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，新毛细血管的发芽对于癌症生长至关重要。抑制整联蛋白AV-BETA3/AV-BETA5，血管生成至关重要的细胞表面受体，诱导内皮细胞凋亡，破坏血管生成并抑制小鼠模型中的脑肿瘤生长。癌症治疗中整合素AV-BETA3/AV-BETA5抑制作用的潜在效用变得显而易见，这是对RGDFV的令人鼓舞的反应，RGDFV是一种整联蛋白 - 功能阻断肽，该肽在成人复发性神经胶质瘤的成年人中完成了一项相位I的临床试验。尽管在癌症治疗中尤其是针对脑部肿瘤的AV-BETA3/AV-BETA5整联蛋白抑制的新兴使用，但这种抑制作用的分子机制知之甚少，排除了联合疗法的理性设计用于未来试验。我们已经表明，整联蛋白抑制增加了细胞内神经酰胺，这是一种促凋亡的脂质第二信使。尚不清楚整联蛋白AV-BETA3/AV-BETA5抑制是否需要这种神经酰胺增加。我们最近的数据表明，酸鞘磷脂酶在该机制中至关重要。我们假设由酸鞘磷脂酶产生的神经酰胺增加并由整联蛋白AV-BETA3/AV-BETA5抑制诱导的内皮细胞凋亡是必需的，以及RGDFV对体内脑肿瘤的影响。我们的具体目的是：1）确定神经酰胺，整联蛋白AV-BETA3/AV-BETA5和凋亡之间的分子相互作用，以及2）使用颅内小鼠脑肿瘤模型比较RGDFV和ASMase缺乏小鼠RGDFV的抑制作用。 在体外，我们将使用镀膜上镀膜的ASMase缺陷或竞争性内皮细胞，并比较其神经酰胺和对RGDFV的凋亡反应。在体内，我们将在ASMase敲除小鼠和野生型同窝仔中植入颅内脑肿瘤，并确定两组之间RGDFV或对照处理的小鼠的存活率，肿瘤生长和血管生成的差异。证明在AV-BETA3/AV-BETA5整合蛋白介导的内皮细胞凋亡中酸性鞘磷脂酶的需求将是神经酰胺在整联蛋白信号传导中起因作用的第一个证据。整合素信号传导中神经酰胺代谢的需求通过提供分子原理，以将整联蛋白抑制药物与旨在优化神经酰胺反应的剂相结合，从而有可能提高抗癌能力。