Engineering Cell Type Specific Toxins

工程细胞类型特异性毒素

• 批准号: 7323060
• 负责人: Richard James Youle
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF NEUROLOGICAL DISORDERS AND STROKE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7323060
• 关键词: Engineering; Cell; Type; Specific; Toxins

Monoclonal antibodies selectively bind tumor cell differentiation antigens in vitro and in vivo. We have devised methods of linking extremely toxic proteins to the antibodies to selectively kill tumor cells by cloning the toxins and mutating them to decrease non-target cell toxicity. Some designs using a point mutant of diphtheria toxin allow 200,000 times more toxicity to target tumor cells than nontarget cells. The transferrin receptor is particularly attractive as a target on brain tumors because it is very low or absent on neurons and glial cells and because it is highly expressed on many different types of brain tumor. In phase I and phase II clinical trials of transferrin linked to a mutant diphtheria toxin many patients showed a significant decrease in brain tumor size in response to the treatment. The dose limiting toxicity in patients appeared to be vascular damage. In animal models we have explored a new strategy to prevent this vascular toxicity by systemic delivery of chloroquine to protect the brain vasculature but not protect the brain tumor cells for the immunotoxin. We have also developed immunotoxins for treatment of dystonia and other muscle spasm diseases by targeting ricin to muscle cells. One limitation of these approaches for systemic therapy and perhaps also for brain cancer is that patients can develop an immune response to the toxin. Therefore we have explored ways to use human proteins that may be nonimmunogenic to initiate tumor cell death. Human cytotoxic proteins such as the eosinophil derived neurotoxin have been engineered and linked to antibodies and found to specifically kill tumor cells. Toxic proteins in the Bcl-2 family, Bax and Bad, that induce apoptosis, have also been engineered to bind cells and specifically kill them. As Bax and Bad are members of the Bcl-2 family of proteins that also includes anti-apoptotic members we sought to develop a new strategy to prevent neuron loss by targeting Bcl-xl to cells. Recent results show that Bcl-xl can be delivered to cells in vitro and in vivo to prevent neuron apoptosis and may have potential for inhibiting neuron loss during spinal cord injury and stroke.

单克隆抗体在体外和体内选择性结合肿瘤细胞分化抗原。我们已经设计了将极具毒性蛋白与抗体联系起来的方法，从而通过克隆毒素并将其突变以降低非靶向细胞毒性来选择性地杀死肿瘤细胞。一些使用白喉毒素点突变体的设计比非目标细胞靶向肿瘤细胞的毒性超过200,000倍。作为脑肿瘤的靶标，转铁蛋白受体特别有吸引力，因为它在神经元和神经胶质细胞上非常低或不存在，并且因为它在许多不同类型的脑肿瘤上高度表达。在与突变的白喉毒素相关的第I阶段和II期临床试验中，许多患者在响应治疗后显示出脑肿瘤大小的显着降低。限制患者毒性的剂量似乎是血管损伤。在动物模型中，我们探索了一种新的策略，可以通过全身递送氯喹以保护脑血管，但不能保护免疫毒素的脑肿瘤细胞，以防止这种血管毒性。我们还开发了免疫毒素，用于通过将ricin靶向肌肉细胞来治疗肌张力障碍和其他肌肉痉挛。这些方法进行全身治疗的局限性，也许对脑癌的局限性是患者可以对毒素产生免疫反应。因此，我们探索了使用可能非免疫原性来启动肿瘤细胞死亡的方法。人类细胞毒性蛋白（例如嗜酸性粒细胞衍生的神经毒素）已被设计并与抗体相关，并发现特异性杀死肿瘤细胞。诱导凋亡的Bcl-2家族中的有毒蛋白Bax和Bad也已设计为结合细胞并特别杀死它们。由于BAX和BAD是Bcl-2蛋白质家族的成员，还包括抗凋亡成员，因此我们试图通过将BCL-XL靶向细胞来制定一种新的策略，以防止神经元丧失。最近的结果表明，BCL-XL可以在体外和体内输送到细胞，以防止神经元凋亡，并且可能有可能在脊髓损伤和中风期间抑制神经元丧失。