Modulation of Mcl-1 for Treatment of Lung Cancer

摘要 KRAS突变激活Raf/MEK/ERK1/2，直接磷酸化T163位Mcl-1，增强Mcl-1‘S 功能。KRAS突变还激活PI3K/AKT，使GSK-3失活，抑制GSK-3介导 PMcl-1在S159，以减少Mcl-1的降解。我们假设KRAS突变激活的ERK1/2和 PI3K/AKT通路通过上调pMcl-1在T163的表达和下调对Mcl-1的稳定起作用 肺癌组织中pMcl-1基因S159的表达。我们的初步数据显示，在T163的肿瘤组织中pMcl-1增加 与预后较差的NSCLC患者相关，提示pMcl-1基因T163位可能提供了一种 非小细胞肺癌患者新的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)介导的过程中起着关键作用 DNA双链断裂的修复。基于这个新函数，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BH1口袋相互作用，抑制HR活性。 MI-223在体内外均具有较强的抗肺癌活性。奥拉帕利是FDA批准的 具有抗癌效果的PARP-1抑制剂；然而，只有HR缺乏的患者(例如BRCA1/2突变) 对奥拉帕利治疗有反应。由于MI-223抑制HR介导的DNA修复，这为 MI-223和奥拉帕利联合治疗各种癌症，包括那些没有BRCA1/2突变的癌症。 MI-223和奥拉帕利联合治疗对肺癌的体外和体外生长抑制作用 活着。由于我们的数据表明KRAS突变可以激活Mcl-1，我们假设MI-223单独或在 与奥拉帕利联合治疗KRAS突变的肺癌可能是有效的。MI-223诱导的双链断裂 突变KRAS驱动的肺癌模型中肿瘤组织中PD-L1的上调，提示MI-L1联合 223联合抗PD-L1可克服KRAS突变肺癌对PD-1抑制剂的耐药性。描述和描述 开发这种新型的Mcl-1抑制剂MI-223用于肺癌的治疗，我们提出了两个具体的目标：(1) 确定KRAS突变是否以及如何激活Mcl-1导致人肺耐药 癌细胞。研究将确定T163位的pMcl-1是否是一种新的预后生物标志物和治疗方法 靶向非小细胞肺癌；(2)确定新型Mcl-1抑制剂MI-223的杀伤作用机制 人类肺癌细胞。研究将测试MI-223单独或与PARP抑制剂联合使用的效力 奥拉帕利在患者来源的肺癌异种移植瘤(PDX)、放射抵抗和KRAS突变肺癌中的应用 异种移植物。确定MI-223是否与奥拉帕利布或抗PD-L1协同作用以更有效地抑制 在基因工程突变的KRAS驱动的肺癌动物模型中肿瘤生长和延长生存期。 通过靶向Mcl-1，我们期望开发一类新的抗癌药物和针对肺癌的联合策略。 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.