Molecular mechanisms of TRAIL resistance in glioblastoma

胶质母细胞瘤TRAIL耐药的分子机制

• 批准号: 8009820
• 负责人: CHUNHAI Charlie HAO
• 金额: $ 31.2万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-01-01 至 2013-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8009820
• 关键词: Address; Apoptosis; Binding; Binding Proteins; Biological Assay; Brain Neoplasms; CASP8 and FADD-like apoptosis regulating protein; Cell Line; Cells; Cessation of life; Cleaved cell; Clinical Treatment; Clinical Trials; Collection; Combined Modality Therapy; Complex; Death Domain; Death Receptor 5; Detection; Diabetes Mellitus; Dimerization; Enzymes; Gene Dosage; Glioblastoma; Goals; Health; Human; Libraries; Ligands; Link; Lysine; Malignant Neoplasms; Mediating; Molecular; Mus; Names; Patients; Phase I/II Trial; Phosphoproteins; Polyubiquitin; Positioning Attribute; Process; Proteins; Reporting; Research Proposals; Resistance; Role; Scheme; Signal Transduction; Testing; Therapeutic Agents; Tissues; Treatment Efficacy; Tumor Necrosis Factor-alpha; Tumor Tissue; Ubiquitin; Ubiquitination; Xenograft procedure; base; cancer cell; cancer therapy; caspase-8; dimer; human RIPK1 protein; in vivo; mutant; novel therapeutics; overexpression; protein complex; receptor; therapeutic target; tumor; ubiquitin ligase; ubiquitin-protein ligase

DESCRIPTION (provided by applicant): Glioblastoma is the most common and lethal brain tumor for which there is no curative treatment. In search for new therapeutic agents, we have shown that TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) can induce programmed cell death (apoptosis) in glioblastoma cells and it may offer a new hope for a cure. TRAIL has therefore entered the clinical trials for cancer treatment. Earlier reports from the trials, unfortunately, have shown a limited antitumor activity and indicated that the majority of human cancers including glioblastomas are resistant to TRAIL. The current research proposal will therefore examine the molecular basis of TRAIL resistance in glioblastomas. TRAIL-induced apoptosis occurs through binding to the death receptor DR5 and the recruitment of caspase-8 to DR5 for the formation of DISC (death-inducing signaling complex). In the DISC, caspase-8 forms dimers and then becomes proteolytically active in the initiation of the programmed cell death. Our Preliminary Studies show that the caspase-8 dimerization and cleavage are inhibited in TRAIL-resistant glioblastoma cells. In search for the mechanism in the caspase-8 inhibition, we have discovered a DR5-associated proteins complex that is formed prior to TRAIL treatment and we therefore name the PLAC (pre-ligand assembly complex). Our Preliminary Studies show that the PLAC components define the subsequent formation of the DISC and thus control caspase-8 dimerization and cleavage. Specifically, the Preliminary Studies identify RIP (receptor-interacting protein) and A20, a RIP ubiquitin enzyme in the PLAC and show that TRAIL treatment leads to the RIP ubiquitination and caspase-8 inhibition during the TRAIL-induced formation from the PLAC to the DISC. We therefore hypothesize that A20-mediated RIP ubiquitination inhibits caspase-8 dimerization and cleavage. To test this hypothesis, we will define the role of A20 as the RIP ubiquitin ligase, determine the polyubiquitin chain attached to RIP and identify the polyubiquitin binding domain on caspase-8. In addition, we will generate mouse xenografts and primary cultures from patient's glioblastomas and determine whether A20 is overexpressed in the tumors and thus defines the TRAIL resistance in the tumors. Upon the completion, this study will identify A20 as a therapeutic target and thus benefit human health by developing the combination therapy that can target A20 inhibitory mechanisms to overcome the tumor resistance to TRAIL treatment. PUBLIC HEALTH RELEVANCE: The objective of this proposal is to develop TRAIL as a therapeutic agent in treating of glioblastomas. This proposal will yield significant results, with immediate and long term impact on clinical treatment of human glioblastoma, one of the most deadly human cancers.

描述（由申请人提供）：胶质母细胞瘤是没有治疗性治疗的最常见和致命的脑肿瘤。在寻找新的治疗剂时，我们表明TRAIL（肿瘤坏死因子相关的凋亡诱导配体）可以在胶质母细胞瘤细胞中诱导程序性细胞死亡（凋亡），并且可能为治疗提供新的希望。因此，TRAIL已进入癌症治疗的临床试验。不幸的是，来自试验的早期报告显示出有限的抗肿瘤活性，并表明包括胶质母细胞瘤在内的大多数人类癌症都对TRAIL具有抵抗力。因此，当前的研究建议将检查胶质母细胞瘤中跟踪抗性的分子基础。通过与死亡受体DR5结合以及caspase-8与DR5的募集来形成（诱导死亡诱导信号复合物），从而引起了跟踪诱导的细胞凋亡。在椎间盘中，caspase-8形成二聚体，然后在蛋白水解的启动中开始蛋白水解。我们的初步研究表明，caspase-8二聚化和裂解被抑制在耐踪迹胶质母细胞瘤细胞中。为了寻找caspase-8抑制中的机制，我们发现了在跟踪处理前形成的与DR5相关的蛋白质复合物，因此我们将其命名为PLAC（配体组装前组合）。我们的初步研究表明，PLAC成分定义了椎间盘的后续形成，从而控制了caspase-8二聚和切割。具体而言，初步研究鉴定了PLAC中的RIP（受体相互作用蛋白）和A20，A20是PLAC中的RIP泛素酶，并表明步道处理在从PLAC到圆盘的轨迹形成过程中导致裂纹泛素化和caspase-8抑制作用。因此，我们假设A20介导的RIP泛素化抑制了caspase-8二聚化和裂解。为了检验这一假设，我们将将A20的作用定义为RIP泛素连接酶，确定附着在RIP上的多泛素链，并识别caspase-8上的多泛素结合结构域。此外，我们将从患者的胶质母细胞瘤中产生小鼠异种移植物和原发性培养物，并确定A20是否在肿瘤中过表达，从而定义了肿瘤中的越野阻力。完成后，这项研究将识别A20是一种治疗靶标，从而通过开发可以针对A20抑制性机制来克服肿瘤耐肿瘤治疗的联合疗法来使人类健康受益。公共卫生相关性：该提案的目的是发展作为治疗胶质母细胞瘤的治疗剂的进攻。该提案将产生重大的结果，对人类胶质母细胞瘤的临床治疗（人类最致命的人类癌症之一）的临床治疗产生重大影响。