Project 1: Strategies to enhance MEK inhibitor efficacy in MUTNRAS melanoma

项目1摘要 突变靶向小分子抑制剂和免疫检查点阻断剂或ICB（抗PD-1和抗CTLA-4 抗体）延长了晚期BRAFMUT黑色素瘤患者的生活质量和数量。超出 ICB在高达60%的患者中无效，晚期NRASMUT黑色素瘤患者没有标准- 护理选项。由于耐药性的快速发生，MEK抑制剂（MEKi）单一疗法具有有限的临床应用。 对NRASMUT黑色素瘤的活性，但先前暴露于ICB的黑色素瘤可能除外 (the NEMO试验）。在这里，我们建议设计基于MEKi的联合序贯方案， NRASMUT黑素瘤。首先，我们将测试通过抗PD-1/L1启动MEKi反应性的概念， 治疗前（无论抗PD-1/L1敏感性如何）。我们将测试这一概念，以及剖析机制 在人类受试者中的作用和先天/获得性抗性（通过进行II期代谢启动试验） 和同基因黑色素瘤模型。其次，我们将测试结合下一代皇家空军的概念， 抑制剂（RAFi）与MEKi结合以克服和防止MEKi抗性。这些研究将在 人黑素瘤细胞系、患者来源的异种移植物（PDX）和同基因模型。第三，我们将测试 通过充分利用耐药的标志性脆弱性来克服MEKi耐药的概念 肿瘤：MEKi成瘾或MEKi戒断诱导的肿瘤细胞死亡。具体来说，就是诱导退化 在多种NRASMUT MEKi抗性PDX模型中，我们将测试一种涉及测序的策略， MEKi至聚ADP核糖聚合酶抑制剂（PARPi）或涉及MEKi之间的旋转的另一策略 和PARPi。我们还将测试这些测序/旋转策略是否通过诱导不同程度的 免疫原性细胞死亡和/或先天免疫，将使NRASMUT黑素瘤对组合的抗PD-1/L1敏感 疗法在这些临床和临床前研究中，我们将获得多组学数据并评估候选途径 来识别预测性生物标志物。除了基于大量肿瘤的多组学分析（外显子组，基因组， 转录组、甲基化组、染色质可及性、蛋白质组、TCR克隆型）， 我们还将剖析NRASMUT黑色素瘤的单细胞（scRNA-seq，CyTOF）进化，以确定其他的 组合顺序的目标，以克服，然后防止耐药性。这些研究需要密切 与项目2和3以及核心A-C在共享技术专长、试剂/模型和 初步数据，这种合作是基于10年的联合出版物的跟踪记录， 导致对临床相关黑色素瘤生物学的深入了解，多项临床试验，甚至批准 治疗肿瘤学和皮肤病学专业知识（Ribas和Lo）和实验室的结合， 补充方法（Ribas，Lo，Graeber）有望加速科学概念的临床试验。

PROJECT 1 ABSTRACT Mutation-targeted small molecular inhibitors and immune checkpoint blockade or ICB (anti-PD-1 and -CTLA-4 antibodies) have extended the quality and quantity of life for patients with advanced BRAFMUT melanoma. Beyond ICB, which is ineffective in up to 60% of patients, patients with advanced NRASMUT melanoma have no standard- of-care options. Due to the rapid onset of resistance, MEK inhibitor (MEKi) monotherapy has limited clinical activity against NRASMUT melanoma, with the potential exception of those melanoma previously exposed to ICB (the NEMO trial). Here, we propose to design MEKi-based combinatorial-sequential regimens against advanced NRASMUT melanoma. First, we will test the concept of priming MEKi responsiveness via anti-PD-1/L1 pretreatment (regardless of anti-PD-1/L1 sensitivity). We will test this concept as well as dissect the mechanisms of action and innate/acquired resistance in human subjects (by conducting a phase II investigator-initiated trial) and in syngeneic melanoma models. Second, we will test the concept of combining a next-generation RAF inhibitor (RAFi) with a MEKi to overcome and to prevent MEKi resistance. These studies will be conducted in human melanoma cell lines, patient-derived xenografts (PDXs), and syngeneic models. Third, we will test the concept of overcoming MEKi resistance by pharmacologically exploiting a hallmark vulnerability of resistant tumors: MEKi-addiction or tumor cell death induced by MEKi withdrawal. Specifically, to induce the regression of a diverse array of NRASMUT MEKi-resistant PDX models, we will test one strategy involving sequencing from a MEKi to a poly-ADP ribose polymerase inhibitor (PARPi) or another strategy involving rotations between MEKi and PARPi. We will also test whether these sequencing/rotational strategies, by inducing various extents of immunogenic cell death and/or innate immunity, would sensitize NRASMUT melanoma to combined anti-PD-1/L1 therapy. In these clinical and preclinical studies, we will derive multi-omic data and evaluate candidate pathways to identify predictive biomarkers. In addition to bulk tumor-based, multi-omic analysis (exome, genome, transcriptome, methylome, chromatin accessibility, proteome, TCR clonotypes) of longitudinal tumor samples, we will also dissect the single-cell (scRNA-seq, CyTOF) evolution of NRASMUT melanoma to identify additional combinatorial-sequential targets to overcome and then to prevent resistance. These studies require a close collaboration with Projects 2 and 3 and Cores A-C at levels of shared technical expertise, reagents/models and preliminary data, and this collaboration is grounded on a 10-year track record of joint publications that have resulted in deep insights into clinically relevant melanoma biology, multiple clinical trials and even approved therapies. The combination of oncology and dermatology expertise (Ribas and Lo) and laboratories with complementary approaches (Ribas, Lo, Graeber) promises to accelerate scientific concepts to clinical testing.