Xenograft-like rejection of tumors in a-gal glycolipids

描述（由申请人提供）： 治疗难治性病变是实体瘤患者死亡的主要原因。尽管在这种病变中的肿瘤细胞表达各种肿瘤相关抗原（TAA），但由于肿瘤内的免疫抑制微环境、调节性T（Treg）细胞的活性以及抗原呈递细胞（APC）缺乏对TAA的适当呈递，它们通常被免疫系统“隐藏”。我们提出了一种新的免疫疗法，以破坏这种病变，并将其转化为内源性肿瘤疫苗瘤内注射的胶束鞘糖脂轴承α-半乳糖抗原表位（Gala 1 - 3Galb 1 -4GlcNAc-R）（指定GSL？gal）。由于天然抗Gal抗体（人体免疫球蛋白的1%）与GSL的α-gal表位结合，这种注射诱导了强烈的肿瘤内炎症反应。加抗Gal与在非灵长类哺乳动物（例如猪）的细胞上天然表达的α-gal表位的结合在人和猴中诱导异种移植物的快速排斥。我们假设瘤内注射GSL？gal将以类似于异种移植物排斥的机制导致损伤的破坏，并将诱导针对微转移的保护性免疫应答，其足以克服Treg细胞的抑制作用。GSL的影响？gal将通过以下机制介导：1.由于抗Gal/GSL？激活补体而产生趋化因子gal相互作用2.插入GSL？半乳糖进入细胞膜，导致抗半乳糖介导的肿瘤细胞破坏，如异种移植排斥。3.通过抗Gal对肿瘤细胞进行调理作用，靶向它们以被炎症募集到肿瘤中的APC有效摄取，从而将肿瘤转化为内源性疫苗。我们在缺乏α-gal表位并产生抗-Gal的敲除小鼠中的初步研究证明了治疗的黑素瘤病变的破坏及其在大部分小鼠中转化为疫苗。我们的具体目标是：1.研究GSL？半乳糖诱导B16黑色素瘤病变内的炎症。2.评估Treg细胞在预防约30%对GSL无反应的小鼠诱导局部和全身保护性抗肿瘤免疫应答中的作用？gal治疗。3.确定在自发性乳腺癌模型中瘤内GSL的保护作用？半乳糖注射在原发性病变的发展和诱导保护性免疫应答以防止其他病变和转移中的作用。这些研究的成功将使我们能够建立GSL的临床试验？半乳糖苷在化疗难治性肿瘤患者中的应用 我们的目标是开发一种新的方法，用于治疗复发性化疗难治性实体瘤的癌症患者，通过向病变中注射一种称为鞘糖脂的物质，该物质含有称为α-gal表位的碳水化合物结构。这种物质被称为GSL？加这种治疗方法利用了这样一个事实，即所有人都有一种称为抗Gal的天然抗体。该抗体与GSL上的α-gal表位相互作用？gal并引起局部炎症。注射GSL？将半乳糖注入肿瘤病灶，在抗半乳糖的辅助下破坏病灶，并将治疗的病灶转化为自身疫苗。这种疫苗“教育”免疫系统识别微转移中的肿瘤细胞（各种器官中的小肿瘤细胞群）作为必须被摧毁的细胞。我们将在模拟相关人类免疫学参数的独特小鼠模型中研究这种治疗。小鼠模型研究的成功将使我们能够将这种治疗方法应用于癌症患者。

DESCRIPTION (provided by applicant): Therapy refractory lesions are the main cause of death in solid tumor patients. Although the tumor cells in such lesions express various tumor associated antigens (TAA), they are usually "concealed" from the immune system because of immunosuppressive microenvironment within the tumor, activity of regulatory T (Treg) cells and lack of appropriate presentation of TAA by antigen presenting cells (APC). We propose a novel immunotherapy to destroy such lesions and convert them into endogenous tumor vaccines by intratumoral injection of micelles of glycosphingolipids bearing a-gal epitopes (Gala1-3Galb1-4GlcNAc-R) (designated GSL?gal). This injection induces a strong intratumoral inflammatory reaction due to binding of the natural anti- Gal antibody (1% of immunoglobulins in humans) to a-gal epitopes of GSL?gal. Anti-Gal binding to a-gal epitopes naturally expressed on cells of non-primate mammals (e.g. pigs) induces rapid rejection of xenografts in humans and monkeys. We hypothesize that intratumoral injection of GSL?gal will result in destruction of lesions in a mechanism similar to xenograft rejection and will induce a protective immune response against micrometastases, potent enough to overcome the suppressive effect of Treg cells. The effects of GSL?gal will be mediated by the following mechanisms: 1. Chemotactic factors generation due to complement activation by Anti-Gal/GSL?gal interaction. 2. Insertion of GSL?gal into cell membranes, resulting in anti-Gal mediated destruction of tumor cells as in xenograft rejection. 3. Opsonization of tumor cell by anti-Gal, targeting them for effective uptake by APC recruited into the tumor by the inflammation, thereby converting tumors into endogenous vaccines. Our preliminary studies in knockout mice lacking a-gal epitopes and producing anti-Gal, demonstrated destruction of treated melanoma lesions and their conversion into vaccine in a large proportion of mice. Our specific aims are: 1. To study the mechanisms by which GSL?gal induces inflammation within of B16 melanoma lesions. 2. To evaluate the role of Treg cells in preventing induction of a local and systemic protective anti-tumor immune response in the ~30% of mice that do not respond to GSL?gal treatment. 3. To determine in a model of spontaneous mammary carcinoma the protective effect of intratumoral GSL?gal injection in the development of the primary lesion and on induction of a protective immune response preventing additional lesions and metastases. Success in these studies will enable us to establish clinical trials with GSL?gal in cancer patients with chemotherapy refractory lesions. Our objective is to develop a novel method for treating cancer patients with recurrent chemotherapy refractory solid tumors, by injection into the lesion a substance called glycosphingolipids containing a carbohydrate structure called the a-gal epitope. This substance is referred to as GSL?gal. The treatment exploits the fact that all humans have a natural antibody called anti-Gal in very large amounts. This antibody interacts with a-gal epitopes on GSL?gal and induces local inflammation. Injection of GSL?gal into tumor lesions destroys the lesions with the assistance of anti-Gal and convert treated lesions into a self vaccine. This vaccine "educates" the immune system to recognize tumor cells in micrometastases (small groups of tumor cells in various organs) as cells that have to be destroyed. We will study this treatment in a unique mouse model that simulates the pertinent human immunological parameters. Success in the studies in the mouse model will enable us to apply this treatment to cancer patients.