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

项目摘要/摘要 肿瘤的发生需要细胞绕过或逃脱两个独立的、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 端粒去保护，并涉及到对肿瘤抑制通路p53-p21WAF1和/或p16INK4A的刺激- RB。细胞周期检查点的中断使细胞能够绕过衰老并继续 增殖，而端粒进一步缩短。最终，这些细胞启动一种称为复制体的终端反应 危机，在此期间，非常短的端粒受到端到端融合的影响，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走出来，并朝着 恶性，但危机中的细胞死亡和危机逃脱的潜在机制还没有定义。乔·纳苏尔博士 最近发现了宏自噬(下称自噬)在消除中的一个未被认识的功能 危机期间的细胞数量。因此，自噬是应对危机所需的一个重要组成部分 去除有恶变风险的细胞。这表明自噬缺陷可能是分子 肿瘤发生的基础。 在他的独立之路奖(K99/R00)提案中，纳苏尔博士和他的导师简博士 卡尔赛德和他的共同导师鲁本·肖博士、马丁·赫策博士和彼得·亚当斯博士设计了一种专门的 培训计划，并提出了一个研究项目，着手剖析哺乳动物的分子基础 自噬及其在人类癌症早期的潜在治疗作用。特别是，纳苏尔博士将 重点破译危机中依赖自噬的细胞死亡的机制(目标1)，阐明 自噬和基因组稳定性之间的相互作用(目标2)，并评价自噬在肿瘤中的作用 通过摆脱危机实现转型(目标3)。AIM 3的体内相关性将通过使用 基因敲除和转基因小鼠模型易受端粒功能障碍驱动的致癌作用。这个 将检查组织中细胞危机的发生以及自噬对肿瘤发病率的影响。这 研究将为自噬在癌症生物学中的作用提供新的见解，并应该提供一个理论基础 用于开发自噬调节方法以改善癌症治疗的疗效。 纳苏尔博士的培训计划将提供所有必要的专业发展，以指导独立的 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 明确癌症中自噬的机制和功能。该奖项中的培训模块包括： NGS数据的计算分析和生物信息学，处理和约束小鼠的方法， 转基因小鼠技术，以及教学和拨款撰写等指导技能；这些都将是 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.