Modulation of Mcl-1 for Treatment of Lung Cancer

总结 KRAS突变激活Raf/MEK/ERK 1/2，其可以在T163处直接磷酸化Mcl-1，增强Mcl-1的 功能KRAS突变还激活PI 3 K/AKT，PI 3 K/AKT可以抑制GSK-3 β，并抑制GSK-3 β介导的 在S159处的pMcl-1以减少Mcl-1降解。我们假设KRAS突变激活的ERK 1/2和 PI 3 K/AKT通路通过上调T163处的pMcl-1和下调T163处的pMcl-1来稳定Mcl-1 pMcl-1在肺癌中S159的表达。我们的初步数据显示，在T163肿瘤组织中pMcl-1增加， 在NSCLC患者中，与较差的生存结局相关，这表明T163处的pMcl-1可能提供了一种治疗NSCLC的方法。 NSCLC患者的新治疗靶点和预后生物标志物。我们发现Mcl-1除了它的 典型的抗凋亡功能，在支持同源重组（HR）介导的 修复DNA双链断裂（DSB）。基于这个新颖的函数，我们发现了一个全新的类 小分子Mcl-1抑制剂MI-223与Mcl-1的BH 1口袋相互作用并抑制HR活性。 MI-223在体外和体内对肺癌具有有效的抗肿瘤活性。奥拉帕尼是FDA批准的 具有抗癌疗效的PARP-1抑制剂;然而，仅HR缺陷患者（例如BRCA 1/2突变） 对奥拉帕尼治疗有反应。由于MI-223抑制HR介导的DNA修复，这为以下研究提供了依据： 联合MI-223和奥拉帕尼治疗各种癌症，包括那些没有BRCA 1/2突变的癌症。 MI-223和奥拉帕尼联合治疗在体外和体内协同抑制肺癌生长 vivo.由于我们的数据表明KRAS突变可以激活Mcl-1，我们假设MI-223单独或联合 与奥拉帕尼联合治疗可能对具有KRAS突变的肺癌有效。MI-223诱导的DSB 在来自突变KRAS驱动的肺癌模型的肿瘤组织中上调PD-L1，表明MI- 223与抗PD-L1可以克服PD-1抑制剂耐药KRAS突变型肺癌。来表征和 开发这种新型Mcl-1抑制剂MI-223用于治疗肺癌，我们提出两个具体目标：（1） 确定KRAS突变是否以及如何激活Mcl-1导致人肺的治疗耐药性 癌细胞研究将确定T163的pMcl-1是否是一种新的预后生物标志物和治疗性药物。 （2）确定新型Mcl-1抑制剂MI-223在杀伤NSCLC患者中的作用机制 人肺癌细胞研究将检测MI-223单独或与PARP抑制剂联合使用的效力 奥拉帕尼在患者来源的肺癌异种移植物（PDX）、放射抗性和KRAS突变型肺癌中的应用 异种移植确定MI-223是否与奥拉帕尼或抗PD-L1协同作用，以更有效地抑制 肿瘤生长和延长生存的基因工程突变KRAS驱动的肺癌动物模型。 通过靶向Mcl-1，我们期望开发出一类新的肺癌治疗药物和联合治疗策略。 癌症治疗

Summary KRAS mutations activate Raf/MEK/ERK1/2 that can directly phosphorylate Mcl-1 at T163, enhancing Mcl-1’s function. KRAS mutations also activate PI3K/AKT that can inactivate GSK-3 and inhibit GSK-3-mediated pMcl-1 at S159 to reduce Mcl-1 degradation. We hypothesize that KRAS mutation-activated ERK1/2 and PI3K/AKT pathways contribute to stabilization of Mcl-1 via upregulation of pMcl-1 at T163 and downregulation of pMcl-1 at S159 in lung cancer. Our preliminary data show increased pMcl-1 at T163 in tumor tissues from NSCLC patients, which associated with worse survival outcome, suggesting that pMcl-1 at T163 may provide a new therapeutic target and a prognostic biomarker in NSCLC patients. We found that Mcl-1, in addition to its canonical antiapoptotic function, plays a critical role in supporting homologous recombination (HR)-mediated repair of DNA double-strand breaks (DSBs). Based on this novel function, we discovered an entirely new class of small molecule Mcl-1 inhibitor, MI-223, that interacts with the BH1 pocket of Mcl-1 and inhibits HR activity. MI-223 has potent anti-tumor activity against lung cancer in vitro and in vivo. Olaparib is an FDA-approved PARP-1 inhibitor with anti-cancer efficacy; however, only patients with HR deficiency (e.g. BRCA1/2 mutations) respond to olaparib therapy. Since MI-223 inhibits HR-mediated DNA repair, this provides a rationale for combining MI-223 and olaparib to treat various cancers, including those without BRCA1/2 mutations. Combined treatment with MI-223 and olaparib synergistically suppresses lung cancer growth in vitro and in vivo. Since our data indicate that KRAS mutations can activate Mcl-1, we hypothesize that MI-223 alone or in combination with olaparib may be effective against lung cancers with KRAS mutations. MI-223-induced DSBs upregulate PD-L1 in tumor tissue from mutant KRAS driven lung cancer model, suggesting combination of MI- 223 with anti-PD-L1 may overcome PD-1 inhibitor resistance in KRAS-mutant lung cancer. To characterize and develop this novel Mcl-1 inhibitor MI-223 for the treatment of lung cancer, we propose two specific aims: (1) Determine whether and how KRAS mutations activate Mcl-1 leading to treatment resistance in human lung cancer cells. Studies will determine whether pMcl-1 at T163 is a novel prognostic biomarker and therapeutic target in patients with NSCLC; (2) Determine mechanism of action of novel Mcl-1 inhibitor MI-223 in killing human lung cancer cells. Studies will test the potency of MI-223 alone or in combination with PARP inhibitor olaparib in patient-derived lung cancer xenograft (PDX), radioresistant, and KRAS-mutant lung cancer xenografts. Determine whether MI-223 synergizes with olaparib or anti-PD-L1 to more effectively suppress tumor growth and prolong survival in genetically engineered mutant KRAS-driven lung cancer animal models. By targeting Mcl-1, we expect to develop a new class of anti-cancer agents and combination strategies for lung cancer treatment.