ANTIBODY-TOXIN CONJUGATES FOR THE TREATMENT OF HUMAN BRAIN TUMORS

用于治疗人脑肿瘤的抗体-毒素结合物

• 批准号: 6163051
• 负责人: R J 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/6163051
• 关键词: Macaca mulatta; athymic mouse; blood brain barrier; brain neoplasms; cerebrospinal fluid; clinical research; cytotoxicity; diphtheria toxin; dosage; drug administration routes; drug delivery systems; drug screening /evaluation; guinea pigs; human subject; human therapy evaluation; immunoconjugates; laboratory rat; monoclonal antibody; neoplasm /cancer immunotherapy; neurotoxins; nonhuman therapy evaluation; pancreatic ribonuclease; pharmacokinetics; ricin; transferrin

We have engineered immunotoxins into exquisitely cell type specific regents with promise for cancer therapy. Exploring their applications in vivo, we have found that 1) there are powerful pharmacologic barriers that limit protein access to tumor cells; 2) this problem is exacerbated in the brain where the blood-brain barrier prevents macromolecule movement into the brain tissue; 3) the plant and bacterial toxins used for construction of immunotoxins are highly immunogenic and soon after treatment antibodies arise that inactivate reagent. Thus, to overcome the problems of delivery and immunogenicity, we have pursued regional delivery of immunotoxins to the brain as a way to treat brain tumors. Since cancer can spread and grow in the cerebrospinal fluid, a condition known as leptomeningeal carcinomatosis, immunotoxins were initially injected directly into the cerebrospinal fluid to access tumor cells and were found to kill 99% to 99.9% of the tumor cells in vivo with occasional animals cured. An intriguing dose limiting toxicity was found specifically related to this route of administration. Purkinje cells were killed by diphtheria toxin derived immunotoxin in guinea pigs and ricin derived immunotoxins in rats and monkeys. Another protein, called the eosinophil-derived neurotoxin is homologous to RNases A and also selectively kills Purkinje cells. 4) Comparing a family of homologous RNases, we found 5000-fold variation in cytotoxicity. The molecular basis of toxicity was explored and cell binding, RNase inhibitor sensitivity and/or enzyme activity all appear to contribute. 5) We have determined the dose limiting toxicity of immunotoxins in three model species, guinea pigs, rats and rhesus monkeys, and in man. 6) We have explored the potential of diffusion of transferrin (Tf)- CRM107 for brain tumor therapy. Tf-CRM107 is an immunotoxin we designed that has extremely potent and specific tumor cell toxicity. Direct intratumoral injection of brain tumors grown in the flanks of nude mice with Tf-CRM107 effected frequent cures of animals. The toxicity of Tf- CRM107 infused into brain was determined. Concentrations of Tf-CRM107 below 1 x 10-8 M were not toxic whereas higher concentrations caused brain infarction. The normal brain tolerated doses of Tf-CRM107 3000- fold higher than the doses that were toxic to a number of human brain tumor cell lines in vitro. The promising bioactivity of the drug and favorable safety profile suggested Tf-CRM107 may be a valuable therapeutic drug. 7) Recent findings of similar bioactivity and structure shared by diphtheria toxin and Bcl-2 family members will be used to design new apoptosis-regulating immunotoxins.

我们已经将免疫毒素设计成精确的细胞类型特异性 有望成为癌症治疗的董事 探索其应用 在体内，我们发现：1）存在强大的药理学屏障 限制蛋白质进入肿瘤细胞; 2）这个问题是 血脑屏障阻止了 大分子运动进入脑组织; 3）植物和细菌 用于构建免疫毒素的毒素是高度免疫原性的， 在治疗后不久，抗体出现在抗病毒试剂中。 因此，在本发明中， 为了克服递送和免疫原性的问题， 局部注射免疫毒素治疗脑损伤 肿瘤的 由于癌症可以在脑脊液中扩散和生长， 一种被称为软脑膜癌病的疾病， 最初直接注射到脑脊液中以进入肿瘤 细胞，并发现在体内杀死99%至99.9%的肿瘤细胞 偶尔有动物被治愈。 一个有趣的剂量限制性毒性是 发现与这种给药途径特别相关。 Purkinje 用白喉毒素免疫毒素杀死豚鼠成纤维细胞 以及蓖麻毒素衍生的免疫毒素。 另一种蛋白质， 称为嗜酸性粒细胞衍生的神经毒素与RNA酶A同源， 也选择性地杀死浦肯野细胞。 4)比较一个家庭 同源RNA酶，我们发现5000倍的细胞毒性变异。 的 探讨了毒性的分子基础，细胞结合，核糖核酸酶 抑制剂敏感性和/或酶活性似乎都起作用。 5)我们已经确定了免疫毒素的剂量限制毒性， 三个模型物种，豚鼠、大鼠和恒河猴，以及人类。 6)我们探讨了转铁蛋白（Tf）扩散的潜力- CRM 107用于脑肿瘤治疗。 Tf-CRM 107是我们设计的一种免疫毒素， 它对肿瘤细胞有极强的特异性毒性 直接 瘤内注射生长在裸鼠侧腹的脑肿瘤 用Tf-CRM 107治疗动物的效果很好。 Tf的毒性- 测定CRM 107脑内灌注量。 Tf-CRM 107浓度 低于1 x 10-8 M没有毒性，而更高的浓度会导致 脑梗塞 正常脑耐受剂量的Tf-CRM 107 3000- 比对人类大脑有毒的剂量高出一倍 体外培养的肿瘤细胞系。 该药物具有良好的生物活性， 有利的安全性特征表明Tf-CRM 107可能是一种有价值的 治疗药物 7)最近发现类似的生物活性和 白喉毒素和Bcl-2家族成员共有结构将 用于设计新的调节免疫毒素。