GLYCOSPHINGOLIPIDS IN ONCOGENESIS AND DIFFERENTIATION

本课题的研究目标是：（1）分析 来自正常供体白细胞的鞘糖脂和神经节苷脂 和白血病患者;（2）找到一种人白血病细胞系用作 模型系统，以评估中性鞘糖脂的调节， 人白细胞;和（3）确定人的鞘糖脂是否 白细胞是I，i抗原。 我们已经完成了 正常人中性鞘糖脂和神经节苷脂 白细胞和白血病细胞。 这些研究表明，成熟 人白细胞可以根据其中性白细胞的大小来区分。 鞘糖脂（即，骨髓细胞表达新乳糖化合物， 淋巴样细胞表达globo化合物）。 我们还发现， 细胞同时表达globo和neolacto化合物，表明 细胞分化和糖脂表达之间的联系。 我们已经评估 GD分布3 神经节苷脂在人白细胞中的表达 抗gd3 结果表明，正常白细胞和CML 细胞不表达这种化合物，而所有其他类型的白血病 白细胞有GD3. 因此，GD3 似乎在其限制 分布于白血病母细胞和慢性淋巴细胞。 携带i-抗原的糖脂已从CML细胞中纯化， 结构表征并通过用抗I 抗体的 我们净化了 14C-半乳糖标记的糖脂， 三种髓系白血病细胞系，并在结构上表征了它们 使用糖苷酶和它们的全苄基化衍生物的HPLC。 的 这些分析的结果表明， 鞘糖脂的表达发生在成髓细胞阶段之后， 分化之前或在早幼粒细胞阶段。 的比较 未处理细胞和处理细胞合成的鞘糖脂 用分化剂（丁酸盐、二甲基亚砜和佛波醇 二酯）将被制备。 这些研究的结果将有助于 确定糖脂的种类是否存在变化 由不同的白血病细胞合成， 分化导致糖脂生物合成的改变， 与新鲜分离的白细胞中发生的那些相关。 （密歇根州）

The objectives of this project are to: (1) analyze the neutral glycosphingolipids and gangliosides from the leukocytes of normal donors and leukemic patients; (2) find a human leukemia cell line(s) to use as a model system to evaluate the regulation of neutral glycosphingolipids in human leukocytes; and (3) determine if the glycosphingolipids of human leukocytes are I,i antigens. We have completed structural characterization of the neutral glycosphingolipids and gangliosides of normal human leukocytes and leukemia cells. These studies have demonstrated that mature human leukocytes can be distinguished on the basis of their neutral glycosphingolipids (i.e., myeloid cells express neolacto compounds and lymphoid cells express globo compounds). We have also found that immature cells express both globo and neolacto compounds, suggesting a relationship between cell differentiation and glycolipid expression. We have evaluated the distribution of GD3 ganglioside among human leukocytes using an anti-GD3 monoclonal antibody and found that normal Ieukocytes and CML cells do not express this compound, whereas all other types of leukemic leukocytes have GD3. Therefore, GD3 appears to be restricted in its distribution to leukemic blast cells and chronic lymphocytic cells. Glycolipids carrying the i-antigen have been purified from CML cells and structurally characterized and detected by immunostaining with anti-i antibodies. We have purified 14C-galactose-labeled glycolipids from three myeloid leukemic cell lines and have structurally characterized them using glycosidases and HPLC of their perbenzolylated derivatives. The results of these analyses demonstrate that alterations in neutral glycosphingolipid expression occur after the myeloblastic stage of differentiation and before or at the promyelocyte stage. A comparison of the glycosphingolipids synthesized by untreated cells and cells treated with differentiating agents (butyrate, dimethyl sulfoxide, and phorbol diesters) will be made. The results from these studies will be useful in determining if there are variations in the classes of glycolipids synthesized by different leukemic cells and if chemically induced differentiation leads to alterations in glycolipid biosynthesis that are related to those occurring in freshly isolated leukocytes. (MI)