Novel Polyamine-conjugated Dendrimers for Pretargeted Chemotherapy of Ovarian Can

背景：卵巢癌是美国女性癌症死亡的第四大常见原因，在妇科恶性肿瘤中排名第二，占女性所有癌症的4%。卵巢癌的一线化疗包括顺铂-紫杉醇联合治疗。然而，这些药物具有严重的毒副作用，如顺铂具有神经毒性、肾毒性和呕吐，限制了它们的使用。约75%的晚期卵巢癌患者由于对化疗产生耐药性或对残余疾病的治疗效率低下而对常规治疗无效。因此，本研究旨在利用树状大分子作为顺铂腹腔内递送载体，通过多步靶向方法有效地根除或控制这些微型肿瘤。基本原理：我们提出了一种新的治疗策略，可以作为卵巢癌现有主要治疗模式的辅助治疗，以增加卵巢癌患者的寿命和改善生活质量。我们的策略包括对卵巢癌相关抗原（CA-125）和生物素具有特异性的双特异性抗体的管理。双特异性抗体与肿瘤表面结合。这一步之后，将装载药物的生物素化、多胺缀合的树突状分子用于靶向癌细胞。预靶向策略为双特异性抗体先前靶向的肿瘤提供高剂量的药物，从而获得更好的疗效和降低毒性。研究设计：采用化学交联法制备双特异性抗体，采用柱层析纯化。双特异性抗体的纯度由SDS页面测试和免疫反应性与OVCAR-3细胞将被绑定测试研究使用ELISA和共焦显微镜ii)的吸收动力学双特异性抗体在肿瘤细胞将perfdormed共焦显微镜iii)多胺将共轭树枝状分子的羧基终端EDC偶联反应及其药物装载效率将由高效液相色谱检测方法(四)pretargeting策略在NIH OVCAR-3裸鼠中进行评价。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，以增加这些晚期卵巢癌患者，并提高他们的生活质量。这种新方法减少了与卵巢癌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.