Targeting Caveolae in Breast Tumors

 描述(由申请人提供)：我们已经确定了一个有用的肿瘤诱导靶点，它集中在内皮细胞表面的特殊囊泡转运体中，称为小凹。它是一种翻译后修饰的Annexin A1(AnnA1)形式，具有足够的特异性和可及性，能够在静脉注射新创建的针对AnnA1的单抗后实现肿瘤选择性递送。小凹病毒迅速将这种抗体与附着的货物一起泵过血管内皮细胞，达到实体肿瘤内的浓度，远远超过最高血液水平。本项目的重点是测试第一抗体靶向肿瘤内皮细胞小窝和主动穿透实体肿瘤的治疗效用。它评估了我们创新的治疗交付策略的原则证明，并通过评估小凹免疫靶向和注入肿瘤可以增强化疗和放射治疗的治疗效果的情况，走向临床翻译。各种放射性核素和化疗药物将与AnnA1抗体偶联，以创建新的肿瘤小窝靶向治疗药物，这种药物将在使用小鼠和人类组织的乳腺癌模型中进行增强递送和治疗效果的测试。我们假设，通过向肿瘤中注入武装抗体，小窝可以迅速而特异地将治疗剂集中在肿瘤内，以加强对肿瘤的破坏，并减少体内其他部位的有毒暴露。这种新的小窝靶向策略应该会减少疗效所需的剂量，并增加治疗指数。本项目的具体目标是：目的1.研究系统靶向小凹的放射免疫治疗在啮齿动物乳腺肿瘤模型中的传递和疗效。目的2.探讨小窝免疫靶向促进乳腺肿瘤转移的作用及化疗药物在啮齿动物模型中的作用。目的3.在具有正常人体血管的IVM人乳腺肿瘤模型中，评价抗人mAnnA1裸体抗体和武装抗体的靶向、组织加工和治疗效果。该项目将利用来自基因工程小鼠的自发乳腺肿瘤以及我们新的活体显微镜(IVM)肿瘤模型系统。IVM允许直接可视化靶向和内皮处理以及间质和肿瘤细胞反应，所有这些都可以量化，以帮助提供对肿瘤治疗机制的新见解。靶向小凹打开了一条跨越限制性血液的特定通道：肿瘤界面。它的先进交付更接近于实现更有效疗法所需的理想靶向。我们已经证明，AnnA1在人类原发和转移性乳腺肿瘤的血管和小窝中都有表达。因此，这些研究可能会产生新的给药平台，为人类的许多乳腺肿瘤创造新的诊断显像剂和肿瘤靶向治疗。

 DESCRIPTION (provided by applicant): We have identified a useful tumor-induced target concentrated in specialized vesicular transporters at the endothelial cell surface called caveolae. It is a post-translationally modified form of Annexin A1 (AnnA1) that is sufficiently specific and accessible to enable tumor-selective delivery after intravenous injection of a newly created monoclonal antibody that is specific for AnnA1. Caveolae rapidly pump this antibody with attached cargo across the endothelium to reach concentrations actually inside solid tumors that greatly exceed maximum blood levels. This project focuses on testing the therapeutic utility of the first antibody to target tumor endothelial caveolae and to actively penetrate solid tumors. It evaluates proof-of-principle of our innovative delivery strategy for therapy and moves toward clinical translation by assessing how well caveolae immunotargeting and pumping into tumors can enhance the therapeutic impact of chemotherapy and radiotherapy. Various radionuclides and chemotherapeutic agents will be conjugated to AnnA1 antibody to create new tumor caveolae-targeted therapeutics that will be tested for enhanced delivery and therapeutic efficacy in breast cancer models using mouse and human tissues. We hypothesize that by pumping armed antibodies into tumors, caveolae can rapidly and specifically concentrate therapeutic agents inside tumors to enhance tumor destruction and reduce toxic exposure elsewhere in the body. This novel caveolae targeting strategy should reduce dosages required for efficacy and increase therapeutic indices. The Specific Aims of this Project are: Aim 1. To investigate the delivery and efficacy of systemic radioimmunotherapies targeting caveolae in rodent mammary tumor models. Aim 2. To investigate the utility of caveolae immunotargeting to enhance mammary tumor delivery and efficacy of chemotherapeutic agents in rodent models. Aim 3. To assess targeting, tissue processing and therapeutic efficacy of naked and armed antibodies to human mAnnA1 in an IVM human breast tumor model with functional human blood vessels. This project will utilize spontaneous mammary tumors from genetically engineered mice as well as our new intravital microscopy (IVM) tumor model system. IVM permits direct visualization of targeting and endothelial processing as well as stroma and tumor cell responses, all of which can be quantified to help provide new insights into therapeutic mechanisms in tumors. Targeting caveolae opens a specific gateway across the restrictive blood:tumor interface. It has advanced delivery much closer to ideal targeting needed to achieve more effective therapies. We have demonstrated that AnnA1 is expressed in the vasculature and caveolae of human primary and metastatic breast tumors. Thus, these studies are likely to yield new delivery platforms to create novel diagnostic imaging agents and tumor targeting therapies for many breast tumors in humans.