The role of autophagy in the escape from replicative crisis and tumorigenesis

项目总结/摘要 肿瘤发生需要细胞绕过或逃避两个离散和独特的抗增殖屏障： 复制性衰老和危机。衰老是一种永久性的细胞周期停滞，作为一种主要反应被激活 端粒脱保护，并涉及刺激肿瘤抑制途径p53-p21 WAF 1和/或p16 INK 4A- RB.细胞周期检查点的破坏使细胞能够绕过衰老并继续 增殖，而端粒进一步缩短。最终这些细胞会启动一种叫做复制的终末反应 危机，在此期间，非常短的端粒会发生端到端融合，导致大量细胞 死亡在极少数情况下，一小群细胞会自发地从危机中出现， 恶性肿瘤，但在危机和危机逃逸的细胞死亡的机制还没有定义。Joe Nassour博士 最近发现了一种未被认识到的功能，巨自噬（以下简称自噬）在消除 细胞在危机中。因此，自噬是危机应对的一个重要组成部分， 去除有恶性转化风险的细胞。这表明自噬缺陷可能是 肿瘤发生的基础。 在他的独立之路奖（K99/R 00）提案中，Nassour博士和他的导师Jan博士 Karlseder和他的共同导师Reuben Shaw博士，Martin Hetzer博士和Peter亚当斯博士设计了一个专门的 培训计划并提出了一个研究项目，旨在剖析哺乳动物的分子基础 自噬及其在人类癌症早期阶段的潜在治疗作用。尤其是纳苏尔博士 致力于破译危机中自噬依赖性细胞死亡的机制（目标1），阐明 自噬和基因组稳定性之间的相互作用（目的2），并评估自噬在肿瘤发生中的作用。 通过危机逃避实现转型（目标3）。目标3的体内相关性将通过采用 基因敲除和转基因小鼠模型对端粒功能障碍驱动的致癌作用敏感。的 将检查组织中细胞危象的发生以及自噬对肿瘤发病率的影响。这 这项研究将为自噬在癌症生物学中的功能提供新的见解，并应提供一个理论基础。 用于开发自噬调节方法以改善癌症治疗的功效。 博士纳苏尔的培训计划将提供所有必要的专业发展，以指导一个独立的 实验室使用基于下一代测序（NGS）的“组学”方法和转基因小鼠模型， 定义自噬在癌症中的机制和功能。该奖项的培训模块包括： NGS数据的计算分析和生物信息学，小鼠的处理和限制方法， 转基因小鼠技术，以及指导技能，如教学和拨款写作;这一切都将是 这是向独立过渡后取得成功所必需的。

Project Summary / Abstract Tumorigenesis requires cells to bypass or escape two discrete and distinctive anti-proliferative barriers: replicative senescence and crisis. Senescence is a permanent cell cycle arrest, activated as a primary response to telomere deprotection and involves stimulation of the tumor suppressor pathways p53-p21WAF1 and/or p16INK4A- Rb. Disruption of cell-cycle checkpoints renders cells capable of bypassing senescence and continuing proliferation, while telomeres shorten further. Eventually such cells initiate a terminal response called replicative crisis, during which critically short telomeres become subject to end-to-end fusions, resulting in massive cell death. On rare occasion, a small group of cells will emerge spontaneously from crisis and evolve towards malignancy, yet the mechanisms underlying cell death in crisis and crisis escape are not defined. Dr. Joe Nassour has recently discovered an unrecognized function for macroautophagy (hereafter autophagy) in the elimination of cells during crisis. Autophagy is therefore an essential component of the crisis response required for the removal of cells at risk for malignant transformation. This suggests that autophagy defects can be the molecular basis for tumorigenesis. In his Pathway to Independence Award (K99/R00) proposal, Dr. Nassour, together with his Mentor Dr. Jan Karlseder, and his Co-Mentors Dr. Reuben Shaw, Dr. Martin Hetzer, and Dr. Peter Adams, designed a dedicated training plan and proposed a research project that sets out to dissect the molecular basis of mammalian autophagy and its potential therapeutic role in the earliest stages of human cancer. In particular, Dr. Nassour will focus on deciphering the mechanism of autophagy-dependent cell death in crisis (Aim 1), elucidating the interplay between autophagy and genome stability (Aim 2), and evaluating the role of autophagy in neoplastic transformation through crisis escape (Aim 3). The in vivo relevance of Aim 3 will be examined by employing knockout and transgenic mouse models susceptible to telomere dysfunction-driven carcinogenesis. The occurrence of cellular crisis in tissues and the impact of autophagy on tumor incidence will be examined. This research will provide new insights into the function of autophagy in cancer biology, and should provide a rationale for developing autophagy modulation approaches to ameliorate the efficacy of cancer therapy. Dr. Nassour’s training plan will provide all the necessary professional development to direct an independent laboratory using next-generation sequencing (NGS)-based ‘omics’ approaches and transgenic mouse models to define the mechanisms and function of autophagy in cancer. Training modules in this award include: Computational analysis and bioinformatics for NGS data, methods for handling and restraint in the mouse, transgenic mouse technology, and mentorship skills such as teaching and grant writing; which will all be necessary for the success following the transition to independence.