Globotriaosyl Ceramide (Gb3/CD77) in Burkitt's Lymphoma

Globottriosyl Ceramide (Gb3/CD77) 在伯基特淋巴瘤中的应用

• 批准号: 7076147
• 负责人: MARK D MALONEY
• 金额: $ 17.06万
• 依托单位: SPELMAN COLLEGE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7076147
• 关键词: B lymphocyte; Burkitt' s lymphoma; apoptosis; binding sites; biological signal transduction; cell growth regulation; cell line; cell population study; cell surface receptors; cellular pathology; ceramides; chemical structure function; computer simulation; cysteine endopeptidases; cytochrome c; flow cytometry; gene expression; genetic regulation; glycosphingolipids; intermolecular interaction; molecular oncology; neoplastic cell; receptor binding; shiga toxin

Verotoxins (VT's, also called Shiga toxins) produced by E. coli serotype 0157:H7 and other serotypes have been implicated as causative agents of hemolytic uremic syndrome, hemorrhagic colitis, and thrombocytopenic purpura. The receptors for VT's are globotriaosyl ceramide (Gb3 or CD77) and possibly other glycosphingolipids which contain Gal alpha1-4 Gal residues. Gb3 is expressed at the germinal center stage of B lymphocyte development. Because of their phenotypic resemblance, Daudi cells and other Burkitt's lymphoma-derived cell lines serve as in vitro models of GC B lymphocytes. The Gb3-binding VT B subunits mimic the IFNAR-1 subunit of the interferon-alpha receptor, the B cell protein CD19, and MHC class II proteins in their amino acid sequences. Experimental evidence to date indicates that Gb3 and Gb3-binding proteins are essential components of a number of signal transduction pathways in Burkitt's lymphoma and GC B lymphocytes. These include a role for Gb3/IFNAR-1 in IFN-alpha induced growth inhibition and adhesion, Gb3/CD19 interaction in adhesion and Gb3/VT B-subunit interaction in the induction of apoptosis. However, there is relatively little data available concerning which signal transduction pathways require Gb3, or the precise role of Gb3 in the pathways leading to the observed responses. Our preliminary investigations indicate that Gb3 may play a major role in a number of apoptotic pathways in Gb3-positive B cells. We propose to further investigate the role of Gb3 in signal transduction relating to apoptosis using the Daudi cell line, which expresses high levels of Gb3, and the Daudi-derived Gb3-deficient VT500 cell line. The long term objectives of the proposed research are to determine the cellular functions of Gb3 and other Gal alpha 1-4 Galcontaining glycolipids and their endogenous protein ligands, and to determine how the targeting of Gb3-positive cells by VT affects immune responses and the pathogenesis of VT producing E. coli infection. Specific aims are to: 1) Identify and define apoptosis pathways which require Gb3 by comparing such pathways in Gb3+ and Gb3- Burkitt's lymphoma cell lines. 2) Determine differential gene expression in Gb3+ and Gb3- Burkitt's lymphoma cells prior to and following treatment with inducers of apoptosis by performing microarray analysis, RT-PCR and northern analysis. 3) Identify and model potential VT-like Gb3-binding sites on proteins involved in apoptosis pathways which require Gb3.

由0157：H7型大肠杆菌和其他血清型产生的VT毒素(VT‘s，又称志贺毒素)被认为是溶血性尿毒症综合征、出血性结肠炎和血小板减少性紫癜的病原体。VT的受体是球状三糖神经酰胺(Gb3或CD77)和其他可能含有Galα1-4 Gal残基的神经鞘糖脂。Gb3在B淋巴细胞发育的生发中心阶段表达。由于它们的表型相似，Daudi细胞和其他Burkitt淋巴瘤来源的细胞系可以作为GC B淋巴细胞的体外模型。与Gb3结合的VT B亚基在氨基酸序列上模拟干扰素-α受体的IFNAR-1亚基、B细胞蛋白CD19和MHC II类蛋白。到目前为止的实验证据表明，Gb3和Gb3结合蛋白是Burkitt淋巴瘤和 GC B淋巴细胞。其中包括Gb3/IFNAR-1在干扰素-α诱导的生长抑制和黏附中的作用，Gb3/CD19相互作用在黏附中的作用，以及Gb3/VT B-亚基相互作用在诱导细胞凋亡中的作用。然而，关于哪些信号转导通路需要Gb3，或者Gb3在导致观察到的反应的通路中的确切作用，可用的数据相对较少。我们的初步研究表明，在Gb3阳性的B细胞中，Gb3可能在许多凋亡途径中发挥重要作用。我们建议使用高水平表达Gb3的Daudi细胞系和Daudi来源的Gb3缺陷VT500细胞系进一步研究Gb3在与凋亡相关的信号转导中的作用。这项研究的长期目标是确定Gb3和其他含Galα1-4半乳糖的糖脂及其内源性蛋白配体的细胞功能，并确定VT靶向Gb3阳性细胞如何影响免疫反应和VT产生大肠杆菌感染的发病机制。具体目的是：1)通过比较Gb3+和Gb3-Burkitt淋巴瘤细胞系中的Gb3+和Gb3-Burkitt淋巴瘤细胞系中需要Gb3的凋亡途径，来确定和定义这些途径。2)通过基因芯片分析、RT-PCR和Northern分析，确定Gb3+和Gb3-Burkitt淋巴瘤细胞在诱导凋亡前后的差异基因表达。3)在需要Gb3参与细胞凋亡途径的蛋白质上，确定并模拟潜在的VT样Gb3结合位点。