Targeting Alterations of the NOTCH1 Pathway in Head & Neck Squamous Cell Carcinoma (HNSCC)

项目摘要 头颈部鳞状细胞癌（HNSCC）是癌症相关死亡的第七大原因 在世界范围内，迄今为止，在这种疾病中鉴定的基因组改变尚未对临床产生影响。 在乎我们的研究组是最早报道HNSCC中NOTCH 1频繁失活突变的研究组之一。更 最近，在超过500例HNSCC患者中发现NOTCH 1突变的发生率约为20 作为癌症基因组图谱（TCGA）项目的一部分，NOTCH 1被列为前五名 最常发生突变的基因携带NOTCH 1突变的HNSCC细胞系是 对靶向PI 3 K/mTOR通路的六种不同药物的敏感性显著高于HNSCC细胞系， 野生型（wt）NOTCH 1。与仅表现出生长停滞的具有PIK 3CA突变的HNSCC肿瘤不同， 在用PI 3 K/mTOR抑制剂处理后，具有NOTCH 1突变的细胞系也经历细胞死亡。 携带NOTCH 1突变和耐药的药物敏感HNSCC细胞系的蛋白质组学分析 在药物治疗之前和之后，具有wt NOTCH 1的HNSCC系显示在调节细胞凋亡方面没有差异。 许多药物直接靶向PI 3 K的下游，包括AKT。然而，NOTCH 1突变体经历了 药物诱导的3-磷酸肌醇依赖性激酶1（PDK 1）的总表达降低幅度更大， 极光激酶B。总的来说，这些数据导致了这样的假设，即具有NOTCH 1突变的HNSCC肿瘤 对PI 3 K抑制剂高度敏感，因为PI 3 K信号通路与总的 PDK 1蛋白水平，影响磷脂酰肌醇依赖性和非依赖性PDK 1功能，在这一过程中， 基因亚型因此，靶向PI 3 K/mTOR的药物应有效治疗HNSCC患者， NOTCH 1突变型肿瘤。我们将通过临床试验（目标1）和体外试验来解决这些假设。 机制研究（目标2）和临床前研究，以确定增强HNSCC肿瘤杀伤的方法 通过联合治疗携带NOTCH 1突变的人（Aim 3）。该研究计划将有一个 积极的影响，因为它将是第一个建立NOTCH 1突变型HNSCC的治疗脆弱性， 任何类别的药物，并可能告知第一个生物标志物驱动的HNSCC靶向治疗的发展。 此外，我们可以定义一个以前未知的PDK 1调节机制，并在临床上确定 增强NOTCH 1突变型HNSCC中PI 3 K抑制的功效和持久性的相关靶点。 由于NOTCH 1功能缺失突变在其他鳞状细胞癌中很常见，包括那些 皮肤、食管和肺的这些发现可能会有超出HNSCC的影响。

PROJECT SUMMARY Head and neck squamous cell carcinoma (HNSCC) is the seventh leading cause of cancer-related deaths worldwide, and thus far the genomic alterations identified in this disease have not had an impact on clinical care. Our group was among the first to report frequent inactivating mutations of NOTCH1 in HNSCC. More recently, the incidence of NOTCH1 mutations was found to be roughly 20% among over 500 patient HNSCC tumors sequenced as part of The Cancer Genome Atlas (TCGA) project, placing NOTCH1 among the top five most frequently mutated genes in this cancer type. HNSCC cell lines harboring NOTCH1 mutations are significantly more sensitive to six different drugs targeting the PI3K/mTOR pathway than HNSCC cell lines with wild-type (wt) NOTCH1. Unlike HNSCC tumors with PIK3CA mutations, which exhibited only growth arrest after treatment with PI3K/mTOR inhibitors, cell lines harboring NOTCH1 mutation also underwent cell death. Proteomic profiling of drug-sensitive HNSCC cell lines harboring NOTCH1 mutations and drug-resistant HNSCC lines with wt NOTCH1 before and after drug treatment revealed no differences in the modulation of many drug targets directly downstream of PI3K, including AKT. However, NOTCH1 mutants experienced greater drug-induced decreases in total expression of 3-phosphoinositide dependent kinase 1 (PDK1) and Aurora kinase B. Collectively, these data led to the hypothesis that HNSCC tumors with NOTCH1 mutations are highly sensitive to PI3K inhibitors because the PI3K signaling pathway is uniquely tied to regulation of total PDK1 protein levels, impacting both phosphatidylinositol-dependent and -independent PDK1 function in this genomic subtype. Therefore, drugs targeting PI3K/mTOR should be effective for treating HNSCC patients with NOTCH1-mutant tumors. We will address these hypotheses with a clinical trial (Aim 1) and conduct in vitro mechanistic studies (Aim 2) and preclinical studies to identify ways to enhance killing of HNSCC tumors harboring NOTCH1 mutations through combination therapy (Aim 3). The proposed research will have a positive impact because it will be the first to establish a therapeutic vulnerability of NOTCH1-mutant HNSCC to any class of drugs and may inform the development of the first biomarker-driven targeted therapy for HNSCC. Additionally, we may define a previously unknown mechanism of PDK1 regulation and identify clinically relevant targets that enhance the efficacy and durability of PI3K inhibition in NOTCH1-mutant HNSCC. Because NOTCH1 loss-of-function mutations are common in other squamous cell carcinomas, including those of the skin, esophagus, and lung, these findings will likely have implications beyond HNSCC.