THE SURFACE MEMBRANES OF NORMAL AND CANCER CELLS

正常细胞和癌细胞的表面膜

• 批准号: 3165101
• 负责人: LEONARD WARREN
• 金额: $ 3万
• 依托单位: WISTAR INSTITUTE
• 依托单位国家: 美国
• 财政年份: 1978
• 资助国家: 美国
• 起止时间: 1978-12-01 至 1985-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3165101
• 关键词: L cell; O glycosidase; Rous sarcoma virus; affinity chromatography; covalent bond; electrofocusing; glycolipids; glycopeptides; human tissue; membrane activity; membrane structure; neoplasm /cancer immunology; neoplastic cell; oncogenic virus; phagocytosis; radionuclide double label; temperature sensitive mutant; transferase

In order to understand the role of protein-bound carbohydrates in nature and in pathological processes, we have further documented the observation that these structures can change in a programmed manner. We have found that mouse teratocarcinoma cells (F9) produce fibronectin of Mr\= 250,000 containing covalently bound heparan sulfate and lactosaminoglycan. Upon differentiation to become the FAACC19 cell, it continues to make fibronectin, but the Mr = 220,000, and it lacks the two carbohydrate polymers. Attempts are being made to determine how the cell can effect this genetically programmed change by examining the levels of various enzymes involved in the metabolism of carbohydrates. We have found that the sialic acid (NAN) content of the differentiated cell is double that of the undifferentiated cell and that sialyl transferase is increased 5-\to 9-fold. This increased sialylation of growing carbohydrate chains could prevent the synthesis of the lactosylaminoglycans. We have also found that the enzyme that cleaves sialic acid into pyruvate and N-acetylmannosamine and could control the level of sialic acid in the cell rises 10-fold upon differentiation of F9 into PyS cells and at least 80-fold within 2 days in the promyelocytic leukemic cell, HL60, that is induced to differentiate into a macrophage by phorbol ester. The level goes up several-fold in growing cells and drops precipitously when cells stop dividing (manuscript in preparation). The level decreases 2-\to 4-fold in four sets of malignant cells tested. At least 30% of the activity is in the nucleus, the locus of the sialic acid-activating enzyme. On the other hand, the rates of biosynthesis of NAN and its activation (to CMPNAN) are approximately the same in F9 and PyS. This suggests that control of the level of sialic acid in a cell may reside in the rate of its degradation. We have observed significant changes in the rates of degradation of activated sugars (UDP-galactose, UDP-N-acetylglucosamine, GDP-mannose) with growth, differentiation, and malignant transformation. Studies are demonstrating the influence of environment, drugs, and composition of culture medium on the carbohydrate structures of the IgG produced by hybridoma cells. IgG, devoid of carbohydrate or with altered carbohydrate groups, appears to have differing affinities for different types of cells, suggesting that the pattern of glycosylation of IgG, while not having an effect on the antigen-antibody reaction, may have a role in the specificity of cellular targeting of IgG. (A)

为了了解蛋白质结合碳水化合物在自然界中的作用 在病理过程中，我们进一步记录了观察结果， 这些结构可以按程序改变。 我们发现 小鼠畸胎瘤细胞（F9）产生Mr = 250，000纤维连接蛋白 含有共价结合的硫酸乙酰肝素和乳糖胺聚糖。 后 分化成为FAACC 19细胞，它继续使 纤连蛋白，但Mr = 220，000，并且缺乏两种碳水化合物 聚合物 目前正在试图确定细胞如何影响 这种基因程序化的变化，通过检查各种 参与碳水化合物代谢的酶。 我们发现 分化细胞的唾液酸（NAN）含量是 未分化细胞和唾液酸转移酶增加5-β， 九倍。 这种不断增长的碳水化合物链的唾液酸化增加， 阻止乳糖胺聚糖的合成。 我们还发现 将唾液酸分解为丙酮酸和N-乙酰甘露糖胺的酶 并且可以控制细胞中唾液酸的水平， F9向PyS细胞的分化，并且在2天内至少80倍， 早幼粒细胞白血病细胞，HL 60，被诱导分化 转化成巨噬细胞 水平上升了好几倍， 当细胞停止分裂时，细胞生长和急剧下降（手稿 准备中）。 在四组中，水平降低2- 1至4倍。 检测恶性细胞。 至少30%的活动在细胞核中， 唾液酸激活酶的所在地。 另一方面 NAN的生物合成速率及其活化（至CMPNAN）是 在F9和PyS中大致相同。 这表明，控制 细胞中唾液酸的水平可能取决于其降解速率。 我们观察到， 活性糖（UDP-半乳糖、UDP-N-乙酰葡糖胺、GDP-甘露糖）， 生长、分化和恶性转化。 研究表明，环境、药物和 培养基组成对IgG的碳水化合物结构的影响 由杂交瘤细胞产生。 IgG，缺乏碳水化合物或改变 碳水化合物基团，似乎对不同的 类型的细胞，这表明IgG的糖基化模式，而 对抗原-抗体反应没有影响，可能在 IgG的细胞靶向特异性。 （一）