(PQ9) Prevention of Bleomycin-induced Pulmonary Toxicity by Dichloroacetate (DCA)

项目总结 博莱霉素已被证明是治疗各种人类癌症的有效化疗药物， 特别是与其他药剂联合使用时，治愈率可达90%。然而，它的功效是 因其严重的肺部毒性而显著受阻。接受博莱霉素治疗的癌症患者中有10%发生 致命的肺纤维化。目前还没有治疗肺纤维化的有效方法。博莱霉素诱导 肺纤维化的特征是肌成纤维细胞的激活，进而产生过量的 细胞外基质。缺氧是严重组织损伤的一个重要组成部分，如纤维化，原因是 破坏血管系统，增加高代谢需求的浸润性细胞的氧气消耗。 对缺氧的重塑反应主要受缺氧诱导因子-1(HIF-1)控制。缺氧诱导因子-1 信号转导与严重的组织损伤和纤维化有关，然而，调节 成纤维细胞/肌成纤维细胞在低氧微环境下对纤维化进展的贡献 人们对此了解甚少。我们试图确定成纤维细胞缺氧信号与血管紧张素转换酶之间的关系。 利用HIF-1α基因条件性敲除系统研究肺纤维化 在成纤维细胞中特定地被消融，成纤维细胞是参与肺纤维化发病的基本细胞。 成纤维细胞特异性HIF-1α缺失或药物抑制HIF-1α靶标丙酮酸脱氢酶 激酶1(PDK1)，一种通过抑制线粒体来增强细胞糖酵解通量的线粒体激酶 呼吸，导致博莱霉素诱导的肌成纤维细胞活化和纤维化显著减少 进步。二氯乙酸酯(DCA)是一种PDK抑制剂，有效地抑制了纤维化的进展。这些 这些发现使我们假设成纤维细胞HIF-1/PDK轴通过以下途径促进纤维化进展 PDK介导的糖酵解代谢重编程可作为治疗靶点 抗肺纤维化毒性。为了测试这一点，Aim 1将确定成纤维细胞HIF-1/PDK介导的 糖酵解重编程促进肌成纤维细胞的激活和分化。利用肿瘤/肺 纤维化模型，Aim 2也将表征博莱霉素和DCA潜在的协同抗癌活性 AS、DCA的抗肝纤维化作用。我们提议的研究将专门描绘成纤维细胞缺氧 反应，重点是HIF-1/PDK在纤维化过程中介导的代谢重编程。这 成纤维细胞中以前未被描述的代谢改变可以被用作一种新的治疗策略 预防肺部毒性和纤维化，特别是考虑到DCA已经成功和安全地应用于 患有代谢紊乱30多年的人类，最近正在接受针对癌症的评估 新陈代谢，这使博莱霉素治疗的癌症患者的临床应用更加合理。本研究 将导致更有效和更安全的博莱霉素联合方案的创新设计在一些 通过提高抗癌效果，同时防止其致命的肺部副作用来治疗人类癌症。

PROJECT SUMMARY Bleomycin has proven to be an effective chemotherapeutic agent for the treatment of various human cancers, particularly when combined with other agents, and can achieve up to 90% cure rate. However, its efficacy is significantly hampered by its serious pulmonary toxicity. 10% of cancer patients treated with bleomycin develop fatal pulmonary fibrosis. No effective therapy for pulmonary fibrosis is currently available. Bleomycin-induced pulmonary fibrosis is characterized by myofibroblastic activation, which in turn, produces excessive amounts of extracellular matrix. Hypoxia is a prominent component of severe tissue injuries, such as fibrosis, due to damaged vasculature and increased oxygen consumption from infiltrated cells with high metabolic demands. The remodeling response to hypoxia is controlled primarily by hypoxia-inducible factor-1 (HIF-1). HIF-1 signaling has been implicated in severe tissue injury and fibrosis, yet, molecular mechanisms that regulate the contributions of fibroblasts/myofibroblasts to fibrotic progression in the context of the hypoxic microenvironment are poorly understood. We sought to determine the relationship between fibroblast hypoxic signaling and the development of pulmonary fibrosis utilizing a conditional knock-out system in which the Hif-1α gene is specifically ablated in fibroblasts, the essential cells contributing to the pathogenesis of pulmonary fibrosis. Fibroblast-specific Hif-1α deletion or pharmacological inhibition of HIF-1α target, pyruvate dehydrogenase kinase1 (PDK1), a mitochondrial kinase that enhances cellular glycolytic flux by suppressing mitochondrial respiration, resulted a significant reduction of bleomycin-induced myofibroblast activation and fibrotic progression. Dichloroacetate (DCA), a PDK inhibitor, effectively suppresses fibrotic progression. These findings lead us to hypothesize that fibroblast HIF-1/PDK axis promotes the profibrotic progression by PDK-mediated glycolytic metabolic reprogramming, which can exploited as a therapeutic target against pulmonary fibrotic toxicity. To test this, Aim 1 will determine if fibroblast HIF-1/PDK-mediated glycolytic reprogramming promotes myofibroblastic activation and differentiation. Utilizing a tumor/pulmonary fibrosis model, Aim 2 will characterize potential synergistic anti-cancer activity of bleomycin and DCA, as well as, the anti-fibrotic effects of DCA. Our proposed study will specifically delineate the fibroblast hypoxic response with emphasis on HIF-1/PDK–mediated metabolic reprogramming in the fibrogenic process. This previously undescribed metabolic alteration in fibroblasts can be exploited as a novel therapeutic strategy for preventing pulmonary toxicity and fibrosis especially given that DCA has been used successfully and safely on humans with metabolic disorders for more than 30 years, and is recently being evaluated for targeting cancer metabolism, which rationalizes a facilitated clinical application for bleomycin-treated cancer patients. This study will lead to the innovative design of more effective and safer bleomycin combinational regimens in a number of human cancers by improving anti-cancer effects and preventing its fatal pulmonary side effects simultaneously.