The role of NSD1 inactivation in the development and treatment of oral squamous cell carcinoma

项目总结： 头颈部鳞状细胞癌(HNSCC)是一种毁容并通常是致命的疾病，其中 口腔是最常见的部位。大多数HNSCC患者将在疾病的头30个月内死亡， 糟糕的统计数字很大程度上反映了缺乏有效的治疗策略。这一挑战突显了当前 未满足的需要确定1)不同的HNSCC分子亚群和2)预后生物标记物 针对不同分组的治疗计划。我的实验室发现了一个以前未被认可的HNSCC子组 通过NSD1的改变，组蛋白甲基转移酶在高达15%的HPV(-)HNSCC中发生突变。NSD1 具有针对组蛋白H3赖氨酸36(H3K36)的特异性二甲基酶活性。甲基化H3K36的形成 与开放染色质和转录激活有关。NSD1有几个明显的特征- 突变的HPV(-)HNSCC肿瘤，包括a)增加患者吸烟史和突变负担；b)a 预后明显改善；c)肿瘤内免疫细胞浸润减少。这些相关的发现 提示NSD1在调节HNSCC肿瘤对化疗药物和免疫应答中的作用 靶向治疗，但因果关系和潜在机制仍不清楚。建立在我们的 初步结果以及我的赞助商和顾问的综合专业知识，我的提案将检验 中心假设NSD1失活促进口腔鳞状细胞癌的发展 免疫渗透性差，对顺铂治疗敏感。口腔鳞状细胞NSD1缺失模型的建立 在致癌方面，我已经产生了有条件的NSD1基因敲除(KO)小鼠，以特异性地删除NSD1在 舌上皮。在目标1中，我将使用这个模型来检验NSD1(A)失活的假设 加速HNSCC的发展和(B)产生在基因组上不稳定且包含 低水平的免疫细胞渗透。在目标2中，我将调查观察到的NSD1突变体HNSCC 患者的寿命更长，这被假设为反映了对顺铂的敏感性增强。我会确定顺铂是否 治疗对荷瘤的NSD1KO小鼠的生存有好处。为了更好地理解潜在的 机制，我将执行NSD1的Chip-seq和ATAC-seq来测试我们的假设，NSD1直接绑定到， 或接近，基因在Fanconi贫血途径中，导致H3K36me2的浓缩和更容易获得 染色质状态。这项拟议的研究有望拓宽我们对非典型肺炎1‘S肿瘤的理解 HPV(-)HNSCC的抑制功能及NSD1作为指导HNSCC临床有用的生物标志物的研究 治疗。这个项目也为我提供了一个理想的培训机会，以获得概念上的理解 口腔病理学、小鼠遗传学和染色质生物学领域的实验技能。与 我以前的背景，这个建议将有助于我的事业发展成为一名独立的 内科医生-科学家，主要研究颅面和口腔疾病的遗传机制。

Project Summary: Head and neck squamous cell carcinoma (HNSCC) is a physically disfiguring and often fatal disease, of which the oral cavity is the most common site. Most HNSCC patients will die within the first 30 months of disease, an abysmal statistic largely reflecting a lack of effective treatment strategies. This challenge highlights the current unmet need to identify 1) distinct molecular subgroups of HNSCC and 2) prognostic biomarkers that can inform subgroup-specific treatment plans. My lab has identified a previously unappreciated HNSCC subgroup defined by alteration in NSD1, a histone methyltransferase enzyme mutated in up to 15% of HPV(-) HNSCC. NSD1 has specific di-methylase activity targeting histone H3 lysine 36 (H3K36). The formation of methylated H3K36 is associated with open chromatin and transcriptional activation. There are several distinct features of NSD1- mutant HPV(-) HNSCC tumors, including a) increased patient smoking history and mutational burden; b) a significantly better prognosis; and c) reduced immune cell infiltration in the tumor. These correlative findings suggest a role of NSD1 in modulating HNSCC tumor responsiveness to chemotherapeutics and immune- targeting treatments, yet the causal relationship and the underlying mechanism remain unclear. Building on our preliminary results and the combined expertise of my sponsors and consultants, my proposal will test the central hypothesis that NSD1-inactivation facilitates the development of oral squamous cell carcinomas that are poorly immune-infiltrated and sensitive to treatment with cisplatin. To model NSD1 loss in oral squamous carcinogenesis, I have generated conditional Nsd1 knockout (KO) mice to specifically delete NSD1 in the tongue epithelium. In Aim 1, I will use this model to test the hypotheses that inactivation of NSD1 (a) accelerates HNSCC development and (b) generates tumors that are both genomically unstable and contain low levels of immune cell infiltration. In Aim 2, I will investigate the observation that NSD1-mutant HNSCC patients live longer, which is hypothesized to reflect enhanced sensitivity to cisplatin. I will determine if cisplatin treatment provides a survival benefit in tumor-bearing Nsd1 KO mice. To better understand the underlying mechanism, I will perform ChIP-seq of NSD1 and ATAC-seq to test our hypothesis that NSD1 directly binds to, or close to, genes in the Fanconi anemia pathway, leading to H3K36me2 enrichment and a more accessible chromatin state. The proposed research is expected to broaden our understanding of NSD1’s tumor suppressive function in HPV(-) HNSCC and to establish NSD1 as a clinically useful biomarker to guide HNSCC treatment. This project also provides an ideal training opportunity for me to obtain conceptual understanding and experimental skills in the areas of oral pathology, mouse genetics and chromatin biology. Combined with my previous background, this proposal will facilitate my career development to become an independent physician-scientist focusing on dissecting genetic mechanisms underlying craniofacial and oral cavity diseases.