Sulfhydryl switches and free-radical scavenger involveme

巯基开关和自由基清除剂涉及

• 批准号: 7291846
• 负责人: David Gius
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7291846
• 关键词: Sulfhydryl; switches; free; radical; scavenger

Rationale: Intracellular redox balance is believed critical to maintaining normal functioning of cells of all types, including regulation of cell cycle progression, proliferation, and response to cytotoxic challenges. Aberrations in redox state have implications for a variety of fields, including aging and cancer progression. One mechanism through which redox state determines stress response is through intracellular signaling. Cysteine amino acid residues present in many peptide chains contain sulfhydryl bonds which behave as redox "switches." These "switches," and the proteins they compose, are activated or suppressed depending on oxidative stimuli, including glucose deprivation, hydrogen peroxide exposure, chemotherapeutic agents treatment, and ionizing radiation (IR) exposure. We investigated the effect of redox signaling factor modulation on the tumor cellular response to oxidative stressors.Research Synopsis: As glycolytic metabolism is essential to maintaining cell function and involves electron transport, we investigated the redox component of this process. Altering glycolysis with a glucose mimetic, 2-deoxy-D-glucose (2DG), in HeLa cells instilled sensitivity to IR, an effect that was reversed by pretreatment with a free radical scavenger, N-acetyl-cyteine (Cancer Res 63: 3413-3417). This result reaffirms the role of electron transfer and redox state in metabolism and cytotoxicity. Additionally, we have recently re-inspected our results involving heat-induced radiosensitization in light of a potential for redox modulation of intracellular pathways. In this case also, heat and radiation appear to instill a unique response to both modalities when administered in close temporal proximity that likely has a large redox component (Mattson et al, accepted for publication). As a corollary of these observations, we attempted to modulate the function of additional redox-responsive elements in tumor cells. When thioredoxin reductase (TR) is activated by redox imbalance, it is able to reduce and activate its client protein, thioredoxin (TRX), which in turn activates redox-sensitive signaling machinery, including AP-1 and NF-kB (Cancer Res 60: 6688-6695 and Oncogene 21: 6317-6327). Additionally, we found differences in transcription factor activation based on genetic and pharmacological models of affecting TR activity. Transcription factor modulation correlates with a variety of physiological effects, include cell cycle progression, apoptosis, necrosis, and oxidative stress survival (Ortiz et al, in preparation). Redox-sensitive signaling pathways, including TR and TRX, may therefore represent viable therapeutic molecular targets for interventional therapy that could enhance the tumor response to oxidative damage.Project Roles: Our work on this project has been performed in close collaboration with Drs. Douglas Spitz (previously of Washington University and recently of the University of Iowa) and Rebecca Aft (Washington University). Four manuscripts depicting our findings have been published or are in press and one is in preparation for submission. I am a contributing author on each of these, due to my active roles in formation of the hypotheses, performing the experiments, presenting preliminary results at scientific conferences, and preparing the results for peer-review.

基本原理：细胞内氧化还原平衡被认为对维持所有类型细胞的正常功能至关重要，包括细胞周期进程、增殖和对细胞毒性挑战的响应的调节。氧化还原状态的异常对各种领域都有影响，包括衰老和癌症进展。氧化还原状态决定应激反应的一种机制是通过细胞内信号传导。存在于许多肽链中的半胱氨酸氨基酸残基含有巯基键，其表现为氧化还原“开关”。这些“开关”及其组成的蛋白质被激活或抑制，取决于氧化刺激，包括葡萄糖剥夺，过氧化氢暴露，化疗药物治疗和电离辐射（IR）暴露。我们研究了氧化还原信号因子调制对肿瘤细胞对氧化应激的反应的影响。研究概要：由于糖酵解代谢对维持细胞功能至关重要，并涉及电子传递，我们研究了这一过程的氧化还原组分。用葡萄糖模拟物2-脱氧-D-葡萄糖（2DG）改变HeLa细胞中的糖酵解，灌输对IR的敏感性，这种作用通过用自由基清除剂N-乙酰基-半胱氨酸预处理而逆转（Cancer Res 63：3413-3417）。这一结果再次证实了电子转移和氧化还原状态在代谢和细胞毒性中的作用。此外，我们最近重新检查了我们的结果，涉及热诱导的放射增敏光的细胞内途径的氧化还原调节的潜力。同样在这种情况下，当在可能具有大的氧化还原组分的时间上接近施用时，热和辐射似乎对两种方式都灌输了独特的反应（Mattson等人，接受出版）。作为这些观察的必然结果，我们试图调节肿瘤细胞中额外的氧化还原反应元件的功能。当硫氧还蛋白还原酶（TR）被氧化还原不平衡激活时，它能够还原并激活其客户蛋白硫氧还蛋白（TRX），这进而激活氧化还原敏感性信号传导机制，包括AP-1和NF-kB（Cancer Res 60：6688-6695和Oncogene 21：6317-6327）。此外，我们发现了基于影响TR活性的遗传和药理学模型的转录因子激活的差异。转录因子调节与多种生理效应相关，包括细胞周期进展、凋亡、坏死和氧化应激存活（Ortiz等，准备中）。氧化还原敏感的信号通路，包括TR和TRX，因此可能代表可行的治疗分子靶点的介入治疗，可以提高肿瘤对氧化damage.Project角色的反应：我们在这个项目上的工作已经进行了密切的合作与博士道格拉斯斯皮茨（以前的华盛顿大学，最近的爱荷华州大学）和丽贝卡Aft（华盛顿大学）。描述我们调查结果的四份手稿已经出版或正在印刷，一份正在准备提交。我是其中每一个的贡献作者，由于我在形成假设，执行实验，在科学会议上提出初步结果，并为同行评审准备结果的积极作用。