ER STRESS AS EARLY SENSOR OF NUTRIENT DEPRIVATION

肿瘤细胞的快速扩张可能导致微环境，在这种微环境中，葡萄糖、氧气和生长因子等代谢营养物质变得有限，因为细胞体积扩张超过了组织已建立的血管。在正常细胞中，营养物质供应的限制会引发生长停滞和/或细胞凋亡，从而阻止细胞在这种条件下扩张。这项建议的目的是确定内质网应激反应在感知葡萄糖供应限制方面的作用，从而促进细胞适应。我们的初步工作支持一个模型，在该模型中，PERK协调细胞周期停滞与细胞存活，从而发挥细胞对代谢应激适应的关键调节作用。 根据我们的初步工作，我们假设营养胁迫后的细胞适应依赖于增加的基因表达和减少的蛋白质翻译之间的协调，并且PERK起着这种反应的中央协调者的作用。为了验证这一假说，我们提出了以下具体目标：1)确定葡萄糖剥夺后细胞周期蛋白d1蛋白丢失的调节机制(S)；2)确定perk和细胞周期蛋白d1丢失对细胞存活和肿瘤进展的贡献；3)确定依赖于perk的细胞存活的翻译非依赖性效应因子；4)确定在依赖于Nrf2的细胞中，葡萄糖剥夺会增加或减少其表达的基因。 举止。这些研究将为PERK蛋白激酶调节细胞内稳态以应对压力的机制提供关键的新见解。这一建议和项目1之间有明显的交叉点，因为慢性内质网应激是一种有效的细胞凋亡诱导剂；在本项目和项目2中，低氧被证明以一种依赖于Perk和独立的方式调节蛋白质的合成。通过这个项目促成的合作，我们将研究低氧调节细胞周期机制的机制(项目2)。我们将研究营养剥夺(项目1)和低氧如何影响PERK启动的促生存信号。这些合作努力的性质将提供关于在肿瘤进展过程中被颠覆的新的调控相互作用的信息。这里揭示的发现将提供必要的基础 新型抗癌药物的设计。

The rapid expansion of tumor cells can result in a microenvironment wherein metabolic nutrients such as glucose, oxygen and growth factors become limiting as cellular volume expands beyond the established vasculadty of the tissue. In normal cells, limits in nutrient availability trigger growth arrest and/or apoptosis thereby preventing cellular expansion under such conditions. The ,qoalof this proposal is to determine the role of the endoplasmic reticulum stress response in sensing limitations in glucose availability and thereby facilitating cellular adaptation. Our preliminary work supports a model wherein PERK coordinates cell cycle arrest with cell survival thereby functioning as a pivotal regulator of cellular adaptation to metabolic stress. Based on our preliminary work, we hypothesize that cellular adaptation following nutrient stress depends upon the coordination of increased gene expression with decreased protein translation and that PERK functions as the central coordinator of this response. To test this hypothesis, we propose the following specific aims: 1) determine the mechanism(s) that regulates cyclin D1 protein loss following glucose deprivation; 2) determine the contribution of PERK and cyclin D1 loss to cell survival and tumor progression; 3) identification and characterization of a translation-independent effector of PERK-dependent cell survival; 4) identify genes whose expression is increased or decreased by glucose deprivation in an Nrf2-dependent manner. These studies will provide critical new insight into the mechanisms whereby the PERK protein kinase regulates cell homeostasis in response to stress. There are obvious points of cross-talk between this proposal and Project 1 as chonic ER stress is a potent inducer of apoptosis; with this project and Project 2 as hypoxia has been documented to regulate protein synthesis in a PERK-dependent and -independent manner. Through collaborations faciliated by this program, we will investigate the mechanisms whereby hypoxia (Project 2) regulates the cell cycle machinery. We will investigate how both nutrient deprivation (Project 1) and hypoxia impinge upon pro-survival signals initiated by PERK. The nature of these cooperative efforts will provide information regarding novel regulatory interactions that are subverted during neoplastic progression. The findings that revealed herein will provide the foundatioin necessary for the design of novel anti-cancer therpeutics.