Polyploid cell cycle regulation and genome instability

多倍体细胞周期调控和基因组不稳定性

• 批准号: 8962579
• 负责人: BRIAN R CALVI
• 金额: $ 30.81万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-08-12 至 2019-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8962579
• 关键词: Ablation; Aneuploid Cells; Aneuploidy; Apoptosis; Apoptotic; Biological Assay; Cell Cycle; Cell Cycle Regulation; Cell Survival; Cell division; Cells; Centrosome; Chromatin; Chromosome Fragile Sites; Chromosome Segregation; Collection; Competence; Complex; Cytokinesis; DNA; DNA Damage; DNA Sequence Alteration; DNA biosynthesis; Data; Defect; Development; Disease Progression; Drosophila genus; Gap Junctions; Gene Expression Profile; Gene Targeting; Genes; Genetic; Genetic Screening; Genome Stability; Genomic Instability; Genotoxic Stress; Goals; Human; Image; Investigation; Kinetochores; Knowledge; Lead; Life; Link; Malignant Neoplasms; Mammals; Mediating; Methods; Mitosis; Mitotic; Molecular; Molecular Genetics; Mus; One-Step dentin bonding system; Outcome; Pathway interactions; Polyploid Cells; Polyploidy; Process; Proteins; Publishing; Recruitment Activity; Regulation; Repression; Research; Resolution; S Phase; Stress; Testing; Tissues; Variant; cancer cell; cancer therapy; cell type; cellular imaging; daughter cell; fly; genome integrity; insight; novel; programs; public health relevance; research study; therapy resistant; transcription factor; tumor

 DESCRIPTION (provided by applicant): Cell division cycles and checkpoints are altered during both development and cancer. In this proposal, we focus on a developmental cell cycle variation called the endocycle (G/S cycle), which results in polyploid cells. Evidence suggests that an inappropriate switch into an endocycle contributes to genome instability and cancer. There is a large knowledge gap, however, in understanding how this alternative cell cycle is regulated and how it compromises genome integrity. Our overall objective is to define mechanisms in endocycling cells that repress apoptosis and contribute to aneuploidy when these cells return to mitosis. To achieve this goal, our proposal leverages the complementary expertise of the Calvi and Walczak labs in Drosophila endocycles and human cell mitosis respectively. Our central hypothesis is that a specific remodeling of the cell cycle transcriptome promotes endocycles, represses apoptosis, and causes genome instability. This hypothesis emanates from our discovery that endocycling cells in Drosophila development repress apoptosis by blocking the p53 genotoxic stress pathway. Experimental ablation of mitosis in Drosophila creates induced endocycling cells (iECs), and is sufficient to repress apoptosis. This suggests that there is an unsuspected link between cell cycle programs and apoptotic pathways. iECs can later resume mitotic divisions that are error prone, resulting in proliferative aneuploid daughter cells. We are also evaluating conservation to humans. Ablation of mitosis also creates human polyploid iECs, which can return to a mitosis that is severely error prone. Our transcriptome analysis has provided crucial insights into mechanism and leads to a unifying hypothesis for how endocycle regulation is linked to the repression of apoptosis and genome instability. Our central hypothesis will be tested in three specific aims: In Aim 1, we will define the molecular mechanisms by which the cell cycle and apoptotic pathways are linked in Drosophila. A novel unbiased genetic screen also exploits the power of Drosophila to discover new players in this process. Aim 2 uses molecular and genetic methods to test the hypothesis that persistent replication stress in Drosophila iECs compromises genome integrity. Aim 3 takes advantage of our expertise in human cell mitosis and advanced cellular imaging to define the mechanisms of chromosome segregation errors when human iECs return to mitosis. We also test the hypothesis that a specific remodeling of the cell cycle contributes to these errors, spawning proliferative, aneuploid daughter cells. The outcome of these integrated aims will show how endocycling cells avoid apoptosis despite persistent replication stress, and how this stress, with errors in mitosis, generates aneuploid cells. A transient switch to an endocycle may contribute to therapy resistance of the cancer cell, with a return to mitosis generating high rates of aneuploidy that contributes to disease progression. This research is significant because the outcomes will define new mechanisms for cell survival and aneuploidy, and will ultimately lead to more effective cancer therapies.

 描述（由申请人提供）：细胞分裂周期和检查点在发育和癌症过程中都会改变。在这个建议中，我们专注于一个发育细胞周期的变化称为内循环（G/S周期），这导致多倍体细胞。有证据表明，一个不适当的开关到一个内循环有助于基因组的不稳定性和癌症。然而，在理解这种替代细胞周期如何调节以及它如何损害基因组完整性方面存在很大的知识差距。我们的总体目标是确定内循环细胞抑制凋亡的机制，并在这些细胞恢复有丝分裂时导致非整倍体。为了实现这一目标，我们的提案利用了Calvi和Walczak实验室分别在果蝇内循环和人类细胞有丝分裂方面的互补专业知识。我们的中心假设是细胞周期转录组的特定重塑促进内循环，抑制凋亡，并导致基因组不稳定。这一假说源于我们的发现，即果蝇发育中的内循环细胞通过阻断p53基因毒性应激途径抑制细胞凋亡。果蝇有丝分裂的实验性消融产生诱导的内循环细胞（iECs），并且足以抑制细胞凋亡。这表明细胞周期程序和凋亡途径之间存在着未知的联系。iEC可以在以后恢复有丝分裂，这是容易出错的，导致增殖的非整倍体子细胞。我们也在评估对人类的保护。有丝分裂的消融还产生人多倍体iEC，其可以返回到严重容易出错的有丝分裂。我们的转录组分析提供了重要的见解机制，并导致一个统一的假设，如何内循环调控与细胞凋亡和基因组不稳定性的抑制。我们的中心假设将在三个具体目标中进行测试：在目标1中，我们将定义 果蝇细胞周期和凋亡途径的分子机制。一种新的无偏见的遗传筛选也利用果蝇的力量来发现这个过程中的新参与者。目的2利用分子和遗传学方法验证果蝇iECs持续复制应激损害基因组完整性的假设。目的3利用我们在人类细胞有丝分裂和先进的细胞成像方面的专业知识，确定人类iEC返回有丝分裂时染色体分离错误的机制。我们还测试的假设，一个特定的重塑细胞周期有助于这些错误，产卵增殖，非整倍体的子细胞。这些综合目标的结果将显示内循环细胞如何避免细胞凋亡，尽管持续的复制压力，以及这种压力，错误的有丝分裂，产生非整倍体细胞。向内循环的瞬时转换可能有助于癌细胞的治疗抗性，其中返回到有丝分裂产生高速率 导致疾病进展的非整倍体。这项研究意义重大，因为其结果将定义细胞存活和非整倍体的新机制，并最终导致更有效的癌症治疗。