Molecular mechanisms of TRAIL resistance in glioblastoma

胶质母细胞瘤TRAIL耐药的分子机制

• 批准号: 8206632
• 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/8206632
• 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）：胶质母细胞瘤是最常见和致命的脑肿瘤，目前尚无治愈方法。在寻找新的治疗药物的过程中，我们发现TRAIL（肿瘤坏死因子相关凋亡诱导配体）可以诱导胶质母细胞瘤细胞的程序性细胞死亡（凋亡），这可能为治疗带来新的希望。 TRAIL因此进入癌症治疗的临床试验。不幸的是，早期的试验报告显示抗肿瘤活性有限，并表明包括胶质母细胞瘤在内的大多数人类癌症对 TRAIL 具有耐药性。因此，当前的研究计划将检查胶质母细胞瘤中 TRAIL 耐药性的分子基础。 TRAIL 诱导的细胞凋亡是通过与死亡受体 DR5 结合并将 caspase-8 募集到 DR5 来形成 DISC（死亡诱导信号复合物）而发生的。在 DISC 中，caspase-8 形成二聚体，然后在程序性细胞死亡的启动中变得具有蛋白水解活性。我们的初步研究表明，TRAIL 耐药的胶质母细胞瘤细胞中 caspase-8 二聚化和裂解受到抑制。在寻找 caspase-8 抑制机制的过程中，我们发现了在 TRAIL 处理之前形成的 DR5 相关蛋白复合物，因此我们将其命名为 PLAC（前配体组装复合物）。我们的初步研究表明，PLAC 成分决定了 DISC 的后续形成，从而控制 caspase-8 二聚化和裂解。具体来说，初步研究鉴定了 PLAC 中的 RIP（受体相互作用蛋白）和 A20（一种 RIP 泛素酶），并表明在 TRAIL 诱导的从 PLAC 到 DISC 的形成过程中，TRAIL 处理导致 RIP 泛素化和 caspase-8 抑制。因此，我们假设 A20 介导的 RIP 泛素化抑制 caspase-8 二聚化和切割。为了检验这一假设，我们将 A20 的作用定义为 RIP 泛素连接酶，确定连接到 RIP 的多聚泛素链并鉴定 caspase-8 上的多聚泛素结合域。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代培养物，并确定 A20 在肿瘤中是否过度表达，从而确定肿瘤中的 TRAIL 耐药性。完成后，这项研究将确定A20作为治疗靶点，通过开发针对A20抑制机制的联合疗法，克服肿瘤对TRAIL治疗的耐药性，从而造福人类健康。公共卫生相关性：该提案的目的是开发 TRAIL 作为治疗胶质母细胞瘤的治疗剂。该提案将产生重大成果，对人类胶质母细胞瘤（最致命的人类癌症之一）的临床治疗产生直接和长期的影响。