Sulfhydryl switches and free-radical scavenger involveme

巯基开关和自由基清除剂涉及

• 批准号: 6952165
• 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/6952165
• 关键词: AP1 protein; HeLa cells; NAD(P)H oxidoreductase; cell growth regulation; cytotoxicity; free radical scavengers; glycolysis; neoplastic cell; nuclear factor kappa beta; oxidation reduction reaction; oxidative stress; radiation sensitivity; thioredoxin; transcription factor

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.

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节对肿瘤细胞对氧化应激反应的影响。 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，因此我们研究了该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）。因此，包括TR和TRX在内的氧化还原敏感性信号通路可能代表了介入治疗的可行治疗分子靶点，这些靶点可以增强肿瘤对氧化损伤的反应。