GANGLIOSIDE SIGNALING CASCADES FOR GLIOMA GROWTH

描述：(改编自研究人员的摘要)神经节苷脂是 强大的细胞生长调节剂，可能对胶质瘤产生深远影响 扩散。一般的假设是神经节苷脂可以刺激 通过激活特定的信号转导通路促进胶质瘤的增殖。 这是基于他们的发现，外源性治疗U-1242 MG胶质瘤 神经节苷脂GM-I通过信号转导刺激DNA合成 涉及细胞外快速激活的机制 信号调节蛋白激酶2(ERK2)和p70S6K(P70S6K)。他们 将使用这些细胞作为研究机制的模型 神经节苷脂刺激信号转导，并认为研究应该 阐明神经节苷脂在细胞增殖中的作用，这一点很重要 在人类脑瘤中。 在具体目标1中，他将描述神经节苷脂的相互作用 并与ERK2和ERK2的激活有关 P70S6K信号级联。他将使用代谢抑制剂来测试 内源性神经节苷脂的生物合成在外源信号转导中起重要作用 他还将测试ERK2的激活是否与 GM L与细胞表面蛋白或与插入的稳定结合 GMI进入细胞膜。基于对Wortmannin的研究，一种特殊的 磷脂酰肌醇3‘-激酶抑制剂(PI3K)，他提出GM I 激活PI3K。在特定的目标2中，他将测量体内刺激的GM1 测定PI3K活性和测定PI3K活性的3-磷酸肌醇 酪氨酸激酶抑制剂和G蛋白抑制剂对此的影响 活动。在第二部分中，他将确定受GMI刺激的分子 PI3K使用生化、免疫学和分子方法。在c部分 他将创造对PI3K激活有缺陷的细胞，并将它们用于 研究GM1介导的ERK2和p70 S6K的激活。 GM1通过激活Raf-1激活ERK2 并通过一种未知的途径刺激p70S6K。在……里面 具体目标3，他将使用遗传和生化方法来检查 GM1是否刺激RAF-1的激活因子RAS。他还将 使用新的Raf突变体和磷酸氨基酸图谱来鉴定新的 GM1刺激的Raf调节。他还将使用体外激酶分析来 检测GM1是否通过丝氨酸/苏氨酸激酶Akt激活p70S6K。

DESCRIPTION: (adapted from the investigator's abstract) Gangliosides are potent modulators of cell growth and could have profound effects on glioma proliferation. The general hypothesis is that gangliosides can stimulate glioma proliferation by activating specific signal transduction pathways. This is based on their finding that exogenous treatment of U-1242 MG glioma cells with ganglioside GM I stimulated DNA synthesis by a signaling mechanism involving the rapid activation of the extracellular signal-regulated protein kinase 2 (Erk2) and p70 S6 kinase (p70s6k). They will use use these cells as a model for studying the mechanisms by which gangliosides stimulate signal transduction, and believes the studies should clarify the role of gangliosides in cell proliferation and this is important in human brain tumors. In Specific Aim 1 he will characterize ganglioside interactions at and within the cell surface and relate these to activation of the Erk2 and p70s6k signaling cascades. He will use metabolic inhibitors to test whether endogenous ganglioside biosynthesis is important for signaling by exogenous GM 1. He will also test whether activation of Erk2 correlates with the stable association of GM l with cell surface proteins or with the insertion of GM I into the membrane. Based on studies with wortmannin, a specific inhibitor of phosphatidylinositol 3'-kinase, (PI3K), he proposes that GM I activates PI3K. In Specific Aim 2 he will measure GM1stimulated in vivo production of 3-phosphoinositides to estimate PI3K activation and determine the effects of tyrosine kinase inhibitors and G-protein inhibitors on this activity. In part b he will identify GMI-stimulated molecules that regulate PI3K using biochemical, immunological and molecular approaches. In part c he will create cells that are defective for PI3K activation and use them for studying GM1 -mediated activation of Erk2 and p70 s6k. GM1 stimulates Erk2 by a mechanism involving activation of the Raf-1 oncoprotein as well as stimulates p70s6k by an uncharacterized pathway. In Specific Aim 3, he will use genetic and biochemical approaches to examine whether GM1 stimulates Ras, a well known activator of Raf-1. He will also use novel Raf mutants and phosphoamino acid profiles to to identify novel GM1-stimulated regulation of Raf. He will also use in vitro kinase assays to test whether GM1 activates p70s6k through the serine/threonine kinase Akt.