Targeted EGFR Antisense Gene Therapy of Brain Cancer

描述（由申请人提供）：脑癌在美国的发病率惊人地高，并且包括每年15，000例高度恶性的原发性脑癌、多形性胶质母细胞瘤（GBM）的新病例，以及每年约150，000例脑转移癌。表皮生长因子受体（EGFR）在每年超过100，000例脑癌病例中发挥致癌作用，并且是正在开发的新癌症治疗方法的头号目标。高达50%的脑癌患者表达EGFR的突变形式，其通常对阻断野生型EGFR的药物具有抗性。此外，脑的抗EGFR癌症治疗的成功受到血脑屏障（BBB）的存在的限制，血脑屏障在脑癌的早期阶段是完整的，此时治疗仍然是可能的。没有大分子药物（单克隆抗体、癌症疫苗、基因疗法）穿过BBB，并且>98%的小分子癌症疗法不穿过BBB。因此，BBB药物/基因靶向技术的发展是对抗脑癌的关键一步。目前的工作将开发一种新形式的非病毒，非侵入性的脑基因治疗EGFR依赖性GBM或转移性癌症的治疗。新的基因递送技术采用聚乙二醇化免疫脂质体（PIL），并且是非侵入性的，仅需要每周静脉注射。PIL基因转移技术将与反义机制的力量相结合，以开发新的脑癌基因疗法，能够敲除>90%的野生型或突变型EGFR。由于基于RNA形式的反义药物在体内不稳定，本工作将开发新的基于质粒的基因药物，其在靶癌细胞内产生特异性攻击野生型或突变型EGFR mRNA的反义RNA。EGFR反义编码基因药物将与基因工程重组蛋白一起被递送到脑癌中，该蛋白充当分子特洛伊木马（MTH）。这种MTH运送携带基因药物的PIL穿过体内将血液与脑癌细胞核分开的膜屏障。MTH触发连续的受体介导的PIL穿过BBB的转胞吞作用，以及受体介导的PIL内吞作用进入脑癌细胞。

DESCRIPTION (provided by applicant): The incidence of brain cancer in the U.S. is surprisingly high, and includes 15,000 new cases per year of the highly malignant primary brain cancer, glioblastoma multiforme (GBM), and about 150,000 cases per year of metastatic cancer to brain. The epidermal growth factor receptor (EGFR) plays an oncogenic role in over 100,000 cases of brain cancer per year, and is the number 1 target of new cancer therapeutics in development. Up to 50% of patients with brain cancer express mutant forms of the EGFR, which are generally resistant to drugs that block the wild type EGFR. Moreover, the success of anti-EGFR cancer therapeutics for the brain is limited by the presence of the blood-brain barrier (BBB), which is intact in the early phase of brain cancer, when treatment is still possible. None of the large molecule drugs (monoclonal antibodies, cancer vaccines, gene therapies) cross the BBB, and >98% of small molecule cancer therapeutics do not cross the BBB. Therefore, the development of BBB drug/gene targeting technologies is a crucial step in the war against cancer of the brain. The present work will exploit a new form of non-viral, non-invasive gene therapy of the brain for the treatment of EGFR-dependent GBM or metastatic cancer. The new gene delivery technology employs pegylated immunoliposomes (PILs) and is non-invasive, requiring only weekly intravenous injections. The PIL gene transfer technology will be combined with the power of antisense mechanisms to develop new gene therapies of brain cancer that are capable of >90% knockdown of either the wild type or mutant EGFR. Since RNA-based forms of antisense drugs are unstable in vivo, the present work will develop new plasmid based gene medicines that produce antisense RNA within the target cancer cell that specifically attack either the wild type or mutant EGFR mRNA. The EGFR antisense encoding gene medicine will be delivered to brain cancer with a genetically engineered recombinant protein that acts as a molecular Trojan horse (MTH). This MTH ferries the PIL carrying the gene medicine across the membrane barriers in the body that separate the blood from the nucleus of the brain cancer cell. The MTH triggers the sequential receptor-mediated transcytosis of the PIL across the BBB, and the receptor-mediated endocytosis of the PIL into the brain cancer cell.