Rap1Gap and Tumor Progression

Rap1Gap 和肿瘤进展

• 批准号: 8074533
• 负责人: JUDY L MEINKOTH
• 金额: $ 32.2万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8074533
• 关键词: Adherent Culture; Angioinvasion; Attenuated; Cell Line; Cell physiology; Cell-Cell Adhesion; Cells; Cellular Structures; Clinical; Complement; Data; Defect; Disease; Dissociation; Down-Regulation; E-Cadherin; Employee Strikes; Environment; Epithelial; Exhibits; Genes; Guanosine Triphosphate Phosphohydrolases; Health; Human; In Vitro; Intercellular Junctions; Maintenance; Malignant Epithelial Cell; Malignant Neoplasms; Malignant neoplasm of thyroid; Molecular; Morphology; Neoplasm Metastasis; Outcome; Papillary thyroid carcinoma; Pathogenesis; Primary Neoplasm; Property; Rattus; Regulation; Role; Sampling; Signal Transduction; Specimen; Structure; Testing; Thyroid Gland; Thyroid carcinoma; Tumor Cell Line; Vimentin; base; cell motility; clinically significant; epithelial to mesenchymal transition; human tissue; lymph nodes; matrigel; neoplastic cell; outcome forecast; research study; thyroid neoplasm; tumor; tumor progression

DESCRIPTION (provided by applicant): One of the most critical steps in the progression to malignancy is the acquisition by tumor cells of the ability to metastasize. The hypothesis to be tested in this proposal is that downregulation of Rap1GAP contributes to thyroid tumor progression. This notion is based on data showing that Rap1GAP is highly expressed in normal human thyroid cells, and that its expression is dramatically reduced in the majority of invasive papillary thyroid carcinomas. Studies in human thyroid carcinoma cell lines revealed a striking correlation between loss of Rap1GAP and loss of epithelial structure. Rap1GAP-deficient tumor cells lacked E-cadherin and acquired the expression of vimentin, indicative of epithelial-to-mesenchymal transition. These cells exhibited enhanced migratory and invasive properties compared to tumor cells that retained Rap1GAP. Restoring Rap1GAP to Rap1GAP-deficient cells inhibited cell migration, invasion and anchorage-independent proliferation. Silencing Rap1GAP expression in thyroid carcinoma cells that retain an epithelial morphology caused the cells to disperse, enhanced the dissociation of cell aggregates, and dysregulated E-cadherin, suggestive of defects in cell/cell adhesion. As disruption of cell/cell junctions is associated with serious pathological consequences, we propose that downregulation of Rap1GAP contributes to the pathogenesis of thyroid tumors by attenuating cell/cell adhesion. In vitro studies will explore the molecular mechanism through which decreased Rap1GAP expression attenuates cell/cell adhesion and assess whether eliminating Rap1GAP endows tumor cells with altered migratory properties and invasive potential. As TSH regulation of Rap1GAP is lost from the human thyroid tumor cell lines, but is likely to be retained in primary thyroid tumors, complementary studies will be performed in differentiated rat thyroid cells. These studies will be conducted in cells in three-dimensional environments, conditions that more closely reproduce the matrix compliance of human tissues and where cell/cell contacts are maximized. The in vitro studies are complemented with studies in human tumor specimens that will identify the subtypes of thyroid tumors in which Rap1GAP expression is decreased and probe the clinical significance of loss of Rap1GAP. In summary, this proposal presents a highly cohesive plan to investigate the contribution and clinical significance of Rap1GAP depletion to the progression of human thyroid tumors. PUBLIC HEALTH RELEVANCE: This proposal investigates the contribution and clinical significance of decreased Rap1GAP expression to the progression of human thyroid tumors. Studies in human thyroid tumor cell lines will elucidate the mechanism through which downregulation of Rap1GAP attenuates cell/cell adhesion and investigate whether loss of Rap1GAP enhances migratory and invasive potential. Studies in human tumor specimens will identify the subtypes of thyroid tumors that exhibit Rap1GAP downregulation, assess whether decreased expression of Rap1GAP is correlated with the presence of metastatic disease at presentation, examine whether Rap1GAP expression is further decreased in lymph node metastases compared to primary tumors and assess whether Rap1GAP expression is correlated with the presence of angioinvasion or lymphoinvasion, markers of poor prognosis.

描述（由申请人提供）：进展为恶性肿瘤的最关键步骤之一是肿瘤细胞的转移能力获得。该提议中要检验的假设是RAP1GAP的下调有助于甲状腺肿瘤进展。该概念基于数据表明RAP1GAP在正常的人甲状腺细胞中高度表达，并且在大多数浸润性甲状腺甲状腺癌中，其表达大大降低。在人甲状腺癌细胞系中进行的研究表明，RAP1GAP的丧失与上皮结构的丧失之间存在显着的相关性。 RAP1GAP缺陷型肿瘤细胞缺乏E-钙粘蛋白并获得了波形蛋白的表达，表明上皮到间质转变。与保留RAP1GAP的肿瘤细胞相比，这些细胞表现出增强的迁移和侵入性特性。恢复RAP1GAP至RAP1GAP缺陷型细胞抑制了细胞迁移，侵袭和无关的增殖。在保留上皮形态的甲状腺癌细胞中的RAP1GAP表达沉默导致细胞分散，增强细胞聚集体的分离和失调的E-钙粘着蛋白，这表明细胞/细胞粘附中缺陷。由于细胞/细胞连接的破坏与严重的病理后果有关，我们建议RAP1GAP的下调通过减弱细胞/细胞粘附而导致甲状腺肿瘤的发病机理。体外研究将探索分子机制，通过这种机制，Rap1GAP表达降低会减轻细胞/细胞粘附，并评估消除RAP1GAP的肿瘤细胞是否具有改变的迁移特性和侵入性潜力。由于RAP1GAP的TSH调节因人甲状腺肿瘤细胞系而丢失，但可能保留在原发性甲状腺肿瘤中，因此将在分化的大鼠甲状腺细胞中进行互补研究。这些研究将在三维环境中的细胞中进行，这些条件更接近地重现人体组织的基质依从性以及最大化细胞/细胞接触的情况。体外研究补充了人类肿瘤标本的研究，这些研究将鉴定甲状腺肿瘤的亚型，其中rap1gap表达降低并探测了RAP1GAP丧失的临床意义。总而言之，该提案提出了一个高度凝聚力的计划，以研究RAP1GAP耗竭对人甲状腺肿瘤进展的贡献和临床意义。公共卫生相关性：该提案调查了RAP1GAP表达降低对人甲状腺肿瘤进展的贡献和临床意义。在人甲状腺肿瘤细胞系中进行的研究将阐明RAP1GAP下调减弱细胞/细胞粘附的机制，并研究RAP1GAP的丢失是否增强了迁移和侵入性潜力。人类肿瘤标本中的研究将确定表现出RAP1GAP下调的甲状腺肿瘤的亚型，评估RAP1GAP表达的降低与介绍中转移性疾病的存在相关，研究RAP1GAP表达是否进一步降低了与主肿瘤相比的淋巴结转移的淋巴结转移的较差或符号表达的较差，是ARPINE的表达是否易于体形症状。预后。