Imaging mitochondrial heterogeneity in LKB1 mutant lung cancer

摘要（30行）： R01更新的首要目标是促进我们对LKB 1失活的影响的理解， 对肺癌线粒体生物能量学、代谢和治疗反应的影响。为了实现这一目标，我们 将对肺中LKB 1失活后的线粒体异质性进行结构和功能研究 腺癌（LUAD）。LKB 1肿瘤抑制基因的失活突变经常发生在 LUAD。LKB1作为调节细胞能量学和线粒体功能的主激酶发挥作用 通过激活腺苷一磷酸激活激酶（AMPK）。因此，LKB1突变（LKB1-/-） 导致肺肿瘤的细胞能量学和线粒体稳态的严重缺陷，其特征在于 不同大小、形态和功能的非典型线粒体。然而，在我们的工作中仍然存在差距。 了解LKB1失活如何在生理和机制水平上失调线粒体 结构和功能。为了解决这一差距，我们功能成像LUAD中的线粒体活性， 利用正电子发射断层扫描（PET）成像示踪剂4-[18F]氟苄基-三苯基膦， （18FBnTP），并发现18FBnTP是线粒体生物能量学的体内生物标志物。在此基础上， 我们对肺肿瘤进行了三维扫描电子显微镜（3D SBEM）， 体内线粒体结构。作为我们分析LKB 1 +/+和LKB 1 +/+内线粒体网络的直接结果， 在LKB 1-/-小鼠肺癌模型中，我们发现存在不同的线粒体亚群。 每个线粒体亚群都携带着一套独特的生物能量活动和对生物能量的敏感性。 凋亡重要的是，LKB 1的缺失直接改变了线粒体亚群的结构景观 从而改变肿瘤的功能和代谢状况。我们假设LKB1缺失诱导了 肺肿瘤中线粒体亚群的重塑和空间重组导致 OXPHOS和细胞存活途径。为了验证这一假设，我们将利用PET成像结合3- 三维扫描电子显微镜（3D SBEM）和呼吸测定法研究线粒体 异质性LKB 1突变LUAD。在目标1中，我们将研究mTORC1-Drp1轴作为 肺肿瘤中LKB 1失活后线粒体分裂和嵴重塑。在目标2中， 研究LKB1/AMPK通路作为一种新的调节peridrolet线粒体和脂肪酸氧化， 肺癌在目标3中，我们将测试新的PTPMT1抑制剂作为化疗增敏剂，以克服治疗 抗LKB 1突变LUAD。拟议中的研究有望推进我们的基本理解 线粒体生物学和线粒体异质性对促进肺肿瘤发生的影响。 拟议的工作与人类健康的成像诊断领域和 开发新的疗法，以改善肺癌患者的治疗和预后。

Abstract (30 line): The overarching goal of this R01 renewal is to advance our understanding of the impact that LKB1 inactivation has on mitochondrial bioenergetics, metabolism and therapy response in lung cancer. To accomplish this we will perform a structural and functional study of mitochondrial heterogeneity following LKB1 inactivation in lung adenocarcinomas (LUADs). Inactivating mutations of the LKB1 tumor suppressor gene frequently occur in LUADs. LKB1 functions as a master kinase that regulates cellular energetics and mitochondrial function through activation of adenosine monophosphate activated kinase (AMPK). As such, LKB1 mutations (LKB1-/-) result in severe defects in the cellular energetics and mitochondrial homeostasis of lung tumors, characterized by atypical mitochondria of varying size, morphology, and function. However, there remains a gap in our knowledge at a physiological and mechanistic level of how LKB1 inactivation disregulates mitochondrial structure and function in LUAD. To address this gap, we functionally imaged mitochondrial activity in LUADs utilizing the positron emission tomography (PET) imaging tracer 4-[18F]fluorobenzyl-triphenylphosphonium (18FBnTP) and found that 18FBnTP is an in vivo biomarker of mitochondrial bioenergetics. Expanding upon this, we performed 3-dimensional scanning blockface electron microscopy (3D SBEM) on lung tumors to map mitochondrial structure in vivo. As a direct result of our analysis of mitochondrial networks within LKB1+/+ and LKB1-/- mouse models of lung cancer we discovered the existence of distinct mitochondrial subpopulations. Each mitochondrial subpopulation carries with it a unique set of bioenergetic activities and sensitivities to apoptosis. Importantly, loss of LKB1 directly alters the structural landscape of mitochondrial subpopulations thus altering the functional, metabolic landscape of the tumor. We hypothesize that LKB1 loss induces remodeling and spatial reorganization of mitochondria subpopulations in lung tumors leading to disregulation of OXPHOS and cell survival pathways. To test this hypothesis we will utilize PET imaging in combination with 3- dimensional scanning blockface electron microscopy (3D SBEM) and respirometry to study mitochondrial heterogeneity LKB1 mutant LUADs. In Aim 1 we will investigate the mTORC1-Drp1 axis as a regulator of mitochondrial fission and cristae remodeling following inactivation of LKB1 in lung tumors. In Aim 2 we will investigate the LKB1/AMPK pathway as a novel regulator of peridroplet mitochondria and fatty acid oxidation in lung cancer. In Aim 3 we will test novel PTPMT1 inhibitors as chemosensitizing agents to overcome therapy resistant LKB1 mutant LUADs. The proposed studies hold promise to advance our fundamental understanding of mitochondrial biology and the impact that mitochondrial heterogeneity has on promoting lung tumorigenesis. The proposed work has relevance to human health in the areas of imaging based diagnosis and the development of new therapies to improve the treatment and outcomes of lung cancer patients.