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

低氧是癌症治疗成功的主要障碍，因为肿瘤越低氧，患者的反应就越差。这个项目将集中在循环缺氧的生理相关条件上，在这种情况下，癌细胞经历氧气水平的波动，而不是持续暴露在缺氧中。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有很大不同，这包括循环条件下氧化还原反应的变化。由于氧化还原元素在基础生物学、农业、疾病和医学中的作用，了解生物系统中氧化还原元素的动力学具有重要意义。然而，量化氧化还原元素的变化仍然是化学生物学面临的主要挑战。决定细胞氧化还原环境的关键因素包括活性氧簇(ROS)、活性氮簇(RNS)、含硫分子包括硫化氢和谷胱甘肽(GSH)、低氧(低于正常[O2])以及蛋白质中氨基酸残基的翻译后修饰。这些成分的相对浓度和相互作用决定了细胞的氧化还原环境，这与代谢通过糖酵解和氧化磷酸化等过程内在地联系在一起。细胞代谢和氧化还原状态反过来又与表观遗传调节有关，因为染色质的修饰涉及重要代谢物和氧化还原活性分子的消耗。因此，新陈代谢和氧化还原环境都可以通过染色质重塑来影响转录，因此细胞命运的决定与代谢活动和氧化还原环境的变化密切相关。这个项目将研究循环缺氧中的氧化还原压力，以及这如何有助于生物学反应和对癌症治疗的敏感性。具体的方法将包括，例如，对细胞在持续和循环缺氧中的基因表达分析(RNA-seq)。该项目还将受益于及早获得康威实验室产生的探头，这将允许表征氧化还原压力。

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.