Investigation of the contribution of redox stress to the therapy resistance of cells experiencing cycling oxygen levels

缺氧是癌症治疗成功的主要障碍，因为肿瘤缺氧越多，患者的反应就越差。该项目将侧重于循环缺氧的生理相关条件，其中癌细胞经历氧气水平的波动，而不是持续暴露于缺氧。哈蒙德实验室的最新发现表明，细胞对循环缺氧的反应与持续暴露显著不同，这包括循环条件下氧化还原酶变化的贡献。了解生物系统中氧化还原元素的动力学是非常重要的，因为它在基础生物学，农业，疾病和医学中的作用。然而，量化REDOX元素的变化仍然是化学生物学的主要挑战。参与定义细胞REDOX环境的关键要素包括活性氧（ROS）、活性氮（RNS）、含硫分子（包括H2S和谷胱甘肽（GSH））、缺氧（低于正常[O2]）和蛋白质中氨基酸残基的翻译后修饰。这些组分的相对浓度和相互作用定义了细胞的REDOX环境，其通过糖酵解和氧化磷酸化等过程与代谢内在相关。细胞代谢和REDOX状态又与表观遗传调控相关，因为染色质的修饰涉及重要代谢物和REDOX活性分子的消耗。因此，代谢和REDOX环境都可以通过染色质重塑影响转录，因此细胞命运决定与代谢活性和REDOX环境的变化密切相关。该项目将研究循环缺氧中的REDOX应激以及这如何有助于生物反应和对癌症治疗的敏感性。具体的方法将包括，例如，在恒定和循环缺氧中细胞的基因表达分析（RNA-seq）。本项目还将受益于抢先体验Conway实验室生成的探针，这将允许表征REDOX应力。

Hypoxia is a major barrier to successful cancer treatment as the more hypoxic a tumour, the less well patients respond. This project will focus on the physiologically relevant condition of cyclic hypoxia in which cancer cells experience fluctuations in oxygen levels as opposed to constant exposure to hypoxia. Recent findings from the Hammond lab suggest that the cellular response to cyclic hypoxia differs significantly from constant exposure and that this includes the contribution of changes in REDOX in the cyclic conditions. Understanding the dynamics of REDOX elements in biological systems is of major importance because of its roles in basic biology, agriculture, disease and medicine. However, quantifying changes in REDOX elements remains a major challenge for chemical biology. Key elements involved in defining the cellular REDOX environment include reactive oxygen species (ROS), reactive nitrogen species (RNS), sulfur-containing molecules including H2S and glutathione (GSH), hypoxia (lower than normal [O2]), and post-translational modification of amino acid residues in proteins. The relative concentration and interaction of these components defines the cellular REDOX environment, which is intrinsically linked to metabolism through processes such as glycolysis and oxidative phosphorylation. Cellular metabolism and REDOX state are in turn linked to epigenetic regulation, because modifications to chromatin involve consumption of important metabolites and REDOX-active molecules. Consequently, both metabolism and the REDOX environment can affect transcription through chromatin remodelling, and therefore cell fate decisions are closely linked to changes in metabolic activity and the REDOX environment. This project will investigate REDOX stress in cyclic hypoxia and how this contributes to biological response and sensitivity to cancer therapies. Specific approaches will include, for example, gene expression analysis (RNA-seq) of cells in both constant and cyclic hypoxia. This project will also benefit from early access to probes being generated in the Conway lab which will allow characterisation of REDOX stress.