Modification of hyperthermia response

这个转化研究项目在当前的资助周期中取得了重要发现。在低pH下生长的黑素瘤细胞主要依赖于单羧酸转运蛋白（MCT）而不是NHE 1来调节细胞内pH，没有表现出Crabtree效应，并且上调负责增强细胞骨架稳定性和耐热性的应激蛋白HSP 27和70。在存在过量葡萄糖和呼吸抑制剂的情况下，黑素瘤异种移植物被急性酸化0.5-0.7 pH单位，pO 2增加。正常组织不受影响。研究发现，热激活一个检查点，通过反式作用因子核仁素抑制DNA复制，核仁素是调节复制蛋白A（RPA）活性的核仁的关键成分。核仁素从核仁移位以促进与RPA的相互作用。这些发现支持了该项目的总体假设，即在低pH下生长提供了肿瘤特有的机制，通过该机制，黑色素瘤可以通过化学手段对pH依赖性治疗剂（如热疗）选择性致敏。长期目标是通过高血糖安全产生的乳酸酸中毒急性酸化与呼吸或乳酸转运抑制剂联合，使黑色素瘤对热放疗敏感。通过四个互动项目和两个核心，该计划将：开发方法，使黑色素瘤异种移植物对体内热放疗敏感（项目1）;开发NMR技术，以提供加热和未加热的黑色素瘤异种移植物急性酸化期间pH、23 Nai、葡萄糖代谢、血流和耗氧量的非侵入性分析（项目2，分包：宾夕法尼亚大学）;定义急性酸化引起的热休克蛋白合成下调、高温期间和之后的凋亡杀伤和克隆存活之间的关系（项目3）;阐明暴露于热和急性酸化的细胞中检查点激活的分子机制，作为消除热诱导的细胞凋亡的策略。 检查点响应（项目4，分包：埃森大学）。测量pHe和 将在核心A中进行体外pHi和鉴定抑制在低pH下生长的黑色素瘤细胞中质子转运的新方法，以使所有项目受益。 核心B为所有项目提供生物统计、电子通信和数据管理支持。结果将有助于指导I/II期临床试验，以证明急性酸化对黑色素瘤对高温肢体灌注的反应的影响，并确定酸化和生物能量学的临床适用措施，以预测对高温治疗的反应。

This translational research program made important discoveries during the current funding cycle. Melanoma cells growing at low pH rely primarily on the monocarboxylic acid transporter (MCT) rather than the NHE1 to regulate intracellular pH, do not demonstrate a Crabtree effect, and upregulate stress proteins HSP27 and 70 that are responsible for enhanced cytoskeletal stability and hyperthermia resistance. In the presence of excess glucose and an inhibitor of respiration melanoma xenografts are acutely acidified by 0.5-0.7 pH unit and pO2 increases. Normal tissues are not affected. It was found that heat activates a checkpoint inhibiting DNA replication through a trans-acting factor, nucleolin, a key component of the nucleolus that regulates the activity of replication protein A (RPA). Nucleolin translocates from the nucleolus to facilitate the interaction with RPA. These findings support the global hypothesis of this program that growth at low pH provides a mechanism unique to tumors by which melanoma can be selectively sensitized by chemical means to pH-dependent therapeutic agents such as hyperthermia. The long-range goal is to sensitize melanoma to thermoradiotherapy by acute acidification from lactic acidosis produced safely by hyperglycemia combined with inhibitors of respiration or lactate transport. Through four interactive projects and two cores this program will: Develop methods to sensitize melanoma xenografts to thermoradiotherapy in vivo (Project 1); Develop NMR techniques to provide non-invasive analysis of pH, 23Nai, glucose metabolism, blood flow and oxygen consumption during acute acidification of heated and unheated melanoma xenografts (Project 2, Subcontract: Univ. of Pennsylvania); Define the relationship between downregulation of heat shock protein synthesis by acute acidification, apoptotic killing during and after hyperthermia, and clonal survival (Project 3); and Elucidate the molecular mechanisms underlying checkpoint activation in cells exposed to heat and acute acidification as a strategy to abrogate heat-induced checkpoint response (Project 4, Subcontract: Univ. of Essen). The measurement of pHe and pHi in vitro and the identification of new methods to inhibit proton transport in melanoma cells grown at low pH will be performed in Core A to benefit all projects. Core B provides biostatistical, electronic communication and data management support for all projects. Results will help direct a Phase I/II clinical trial to demonstrate the effects of acute acidification on melanoma response to hyperthermic limb perfusion, and to identify clinically applicable measures of acidification and bioenergetics to predict response to hyperthermic therapy.