Defining the β-catenin/CBP-catenin/CBP axis in head and neck cancer

头颈部鳞状细胞癌(HNSCC)是一种毁灭性的恶性肿瘤，与严重的 发病率高，死亡率高，治疗选择有限。HNSCC的主要亚部位是口腔，其中 疾病主要表现为与烟草和酒精相关的HPV(-)口腔鳞状细胞癌(OSCC)。 尽管对口腔鳞状细胞癌基因组改变的理解取得了很大进展，但潜在的分子细节 非侵袭性口腔病变发展为晚期淋巴转移疾病的进展仍然很慢。 明白了。为了深入了解口腔鳞状细胞癌发展到转移的机制，我们有 研究了核β-连环蛋白与cAMP反应元件结合蛋白的相互作用 (CBP)通过将我们最新开发的计算方法与基因组、 表观遗传学、分子、生化和功能分析。我们已公布的和初步的研究表明， 小分子拮抗剂ICG001和E7386对口腔鳞癌β-catenin/CBP活性的抑制作用 细胞系在诱导细胞分化的同时抑制细胞增殖和间充质表型。同样， 抑制人口腔鳞状细胞癌裸鼠移植瘤中β-catenin/CBP信号转导的研究 口腔鳞癌干细胞样亚群驱动的肿瘤生长和转移及快速转移的研究 斑马鱼胚胎中的细胞，或癌症干细胞(CSCs)。我们最近的全球染色质免疫沉淀 随后的测序(ChIPseq)研究表明，β-连环蛋白/CBP与组蛋白合作 甲基转移酶MLL1，促进H3K4三甲基化(H3K4me3)在转录起始点(TS) 众多的CSC基因。这一发现得到了我们最近基于RNAseq和 ScRNAseq数据显示，β-连环蛋白/CBP活性与包括CSCs在内的侵略性细胞状态有关。 初步分析还表明，β-连环蛋白/CBP复合体包括河马途径效应器YAP和 TAZ(YAP/TAZ)，与β-连环蛋白一样，与化疗和西妥昔单抗耐药有关 HNSCC(19，20)。使用特征良好的口腔鳞癌细胞系，我们整合了相关的基因表达特征 用来自肿瘤基因组图谱的口腔鳞状细胞癌数据显示β-连环蛋白/CBP轴的抑制 β-连环蛋白/CBP活性与进展性疾病和降低患者存活率有关。建立在这些基础上 我们的集体发现假设，β-连环蛋白/CBP信号的异常激活是扩张的基础 CSCs在HNSCC进展为转移性疾病过程中，其拮抗作用可能抑制晚期疾病。 这一假说将在两个方面得到验证：1)确定β-连环蛋白/CBP轴在人类非小细胞肺癌中的作用 进展为晚期疾病；2)确定β-连环蛋白/CBP活性的分子机制 在CSC表型的诱导中。我们的研究将生成一个动态的整合地图，将β-连环蛋白-CBP- 具有不同攻击性细胞状态的活动及其在基因签名、信号网络和蛋白质中的关联 并为开发新的治疗策略以抗击这种恶性肿瘤提供了理论基础。

Head and neck squamous cell carcinoma (HNSCC) is a devastating malignancy associated with severe morbidity, high mortality and limited treatment options. The main subsite of HNSCC is the oral cavity, where the disease presents primarily as tobacco- and alcohol-associated HPV(-) oral squamous cell carcinoma (OSCC). Despite great progress in the understanding of genomic alterations in OSCC, the molecular details underlying the progression of non-invasive oral lesions to advanced disease with lymph node metastasis remain poorly understood. To gain insights into the mechanisms that contribute to OSCC progression to metastasis we have studied the interaction between nuclear β-catenin and cAMP-response element-binding (CREB)-binding protein (CBP) in OSCC by applying our newly developed computational methodologies coupled with genomic, epigenetic, molecular, biochemical and functional analyses. Our published and preliminary studies show that inhibition of β-catenin/CBP activity with small molecule antagonists, ICG-001 and E7386, in a panel of OSCC cell lines inhibits cell proliferation and mesenchymal phenotype while inducing cellular differentiation. Similarly, inhibition of β-catenin/CBP signaling in human OSCC cell line-derived tumor xenografts in nude mice inhibits tumor growth and metastasis and abrogates rapid metastases driven by subpopulations of OSCC stem cell-like cells, or cancer stem cells (CSCs), in embryonic zebrafish. Our recent global chromatin immunoprecipitation followed by sequencing (ChIPseq) studies show that β-catenin/CBP collaborates with the histone methyltransferase, MLL1, to promote global H3K4 trimethylation (H3K4me3) at transcription start sites (TSS) of numerous CSC genes. This finding is supported by our recent genomic analyses based on RNAseq and scRNAseq data showing that β-catenin/CBP activity is associated with aggressive cell states, including CSCs. Preliminary analyses also suggest that β-catenin/CBP complexes include the Hippo pathway effectors YAP and TAZ (YAP/TAZ), which, like β-catenin, are associated with resistance to both chemotherapy and cetuximab in HNSCC (19,20). Using well characterized OSCC cell lines, we integrated gene expression signatures associated with the inhibition of the β-catenin/CBP axis with OSCC data from The Cancer Genome Atlas (TCGA) to show that β-catenin/CBP activity is associated with progressive disease and reduced patient survival. Building on these collective findings we hypothesize that aberrant activation of β-catenin/CBP signaling underlies the expansion CSCs during HNSCC progression to metastatic disease and that its antagonism may inhibit advanced disease. This hypothesis will be tested in two aims that will: 1) define the role of the β-catenin/CBP axis in HNSCC progression to advanced disease; and 2) determine the molecular mechanisms underlying β-catenin/CBP activity in the induction of CSC phenotypes. Our studies will generate a dynamic integrated map aligning β-catenin-CBP- activity with distinct aggressive cell states and their associated in gene signatures, signaling networks and protein assemblies and provide a rationale for the development of new treatment strategies to combat this malignancy.