Targeted Prodrug Therapy of Liver Cancers

肝癌的靶向前药治疗

• 批准号: 6735429
• 负责人: JOHN Y CHAN
• 金额: $ 10万
• 依托单位: ACCLAIM BIOTECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-06 至 2005-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6735429
• 关键词: aminohydrolases; bacterial proteins; biotechnology; cell line; chimeric proteins; circumsporozoite protein; colorectal neoplasms; flucytosine; fluorouracil; gene deletion mutation; hepatocellular carcinoma; liver neoplasms; metastasis; mutant; neoplasm /cancer chemotherapy; prodrugs; protein engineering; recombinant proteins

DESCRIPTION (provided by applicant): Hepatocellular carcinoma (HCC) and colorectal cancer (CRC) are among the most common and deadly malignancy worldwide. CRC is the second leading cause of cancer-related death in the USA, mostly due to metastases to the liver. 5-fluorouracil (5-FU) remains the mainstay of combination chemotherapy for liver cancers including non-resectable liver metastases. Recent studies demonstrated that regional 5-FU-based chemotherapy by directly hepatic infusion showed improved response rates and survival for CRC patients as compared with those with systemic treatment. However, this delivery system is technically complicated, highly invasive, risky and costly. The present application is a patented delivery system for improved chemotherapy of liver cancer and metastasis. It utilizes a recombinant fusion protein consisted of the malarial circumsporozoite (CS) protein, a hepatocyte-specific targeting ligand, linked to the bacterial cytosine deaminase (CD), a suicidal gene product which catalyzes the production of 5-FU from its prodrug 5- fluorocytosine (5-FC). We have demonstrated that the CD-CS fusion protein can be internalized in a cell type-specific manner. More importantly, the internalized protein is stable for at least four weeks and exerts bystander cell-killing effects upon the administration of the prodrug 5-FC. The prolonged stability can be attributed to the fact that the internalized fusion protein is entrapped in the particular compartment(s) that are free from the cytoplasmic degradation machinery. To further develop and commercialize this system, we propose the following 2 specific aims: (1) to construct deletion mutants and modified versions of CD-CS for increasing yield, stability and activity of the fusion protein; and (2) to optimize the production of the modified CD-CS protein and to determine their effectiveness in scale-up preparations for product manufacturing and future clinical trials. This novel prodrug targeting therapy is effective, technically simple, non-invasive and cost effective, which should have enormous commercial potential.

描述（由申请人提供）：肝细胞癌（HCC）和结直肠癌（CRC）是全球最常见和最致命的恶性肿瘤之一。CRC是美国癌症相关死亡的第二大原因，主要是由于转移到肝脏。5-氟尿嘧啶（5-FU）仍然是肝癌（包括不可切除的肝转移瘤）联合化疗的主要药物。最近的研究表明，区域性5-FU为基础的化疗，直接肝灌注显示出改善的反应率和生存率的CRC患者相比，与全身治疗。然而，这种输送系统在技术上是复杂的、高度侵入性的、有风险的和昂贵的。本申请是一种用于改善肝癌和转移化疗的专利递送系统。它利用由疟疾环子孢子（CS）蛋白（一种肝细胞特异性靶向配体）与细菌胞嘧啶脱氨酶（CD）连接组成的重组融合蛋白，CD是一种自杀基因产物，可催化前药5-氟胞嘧啶（5-FC）生成5-FU。我们已经证明了CD-CS融合蛋白可以以细胞类型特异性的方式内化。更重要的是，内化的蛋白质在至少四周内是稳定的，并且在前药5-FC给药后发挥旁观者细胞杀伤作用。延长的稳定性可归因于内化的融合蛋白被截留在不含细胞质降解机制的特定隔室中的事实。为了进一步开发和商业化该系统，我们提出了以下2个具体目标：（1）构建缺失突变体和修饰版本的CD-CS，以增加融合蛋白的产量、稳定性和活性;和（2）优化修饰的CD-CS蛋白的生产，并确定其在用于产品生产和未来临床试验的放大制备中的有效性。这种新型的前药靶向治疗方法具有疗效好、技术简单、无创、成本低等优点，具有巨大的商业潜力。