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

项目摘要/摘要-项目2： 肺癌是美国第二大、最致命的癌症[1]。尽管最近 在过去的40年里，5年生存率基本保持在11-17%[2]。 迫切需要采取更多的办法来改善结果。药理抗坏血酸(P-Asch-；高 剂量静脉注射维生素C)最近重新成为一种增强癌细胞对 细胞培养和动物模型中的放射和化疗。初步数据显示选择性毒性为 以及人非小细胞肺癌(NSCLC)与正常非小细胞肺癌(NSCLC)的化疗-放射增敏 用P-Asch处理转化的支气管上皮细胞(HBEpc)。然而，潜在的机制 肺癌细胞和正常细胞对P-Asch-的不同敏感性尚不清楚。基于强大的Pre 来自NSCLC正在进行的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细胞对放射和化疗敏感。 氧化还原活性铁代谢的特定干扰所致的过氧化氢水平 内源O2、-/H2O2水平。这一假设将在目标1的临床前模型中进行机械测试。 以及在AIM 2中对III期不能手术的肺癌患者进行1B/2期临床试验。AIM 1将 体外和体内测定O2、-和H_2O_2对氧化还原活性铁库的不同调节是否导致 铁代谢(转铁蛋白受体、铁蛋白、铁-S蛋白)在P-Asch_2诱导中的变化 非小细胞肺癌与正常肺上皮细胞的放化疗增敏。目标2将在一个阶段确定 1B/2期临床试验：P-Asch-1联合放疗+卡波/紫杉醇可提高分期疗效 IIIA/B不能手术的非小细胞肺癌患者，由中位总生存期的增加决定。FDG的生物标志物 4HNE修饰的FDG PET-CT成像测定治疗前后的摄取、转铁蛋白饱和度 蛋白质和循环中不稳定铁的水平将在临床试验中测定，并与临床相关 回应。该项目的成功完成将确定涉及O2、-/H2O2的生化机制 P-Asch介导的铁代谢紊乱--选择性毒性和放化疗 NSCLC与正常细胞的致敏作用以及为临床使用P-Asch提供了一种新的范例 利用癌症与正常细胞代谢的根本差异，提高分期治疗效果 IIIA/B不能手术的肺癌患者使用传统的放化疗。

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.