ROLE OF CELL-SURFACE GLYCOSYLATION IN TUMOR METASTASIS

肿瘤细胞转移是大多数人死亡的主要原因 癌症。无数的实验室已经证明了 糖基化细胞表面与能力的相关性 肿瘤细胞分离和转移的可能性。我们将继续 利用最先进的技术来研究 糖共轭生物化学以阐明其结构 改变的基础和背后的生化机制 高转移肿瘤细胞表面的糖基化。 我们的计划是继续使用现有的B16黑色素瘤变种 具有截然不同的转移表型。此外，我们 将检查某些其他转移模型，包括细胞 用多种致癌基因和一系列小鼠肾上腺 癌转移变异体。具体目标如下：1) 继续对低聚糖进行结构分析 糖蛋白中重要的糖基化位点 转移表型。低聚糖结构分析将 在隔离的I类和II类组织相容部位进行 抗原、层粘连蛋白、Lamp-L和GP-70。2)继续使用 纯化的糖基转移酶与适当的 糖苷酶作为细胞表面糖的嵌入探针 活体转移性肿瘤细胞变异的地形图。细胞表面 转移变异体的糖链结构将被检查。 使用几种不同的高纯度糖基转移酶 以前都被认为与转移有关。3)净化和 B1-4GlcNAc半乳糖基转移酶升高的特征 自发转移性B16黑色素瘤表面4倍 细胞。底物专一性，细胞定位方式- 表面和酶在转移中的可能作用将是 调查过了。4)研究染色体蛋白质的糖基化 在转移的肿瘤细胞变种中。最近我们发现了一个 富含转录的糖基化的新形式 因子、DNA结合蛋白和核孔。我们的目标是 以评估这种类型的糖基化的可能参与 在转移表型中。5)使用转染癌基因和 佛波酯研究生物化学机制导致 转移性肿瘤细胞表面糖基化的改变。 C-H-ras基因转导NIH3T3细胞及对B16的治疗作用 含有佛波酯的黑色素瘤细胞快速诱导转移 表型并伴随改变细胞表面糖基化。我们 将研究细胞表面的生化变化 由这些试剂诱导的寡糖，目的是 阐明蛋白质表达变化之间的联系 激酶C和异常低聚糖的处理。 这些研究使用了现有最好的肿瘤动物模型。 探讨肿瘤转移背后的机制及其作用 糖基化改变在转移表型的产生中。

Tumor cell metastasis is the primary cause of death in most cancers. Numerous laboratories have demonstrated a strong correlation between the glycosylation cell-surface and the ability of a tumor cell to detach and metastasize. We will continue to make use of state-of-the-art technology for the study of glycoconjugate biochemistry in order to elucidate the structure base of and the biochemical mechanisms behind the altered glycosylation of highly metastatic tumor cell-surfaces. Our plan is to continue to use the available B16 melanoma variants that have widely different metastatic phenotypes. In addition, we will examine certain other metastatic models, including cells transfected with various oncogenies, and a series of murine adrenal carcinoma metastatic variants. Specific Aims as follows: 1) To Continue to Perform Structural Analyses On Oligosacharides From Individual Glycosylation Sites of Glycolproteins Important to the Metastatic Phenotype. Oligosaccharide structural analyses will be performed at isolated sites on class I and II histocompatibility antigens, laminin, Lamp-l and Gp-70. 2) To continue to Use Purified Glycosyltransferases, In Conjunction with Appropriate Glycosidases, As Impearment Probes of Cell-Surface Saccharide Topography on Living Metastatic Tumor Cell Variants. Cell surface saccharide topography of the metastatic variants will be examined using several different highly-purified glycosyltransferases that have previously been linked to metastasis. 3) To Purify and Characterize the B1-4 GlcNAc Galactosyltransferase That is Elevated 4-fold on the Surfaces of Spontaneously Metastatic B16 Melanoma Cells. Substrate specificity, mode of localization to the cell- surface and the possible role of the enzyme in metastasis will be investigated. 4) To Study the Glycoylation of Chromosomal Proteins in Metastatic Tumor Cell Variants. Recently we have discovered a novel from of glycosylation that is enriched on transcription factors, DNA-binding proteins, and on nuclear pores. Our aim is to evaluate the possible involvement of this type of glycosylation in the metastatic phenotype. 5) To use Transfected Oncogenies and Phorbol Estes to Investigate the Biochemical Mechanisms Leading to Altered Cell Surface Glycosylation in Metastatic Tumor Cells. Transfection of NIH 3T3 cells with c-H-ras and treatment of B16 melanoma cells with phorbol esters rapidly induce metastatic phenotype and concomitantly alters cell surface glycosylation. We will study the biochemical changes in the cell surface oligosaccharides induced by these agents with the aim of elucidating the connection between altered expression of protein kinase C and abnormal oligosacharide processing. These studies are using the best available animal models of tumor metastasis to examine the mechanisms behind and the roles of altered glycosylation in generation of the metastatic phenotype.