Mitochondria Targeted Anti-oxidant for Treatment of Prostate Cancer

描述(申请人提供)：前列腺癌(CAP)是美国男性癌症死亡的主要原因之一。开发一种成功的治疗药物来治疗激素和化疗难治性晚期转移癌是一个主要的未得到满足的医学需求。一些研究表明，前列腺上皮细胞的氧化应激(OS)可能是CAP发生、复发和进展到晚期激素治疗-难治期的主要因素之一。因此，降低前列腺癌中这种高水平的OS可能是开发用于治疗CAP的化疗和/或化学预防药物的成功策略。线粒体是超氧化物歧化和其他ROS的主要来源。为了在不干扰线粒体电子传递链的情况下降低细胞内的ROS水平，我们重点研究了利用合适的连接物将自旋捕获的氮氧化物类似物靶向线粒体间隙，以清除超氧化物。我们在这类新药物中的两种先导化合物是CPC-404和CPC-410。两者均可阻断雄激素诱导的人帽子细胞中的OS，并对雄激素依赖和雄激素非依赖性培养的人帽子细胞均表现出明显的生长抑制作用。基于这些结果，我们建议开发CPC-410或其最有效的类似物(线粒体靶向化合物)作为治疗CAP的新的化疗/化学预防药物。我们的具体目标是：1)设计、合成和测试CPC-410及其类似物对线粒体超氧化物产生的抗氧化活性，并利用已发表的方案，选择对体外培养的永生化的人前列腺上皮细胞(HPEC)具有最大的抗增殖活性和最低的细胞毒性作用的最有活性的类似物，2)标准化有效的处方和单次静脉给药途径。在使用标准化LC-MS方案的初步药代动力学研究中对候选先导药物进行口服(P.O)，3)在降低动物前列腺组织氧化应激药物剂量的药效学研究中确定候选先导药物的最有效剂量。动物前列腺上皮细胞的体内氧化应激将通过静脉注射后的氢乙啶(HET)染料氧化的标准化荧光分析来确定。4)检测先导化合物对雄激素依赖的人前列腺癌LNCaP和非雄激素依赖的PC-3裸鼠移植瘤的抑制作用，并与多西紫杉醇的疗效进行比较；5)测试先导化合物对转基因小鼠前列腺癌(TRAMP)动物自发性前列腺癌的预防作用，并与比卡鲁胺(Casodex)的治疗效果进行比较。公共卫生相关性：耐受高级雄激素消耗疗法(ADT)的转移性前列腺癌是美国男性癌症死亡的第二大原因。许多前列腺癌被检测出是雄激素依赖型肿瘤，并通过手术或放射治疗，然后进行雄激素耗竭治疗。不幸的是，这些患者中的大多数都是荷尔蒙不耐药的晚期转移性前列腺癌患者，这些肿瘤对目前的任何传统癌症治疗反应都很差。因此，开发新的治疗药物以防止前列腺癌的发生、复发和/或进展从雄激素依赖状态到雄激素非依赖性状态以及治疗晚期雄激素非依赖性肿瘤是一个强烈的未得到满足的医学需求。我们发现，某些线粒体导向的抗氧化剂对雄激素依赖型和雄激素非依赖型前列腺癌都表现出很强的抗增殖作用。在初步的临床前研究中，这些候选药物在动物中耐受性良好。在这里，我们建议进行第一阶段SBIR临床前研究，以确定主要候选药物并将其开发为临床有用的抗前列腺癌药物。

DESCRIPTION (provided by applicant): Prostate cancer (CaP) is among the leading causes of cancer deaths among US men. Developing a successful therapeutic drug to treat hormone- and chemo-therapy refractory advanced metastatic CaP is a major unmet medical need. Several studies have shown that the oxidative stress (OS) in prostate epithelial cells is likely one of the major contributors to CaP occurrence, recurrence and progression to advanced hormone therapy-refractory stage. Therefore, reducing this high level of OS in the prostate gland can be a successful strategy for developing chemotherapeutic and/or chemopreventive drugs for use against CaP. The mitochondria are a major source of superoxide and other ROS. In order to reduce the cellular ROS levels without interfering with the mitochondrial electron transport chain, we focused on targeting spin-trapping nitroxide analogs at the mitochondrial interstitial space with appropriate linker in order to remove the superoxide. Two of our lead compounds in this new class of drugs are CPC-404 and CPC-410. Both blocked androgen-induced OS in human CaP cells and both exhibited marked growth inhibitory effects against androgen-dependent as well as androgen-independent cultured human CaP cells. Based on these results, we propose to develop CPC-410 or its most active analog (a mitochondria targeted compound) as a new chemotherapeutic/chemopreventive drug for CaP treatment. Our Specific Aims are: 1) to design, synthesize and test CPC-410 and its analogs with anti-oxidant activity against mitochondrial superoxide production and to select the most active analog for maximum anti-proliferative activity against human CaP cells and the least cytotoxic effect against the immortalized normal human prostate epithelial cells (HPEC) in culture, using published protocols, 2) to standardize an effective formulation and route of administration using single intravenous (i.v.) or oral (p.o) administration of the lead drug candidate in preliminary pharmacokinetic studies using a standardized LC-MS protocol, 3) To determine the most efficacious dose of the lead drug candidate in pharmacodynamic studies for reduction of oxidative stress in animal prostate tissues treated with increasing drug doses. The in vivo oxidative stress in animal prostate epithelial cells will be determined following a standardized fluorescence assay for hydroethidine (HEt) dye oxidation after i.v. injection of HEt one hour before sacrifice and harvesting of the prostate gland, 4) To test the chemotherapeutic efficacy of the lead compound in inhibiting the growth of human CaP cell lines androgen-dependent LNCaP and androgen- independent PC-3 xenografts in nude mice and to compare its efficacy with that of docetaxel following published procedures used routinely in our laboratory, 5) To test the chemopreventive efficacy of the lead candidate on the occurrence and growth of spontaneous mouse prostate tumors in Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) animals and to compare its therapeutic efficacy with that of bicalutamide (Casodex). PUBLIC HEALTH RELEVANCE: Advanced Androgen Depletion Therapy (ADT)-resistant metastatic prostate cancer is the second leading cause of cancer deaths among US men. Many prostate cancers are detected as androgen-dependent tumors and are treated by surgery or radiotherapy followed by androgen depletion therapy. Unfortunately, a majority of these patients return with advanced hormone-refractory metastatic prostate tumors that respond poorly to any current conventional cancer therapy. Thus, there is a strong unmet medical need to develop novel therapeutic drugs to prevent the occurrence, recurrence and/or progression of prostate tumors from androgen-dependent to androgen-independent states as well as to treat advanced metastatic androgen- independent tumors. We discovered that certain mitochondria-directed anti-oxidant drugs exhibit very strong anti-proliferative effects against both androgen-dependent and androgen-independent prostate cancer. In preliminary preclinical studies, these drug candidates are well-tolerated by animals. Here, we propose Phase I SBIR pre- clinical studies necessary to identify the lead drug candidate and develop as a clinically useful anti-prostate cancer drug.