Stealth Brusatol and Docetaxel-loaded Nanoparticles for Targeted Prostate Cancer Therapy

摘要 大多数化学治疗剂在其作用机制中是增殖依赖性的，并且对快速抗肿瘤有活性。 分裂细胞这是一个挑战，因为前列腺癌在临床上生长缓慢。此外，前列腺癌是 目前使用的药物不能杀死所有的肿瘤细胞群，导致复发和再生 肿瘤。对多西他赛的耐药性是前列腺癌化疗的另一个巨大挑战。 阿糖胞苷是一种细胞内蛋白质合成抑制剂，对核因子红细胞2相关的 因子2（Nrf 2）。因为它抑制蛋白质合成，它可以杀死所有肿瘤细胞，而不管异质性如何。由于其 非选择性作用机制，以及其临床转化的其他挑战，主动靶向或位点特异性 将布鲁沙醇递送至肿瘤是必需的。此外，布鲁沙醇对Nrf 2的影响是短暂的。的持续释放 来自递送系统的brusatol可确保对Nrf 2的类似于重复给药的延长作用。除了其细胞毒性外， 除此之外，布鲁沙醇还可以防止耐药性的发展，并逆转对其他药物的耐药性。 这些方法的创新和优点是多方面的。纳米颗粒平台是必不可少的：（a）防止或 降低对健康细胞的毒性（由于EPR效应，药物将在肿瘤微环境中释放， 通过与PSMA结合而主动靶向），（B）用于持续药物释放，从而逆转对Nrf 2的短暂作用，（c） 以增加肿瘤中的药物浓度，从而增加治疗效果。此外， 纳米颗粒平台中的布鲁沙托和多西他赛允许靶向多个途径， 疗效此外，两种药物的组合可以通过良好的抗肿瘤作用预防和/或逆转多西他赛的耐药性。 已知的报告机制。这可以解决多西他赛耐药的问题。最后，含有布鲁沙托和紫杉醇的 由于在肿瘤微环境中的积累，纳米颗粒可以增强和改善化疗的功效。 放疗多西他赛除了其细胞毒性外，还大大增加了ROS水平，而布鲁沙醇抑制了ROS水平。 抗氧化反应这种效应大大增加了肿瘤内的ROS水平。由于放射治疗发挥其 通过增加ROS和导致DNA链断裂的作用，纳米颗粒平台有望显着提高 增强肿瘤微环境中的放射治疗。 我们的假设是，制造隐形的、有针对性的、载有布鲁沙醇和紫杉醇的纳米颗粒将逆转 通过从纳米颗粒持续、连续释放，对Nrf 2产生短暂的布鲁沙醇效应。纳米颗粒联合治疗 将：（1）抑制和/或逆转多西他赛的耐药性（2）减少不良反应，和（3）增加治疗效果 由于影响癌细胞的多种增殖途径和位点特异性递送而产生的功效。实现 目标的建议，我们有以下目标：（1）制造，表征和优化的隐身，有针对性的 负载布鲁沙醇和紫杉醇的纳米颗粒和对照。(2)细胞毒性和细胞内化研究，流程 将使用荧光染料和药物负载的纳米颗粒进行细胞计数分析和其它体外研究。（三） 将在小鼠中进行生物分布、最大耐受剂量（MTD）和疗效研究。

ABSTRACT Most chemotherapeutic agents are proliferation dependent in their mechanisms of action and are active against rapidly dividing cells. This is a challenge because prostate cancer is clinically slow growing. In addition, prostate cancer is heterogeneous and the drugs currently in use do not kill all populations of tumor cells leading to relapse and regeneration of the tumor. Resistance to docetaxel is another great challenge with chemotherapy of prostate cancer. Brusatol is a protein synthesis inhibitor in cells and it has specific inhibitory activity on nuclear factor erythroid 2-related factor 2 (Nrf2). Because it inhibits protein synthesis, it can kill all tumor cells regardless of heterogeneity. As a result of its non-selective mechanism of action, and other challenges to its clinical translation, the active targeting or site-specific delivery of brusatol to tumors is essential. In addition, the effect of brusatol on Nrf2 is short-lived. The sustained release of brusatol from a delivery system can ensure a prolonged effect on Nrf2 similar to repeated dosing. In addition to its cytotoxic effects, brusatol can also prevent the development of drug resistance and reverse the resistance to other drugs. The innovation and advantages of these approach are numerous. The nanoparticle platform is essential: (a) to prevent or reduce toxicity to healthy cells (the drugs will be released in the tumor microenvironment as a result of the EPR effect and active targeting by binding to PSMA), (b) for sustained drug release and thereby reverse the short-lived effect on Nrf2, (c) to increase drug concentration in the tumor and thereby increase therapeutic efficacy. In addition, combination therapy of brusatol and docetaxel in a nanoparticle platform allows targeting multiple pathways with the resultant improvement in therapeutic efficacy. Furthermore, combination of both drugs can prevent and/or reverse resistance to docetaxel by well- known reported mechanisms. This can solve the problem of docetaxel resistance. Finally, the brusatol- and docetaxel-loaded nanoparticles as a result of accumulation within the tumor microenvironment can augment and improve the efficacy of radiotherapy. Docetaxel, in addition to its cytotoxicity greatly increases the ROS levels while brusatol inhibits the antioxidant response. This effects greatly increase ROS levels specifically within the tumor. Since radiotherapy exerts its effects by increasing ROS and causing DNA strand breaks, the nanoparticle platform holds the promise to significantly augment radiotherapy within the tumor microenvironment. Our hypothesis is that the fabrication of stealth, targeted, brusatol- and docetaxel-loaded nanoparticles will reverse the transient brusatol effect on Nrf2 by sustained, continuous release from nanoparticles. Nanoparticle combination therapy will: (1) suppress and/or reverse chemoresistance to docetaxel (2) reduce adverse effects, and (3) increase therapeutic efficacy as a result of affecting multiple proliferation pathways of cancer cells and site-specific delivery. To achieve the goals of the proposal, we have the following aims: (1) Fabrication, characterization and optimization of stealth, targeted brusatol- and docetaxel-loaded nanoparticles and controls. (2) Cytotoxicity and cellular internalization studies, flow cytometry analyses and other in vitro studies will be carried done using fluorescent dye- and drug-loaded nanoparticles. (3) Biodistribution, maximum tolerable dose (MTD) and efficacy studies will be done in mice.