Therapeutic efficacy of the CRL inhibitor MLN4924 in NF2 mutant mesothelioma

 描述(由申请人提供)：晚期恶性间皮瘤(MM)患者的治疗选择有限。标准的一线化疗方案，培美曲塞/顺铂，与单独使用顺铂相比，可提高9至12个月的存活率。为了开发基于机制的多发性骨髓瘤治疗方法，重要的是确定驱动其发生和维持其发展的致癌基因突变和信号通路。尽管大约75%的多发性骨髓瘤携带编码Merlin的NF2基因突变。我们发现，Merlin的失活通过激活致癌的E3泛素Cullin环连接酶CRL4DCAF1来推动MM的发生和维持，而CRL连接酶CRL4DCAF1反过来又抑制河马途径的肿瘤抑制激酶Lats1/2。我们的初步研究表明，由Millum-Takeda开发的CRL抑制剂MLN4924在NF2突变的MM细胞中显示出选择性的临床前疗效。此外，体外和体内研究表明，MLN4924显著提高了培美曲塞和顺铂对NF2突变MM的疗效。为了建立MLN4924单独和联合化疗对NF2突变MM的临床前和临床活性，我们将追求以下独立但相关的特定目标：1)在一种新型的基因工程小鼠模型(GEMM)中，测试MLN4924单独和联合化疗的临床前活性；Nf2Flox/Flox；Lucr小鼠将在胸膜腔内注射编码CRE的慢病毒，并联合短发夹(Sh)RNAs靶向由CDkn2A或Kn2Flox和BAP1编码的mRNAs。荷瘤小鼠将接受MLN4924、培美曲塞/顺铂或两者兼用的治疗，并接受生物发光成像以监测肿瘤的生长。对肿瘤样本的分子研究将使我们能够验证MLN4924的靶点抑制作用并确定其作用机制。2)检测MLN4924单独和联合化疗对MPM患者来源异种移植(PDX)模型的临床前疗效。携带NF2或BAP1基因座突变的PDX MMS模型将单独使用MLN4924治疗，并与顺铂/培美曲塞联合使用，结果将进行如上所述的检查。未来分离的癌症干细胞对药物的敏感性将在肿瘤器官培养中进行检测。3)通过对胸膜或腹膜MM患者进行I/II期试验来测试MLN4924的临床疗效。我们将进行一项由两个队列组成的单一机构试验：1对NF2突变MM患者进行单药MLN4924的II期试验，以及2)将MLN4924与培美曲塞/顺铂联合用于以前未治疗的患者的I期试验。从新开发的GEMM模型和最先进的PDX模型中进行的临床前研究中获得的信息将有助于完善临床试验中患者样本的分析，反过来， 从临床试验中获得的信息将推动更多的临床前研究。我们预计，以机制为基础的治疗，如这里提出的，将从根本上改善MM患者的预后。

 DESCRIPTION (provided by applicant): Patients with advanced malignant mesothelioma (MM) have limited treatment options. The standard first-line chemotherapy regimen, pemetrexed/cisplatin, improves survival compared to cisplatin alone from 9 to 12 months. In order to develop mechanism-based therapies for MM, it is important to identify the oncogenic mutations and signaling pathways that drive its development and sustain its maintenance. Although about 75% of MM carry mutations at the NF2 locus, which encodes Merlin. We have discovered that inactivation of Merlin drives the development and maintenance of MM by activating the pro-oncogenic E3 ubiquitin Cullin Ring Ligase CRL4DCAF1, which in turn inhibits the Hippo pathway tumor suppressor kinases Lats1/2. Our Preliminary Studies indicate that the CRL inhibitor MLN4924, developed by Millenium-Takeda, exhibits exhibit selective preclinical efficacy in NF2 mutant MM cells. In addition, in vitro and in vivo studies indicate that MLN4924 significantly enhances the efficacy of pemetrexed and cisplatin in NF2 mutant MM. To establish the pre-clinical and clinical activity of MLN4924, alone and in combination with chemotherapy, in NF2 mutant MM, we will pursue the following independent, but interrelated Specific Aims: 1) To test the preclinical activity of MLN4924, alone and in combination with chemotherapy, in a novel Genetically Engineered Mouse Model (GEMM) of MM. Nf2Flox/Flox; LucR mice will be injected in their pleural cavity with lentiviruses encoding Cre in combination with short hairpin (sh) RNAs targeting the mRNAs encoded by Cdkn2a or both Cdkn2a and Bap1. Tumor-bearing mice will be treated with MLN4924, pemetrexed/cisplatinum, or both and subjected to bioluminescent imaging to monitor tumor growth. Molecular studies on tumor samples will enable us to verify target inhibition and to determine the mechanism of action of MLN4924. 2) To test the preclinical efficacy of MLN4924, alone and in combination with chemotherapy, in patient-derived xenograft (PDX) models of MPM. PDX models of MMs carrying mutations at the NF2 locus, the BAP1 locus, or at both loci will be treated with MLN4924, alone and in combination with cispatin/pemetrexed, and the results will be examined as described above. The sensitivity of prospectively isolated cancer stem cells to the drugs will be examined in tumor organoid cultures. 3) To test the clinical efficacy of MLN4924 by conducting a phase I/II trial in patients with pleural or peritoneal MM. We will conduct a single institution trial comprising two cohorts: 1 a phase II trial of single agent MLN4924 in patients with NF2 mutant MM, and 2) a phase I trial combining MLN4924 with pemetrexed/cisplatin in previously untreated patients. Information gained from pre-clinical studies in the newly developed GEMM model and state-of-the-art PDX models will help to refine the analysis of patient samples from the clinical trial and, conversely, information gained from the clinical trial will motivate additional pre-clinical studies. We envisin that mechanism-based therapies, such as the one proposed here, will radically improve the outcome of patients with MM.