NON-CANONICAL FUNCTIONS OF HTERT IN CELL IMMORTALIZATION BY HPV

HTERT 在 HPV 细胞永生化中的非典型功能

• 批准号: 8568104
• 负责人: Xuefeng Liu
• 金额: $ 16.91万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2015-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8568104
• 关键词: Address; Aging; Agreement; Apoptosis; Apoptotic; Binding; Binding Proteins; Biological; Biological Assay; Bypass; Cancer Etiology; Cell Aging; Cell Proliferation; Cell division; Cells; Characteristics; Complex; DNA; Data; Development; Epigenetic Process; Event; Genes; Genetic; Genetic Transcription; Goals; Grant; Growth; HPV E7; HPV-High Risk; Homeostasis; Human; Human Papillomavirus; Inhibition of Apoptosis; Laboratories; Libraries; Low risk HPV; Malignant Neoplasms; Malignant neoplasm of anus; Malignant neoplasm of cervix uteri; Mediating; Methods; Multienzyme Complexes; Mutation; Oncogenes; Oncogenic; Paper; Papillomavirus; Pharmaceutical Preparations; Play; Property; Proteins; RNA Recognition Motif; RNA Splicing; RNA-Directed DNA Polymerase; Research; Research Project Grants; Role; Staging; Stem cells; TERT gene; Telomerase; Telomere Shortening; Tertiary Protein Structure; Time; Transactivation; Transcriptional Activation; United States National Institutes of Health; Variant; Viral; Virus; Work; cell immortalization; expression vector; human TERT protein; immortalized cell; insight; keratinocyte; malignant mouth neoplasm; mutant; neoplastic cell; overexpression; pathogen; prevent; programs; promoter; public health relevance; response; telomerase reverse transcriptase; telomere; therapeutic target; transcription factor; tumor; ubiquitin ligase; uncontrolled cell growth

DESCRIPTION (provided by applicant): Cell immortalization is a critical event in the development of cancer and the oncogenic human papillomaviruses encode an E6 oncogene that is primarily responsible for inducing telomerase activity and consequent immortalization. Recent studies indicate that the HPV E6 protein mediates the increase in telomerase activity via its ability to engage and activate the hTERT promoter and interact directly with at least two promoter-bound proteins, Myc and NFX-1. E6 also has a post-translational mechanism to increase telomerase activity by binding directly to hTERT proteins. In the current grant, we show that hTERT immortalization of primary keratinocytes is independent of its telomerase activity or ability to elongate telomeres. In agreement with recent work with stem cells, our new preliminary findings demonstrate that hTERT can alter the expression of keratinocyte genes as well as increase the expression of HPV genes. We hypothesize that the transcription activation function of hTERT or its potential role in altering apoptotic responses may play an essential role in bypassing the M1/M2 restriction points in cell proliferation and thereby facilitate cell immortalization. In this application, we will evaluate these possibilities using a library of mutan hTERT expression vectors. We will correlate the ability of these mutant proteins to efficiently bypass cellular senescence with their ability to induce reverse transcriptase activity, hTR binding, telomere binding, telomere elongation, promoter transactivation, and modulation of apoptosis. These studies will provide new insights into a basic event in the etiology of cancer.

描述（由申请人提供）：细胞永生化是癌症发展中的关键事件，致癌人乳头瘤病毒编码E6癌基因，该基因主要负责诱导端粒酶活性和随后的永生化。最近的研究表明，HPV E6 蛋白通过其接合和激活 hTERT 启动子并与至少两种启动子结合蛋白 Myc 和 NFX-1 直接相互作用的能力介导端粒酶活性的增加。 E6 还具有翻译后机制，可通过直接与 hTERT 蛋白结合来增加端粒酶活性。在当前的资助中，我们证明原代角质形成细胞的 hTERT 永生化与其端粒酶活性或延长端粒的能力无关。与最近的干细胞研究一致，我们新的初步研究结果表明 hTERT 可以改变角质形成细胞基因的表达并增加 HPV 基因的表达。我们推测 hTERT 的转录激活功能或其在改变细胞凋亡反应中的潜在作用可能在绕过细胞增殖中的 M1/M2 限制点从而促进细胞永生化方面发挥重要作用。在此应用中，我们将使用 mutan hTERT 表达载体库评估这些可能性。我们将把这些突变蛋白有效绕过细胞衰老的能力与它们诱导逆转录酶活性、hTR结合、端粒结合、端粒延伸、启动子反式激活和细胞凋亡调节的能力联系起来。这些研究将为癌症病因学的基本事件提供新的见解。