Development of small molecule RPN13 inhibitors for Treatment of Glioblastoma

抽象的。胶质母细胞瘤(GBM)是一种侵袭性和致命性的脑癌，由于 缺乏有效的靶向治疗。我们的目标是开发一种针对RPN13的小分子抑制剂 19S蛋白酶体复合体中的蛋白质作为治疗GBM的新药。RPN13是一种蛋白酶体泛素受体， 识别泛素结合蛋白，从而通过20S蛋白酶体酶标记进行降解 很复杂。GBM对蛋白酶体的抑制高度敏感，因为它具有侵略性的生长和积累 错误折叠的多泛素化蛋白，尽管蛋白酶体水平增加，但管理不足 蛋白酶体活性增强(即蛋白毒性应激)。UP治疗公司明智地设计了类药物RPN13 用来克服约翰霍普金斯大学发现的RPN13抑制剂RA190原型中的限制。 我们选择UP284作为先导化合物，基于我们的初步研究显示出类似药物的特征， 特异性(与RPN13的Cys88结合)，以及产生细胞毒性堆积的蛋白酶体抑制 多聚Ub蛋白、内质网应激和活性氧物种。UP284治疗选择性地触发固体细胞的细胞凋亡 肿瘤类型包括基底膜细胞系和六钩虫球体。通过测量，选出了合适的UP284配方 使用蛋白酶体依赖的活体报告对小鼠的水溶解性、稳定性和靶向活性进行成像。 UP284可以静脉注射。或口服，并通过血脑屏障穿透。作为治疗的概念证明 在GL261脑内同基因肿瘤模型中，UP284通过抑制GL261肿瘤模型表现出靶向活性 蛋白酶体在肿瘤组织中的功能。UP284还使同基因、异种移植和自发性肿瘤消退。 安全性可接受的卵巢癌模型。飞行员毒理学数据显示UP284相对较好 耐受，没有行为异常的证据，CBC和血液化学检查正常。给定 UP284作为一种新的抗癌药物和GBM作为其先导适应症的潜力，我们建议： Goal1a。确定大脑中杀死GBM六肽球所需的284剂量(1-3个月)：可再生 在培养中形成六钩藻是某些脑肿瘤起始细胞的一个决定性特征。UP284活动 在存在和不存在体外BBB层的情况下，将针对GBM八球的生长进行测试。 目标1b。雌雄CD1小鼠静脉与口服UP284血浆和组织分布的比较研究 (3-6个月)：里程碑：确定大脑所需的GBM治疗水平以及如何将UP284传递到 实现它们。进球2。UP284对大鼠原位基底膜球囊生长的抑制作用 雌性裸鼠(6-12个月)。我们将针对颅内原位移植测试UP284活性 表达萤火虫荧光素酶的Br23C纳米球在荷脑内Br23C裸鼠体内的模型 一种替莫唑胺耐药模型，即携带JHH-27六钩球的裸鼠。里程碑： 证明UP284针对以下情况提供RECIST定义的完全响应(CR)或部分响应(PR 使用六钩螺球衍生的小鼠脑内的GBM模型进行肿瘤生长。

Abstract. Glioblastoma (GBM) is an aggressive and deadly brain cancer with a one year median survival due to the lack of effective targeted treatments. Our goal is to develop a small molecule inhibitor targeting RPN13 protein in the 19S proteasome complex as a new drug for GBM. RPN13 is a proteasome ubiquitin receptor that recognizes ubiquitin-conjugated proteins that are thus tagged for degradation via the 20S proteasome enzymatic complex. GBM is highly sensitive to proteasome inhibition due to its aggressive growth and accumulation of misfolded polyubiquitinated proteins that is insufficiently managed despite increased proteasome levels and enhanced proteasome activity (i.e. proteotoxic stress). Up Therapeutics judiciously designed drug-like RPN13 inhibitors to overcome limitations in the prototype RPN13 inhibitor RA190 identified at Johns Hopkins University. We selected Up284 as lead compound based upon our preliminary studies showing drug-like characteristics, specificity (binding to Cys88 of RPN13), and proteasome inhibition that produces a cytotoxic accumulation of polyUb proteins, ER stress, and reactive oxygen species. Up284 treatment selectively triggers apoptosis in solid tumor types including GBM cell lines and oncospheres. A suitable Up284 formulation was selected by measuring aqueous solubility, stability and on-target activity in mice imaged using a proteasome-dependent in vivo reporter. Up284 can be administered i.v. or orally, and it penetrates through the BBB. As a proof of concept for treatment of GBM, Up284 demonstrated on-target activity in intracranial syngeneic GL261 tumor model by inhibiting proteasome function in tumor tissues. Up284 also regressed tumors in syngeneic, xenograft and spontaneous models of ovarian cancer with acceptable safety profile. Pilot toxicological data indicated Up284 is relatively well tolerated with no evidence of behavioral abnormalities and normal CBC and blood chemistry panel. Given the potential of Up284 as a new cancer drug and GBM as its lead indication, we propose: Goal1a. Determine Up284 dose required in the brain to kill GBM oncospheres (1-3 months): Renewable oncosphere formation in culture is a defining characteristic of certain brain tumor initiating cells. Up284 activity against the growth of GBM oncospheres in the presence and absence of an in vitro BBB layer will be tested. Goal1b. Up284 plasma and tissue distribution studies after IV vs Oral delivery in male & female CD1 mice (3-6 months): Milestones: Identify GBM therapeutic levels needed in the brain and how to deliver Up284 to achieve them. Goal2. Efficacy of Up284 against the growth of orthotopic GBM oncospheres in male & female nude mice (6-12 months). We will test Up284 activity against an intracranial orthotopic transplantation model using firefly luciferase-expressing Br23C oncospheres in nude female mice bearing intracranial Br23C oncospheres or nude male mice bearing JHH-27 oncospheres, a temozolamide resistant model. Milestones: Demonstrate that Up284 provides RECIST-defined complete response (CR) or partial response (PR) against tumor growth using oncosphere-derived GBM models in mouse brain.