Mechanisms by which Proteasome Enhance Apoptosis

蛋白酶体增强细胞凋亡的机制

• 批准号: 6923174
• 负责人: Andrew S Kraft
• 金额: $ 23.94万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2008-02-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6923174
• 关键词: JUN kinase; antineoplastics; apoptosis; athymic mouse; cysteine endopeptidases; drug interactions; enzyme activity; enzyme linked immunosorbent assay; flow cytometry; ligands; membrane proteins; multiple myeloma; neoplasm /cancer chemotherapy; neoplasm /cancer pharmacology; polymerase chain reaction; protease inhibitor; tissue /cell culture; tumor necrosis factor alpha

DESCRIPTION (provided by applicant): The search for more effective chemotherapeutic strategies has resulted in the identification of novel compounds that can overcome the resistance of tumors to cell death; however, these agents are limited in that most are ineffective in the treatment of solid tumors. PS-341, which is a unique inhibitor of the proteasome, has anticancer activity against myeloma cells but does not kill solid tumors. Tumor necrosis factor-related apoptosis inducing ligand (TRAIL) induces apoptosis by ligation of specific receptors; however, most solid tumor cell lines are moderately to completely resistant to this agent. In an attempt to enhance the ability of these agents to kill solid tumors we combined them in non-toxic doses in tissue culture. We observed an extremely high degree of synergism between these agents in their ability to induce apoptosis of tumor cells, including prostate, bladder and colon cancer cell lines, which are resistant to either agent when used individually. Notably, this synergistic apoptosis effect occurs in the presence of expression of resistance genes, e.g., bcl-xL, and in the absence of caspase-9 and Bax. Our preliminary data indicate that the synergism is associated with specific biochemical changes that are induced by treatment with PS-341 treatment. We have shown that the synergistic killing effect requires the presence of Bak protein and that the effects of PS-341 may be secondary to the ability of this compound to elevate the levels of the Dr4 and Dr5 TRAIL receptors, and to increase the levels of the proapoptotic protein, Bim. The goal of this proposal is to investigate the mechanism of action behind this impressive synergy by identifying the mechanisms by which PS-341 regulates: (1) The amount of TRAIL receptors; (2) The activity of the Bak protein; and (3) The levels of Bim. Finally, animal models will be used to evaluate this combination in live hosts. Information generated will facilitate the development of this combined anticancer therapy and shed light on the mechanisms by which solid tumors evade apoptosis thus enabling the design of the next generation of chemotherapeutic agents.

描述（由申请人提供）：寻找更有效的化学治疗策略已导致鉴定出可以克服肿瘤对细胞死亡的抗性的新型化合物。但是，这些药物受到限制，因为大多数药物对实体瘤的治疗无效。 PS-341是蛋白酶体的独特抑制剂，具有对骨髓瘤细胞的抗癌活性，但不会杀死实体瘤。肿瘤坏死因子相关的凋亡诱导配体（TRAIL）通过连接特定受体诱导凋亡。但是，大多数实体瘤细胞系中适度地完全抵抗该药物。为了增强这些药物杀死实体瘤的能力，我们将它们结合在组织培养中的无毒剂量中。我们观察到这些药物之间在诱导肿瘤细胞凋亡（包括前列腺，膀胱和结肠癌细胞系）的能力方面具有极高程度的协同作用，它们在单独使用时对任何一种药物都具有抗性。值得注意的是，这种协同凋亡作用发生在具有抗性基因的表达，例如Bcl-XL，并且在不存在caspase-9和Bax的情况下。我们的初步数据表明，协同作用与PS-341治疗治疗引起的特定生化变化有关。我们已经表明，协同的杀戮效应需要BAK蛋白的存在，并且PS-341的作用可能是该化合物提高DR4和DR5 TRAIL受体水平的能力的继发性，并增加了促凋亡蛋白的水平BIM。 该提案的目的是通过识别PS-341调节的机制来研究这种令人印象深刻的协同作用机理：（1）TRAIL受体的量； （2）BAK蛋白的活性； （3）BIM的水平。最后，动物模型将用于评估活宿主中的这种组合。产生的信息将促进这种联合抗癌疗法的发展，并阐明实体效果逃避凋亡的机制，从而实现下一代化学治疗剂的设计。