Modification of hyperthermia response

这一翻译研究项目在当前的资助周期中取得了重要发现。在低pH条件下生长的黑色素瘤细胞主要依靠单羧酸转运体(MCT)而不是NHE1来调节细胞内的pH，不表现出克拉布特里效应，并上调与增强细胞骨架稳定性和耐热性有关的应激蛋白HSP27和70。在过量葡萄糖和呼吸抑制剂存在的情况下，移植的黑色素瘤细胞急剧酸化，pH值单位为0.5-0.7，氧分压增加。正常组织不受影响。人们发现，热通过一种反式作用因子核仁素激活一个检查点，抑制DNA复制，核仁素是核仁的关键成分，调节复制蛋白A(RPA)的活性。核仁从核仁移位，以促进与RPA的相互作用。这些发现支持了该计划的全球假说，即低pH生长为肿瘤提供了一种独特的机制，通过该机制，黑色素瘤可以通过化学手段选择性地对依赖于pH的治疗剂(如热疗)增敏。长期目标是通过急性酸化使黑色素瘤对热疗敏感，这种酸化是由高血糖与呼吸或乳酸转运抑制剂联合安全产生的乳酸酸中毒引起的。通过四个互动项目和两个核心，该计划将：开发在体内使黑色素瘤移植瘤对热放射治疗敏感的方法(项目1)；开发核磁共振技术，以提供加热和非加热黑色素瘤移植瘤急性酸化期间的pH、23NaI、葡萄糖代谢、血流和氧气消耗的非侵入性分析(项目2，分包合同：UNIV)。定义急性酸化对热休克蛋白合成的下调、高温过程中和高温后的细胞死亡和克隆存活之间的关系(项目3)；并阐明暴露在高温和急性酸化中的细胞中检查点激活的分子机制作为消除热诱导的策略。 检查点响应(项目4，分包合同：大学埃森)。Phe和Phe的测定 在低pH值下生长的黑色素瘤细胞的体外PHI和抑制质子传输的新方法的鉴定将在核心A中进行，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。结果将有助于指导一项I/II期临床试验，以证明急性酸化对黑色素瘤对肢体热疗的反应的影响，并确定酸化和生物能量学的临床适用措施，以预测热疗的反应。

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.