Tumor Gangliosides and TNF Synergize for T Cell Death

肿瘤神经节苷脂和 TNF 协同作用导致 T 细胞死亡

• 批准号: 7007268
• 负责人: CHARLES S. TANNENBAUM
• 金额: $ 26.56万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-15 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7007268
• 关键词: T lymphocyte; apoptosis; biological signal transduction; cell line; cell membrane; clinical research; gangliosides; high performance liquid chromatography; human subject; lipids; mitochondria; neoplasm /cancer immunology; nuclear factor kappa beta; renal cell carcinoma; terminal nick end labeling; tumor necrosis factor alpha

DESCRIPTION (provided by applicant): While there is growing evidence for tumor-associated antigens in renal cell carcinoma (RCC), most spontaneous immune responses to the disease are ineffective at limiting tumor progression. One mechanism by which tumors promote their own progressive growth is by inducing or sensitizing T cells to apoptosis. We recently determined that the ability of several RCC cell lines to mediate significant levels of apoptosis in co-cultured T cells is largely abrogated when the co-incubations are performed either in the presence of neutralizing anti-TNF antibodies, or with ganglioside-depleted tumor cells. This suggestion of a synergistic effect between tumor-derived gangliosides and TNF for inducing T cell apoptosis is corroborated by studies with purified sources of TNF and the RCC-overexpressed ganglioside GM1, which demonstrate similar cooperativity for killing T cells when used together in vitro. Our previous work indicated that select gangliosides can inhibit NFkappaB activation in T cells, thereby sensitizing the lymphocytes to apoptosis by preventing their synthesis of NFkappaB-dependent, anti-apoptotic proteins. The mechanism by which gangliosides cause that defect, and the nature of the second signal actually inducing apoptosis, however, have remained undefined. Preliminary data now suggest that RCC-derived gangliosides and TNF synergize to induce T cell apoptosis by two different mechanisms. We hypothesize that tumor-derived gangliosides disrupt lipid rafts on T cell membranes, preventing effective NFkappaB activation through TNFR1, and hence rendering apoptosis the default pathway induced upon TNF binding. We also have evidence that TNF enhances the effectiveness with which RCC gangliosides induce proapoptotic effects on the mitochondrion, accelerating the onset and intensity of the ROS and MPT mediated by gangliosides alone. The experiments outlined in this proposal will both assess the importance of a TNF/ganglioside synergy to RCC-induced T cell apoptosis, and test our hypothesis that both of the proposed, synergistic mechanisms may be contributing to the T cell dysfunction in RCC.

描述(由申请人提供)：虽然越来越多的证据表明肾细胞癌(RCC)存在肿瘤相关抗原，但大多数对该疾病的自发免疫反应在限制肿瘤进展方面无效。肿瘤促进自身生长的一个机制是通过诱导或敏化T细胞的凋亡。我们最近确定，当几个肾癌细胞系在中和抗肿瘤坏死因子抗体存在的情况下或与去神经节苷脂的肿瘤细胞共同孵育时，在共培养的T细胞中介导显著水平的凋亡的能力在很大程度上被取消。肿瘤源性神经节苷脂和肿瘤坏死因子在诱导T细胞凋亡方面具有协同作用，这一点在对纯化的肿瘤坏死因子来源和肾癌过表达的神经节苷脂GM1的研究中得到了证实，当它们在体外联合使用时，在杀伤T细胞方面表现出类似的协同作用。我们以前的工作表明，选择性神经节苷脂可以抑制T细胞中NFkappaB的激活，从而通过阻止淋巴细胞合成依赖于NFkappaB的抗凋亡蛋白而使其对凋亡敏感。然而，神经节苷脂导致这种缺陷的机制，以及第二种信号实际上诱导细胞凋亡的性质仍然不清楚。目前的初步数据表明，肾癌来源的神经节苷脂和肿瘤坏死因子通过两种不同的机制协同诱导T细胞凋亡。我们假设，肿瘤源性神经节苷脂破坏T细胞膜上的脂筏，通过TNFR1阻止NFkappaB的有效激活，从而使细胞凋亡成为肿瘤坏死因子结合后诱导的默认途径。我们也有证据表明，肿瘤坏死因子增强了肾癌神经节苷脂诱导线粒体促凋亡效应的有效性，加速了神经节苷脂单独介导的ROS和MPT的发生和强度。这项建议中概述的实验将评估肿瘤坏死因子/神经节苷脂协同作用在肾癌诱导T细胞凋亡中的重要性，并验证我们的假设，即这两种协同机制可能是肾癌中T细胞功能障碍的原因。