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

项目总结 头颈部鳞状细胞癌(HNSCC)是癌症相关死亡的第七大原因 全世界，到目前为止，这种疾病中发现的基因组变化还没有对临床产生影响 关心。我们小组是首批报道HNSCC中NOTCH1基因频繁失活突变的小组之一。更多 最近发现，在500多名HNSCC患者中，NOTCH1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，肿瘤被测序，NOTCH1跻身前五名 在这种癌症类型中最常见的突变基因。携带NOTCH1突变的HNSCC细胞系 与HNSCC细胞株相比，针对PI3K/mTOR通路的六种不同药物的敏感性显著提高 野生型(Wt)NOTCH1。与带有PIK3CA突变的HNSCC肿瘤不同，PIK3CA突变仅表现出生长停滞 在用PI3K/mTOR抑制剂处理后，携带NOTCH1突变的细胞株也发生了细胞死亡。 NOTCH1基因突变耐药HNSCC细胞系的蛋白质组学研究 含有wt NOTCH1的HNSCC细胞株在药物治疗前后的调控没有差异。 许多药物靶标直接位于PI3K下游，包括AKT。然而，NOTCH1突变体经历了 药物诱导的3-磷酸肌醇依赖激酶1(PDK1)总表达更大幅度的下降 总之，这些数据导致假设具有NOTCH1突变的HNSCC肿瘤 对PI3K抑制剂高度敏感，因为PI3K信号通路唯一地与总 PDK1蛋白水平，影响磷脂酰肌醇依赖和非依赖的PDK1功能 基因组亚型。因此，靶向PI3K/mTOR的药物治疗HNSCC患者应是有效的。 NOTCH1-突变肿瘤。我们将通过临床试验(目标1)解决这些假说，并在体外进行 机制研究(目标2)和临床前研究以确定增强HNSCC肿瘤杀伤力的方法 通过联合治疗发现NOTCH1突变(目标3)。拟议的研究将有一个 积极的影响，因为这将是第一个确定NOTCH1突变的HNSCC对 任何类别的药物，并可能为第一个生物标记物驱动的HNSCC靶向治疗的开发提供信息。 此外，我们可能会定义一种以前未知的PDK1调节机制，并在临床上确定 提高NOTCH1突变型HNSCC抑制PI3K的有效性和持久性的相关靶点。 因为NOTCH1功能丧失突变在其他鳞癌中很常见，包括 对于皮肤、食道和肺，这些发现可能会产生超出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.