Project 2: Exploiting Labile Iron Pools for Improving NSCLC Therapy Using Pharmacological Ascorbate

项目概要/摘要-项目2： 肺癌是美国第二大流行和最致命的癌症[1]。尽管最近 在过去的40年中，5年生存率基本保持不变，为11-17% [2]， 迫切需要采取更多的办法来改善成果。药理学抗坏血酸（P-AscH-;高 剂量静脉注射维生素C）最近再次出现作为一种药剂，增强癌细胞对 在细胞培养和动物模型中的放射和化学疗法。初步数据显示， 以及人非小细胞肺癌（NSCLC）与正常非小细胞肺癌（NSCLC）的化学放射增敏作用。 转化的支气管上皮细胞（HBEpC）用P-AscH处理。然而， 肺癌与正常细胞对P-AscH-的不同易感性尚不清楚。基于强大的预- 来自正在进行的NSCLC临床试验的临床和临床数据，项目2将检验P-AscH- 通过增加癌细胞的稳定性，选择性地使NSCLC细胞对放疗和化疗敏感， 状态水平的H2 O2作为特定的破坏氧化还原活性铁代谢介导的结果， 内源性O2-/H2 O2水平。这一假设将在目标1的临床前模型中进行机制检验 以及在Aim 2的III期不能手术的肺癌患者中进行的1B/2期临床试验。目标1将 在体外和体内确定O2-和H2 O2对氧化还原活性不稳定铁池的差异调节是否导致 铁代谢（即转铁蛋白受体、铁蛋白、Fe-S蛋白）的改变介导P-AscH诱导的 NSCLC与正常肺上皮细胞的放化疗敏感性。目标2将在一个阶段确定 1b/2临床试验，如果联合P-AscH-与放射+ Carbo/Taxol可以增加阶段的治疗效果 IIIA/B类不可手术的NSCLC受试者，通过中位总生存期的延长确定。FDG的生物标志物 通过FDG PET-CT成像、转铁蛋白饱和度、4 HNE修饰的 将在临床试验中确定蛋白质和不稳定铁的循环水平，并与临床相关。 应答该项目的成功完成将定义涉及O2-/H2 O2的生化机制 P-AscH介导的选择性毒性和放-化疗介导的铁代谢破坏， 与正常细胞相比，在NSCLC中的致敏性，以及提供了一个新的范例，使用P-AscH-临床上， 利用癌症与正常细胞代谢的根本差异，以提高分期治疗的疗效 使用传统放化疗的IIIA/B类不可手术肺癌受试者。

Project Summary/Abstract - Project 2: Lung cancer is the second most prevalent and most lethal cancer in the United States [1]. Despite recent advances, 5-year survival has remained essentially unchanged for the last 40 years at 11-17% [2] and additional approaches are urgently needed to improve outcomes. Pharmacological ascorbate (P-AscH-; high dose intravenous vitamin C) has recently re-emerged as an agent that enhances cancer cell responses to radiation and chemotherapy in cell culture and in animal models. Preliminary data show selective toxicity as well as chemo-radiosensitization of human non-small cell lung cancer (NSCLC) versus normal non- transformed bronchial epithelial cells (HBEpC) with P-AscH- treatment. However the mechanisms underlying the differential susceptibility of lung cancer vs. normal cells to P-AscH- are not known. Based on strong pre- clinical and clinical data from an ongoing clinical trial in NSCLC, Project 2 will test the hypothesis that P-AscH- selectively sensitizes NSCLC cells to radiation and chemotherapy by increasing cancer cell steady- state levels of H2O2 as a result of specific disruptions in redox-active iron metabolism mediated by endogenous levels of O2-/H2O2. This hypothesis will be tested mechanistically in preclinical models in Aim 1 as well as in a phase 1B/2 clinical trial in stage III inoperable lung cancer patients in Aim 2. Aim 1 will determine in vitro and in vivo if differential regulation of redox-active labile iron pools by O2- and H2O2 causes alterations in Fe metabolism (i.e. transferrin receptor, ferritin, Fe-S proteins) that mediate P-AscH--induced radio-chemotherapy sensitization in NSCLC vs. normal lung epithelial cells. Aim 2 will determine in a phase 1b/2 clinical trial if combining P-AscH- with radiation + Carbo/Taxol can increase treatment efficacy in stage IIIA/B inoperable NSCLC subjects as determined by increases in median overall survival. Biomarkers of FDG uptake pre- and post-treatment as determined by FDG PET-CT imaging, transferrin saturation, 4HNE-modified proteins, and circulating levels of labile Fe will be determined in the clinical trial and correlated to clinical responses. The successful completion of this project will define biochemical mechanisms involving O2-/H2O2 mediated disruptions in iron metabolism underlying P-AscH--mediated selective toxicity and radio-chemo- sensitization in NSCLC vs. normal cells as well as providing a new paradigm for using P-AscH- clinically to exploit fundamental differences in cancer vs. normal cell metabolism for increasing treatment efficacy in stage IIIA/B inoperable lung cancer subjects using traditional radio-chemotherapies.