SIGNIFICANCE OF BAX/BCL-2 EXPRESSION RATIO DURING APOPTOTIC PATHWAYS OF HUMAN GLIOMA CELLS

BAX/BCL-2 表达比在人胶质瘤细胞凋亡途径中的意义

• 批准号: 11671364
• 负责人: IWAMA Toru
• 金额: $ 1.41万
• 依托单位: GIFU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11671364/
• 关键词: anti-cancer drugs; apoptosis; Bcl-2 family; caspase; ceramide; glioma; sphingomyelinase; p53; Bcl-2 family; 活性酸素; 抗癌剤感受性; 組織学的分化度(悪性度)

Elevation of intracellular ceramide levels has been observed in response to various extracellular stimuli including γ- irradiation, ultraviolet light, and the chemotherapeutic agents and causes apoptosis and/or cell cycle arrest. The addition of exogenous ceramide, such as cell-permeable C2-ceramide, has been associated with several anti proliferative responses including cell differentiation, apoptosis, and cell cycle arrest. Therefore, ceramide has been proposed as a mediator of apoptosis and as a coordinator of the cellular responses to stresses. To date, however, the interrelationship among expression of Bcl-2 family proteins, caspase activation, and ceramide formation has not yet been understood. Therefore, we have attempted to examine their sequential relation in the etoposide-induced glial apoptosis. Subsequently, in the first paper, we have demonstrated that ceramide induces change of the Bax/Bcl-2 ratio, which regulates cytochrome c release from mitochondria, leading to activat … More ion of caspase-9/-3 cascade. Moreover, in the second paper, we further examined the effects of Bcl-2, Bcl-xL, or Bax on the ceramide-mediated apoptotic pathways were examined in glioma cells overexpressing Bcl-2 or Bax. In conclusion, we have shown that Bax promotes apoptosis regardless of ceramide formation and that Bcl-2 or Bcl-xL prevents ceramide formation by repressing neutral sphingomyelinase as well as ceramide-induced cytochrome c release. However, the mechanism of ceramide formation, in other words, the activation of N-SMase by a DNA-damaging agent, etoposide is poorly understood. Therefore, in the third paper, we have examined the functional relationship between p53 and ceramide, and also tested the intermediary roles of ROS between them. Subsequently, we have revealed that p53 modulates intracellular ceramide levels through the formation of ROS in apoptotic human glioma cells. Further investigations regarding the ceramide pathway, especially identification of the upstream and downstream components of the sphingomyelin-ceramide signaling pathway, will lead to better understanding of the molecular mechanism of apoptosis induced by chemotherapeutic agents, and give us a novel approach for the treatment of malignant gliomas. Less

已经观察到细胞内神经酰胺水平的升高响应于各种细胞外刺激，包括γ-照射、紫外线和化疗剂，并引起细胞凋亡和/或细胞周期停滞。外源性神经酰胺，如细胞可渗透的C2-神经酰胺的加入，已与几种抗增殖反应，包括细胞分化，凋亡和细胞周期阻滞。因此，神经酰胺被认为是细胞凋亡的介质和细胞应激反应的协调者。然而，迄今为止，Bcl-2家族蛋白的表达，半胱天冬酶激活和神经酰胺形成之间的相互关系尚未被理解。因此，我们试图研究它们在依托泊苷诱导的胶质细胞凋亡中的顺序关系。随后，在第一篇论文中，我们证明了神经酰胺诱导Bax/Bcl-2比率的变化，该比率调节细胞色素c从线粒体的释放，导致细胞色素c的激活。 ...更多信息 caspase-9/-3级联反应。此外，在第二篇论文中，我们进一步研究了Bcl-2，Bcl-xL或Bax对神经酰胺介导的凋亡途径的影响，在过表达Bcl-2或Bax的胶质瘤细胞中进行了研究。总之，我们已经表明，Bax促进细胞凋亡，而不管神经酰胺的形成和Bcl-2或Bcl-xL阻止神经酰胺的形成，通过抑制中性鞘磷脂酶以及神经酰胺诱导的细胞色素c的释放。然而，神经酰胺形成的机制，换句话说，DNA损伤剂依托泊苷对N-SM酶的激活机制知之甚少。因此，在第三篇论文中，我们研究了p53和神经酰胺之间的功能关系，并测试了ROS在它们之间的中介作用。随后，我们揭示了p53通过在凋亡的人脑胶质瘤细胞中形成ROS来调节细胞内神经酰胺水平。对神经酰胺信号通路的深入研究，尤其是对神经酰胺-鞘磷脂信号通路上下游组分的鉴定，将有助于更好地理解化疗药物诱导细胞凋亡的分子机制，为恶性胶质瘤的治疗提供新的思路。少

项目成果

S Yoshimura,et al: "Ceramid formation leading to caspase-3 activation in hypoxic neuronal death."J Cereb Blood Flow Metab. 19(suppl 1). s71 (1999)

S Yoshimura 等人：“神经酰胺形成导致缺氧神经元死亡中 caspase-3 激活。”J Cereb Blood Flow Metab。

M Sawada, S Nakashima, Y Banno, H Yamakawa, K Takenaka, J Shinoda, Y Nishimura, N Sakai, Y Nozawa: "Influence of Bax or Bcl/2 overexpression on the ceramide-dependent apototic pathway in glioma cells."Oncogene. 19. 3508-3520 (2000)

M Sawada、S Nakashima、Y Banno、H Yamakawa、K Takenaka、J Shinoda、Y Nishimura、N Sakai、Y Nozawa：“Bax 或 Bcl/2 过度表达对神经胶质瘤细胞中神经酰胺依赖性凋亡途径的影响。”癌基因。

M Sawada, et al: "Influence of Bax or Bcl/2 overexpression on the ceramide-dependent apototic pathway in glioma cells."Oncogene. 19. 3508-3520 (2000)

M Sawada 等人：“Bax 或 Bcl/2 过度表达对神经胶质瘤细胞中神经酰胺依赖性凋亡途径的影响。”癌基因。

M Sawada, et al: "p53 regulates ceramide formation by neutral sphingomyelinase through reazive oxygen species in human glioma cells."Oncogene. (in press).

M Sawada 等人：“p53 通过人神经胶质瘤细胞中的活性氧通过中性鞘磷脂酶调节神经酰胺的形成。”癌基因。