Epigenetic role of GRHL2 in HPV-associated oral cancer

GRHL2 在 HPV 相关口腔癌中的表观遗传作用

• 批准号: 8889761
• 负责人: Mo K. Kang
• 金额: $ 28.4万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-09-24 至 2016-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8889761
• 关键词: Alcohol consumption; Apoptotic; Benzo(a)pyrene; Biological Markers; Biological Process; Boxing; Cell Fraction; Cells; Chronic; Code; Complex; DNA Methylation; Data; Development; Epigenetic Process; Epithelial; Epithelial Cells; Exposure to; Functional RNA; Gene Targeting; Genes; Genetic; Goals; HPV-High Risk; Health; High-Throughput Nucleotide Sequencing; Histones; Human; Human Papillomavirus; Human papilloma virus infection; Human papillomavirus 16; In Vitro; Incidence; Infection; Laboratories; Lead; Maintenance; Malignant Epithelial Cell; Malignant Neoplasms; Mediating; Methylation; MicroRNAs; Modeling; Modification; Oncogenes; Oncogenic; Oral; Oral health; Outcome; Patients; Phenotype; Proteins; Publishing; Regulation; Research; Risk Factors; Role; Smoking History; Solid Neoplasm; Tail; Testing; Tumor Cell Line; Tumorigenicity; Viral Oncogene; Virion; cancer stem cell; chromatin immunoprecipitation; effective therapy; epigenome; epigenomics; histone modification; human TERT protein; immortalized cell; in vivo; keratinocyte; keratinocyte differentiation; knock-down; loss of function; malignant mouth neoplasm; mouth squamous cell carcinoma; novel; novel diagnostics; oral carcinogenesis; oral cavity epithelium; pluripotency; promoter; research study; response; self-renewal; stem; stem cell division; therapeutic target; tumor

DESCRIPTION (provided by applicant): Long-term goal of our research is to discover novel biomarkers and effective therapies against oral cancer. The current project will investigate the role of Grainyhead-like 2 (GRHL2) in mediating oral carcinogenesis by "high risk" human papillomavirus (HPV) through epigenetic mechanisms. GRHL2 regulates keratinocyte cell fate through multiple target genes, including human telomerase reverse transcriptase (hTERT) gene, forkhead box protein 1 (FoxM1), and epidermal differentiation complex (EDC) genes. Our recent published data revealed that GRHL2 is a master regulator of keratinocyte proliferation and differentiation. GRHL2 elicits these effects through epigenetic mechanisms that involve altered DNA methylation and histone modifications at target gene promoters. We found that GRHL2 is notably induced in human oral keratinocytes (HOKs) harboring "high risk" HPV and HPV+ oral squamous cell carcinomas (OSCCs). Furthermore, high level of GRHL2 was detected in OSCC tumor spheroids, which are enriched with cancer stem cells (CSCs). When GRHL2 was knocked down in OSCCs, self-renewal of tumor spheroids in vitro and tumorigenicity in vivo were significantly impaired. Thus, HPV may cause deregulation of GRHL2 to promote its oncogenic activity by inducing the FoxM1 oncogene and enhance CSC self-renewal. Recent studies underscore the importance of non-coding RNAs in regulation of pluripotency and CSC self-renewal. GRHL2 upregulates miR-21, an "oncomir" associated with HPV and CSC phenotype. Thus, differential regulation of non-coding RNAs by GRHL2 may underlie the mechanism of enhancing CSC phenotype in OSCCs. To investigate the pathobiology of HPV in oral carcinogenesis, we have constructed infectious HPV16 virions capable of expressing the viral oncogenes. These novel HPV virions will allow us to test the effects of HPV infection in primary NHOK in well-controlled experiments. In the current project, we will test the hypothesis that GRHL2 is necessary for HPV-associated cellular aberrations by altered epigenetic regulation of its target genes and by enhancing CSC self-renewal, resulting in the maintenance of oral cancer phenotype. This novel hypothesis will be tested by investigating the pathophysiologic role of GRHL2 in HPV-associated cellular aberrations; determining the epigenetic mechanisms by which GRHL2 modulates epithelial proliferation and differentiation, and how GRHL2-associated epigenomic profile is altered by HPV; and investigating whether GRHL2 determines CSC phenotype in HPV-associated oral cancer by regulation of non-coding RNAs. This project will delineate the epigenetic mechanisms by which GRHL2 mediates pathobiology of "high risk" HPV in oral carcinogenesis, and will validate the role of GRHL2 in CSC renewal through regulation of non-coding RNAs, which may be used for discovery of novel diagnostic marker and therapeutic targets.

描述(申请人提供)：我们研究的长期目标是发现新的生物标记物和有效的治疗口腔癌的方法。目前的项目将通过表观遗传学机制研究GRHL2在高危人乳头瘤病毒(HPV)介导口腔癌发生中的作用。Grhl2通过多个靶基因调控角质形成细胞的命运，包括人端粒酶逆转录酶(HTERT)基因、叉头盒蛋白1(FOXM1)和表皮分化复合体(EDC)基因。我们最近发表的数据显示，GRHL2是角质形成细胞增殖和分化的主要调节因子。Grhl2通过表观遗传机制引起这些效应，这些机制包括改变DNA甲基化和目标基因启动子上的组蛋白修饰。我们发现，GRHL2在人类口腔角质形成细胞(HOK)中被显著诱导，这些人口腔角质形成细胞(HOK)携带HPV和HPV+口腔鳞状细胞癌(OSCC)。此外，在口腔鳞癌肿瘤球体中检测到高水平的GRHL2，这些球体富含肿瘤干细胞(CSC)。当GRHL2在口腔鳞状细胞中被敲除后，体外肿瘤球体的自我更新和体内的成瘤性都受到显著的损害。因此，HPV可能通过诱导FOXM1癌基因，使GRHL2失控，促进其致癌活性，促进CSC的自我更新。最近的研究强调了非编码RNA在调节多能性和CSC自我更新方面的重要性。Grhl2上调miR-21，一种与HPV和CSC表型相关的“癌”。因此，GRHL2对非编码RNA的差异调控可能是口腔鳞癌CSC表型增强的机制之一。为了研究HPV在口腔癌发生中的病理生物学作用，我们构建了能够表达病毒癌基因的感染性HPV16病毒载体。这些新的HPV病毒粒子将使我们能够在良好控制的实验中测试HPV感染对初级NHOK的影响。在本项目中，我们将通过改变GRHL2靶基因的表观遗传调控和增强CSC的自我更新来验证GRHL2对于HPV相关细胞异常是必需的假设，从而维持口腔癌的表型。通过研究GRHL2在HPV相关细胞异常中的病理生理学作用，确定GRHL2调节上皮细胞增殖和分化的表观遗传学机制，以及HPV如何改变GRHL2相关的表观基因组图谱，以及调查GRHL2是否通过调节非编码RNA来决定HPV相关口腔癌的CSC表型，将检验这一新假说。本项目将阐明GRHL2在口腔癌发生中介导高危HPV病理生物学的表观遗传学机制，并将通过对非编码RNA的调节来验证GRHL2在CSC更新中的作用，这可能用于发现新的诊断标记和治疗靶点。