Development of VN/14-1 and Related Analogs for Breast Cancer Therapy

简介：流行病学证据强调了维生素A（视黄醇）及其活性代谢物全反式视黄酸（ATRA）对人类乳腺癌和前列腺癌发病率的影响。ATRA是正常人乳腺上皮细胞适当分化所必需的。在一项对208名绝经后乳腺癌手术妇女进行的为期12年的前瞻性研究中，最近有报道称低血浆视黄醇强烈预示着患者的预后较差。我们小组的工作已经确定了新的和有效的CYP26酶抑制剂，负责ATRA在细胞内分解代谢为无活性代谢物。这些CYP26抑制剂也被称为维甲酸代谢阻断剂（RAMBAs）。我们的新药物，除了抑制ATRA代谢外，还具有多种理想的抗乳腺癌特性，因此被称为非典型RAMBAs。我们的先导化合物4-(1)-（1h -咪唑-1-酰基）-(E)-维甲酸（VN/14-1）在几种内分泌敏感和不敏感（即对主要乳腺癌治疗如他莫昔芬和芳香酶抑制剂耐药的肿瘤）乳腺癌异种移植模型中表现出卓越的抗肿瘤功效。在n -甲基-n -亚硝基脲（MNU）诱导的雌激素受体（ER）阳性大鼠乳腺模型中，VN/14-1还能抑制肿瘤的生长，并拮抗雌二醇对子宫的刺激作用。与它对几种乳腺癌细胞系的作用相反，这种化合物几乎没有表现出生长抑制作用(浓度高达100 ？M)正常人乳腺上皮细胞和成纤维细胞。马里兰大学巴尔的摩分校（UMB， PI的前身机构）已与英国癌症研究中心（CRUK）达成临床研究协议，进行VN/14-1的首次人体研究。位于巴尔的摩的切萨皮克生物发现管理有限责任公司（CBDM）最近从UMB获得了RAMBAs技术的全部授权。值得一提的是，在另一个项目中，由该申请的PI发明的CYP17抑制剂/雄激素受体调节剂VN/124-1（现称为TOK-001）最近获得了FDA新药研究（IND）批准，用于前列腺癌患者的I/II期临床试验。虽然VN/14-1在大鼠体内具有出色的口服生物利用度（%F >100%）和抗肿瘤功效，但在小鼠和大鼠体内的半衰期较短，分别为0.34和1.41小时。因此，在这项应用中，我们的目标之一是设计和合成新的类似物，其体内稳定性和抗乳腺癌活性达到或优于VN/14-1。我们设想这种药物将比VN/14- 1具有更强的疗效和更大的治疗指数。此外，我们建议研究新的先导化合物和VN/14-1的两个对映体，即（+）和(-)-VN/14-1中的任何一个的治疗潜力和作用机制。该策略基于一些文献先例，这些文献表明手性化合物/药物的对映体通常在药代动力学（PK），药效学（PD）和不良反应方面存在显着差异。因此，了解单个异构体对药物效价、药物相似度和疗效的影响是很重要的，这样我们就可以避免其他异构体的不良反应。假设：使用我们的先导外消旋VN/14-1，我们已经建立了这类RAMBAs在许多人类和小鼠乳腺癌的体外和体内模型中的有效性的原理证明。本修订申请中所述的主要假设是，第二代非典型RAMBAs的开发（鉴定），VN/14-1的新类似物具有增强的代谢稳定性，药物相似性和有效性，可以潜在地开发为乳腺癌的新疗法（抑制肿瘤生长和转移）。为了验证这一假设，并最大限度地提高实现我们最终目标的可能性，同时最有效地利用资源，我们将实现四个具体目标：1)合成VN/14-1铅的对映体，并修饰VN/14-1以产生更有效/代谢稳定/有效的药物样类似物；2)广泛表征和评估新的类似物作为RAMBAs和人类乳腺癌细胞的抗增殖剂；3)确定先导化合物及最佳类似物对人乳腺癌细胞系的作用机制；4)检测先导化合物及最佳类似物在体内抑制乳腺癌生长、抑制乳腺癌转移的能力，确定疗效标志物。意义：我们的最终目标是发现和开发能够抑制肿瘤细胞生长和转移的新型口服活性乳腺癌药物。重要的是，非典型RAMBAs既能抑制内分泌敏感型和内分泌耐药型乳腺癌，也能拮抗子宫增生，这些特征不同于选择性雌激素受体调节剂（SERMs），如他莫昔芬和芳香酶抑制剂（AIs）。拟议的研究如果成功进行，将确定至少一到两种高度优化的、口服有效的非典型RAMBAs，适合用于乳腺癌治疗的晚期临床前开发。这些研究还将导致对临床试验有用的生物标志物的鉴定。

DESCRIPTION (provided by applicant): Introduction: Epidemiological evidence highlights the influence of vitamin A (retinol) and its active metabolite, all-trans retinoic acid (ATRA) on the incidence of breast and prostate cancers in humans. ATRA is required for the appropriate cellular differentiation of normal human breast epithelial cells. In a 12-year prospective study of 208 postmenopausal women operated on for breast cancer, it was recently reported that low plasma retinol strongly predicts poorer prognosis in patients. Work by our group has identified novel and potent inhibitors of CYP26 enzymes responsible for intracellular catabolism of ATRA into inactive metabolites. These CYP26 inhibitors are also called retinoic acid metabolism blocking agents (RAMBAs). Our novel agents, in addition to inhibiting ATRA metabolism, also possess multiple desirable anti-breast cancer properties, and hence are called atypical RAMBAs. Our lead compound, 4-(1)-(1H-imidazol-1-yl)-(E)-retinoic acid (VN/14-1) exhibits exceptional anti-tumor efficacy in several endocrine-sensitive and insensitive (i.e., tumors that are resistant to mainstay breast cancer therapies such as tamoxifen and aromatase inhibitors) breast cancer xenograft models. VN/14-1 also inhibits the growth of tumors in the N-methyl-N-nitrosourea (MNU)-induced estrogen receptor (ER) positive rat mammary model and antagonizes the stimulatory effect of estradiol on the uterus. In contrast to its effects on several breast cancer cell lines, the compound exhibits virtually no growth inhibition (at concentrations up to 100 ?M) of normal human breast epithelial and fibroblast cells. The University of Maryland, Baltimore (UMB, the PI's former institution) has entered into a clinical research agreement with Cancer Research UK (CRUK) to conduct the first in human study of VN/14-1. Chesapeake BioDiscovery Management LLC (CBDM), Baltimore has recently licensed the entire RAMBAs technology from UMB. It may also be relevant to state here that in another project, a CYP17 inhibitor /androgen receptor modulator, VN/124-1 (now called TOK-001) invented by the PI of this application recently received FDA investigational new drug (IND) approval for phase I/II clinical trials in prostate cancer patients. Although VN/14-1 has outstanding oral bioavailability (%F >100%) in rat and anti-tumor efficacy, it has a short half-life of 0.34 and 1.41 hr, in mouse and rat, respectively. Therefore, in this application, one of our goals is to design and synthesize new analogs with improved in vivo stability and with anti-breast cancer activities as VN/14-1 or better. We envision that such agent would possess enhanced efficacy and a larger therapeutic index than VN/14- 1. In addition, we propose to investigate the therapeutic potential and mechanisms of action the new lead compounds and either of the two enantiomers of VN/14-1, i.e., (+) and (-)-VN/14-1. This strategy is based on several literature precedents which show that the enantiomers in a chiral compound/drug generally show significant differences in their pharmacokinetics (PK), pharmacodynamics (PD) and adverse reactions. Therefore, it is important to know the individual isomer effects on the potency, drug-likeness and efficacy so that we can avoid the adverse effects of the other isomer, if any. Hypothesis: Using our lead racemic VN/14-1, we have established proof-of-principle of the efficacy of this class of RAMBAs in many in vitro and in vivo models of human and murine breast cancers. The major hypothesis to be tested as described in this revised application is that development (identification) of 2nd generation atypical RAMBAs, new analogs of VN/14-1 with enhanced metabolic stability, drug-likeness and efficacy can potentially be developed as new therapy for breast cancer (inhibition of tumor growth and metastasis). Objectives: To test this hypothesis, and to maximize the probability of achieving our ultimate goal while using resources most efficiently, we will carry out four specific aims: 1) To synthesize enantiomers of lead VN/14-1 and to modify VN/14-1 to produce more potent/metabolically stable/efficacious drug-like analogs; 2) To extensively characterize and evaluate new analogs as RAMBAs and as anti-proliferative agents of human breast cancer cells; 3) To determine the mechanism of action of the lead compound and best analogs in human breast cancer cell line; and 4) To test the lead compound and best analogs for their ability to inhibit breast cancer growth, inhibit breast cancer metastasis in vivo and identify markers of efficacy. Significance: Our ultimate goal is to discover and develop new orally active drugs for breast cancer capable of inhibiting the growth of tumor cells and metastasis. Importantly, the atypical RAMBAs inhibit both endocrine- sensitive and endocrine resistant (refractory to endocrine therapies) breast cancers, and also antagonize uterine hyperplasia, characteristics that are distinct from those of selective estrogen receptor modulators (SERMs), such as tamoxifen and aromatase inhibitors (AIs). The proposed studies if successfully conducted will identify at least one or two highly optimized, orally efficacious atypical RAMBAs suitable for advanced preclinical development for breast cancer therapy. The studies would also lead to the identification of biomarkers that would be useful in clinical trials.