ANTI-PDZ DOMAIN ANTIBODIES ENHANCE THE EFFICACY OF RADIOTHERAPY

预后不良的癌症，包括肺癌和胶质母细胞瘤，表现出强烈的TAX过度表达 相互作用蛋白-1(TIP1)。这项拟议的研究是抗癌药物开发的一种新方法 我们的目标是这种伴侣蛋白，它与信号转导蛋白结合，从而提高以下细胞的活力 细胞毒疗法。癌细胞的应激反应被夸大了，而不是正常组织。以下是例子 信号转导途径包括GRP78、PKC、PLC、Rho等。通过这些机制 对电离辐射作出反应而停靠在质膜上的蛋白质包括马达和支架蛋白。 一种覆盖质膜相关信号蛋白羧基末端的支架蛋白，TIP1 在癌症中过表达，并转移到癌细胞的细胞膜表面 暴露在电离辐射中。TIP1的功能结构域是与酶结合的PDZ结合域 调节细胞活性的有PLC、PKC、GPCR和Rho等。我们的初步数据显示，基因沉默 TIP1及结合TIP1 PDZ结构域的封闭抗体增强放射诱导的细胞毒作用 癌症，但不是正常组织。放射治疗肺癌小鼠体内注射抗PDZ结构域抗体 与癌症特异性结合，并显著增强肿瘤生长延迟。我们会研究 增强细胞毒性和改善肿瘤控制的抗体。通过一种机制，抗PDZ结构域 抗体增强放射治疗疗效是通过阻断细胞活性信号转导实现的 途径和随后的程序性细胞死亡，特别是在癌症中。我们将比较抗体片段 (ScFv)与TIP1的PDZ结构域结合的完整IgG抗体，并确定哪些抗体可 肿瘤特异性结合与无正常组织肿瘤放射治疗疗效的提高 毒性。我们将确定实现癌症特异性结合的主要人源性抗TIP1抗体片段和 对癌细胞的细胞毒性。我们的初步数据显示，测量抗TIP1之间相互作用的分析 抗体和放射试验包括克隆形成试验和细胞凋亡试验。我们会比较我们的先导抗体 TIP1上的PDZ结构域的特异性，以确定哪一个是最具癌症特异性和细胞毒性的。我们将决定 抗TIP1/PDZ单链抗体与抗TIP1/PDZ单链抗体在小鼠肿瘤模型中的疗效比较。我们会 确定免疫效应细胞在肿瘤对抗TIP1抗体的反应中的作用。我们假设免疫球蛋白 可通过激活免疫效应细胞进一步提高放射治疗的疗效。我们将研究小鼠模型 缺乏Fc受体且不能激活抗体介导的肿瘤细胞毒作用。这些鼠标模型可以让我们 为了确定抗TIP1抗体的疗效是直接作用于癌细胞还是免疫 效应细胞的激活参与了治疗效果的发挥。

Poor prognosis cancers including cancers of the lung and glioblastoma show robust overexpresion of Tax Interacting Protein-1 (TIP1). The proposed research is a novel approach to cancer drug development in which we target this chaperone protein that binds to signal transduction proteins that enhance cell viability following cytotoxic therapy. Stress responses in cancer cells are exaggerated over that of normal tissues. Examples are signal transduction pathways that include GRP78, PKC, PLC, Rho and others. Mechanisms by which these proteins dock on the plasma membrane in response to ionizing radiation include motor and scaffold proteins. One scaffold protein that caps the carboxyl terminus of plasma membrane-associated signaling proteins, TIP1 is overexpressed in cancer and translocates to the surface of the cell membrane of cancer cells following exposure to ionizing radiation. The functional domain of TIP1 is the PDZ binding domain which binds enzymes that regulate cell viability such as PLC, PKC, GPCR and Rho. Our preliminary data show that gene silencing of TIP1 and blocking antibodies that bind to the PDZ domain of TIP1 enhance radiation-induced cytotoxicity in cancer but not normal tissues. Anti-PDZ-domain antibodies injected into mice bearing irradiated lung cancer bind specifically to cancer and substantially enhance tumor growth delay over that of controls. We will study antibodies that enhance cytotoxity and improve tumor control. One mechanism by which the anti-PDZ domain antibodies enhance the efficacy of radiotherapy is through interruption of cell viability signal transduction pathways and subsequent programmed cell death specifically in cancer. We will compare antibody fragment (scFv) to whole IgG antibodies that bind to the PDZ domain of TIP1 and determine which antibodies achieve cancer specific binding and enhancement of the efficacy of radiotherapy in cancer without normal tissue toxicity. We will determine the lead human anti-TIP1 antibody fragment that achieves cancer specific binding and cytotoxicity in cancer cells. Our preliminary data show that assays which measure the interaction between anti-TIP1 antibodies and radiation include the clonogenic, and apoptosis assays. We will compare our lead antibodies that are specific to the PDZ domain on TIP1 to determine which is the most cancer specific and cytotoxic. We will determine the efficacy of anti-TIP1/PDZ IgG compared to anti-TIP1/PDZ scFv antibodies in mouse models of cancer. We will determine the role of immune effector cells in the cancer response to anti-TIP1 antibodies. We Hypothesize that IgG could further enhance the efficacy of radiotherapy by activating immune effector cells. We will study mouse models that lack Fc receptors and do not activate antibody mediated cancer cytotoxicity. These mouse models will allow us to determine whether the efficacy of the anti-TIP1 antibodies is a direct effect on cancer cells or whether immune effector cell activation contributes to the therapeutic effect.