Exploration and development of antiangiogenic peptides for breast cancer

描述（由申请人提供）：乳腺癌是美国最常见的女性恶性肿瘤。血管生成在乳腺癌的发生和转移中起着重要作用。因此，抗血管生成疗法，无论是作为单一疗法还是与其他疗法组合，都是有希望的，并且在临床前和临床研究中被深入研究。该项目的目标是在人类乳腺癌小鼠模型中测试新型内源性抗血管生成肽。我们将测试在我们的实验室中确定的肽来源于三类蛋白质：血小板反应蛋白I型重复蛋白; CXC趋化因子;和α 5胶原蛋白IV型原纤维。我们已经使用内皮细胞增殖和迁移试验对所鉴定的肽进行了仔细的体外筛选，并在小鼠的几种体内试验中证明了活性，包括皮下基底膜提取物塞、角膜微囊和肿瘤异种移植物。基于这些研究，我们将选择范围缩小到三种主要肽。我们假设所鉴定的肽抑制乳腺癌中的肿瘤血管生成，并且因此可以抑制或显著减少肿瘤生长。为了验证这一假设，我们将使用人类乳腺癌小鼠模型来研究所选肽的抗血管生成特性。两种人乳腺癌细胞系，侵袭性较小的MCF-7和侵袭性较大的MDA-MB-231，将用于在严重免疫缺陷（SCID）小鼠中形成原位肿瘤异种移植物。肽将腹膜内（i. p.）并监测肿瘤大小。除了裸肽之外，包封到聚合物纳米胶束中的肽将用于增加其溶解度、半衰期和增强全身给药。将使用磁共振成像（MRI）无创监测肿瘤血容量和血管通透性。将进行免疫组织化学，以确定对血管系统以及对癌症和基质细胞的影响。我们已经确定了一些肽受体的内皮细胞在体外使用受体中和单克隆抗体。具体来说，我们已经鉴定了受体CD 36、CD 47、CXCR 3以及β-1和β-3整联蛋白。我们将对这些受体在肿瘤异种移植物中的表达进行研究。我们还将进行试点研究，我们将与其他抗血管生成剂（例如，干扰VEGF途径的药物）和化疗药物，以测试它们的作用是相加的还是协同的，以及它们是否可以提供额外的治疗益处。新的抗血管生成药物的开发将对肿瘤血管生成和其他与新血管生成相关的疾病的研究产生重大影响。公共卫生相关性：乳腺癌是美国最常见的女性恶性肿瘤。2007年诊断出约180 000例新的浸润性乳腺癌病例。这项研究与公共卫生的相关性在于，这项工作可能会导致识别新的抗血管生成剂（抑制异常血管生长），用于治疗乳腺癌和潜在的其他形式的癌症。它还将提供对几种组织蛋白在维持健康血管平衡中的作用以及这种作用在疾病条件下如何变化的更好理解。

DESCRIPTION (provided by applicant): Breast cancer is the most commonly diagnosed female malignancy in the United States. Angiogenesis plays a critical role in tumorigenesis and metastasis in breast cancer. Thus, antiangiogenic therapies, either as monotherapy or in combination with other therapies are promising and being intensely investigated in both preclinical and clinical studies. The goal of the proposed project is to test novel endogenous antiangiogenic peptides in mouse models of human breast cancer. We will test peptides identified in our laboratory derived from three classes of proteins: thrombospondin type I repeat-containing proteins; CXC chemokines; and alpha5 fibrils of collagen type IV. We have performed careful in vitro screening of the identified peptides using endothelial cell proliferation and migration assays, and demonstrated activity in several in vivo assays in mice including subcutaneous basement-membrane-extract plugs, corneal micropocket, and tumor xenografts. Based on these studies, we have narrowed the selection to three leading peptides. We hypothesize that the identified peptides inhibit tumor angiogenesis in breast cancer and can therefore inhibit or significantly reduce the tumor growth. To test this hypothesis, we will examine antiangiogenic properties of the selected peptides using a mouse model of human breast cancer. Two human breast cancer cell lines, the less invasive MCF-7 and the more invasive MDA-MB-231, will be used to form orthotopic tumor xenografts in severe immune deficient (SCID) mice. The peptides will be administered intraperitoneally (i.p.) and tumor size will be monitored. In addition to naked peptides, peptides encapsulated into polymer nanomicelles will be used to increase their solubility, half-life, and enhance systemic administration. Tumor blood volume and vascular permeability will be monitored non-invasively using Magnetic Resonance Imaging (MRI). Immunohistochemistry will be performed to determine the effects on the vasculature and on the cancer and stromal cells. We have identified a number of peptide receptors on the endothelial cells in vitro using receptor neutralization by monoclonal antibodies. Specifically, we have identified receptors CD36, CD47, CXCR3, and beta-1 and beta-3 integrins. We will conduct studies on the expression of these receptors in tumor xenografts. We will also conduct pilot studies where we will apply the peptides in combination with other antiangiogenic agents (e.g., agents interfering with the VEGF pathways) and chemotherapeutic agents to test whether their action is additive or synergistic and if they can provide added therapeutic benefits. The proposed development of novel antiangiogenic agents would have a significant impact on research in tumor angiogenesis and other diseases associated with neovascularization. PUBLIC HEALTH RELEVANCE: Breast cancer is the most commonly diagnosed female malignancy in the United States. Approximately 180,000 new cases of invasive breast cancer have been diagnosed in 2007. The relevance of this research to public health is that the work may lead to identification of new antiangiogenic agents (inhibiting abnormal blood vessel growth) for the treatment of breast cancer and potentially other forms of cancer. It will also provide a better understanding of the role of several tissue proteins in maintaining healthy vascular balance and how this role may change in disease conditions.