Heat shock-induced apoptosis

热休克诱导细胞凋亡

基本信息

批准号：
8017397
负责人：
Shawn B Bratton
金额：
$ 29.23万
依托单位：
UNIVERSITY OF TEXAS AT AUSTIN
依托单位国家：
美国
项目类别：
财政年份：
2008
资助国家：
美国
起止时间：
2008-04-08 至 2011-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8017397
关键词：
Address Alkalinization Apoptosis Apoptosis Inhibitor Apoptotic Applications Grants Area Attenuated Caspase Cathepsins Cathepsins B Cell Death Cells Cleaved cell Clinic Clinical Trials Complex Convulsive therapy Cytoplasm Cytoplasmic Granules Cytosol Data Embryo Environment Family member Fever Fibroblasts Future Gene Combinations Grant Health Heat shock proteins Heat-Shock Proteins 70 Heat-Shock Response Heating Imidazole Investigation Lead Light MAP Kinase Kinase Kinase Malignant Neoplasms Mediating Membrane Mitochondria Mitogen-Activated Protein Kinase Kinases Modeling Mus N-terminal Outer Mitochondrial Membrane Pathway interactions Pharmaceutical Preparations Phase Phosphotransferases Process Proteins Protons Publications RNA Interference RNA-Binding Proteins Radiation Radiation therapy Regulation Reporting Resistance Role Signal Transduction Stimulus Stream Stress TNF Receptor-Associated Factors TNF receptor-associated factor 2 Testing Tumor Necrosis Factor Receptor Work aposome base caspase-2 caspase-3 cell killing cellular targeting chemotherapy endoplasmic reticulum stress improved inhibitor/antagonist insight interest novel overexpression prevent pro-caspase-3 response stress-activated protein kinase 1

项目摘要

DESCRIPTION (provided by applicant): Hyperthermia or heat shock therapy is currently being utilized in phase II/III clinical trials, either alone or in combination with radiation or chemotherapy, for the treatment of various cancers. Unfortunately, though intense heat shock induces apoptosis, the underlying mechanisms remain controversial and unclear. We have recently shown that heat shock does not require any of the known initiator caspases or their activating complexes to induce apoptosis. We now hypothesize that heat shock induces cell death, in part by stimulating rapid endo-lysosomal membrane permeabilization (ELMP), which coincides with cytosolic acidification and release of cathepsins into the cytoplasm, both of which participate in the processing of procaspase-3 and the proapoptotic BH3-only protein Bid. Importantly, heat shock-induced mitochondrial outer membrane permeabilization (MOMP) is essential for cell death, as cells that overexpress Bcl-2-or are deficient in Bid or the proapoptotic Bcl-2 family members Bax and Bak-are resistant to cell death. MOMP is critical for cell death most likely because it facilitates the release of inhibitor of apoptosis (IAP) antagonists, which in turn promote caspase activity. Remarkably, heat shock also requires c-Jun N-terminal kinases (JNKs) to induce MOMP, and we find that JNKs are activated through a highly novel pathway involving the formation of so-called cytoplasmic "stress granules" (SGs). We hypothesize that formation of SGs is initiated through heat-induced aggregation of the RNA binding protein TIA-1, and that SGs in turn activate JNKs through a tumor necrosis factor (TNF) receptor-associated factor 2 (TRAF2) and TGF2- activating kinase 1 (TAK1)-dependent pathway. We further speculate that JNKs sensitize cells to heat shock-induced MOMP by activating additional BH3-only proteins, such as Bim, and/or by inhibiting specific antiapoptotic Bcl-2 family members, such as Bcl-xL or Mcl-1. In the following three specific aims, we propose (1) to determine if ELMP elicits cytosolic acidification and to determine how ELMP is regulated by heat shock protein 70 (Hsp70), (2) to establish the roles of cathepsins in the activation of procaspase-3 and Bid, and (3) to characterize the unique SG-TRAF2-TAK1-MAPKK-JNK pathway, its regulation by Hsp70, and the downstream targets of JNK following heat shock. In summary, this grant proposal would determine the basic mechanisms of heat shock-induced apoptosis, which are highly relevant given the renewed interest in hyperthermia as a clinically useful treatment option. PUBLIC HEALTH RELEVANCE: The focus of this grant project is to unravel the cellular mechanisms that mediate heat shock-induced cell death. Heat shock, or hyperthermia, is currently being used in clinical trials, either alone or as an adjunct to chemo- or radiotherapy for the treatment of various cancers. Unfortunately, very little is known about how heat shock kills cells. Our preliminary work in this area suggests that heat shock induces cell death through mechanisms that are very different from other types of stimuli. Thus, it is anticipated that the work proposed herein will significantly improve our understanding of how heat shock works in the clinic and may shed light on new pathways that can be exploited therapeutically in the future.

描述（由申请人提供）：II/III期临床试验目前正在使用高温或热休克疗法，无论是单独或与放射线或化学疗法结合使用，用于治疗各种癌症。不幸的是，尽管强烈的热休克会诱导凋亡，但潜在的机制仍然存在争议和不清楚。我们最近表明，热休克不需要任何已知的引发剂胱天蛋白酶或其活化复合物来诱导凋亡。现在，我们假设热休克会诱导细胞死亡，部分原因是刺激快速的内糖体膜通透性（ELMP）（ELMP），它与细胞质酸化并释放到细胞质中，这两者都参与了procaspase-3的加工，又参与了Propaspase-3的加工和促蛋白酶的蛋白质蛋白质蛋白质蛋白质。重要的是，热休克诱导的线粒体外膜透化（MOMP）对于细胞死亡至关重要，因为过表达Bcl-2-or的细胞在投标或促凋亡的Bcl-2家族成员Bax和Bak-bak-are抗细胞死亡中具有抗性。 MOMP对于细胞死亡至关重要，最有可能是因为它促进了凋亡抑制剂（IAP）拮抗剂的释放，这又促进了caspase活性。值得注意的是，热休克还需要C-JUN N末端激酶（JNK）诱导MOMP，并且我们发现JNK通过高度新颖的途径激活，涉及形成所谓的细胞质“应力颗粒”（SGS）。我们假设SG的形成是通过热诱导的RNA结合蛋白TIA-1的聚集而启动的，而SGS反过来又通过肿瘤坏死因子（TNF）受体相关因子2（TRAF2）和TGF2激活激活激活激活激活激酶1（TAK1） - 依赖性途径激活JNK。我们进一步推测JNK通过激活其他仅BH3蛋白（例如BIM）和/或抑制特定的抗凋亡BCL-2家族成员（例如BCL-XL或MCL-1）来使细胞敏化对电击诱导的MOMP。 In the following three specific aims, we propose (1) to determine if ELMP elicits cytosolic acidification and to determine how ELMP is regulated by heat shock protein 70 (Hsp70), (2) to establish the roles of cathepsins in the activation of procaspase-3 and Bid, and (3) to characterize the unique SG-TRAF2-TAK1-MAPKK-JNK pathway, its regulation by Hsp70,以及热量冲击后JNK的下游目标。总而言之，该赠款提案将确定热休克诱导的细胞凋亡的基本机制，鉴于对热疗的重新兴趣是临床上有用的治疗选择，这是非常相关的。公共卫生相关性：该赠款项目的重点是揭示介导热休克引起的细胞死亡的细胞机制。热休克或高温目前正在临床试验中，无论是单独还是作为化学或放射疗法的辅助治疗各种癌症的辅助。不幸的是，对热冲击如何杀死细胞几乎一无所知。我们在这一领域的初步工作表明，热冲击通过与其他类型的刺激大不相同的机制诱导细胞死亡。因此，预计本文提出的工作将显着提高我们对诊所中热休克的作用的理解，并可能阐明可以将来可以通过治疗剥削的新途径。