characterization of Neutral Glycolipids in the Human Myeloid Leukemias

Human neutrophils and lymphocytes have been shown to have different classes of neutral glycolipids. We have investigated alterations of glycolipids in the human myeloid leukemias to see how their neutral glycolipids differ from those of normal neutrophils. The chemical structures of the neutral glycolipids from large numbers of homogeneously purified leukemia cells were determined using column and thin-layer chromatography, gas-liquid chromatography (GLC), GLC-mass spectrometry, and direct probe mass spectrometry. Our results showed that cells from patients with acute myelogenous leukemia (AML) had less than half the amount of neutral glycolipid per cell than did cells from patients with chronic myelogenous leukemia (CML). Chromatographic mapping of the neutral glycolipids from these cells showed that AML cells had less of the polar, long-chain neutral glycolipids than did CML cells. The studies confirmed that over 99% of the neutral glycolipids were contained in a population of compounds with 1, 2, 3, and 4 sugar-containing neutral glycolipids whose structures are: Glc 1 --> 1 ceramide; Gal 1 --> 1 ceramide; Gal 1 --> 4 Glc 1 --> 1 ceramide; Gal 1 --> 4 Gal 1 --> 1 ceramide; GlcNAc 1 --> 3 Gal 1 --> 4 Glc 1 --> 1 ceramide; and Gal 1 --> 4 GlcNAc 1 --> 3 Gal 1 --> 4 Glc 1 --> 1 ceramide. Lactosyl ceramide was the major glycolipid in both AML and CML cells. The studies show that human myeloid leukemia cells have the same neutral glycolipids as normal neutrophils. The alterations in neutral glycolipid distribution in leukemia suggest that they might be useful as "differentiation markers", with the morphologically more "mature" leukemias having more complex glycolipids. We were unable to detect novel or "malignancy-associated" neutral glycolipids in any of the leukemias we studied.-Klock, J. C., J. L. D'Angona, and B. A. Macher. Chemical characterization of neutral glycolipids in the human myeloid leukemias.