A PTEN-Dependent Size Checkpoint in Human Cancer Cells

人类癌细胞中 PTEN 依赖性大小检查点

• 批准号: 7417921
• 负责人: TODD A WALDMAN
• 金额: $ 24.07万
• 依托单位: GEORGETOWN UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-11 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7417921
• 关键词: Affect; Attenuated; Binding; Biochemical; Biological Models; Cancer cell line; Cell Line; Cell Size; Cells; Characteristics; DNA Damage; Data; Drosophila melanogaster; G2 Checkpoint control; GTP-Binding Proteins; Gene Targeting; Genes; Goals; Guanosine Triphosphate Phosphohydrolases; HCT116 Cells; House mice; Human; Knock-out; Knowledge; Lead; Malignant Neoplasms; Measures; Mutation; Normal Cell; Numbers; Oncogenes; Oncogenic; Organism; Oxidative Stress; PIK3CA gene; PTEN gene; Pathway interactions; Phenotype; Phosphorylation; Phosphotransferases; Poison; Property; Radiation; Radiation, Other; Range; Reporting; Research Personnel; Signal Transduction; Signal Transduction Pathway; Small Interfering RNA; Somatic Cell; Stimulus; System; TP53 Gene Inactivation; TP53 gene; TSC2 gene; Testing; Transfection; Tumor Suppressor Genes; Tumor Suppressor Proteins; Variant; Work; cancer cell; human PIK3CA protein; novel; programs; response; size; small hairpin RNA

DESCRIPTION (provided by applicant): Activation of PIP3 signaling by inactivating mutations in the PTEN tumor suppressor or activating mutations in the PIK3CA oncogene is found in a wide range of common human cancers. Though the biochemical details of PIP3 signal transduction are rapidly emerging, the phenotypic consequences of PIP3 pathway activation in human cancer cells remain less well defined. As such, the long-term goal of this project is to define the effects of PIP3 activation in human cancer cells. In our initial preliminary studies, we employed human somatic cell gene targeting to create isogenic sets of PTEN+/+ and PTEN-/- human cancer cell lines. Using these and related model systems, we found that PTEN controls a novel radiation-induced size checkpoint in human cells that is distinct and genetically separable from the radiation-induced, p53-dependent G1 and G2 checkpoints. To our knowledge, the existence of such a DNA damage-inducible size arrest has neither been postulated or demonstrated in any organism. Since the initial submission of this application we have employed human somatic cell gene targeting to create an isogenic set of PIK3CA gene targeted human cancer cells, and also created NIH3T3 cell lines that express wild-type, oncogenic, or inactive forms of PIK3CA. Using these systems we have obtained preliminary data suggesting that, like PTEN, the PIK3CA oncogene may be able to regulate size checkpoint function as well. In this application we propose three related specific aims to further pursue and extend these observations. Aim #1 - Identify additional inducers of the PTEN-dependent size checkpoint. Aim #2 - Demonstrate the presence of the PTEN-dependent size checkpoint in untransformed human cells. Aim #3 - Characterize crosstalk between the radiation-induced, p53-dependent G1/G2 checkpoints and the radiation-induced, PTEN-dependent cell size checkpoint. Pursuit of these aims will enable us to further characterize the properties and mechanism(s) of a tumor suppressor gene-regulated, radiation-induced cell size checkpoint.

描述（由申请人提供）：在多种常见的人类癌症中发现了通过灭活 PTEN 肿瘤抑制基因中的突变或激活 PIK3CA 癌基因中的突变来激活 PIP3 信号传导。尽管 PIP3 信号转导的生化细节正在迅速浮出水面，但人类癌细胞中 PIP3 通路激活的表型后果仍然不太明确。因此，该项目的长期目标是确定 PIP3 激活对人类癌细胞的影响。在我们最初的初步研究中，我们采用人类体细胞基因靶向来创建 PTEN+/+ 和 PTEN-/- 人类癌细胞系的同基因组。使用这些和相关的模型系统，我们发现 PTEN 控制人类细胞中一种新的辐射诱导的大小检查点，该检查点与辐射诱导的 p53 依赖性 G1 和 G2 检查点不同且在遗传上可分离。据我们所知，这种 DNA 损伤诱导的大小停滞的存在尚未在任何生物体中被假设或证明。自从首次提交该申请以来，我们采用人类体细胞基因靶向来创建一组针对人类癌细胞的 PIK3CA 基因同基因组，并且还创建了表达野生型、致癌性或失活形式 PIK3CA 的 NIH3T3 细胞系。使用这些系统，我们获得了初步数据，表明与 PTEN 一样，PIK3CA 癌基因也可能能够调节大小检查点功能。在本申请中，我们提出了三个相关的具体目标，以进一步追求和扩展这些观察结果。目标#1 - 识别 PTEN 依赖性大小检查点的其他诱导剂。目标 #2 - 证明未转化的人类细胞中存在 PTEN 依赖性大小检查点。目标 #3 - 表征辐射诱导的 p53 依赖性 G1/G2 检查点与辐射诱导的 PTEN 依赖性细胞大小检查点之间的串扰。追求这些目标将使我们能够进一步表征肿瘤抑制基因调节的、辐射诱导的细胞大小检查点的特性和机制。