Epigenetic Control of HPV-associated Oral Carcinogenesis

HPV 相关口腔癌发生的表观遗传控制

• 批准号: 8735930
• 负责人: Reuben Han-Kyu Kim
• 金额: $ 45.34万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-17 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8735930
• 关键词: Binding; Biological Assay; Carcinoma in Situ; Cells; Cervix carcinoma; Chromatin; Complex; DNA Viruses; Development; Epigenetic Process; Gene Activation; Gene Expression; Gene Expression Profiling; Gene Targeting; Genes; Genetic Transcription; Growth; HPV-High Risk; Head and neck structure; Health; Histone H3; Histones; Human; Human Papillomavirus; Human papilloma virus infection; Human papillomavirus 16; Immunohistochemistry; In Situ Hybridization; Incidence; Link; Lysine; Malignant Epithelial Cell; Malignant Neoplasms; Mediating; Methylation; Molecular; Molecular Profiling; Monitor; Oncogene Proteins; Oral; Oral cavity; Oropharyngeal; Oropharyngeal Squamous Cell Carcinoma; Pathway interactions; Play; Process; Proteins; Quality of life; Recruitment Activity; Regulation; Repression; Retinoblastoma Protein; Reverse Transcriptase Polymerase Chain Reaction; Role; Sampling; Sex Behavior; Small Interfering RNA; Squamous Epithelium; Squamous cell carcinoma; Testing; Time; Transcription Factor AP-1; Tropism; Ubiquitin; Western Blotting; base; cell growth; chromatin immunoprecipitation; high risk; human UBE3A protein; in vivo; keratinocyte; knock-down; malignant mouth neoplasm; mouse model; multicatalytic endopeptidase complex; new therapeutic target; novel; oral carcinogenesis; outcome forecast; public health relevance; screening; tumor; tumor growth; tumorigenesis

DESCRIPTION (provided by applicant): The long-term objectives of this application are to understand how epigenetic mechanisms control the high-risk human papillomaviruses (HPV)-associated oral carcinogenesis. Squamous cell carcinoma (SCC) is the most common cancer arising in the oral cavity, oropharynx, head and neck. The high-risk HPV16, a small DNA virus having tropism for squamous epithelia, has been found to be associated with the development and progression of oral and oropharyngeal SCC (OSCC). More importantly, the incidence of HPV-positive OSCC has increased in the USA in the last decade. The high-risk HPV16 expresses two major oncoproteins, E6 and E7. The combination of E6 and E7 (E6/E7) potently immortalizes human oral keratinocytes and promotes oncogenesis. While significant progress has been made in understanding the molecular control of E6/E7-mediated OSCC development, little is known about the interplay between HPV infection and oral keratinocyte chromatin dynamics in OSCC development and progression. Histone methylation is an important process linked to the activation and repression of gene expression, thus playing a critical role in cell growth control and oncogenesis. To explore the epigenetic regulation of HPV-associated OSCC, we systemically profiled the expression of histone demethylases in E6/E7-expressing OSCC cells. Interestingly, we found that E6/E7 potently suppressed KDM5C (also known as SMCX) expression in OSCC cells. KDM5C is a histone demethylase which removes trimethylated histone H3 at lysine 4 (H3K4me3). H3K4me3 is an activation marker, and the inhibition of KDM5C can increase the levels of H3K4me3, leading to gene activation. As a complementary approach to gene expression profiling, our siRNA screening has identified that the histone demethylase KDM4A plays an important role in the epigenetic activation of AP-1 by removing H3K9me3. Previously, we have found that AP-1 plays a critical role in the invasive growth of OSCC which is required for the progression of carcinoma in situ to OSCC. In addition to control of E6/E7 transcription, AP-1 plays an essential role in HPV-mediated oncogenesis. Based on our exciting preliminary studies, in this new application, our novel hypothesis is that KDM5C and KDM4A epigenetically control development and progression of HPV-positive OSCC by modifying H3K4me3 and H3K9me3 marks. Three specific aims are proposed to test our hypothesis. Aim 1 is to determine whether the high-risk HPV16 E6/E7 oncoproteins epigenetically reprogram OSCCs and promote OSCC progression by inhibiting KDM5C. Aim 2 is to determine whether KDM4A epigenetically promotes E6/E7 expression through AP-1. Aim 3 is to determine whether E6/E7 activate AP-1 and promote OSCC development through KDM4A. Since histone demethylases are chemically modifiable, KDM5C and KDM4A might represent novel therapeutic targets for specifically controlling HPV-associated OSCC.

描述（由申请人提供）：本申请的长期目标是了解表观遗传机制如何控制高危人乳头瘤病毒（HPV）相关的口腔癌发生。鳞状细胞癌（SCC）是口腔、口咽、头颈部最常见的癌症。高危型HPV 16是一种嗜鳞状上皮的小DNA病毒，与口腔和口咽鳞癌（OSCC）的发生、发展密切相关。更重要的是，HPV阳性口腔鳞癌的发病率在过去十年中在美国有所增加。高危型HPV 16表达两种主要癌蛋白，E6和E7。E6和E7的组合（E6/E7）有效地使人口腔角质形成细胞永生化并促进肿瘤发生。虽然在理解E6/E7介导的OSCC发展的分子控制方面取得了重大进展，但对HPV感染和口腔角质形成细胞染色质动力学在OSCC发展和进展中的相互作用知之甚少。组蛋白甲基化是一个与基因表达的激活和抑制相关的重要过程，因此在细胞生长控制和肿瘤发生中起着关键作用。为了探索HPV相关OSCC的表观遗传调节，我们系统地分析了表达E6/E7的OSCC细胞中组蛋白脱甲基酶的表达。有趣的是，我们发现E6/E7有效地抑制KDM 5C（也称为SMCX）在OSCC细胞中的表达。KDM 5C是一种组蛋白脱甲基酶，可去除赖氨酸4处的三甲基化组蛋白H3（H3 K4 me 3）。H3 K4 me 3是一种激活标志物，KDM 5C的抑制可以增加H3 K4 me 3的水平，导致基因激活。作为基因表达谱分析的补充方法，我们的siRNA筛选已经确定组蛋白去甲基化酶KDM 4A通过去除H3 K9 me 3在AP-1的表观遗传激活中起重要作用。以前，我们已经发现AP-1在OSCC的侵袭性生长中起着关键作用，这是原位癌向OSCC进展所必需的。除了控制E6/E7转录外，AP-1在HPV介导的肿瘤发生中起重要作用。基于我们令人兴奋的初步研究，在这个新的应用中，我们的新假设是KDM 5C和KDM 4A通过修饰H3 K4 me 3和H3 K9 me 3标记表观遗传控制HPV阳性OSCC的发展和进展。提出了三个具体目标来检验我们的假设。目的1是确定高危型HPV 16 E6/E7癌蛋白是否通过抑制KDM 5C对OSCC进行表观遗传学重编程并促进OSCC进展。目的2是确定KDM 4A是否通过AP-1表观遗传地促进E6/E7表达。目的3：探讨E6/E7是否通过KDM 4A激活AP-1并促进口腔鳞癌的发生发展。由于组蛋白去甲基化酶是化学修饰的，KDM 5C和KDM 4A可能代表特异性控制HPV相关OSCC的新治疗靶点。