Novel Polyamine-conjugated Dendrimers for Pretargeted Chemotherapy of Ovarian Can

描述(申请人提供)：背景：卵巢癌是女性癌症死亡的第四大原因，在美国妇科恶性肿瘤中排名第二，占所有女性癌症的4%。卵巢癌的一线化疗包括顺铂-紫杉醇联合治疗。然而，这些药物都有严重的毒副作用，例如，顺铂表现出神经毒性、肾毒性和呕吐，限制了它们的使用。大约75%的晚期卵巢癌患者对常规治疗没有反应，要么是因为对化疗产生了耐药性，要么是因为对残留病变的治疗无效。因此，本方案旨在通过以树枝状大分子为载体的多步靶向方法有效地根除或控制这些微小肿瘤，从而实现顺铂的腹膜内给药。理论基础：我们提出了一种新的治疗策略，可以作为现有卵巢癌治疗的主要模式的辅助治疗，以延长卵巢癌患者的寿命，改善其生活质量。我们的策略包括注射对卵巢癌相关抗原(CA-125)和生物素具有特异性的双特异性抗体。双特异性抗体与肿瘤表面结合。这一步骤之后是给药加载的生物素化，多胺结合的树枝状大分子，以靶向癌细胞。预靶向策略将大剂量的药物提供给先前被双特异性抗体靶向的肿瘤，从而产生更好的疗效和降低的毒性。研究设计：采用化学交联法制备双功能抗体，柱层析纯化。双特异性抗体的纯度将通过SDS PAGE检测，免疫反应性将通过与OVCAR-3细胞结合的ELISAGE和共聚焦显微镜研究来检测。II)肿瘤细胞摄取双特异性抗体的动力学将通过共聚焦显微镜进行研究；III)多胺通过EDC偶联反应连接到树枝状大分子的羧基末端，其载药效率将通过高效液相方法检测；IV)预靶向策略将在NIH OVCAR-3裸鼠身上进行评估。相关性：晚期卵巢癌患者的五年生存率仅为44%。我们提出了一种有效的治疗策略来增加这些晚期卵巢癌患者的数量，并提高他们的生活质量。这种新的方法减少了与卵巢癌治疗中使用的化疗药物相关的毒副作用。

DESCRIPTION (provided by applicant): Background: Ovarian cancer is the fourth most frequent cause of cancer death among women and it ranks second among the gynecological malignancies accounting 4% of all cancers in women in United States.. The first line of chemotherapy for ovarian cancer comprises of cisplatin-paclitaxel combination therapy. However, these drugs are associated with severe toxic side effects, for instance, cisplatin shows neurotoxicity, nephrotoxicity and emesis, limiting their usage. About 75% of the late stage ovarian cancer patients do not respond to the conventional therapy either due to development of resistance to chemotherapy or the inefficient treatment of the residual disease. Therefore, the present proposal aims at efficiently eradicating or controlling these micro tumors by a multistep targeting approach using dendrimers as carriers for the intraperitoneal delivery of cisplatin. Rationale: We propose a novel therapeutic strategy that could serve as an adjunct therapy to the existing primary modes of the ovarian cancer therapyto increase the life span and to improve the quality of life of the ovarian cancer patients. Our strategy involves administration of the bispecific antibodies with specificity for both Ovarian cancer associated antigen (CA-125) and biotin. The bispecific antibody binds to the tumor surface. This step is followed by the administration of drug loaded biotinylated, polyamine conjugated dendrimers to target the drug to the cancer cells. The pretargeting strategy provides high dose of the drug to the tumors previously targeted by the bispecific antibody resulting in better efficacy and reduced toxicity. Research Design: The bispecific antibodies will be prepared by chemical cross linking and they will be purified by Column chromatography. The purity of the bispecific antibody will be tested by SDS PAGE and the immunoreactivity will be tested by binding studies with OVCAR-3 cells using ELISA and Confocal microscopy ii) Kinetics of the uptake of bispecific antibodies by the tumor cells will be perfdormed by Confocal microscopy iii) Polyamines will be conjugated to the carboxy terminals of the dendrimers by EDC coupling reaction and their efficiency of drug loading will be tested by HPLC method iv)The pretargeting strategy will be evaluated in NIH OVCAR-3 nude mice. Relevance: The Five year survival rate of the late stage ovarian cancer patients is only 44%. We propose an efficient treatment strategy to increase these late stage ovarian cancer patients and also to improve their quality of life. This novel approach reduces the toxic side effects associated with the chemotherapeutics used for the ovarian cancer treatment.