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，集中在内皮细胞表面的专门囊泡转运蛋白中，称为小窝。它是膜联蛋白A1（AnnA1）的一种后修饰形式，具有足够的特异性和可接近性，能够在静脉注射新产生的对AnnA1特异的单克隆抗体后进行肿瘤选择性递送。Caveolae快速泵送这种抗体与附着的货物穿过内皮，以达到实际上在实体瘤内的浓度，大大超过最大血液水平。该项目的重点是测试第一抗体靶向肿瘤内皮小窝和主动穿透实体瘤的治疗效用。它评估了我们创新的治疗输送策略的原理证明，并通过评估免疫靶向和泵入肿瘤的小窝如何增强化疗和放疗的治疗效果而走向临床转化。各种放射性核素和化疗剂将与AnnA1抗体缀合，以产生新的肿瘤小窝靶向治疗剂，将使用小鼠和人组织在乳腺癌模型中测试其增强的递送和治疗功效。我们假设，通过将武装抗体泵入肿瘤，小窝可以快速特异性地将治疗剂集中在肿瘤内，以增强肿瘤破坏并减少体内其他部位的毒性暴露。这种新的小窝靶向策略应减少有效性所需的剂量并增加治疗指数。该项目的具体目标是：目标1。在啮齿类动物乳腺肿瘤模型中研究靶向小窝的全身性放射免疫治疗的给药和疗效。目标2.在啮齿动物模型中研究小窝免疫靶向增强乳腺肿瘤化疗药物递送和疗效的效用。目标3：在具有功能性人血管的IVM人乳腺肿瘤模型中评估人mAnnA1裸抗体和武装抗体的靶向、组织处理和治疗效果。该项目将利用来自基因工程小鼠的自发性乳腺肿瘤以及我们新的活体显微镜（IVM）肿瘤模型系统。IVM允许靶向和内皮加工以及基质和肿瘤细胞反应的直接可视化，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。靶向小窝打开了一个特定的通道，穿过限制性的血液：肿瘤界面。它使递送更接近实现更有效疗法所需的理想靶向。我们已经证明，AnnA1表达在血管和小窝的人原发性和转移性乳腺肿瘤。因此，这些研究可能产生新的递送平台，以创建用于人类许多乳腺肿瘤的新型诊断成像剂和肿瘤靶向疗法。

 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.