Micro-RNA-dependent regulation of the UPR

快速增殖的癌细胞必须在这样的微环境中茁壮成长，在这种微环境中，代谢营养物质，如 随着肿瘤体积的扩大，葡萄糖、氧气和生长因子变得有限 组织的血管性。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， 从而防止在这种条件下的细胞膨胀。这项提案的目标是确定 内质网应激反应/未折叠蛋白反应(UPR)在感觉局限性中的作用 葡萄糖的可用性，从而促进细胞适应。PERK，三个近端信号之一 UPR的转导分子，在调节细胞命运的决定中起着核心作用；该激酶最近被 证明具有促进肿瘤生长和存活的作用。我们理解的核心是 依赖于PERK的生存正在剖析通过ATF4与ATF4的PERK促进生存信号的意义 通过CHOP的诱导产生依赖于PERK的凋亡信号。关键是，支持生存的信号有多大 与促凋亡转录因子CHOP的诱导平衡，人们仍然知之甚少。 已经十多年了。我们的初步工作提出了一个压倒一切的假设，即miR的时间调节- 211在暴露于内质网应激的细胞中协调细胞适应和凋亡。为了测试 这一假设我们将1)确定内质网应激依赖的miR-211诱导的机制 2)阐明调节miR-211稳定性的机制(S)；3)确定miR-211的作用 MIR-211在肿瘤发生中的作用这些研究将为以下机制提供关键的新见解： PERK蛋白激酶在应激反应中调节细胞动态平衡。有明显的交叉点- 这项建议与项目2之间的对话，项目2侧重于UPR如何拮抗myc诱导的细胞凋亡 并增强肿瘤细胞的适应能力。通过与项目2的合作，我们将评估m|R- 在myc依赖的肿瘤发生中，211作为细胞生长和存活的中介。项目1与 项目3通过共同关心PERK如何调控IFNAR1、IFNAR1 E3连接酶和IFNAR1 肿瘤发生过程中的信号传递。通过与Project 3的合作，我们将确定miR-211是如何 调节内质网应激和肿瘤发生过程中IFNAR1的调节以及评估miR-211对 下游干扰素信号。从本文提出的工作中得出的发现将提供一个 为设计新型抗癌药物奠定了基础。 相关性(请参阅说明)： 最近的研究表明，PERK的失活促进了肿瘤的进展，为 肿瘤治疗用PERK小分子抑制剂的研究进展。虽然这些研究提供了明确的 对这种方法的生物学支持，我们对PERK如何调节细胞存活的理解 致癌损伤后的细胞凋亡是有限的。这个项目中描述的工作将描绘出分子 PERK调控细胞凋亡暂时性发生的机制。

Rapidly proliferating cancer cells must thrive in a microenvironment wherein metabolic nutrients such as glucose, oxygen and growth factors become limiting as tumor volume expands beyond the established vascularity of the tissue. In normal cells, limits in nutrient availability trigger growth arrest and/or apoptosis, thereby preventing cellular expansion under such conditions. The goal of this proposal is to determine the role of the endoplasmic reticulum stress response/Unfolded Protein Response (UPR) in sensing limitations in glucose availability, and thereby facilitating cellular adaptation. PERK, one of three proximal signal transducers of the UPR, plays a central role in mediating cell fate decisions; this kinase has recently been demonstrated to function in the potentiation of tumor growth and survival. Central to our understanding of PERK-dependent survival is dissecting the significance of PERK pro-survival signaling through ATF4 versus PERK-dependent apoptotic signals through the induction of CHOP. Critically, how pro-survival signals are balanced with the induction of the pro-apoptotic transcription factor, CHOP, has remained poorly understood for over a decade. Our preliminary work suggests an overarching hypothesis that temporal regulation of miR- 211 coordinates cellular adaptation with apoptosis in cells exposed to endoplasmic reticulum stress. To test this hypothesis we will 1) determine the mechanisms of ER stress-dependent induction of miR-211 accumulation; 2) elucidate the mechanism(s) that regulate miR-211 stability; and 3) determine the role of miR-211 in tumorigenesis. 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 2 which focuses on how the UPR antagonizes myc induced apoptosis and potentiates tumor cell adaptation. Through collaboration with Project 2, we will assess the role of m|R- 211 as a mediator of cell growth and survival in myc-dependent tumorigenesis. Project 1 intersects with Project 3 through common interests on how PERK regulates IFNAR1, the IFNAR1 E3 ligase and IFNAR1 signaling during tumorigenesis. Through collaboration with Project 3, we will detrmine how miR-211 regulates IFNAR1 regulation during ER stress and tumorigenesis as well as assess miR-211 regulation of downstream interferon signaling. The.findings steming from the work proposed herein will provide a foundation for the design of novel anti-cancer therpeutics. RELEVANCE (See instructions): Recent work has revealed that inactivation of PERK promotes tumor progression, providing support for the development of small molecule inhibitors of PERK for cancer treatment. While these studies provide clear biological support for such approaches, our understanding of how PERK regulates cell survival versus ' apoptosis following oncogenic insult is limited. The work described in this project will delineate molecular mechanisms whereby PERK regulates the temporal onset of apoptosis.