Ceramide in angiogenic integrin signaling

神经酰胺在血管生成整合素信号传导中的作用

• 批准号: 7060518
• 负责人: ANAT ERDREICH-EPSTEIN
• 金额: $ 9.59万
• 依托单位: CHILDREN'S HOSPITAL OF LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7060518
• 关键词: RNA interference; angiogenesis; apoptosis; athymic mouse; biological signal transduction; cell line; ceramides; clinical research; enzyme activity; gene expression; genetically modified animals; human tissue; integrins; molecular oncology; neoplasm /cancer blood supply; neoplastic growth; small interfering RNA; sphingomyelin phosphodiesterase; transfection /expression vector; vascular endothelium; vitronectin

DESCRIPTION (provided by applicant): Angiogenesis, the sprouting of new capillaries, is essential for cancer growth. Inhibition of integrins av-beta3/av-beta5, cell surface receptors critical in angiogenesis, induces endothelial apoptosis, disrupts angiogenesis and inhibits brain tumor growth in a mouse model. The potential utility of integrin av-beta3/av-beta5 inhibition in cancer therapy is becoming apparent with the encouraging responses to RGDfV, an integrin-function-blocking peptide that completed a phase-I clinical trial in adults with recurrent gliomas. Despite the emerging use of av-beta3/av-beta5 integrin inhibition in cancer therapy, especially against brain tumors, the molecular mechanism of this inhibition is poorly understood, precluding rational design of combination therapies for future trials. We have shown that integrin inhibition increases intracellular ceramide, a pro-apoptotic lipid second messenger. It is not known whether this ceramide increase is required for the anti-angiogenic action of integrin av-beta3/av-beta5 inhibition. Our recent data suggest that acid sphingomyelinase is critical in this mechanism. We hypothesize that the ceramide increase, generated by acid sphingomyelinase and induced by integrin- av-beta3/av-beta5 inhibition is required for endothelial apoptosis and for the effect of RGDfV against brain tumors in vivo. Our Specific Aims are: 1) To determine molecular interactions between ceramide, integrins av-beta3/av-beta5 and apoptosis, and 2) To compare the inhibitory effect of RGDfV in WT and ASMase deficient mice using an intracranial mouse brain tumor model. In vitro we will use ASMase-deficient or -competent endothelial cells plated on vitronectin and compare their ceramide and apoptotic responses to RGDfV. In-vivo we will implant intracranial brain tumors in ASMase knockout mice and wild type littermates and determine differences in survival, tumor growth and angiogenesis in RGDfV- or control-treated mice between the groups. Demonstration of a requirement for acid sphingomyelinase in av-beta3/av-beta5 integrin-mediated endothelial apoptosis will be the first evidence for a causal role of ceramide in integrin signaling. Requirement for ceramide metabolism in integrin signaling has potentially far-reaching implications by providing a molecular rationale for combining integrin-inhibiting drugs with agents geared to optimize the ceramide response, resulting in improved anti-cancer efficacy.

描述（由申请人提供）：血管生成，即新毛细血管的萌芽，对于癌症生长至关重要。在小鼠模型中，抑制整合素 av-beta3/av-beta5（对血管生成至关重要的细胞表面受体）可诱导内皮细胞凋亡，破坏血管生成并抑制脑肿瘤生长。随着 RGDfV 的令人鼓舞的反应，整合素 av-beta3/av-beta5 抑制在癌症治疗中的潜在效用变得越来越明显，RGDfV 是一种整合素功能阻断肽，已在患有复发性神经胶质瘤的成人中完成了 I 期临床试验。尽管av-beta3/av-beta5整合素抑制在癌症治疗中的应用不断涌现，特别是针对脑肿瘤，但人们对这种抑制的分子机制知之甚少，这妨碍了未来试验中联合疗法的合理设计。我们已经证明，整合素抑制会增加细胞内神经酰胺，这是一种促凋亡脂质第二信使。目前尚不清楚这种神经酰胺的增加是否是整合素 av-beta3/av-beta5 抑制的抗血管生成作用所必需的。我们最近的数据表明酸性鞘磷脂酶在这一机制中至关重要。我们假设由酸性鞘磷脂酶产生并由整合素-av-β3/av-β5抑制诱导的神经酰胺增加是内皮细胞凋亡和RGDfV体内对抗脑肿瘤的作用所必需的。我们的具体目标是：1) 确定神经酰胺、整合素 av-beta3/av-beta5 与细胞凋亡之间的分子相互作用，2) 使用颅内小鼠脑肿瘤模型比较 RGDfV 对 WT 和 ASMase 缺陷小鼠的抑制作用。 在体外，我们将使用涂在玻连蛋白上的 ASMase 缺陷或感受态内皮细胞，并比较它们对 RGDfV 的神经酰胺和细胞凋亡反应。在体内，我们将在 ASMase 敲除小鼠和野生型同窝小鼠中植入颅内脑肿瘤，并确定 RGDfV 或对照治疗小鼠各组之间存活、肿瘤生长和血管生成的差异。证明 av-beta3/av-beta5 整合素介导的内皮细胞凋亡需要酸性鞘磷脂酶，这将是神经酰胺在整合素信号传导中因果作用的第一个证据。整合素信号传导对神经酰胺代谢的要求具有潜在的深远影响，它为将整合素抑制药物与旨在优化神经酰胺反应的药物相结合提供了分子原理，从而提高了抗癌功效。