Investigating the heterogeneity of glucose transport in lung adenocarcinoma

项目概要/摘要 肺癌是癌症相关死亡的主要原因;肺腺癌（LUAD）是最常见的癌症。 频繁型。LUAD的发病机制知之甚少。我们最近发现钠葡萄糖 转运蛋白2（SGLT 2）是一种以前未被认识的代谢供应系统，在早期- LUAD阶段，并且是肺癌发生所必需的。SGLT 2抑制延长生存期，延迟癌症 在基因工程小鼠模型（GEMM）和患者中， 衍生的LUAD异种移植物（PDX）。癌前病变和早期LUAD表达SGLT 2，但不表达 众所周知的GLUT 1转运蛋白，而更晚期的肿瘤显示SGLT 2的异质性表达 在同一肿瘤的低级别区域和高级别区域的GLUT 1。为什么肿瘤需要从SGLT 2转换为 GLUT 1随着进展？我们的数据表明，这种开关与葡萄糖的重新编程有关。 代谢：SGLT 2+肿瘤使用氧化葡萄糖代谢，GLUT 1+肿瘤使用糖酵解。葡萄糖 摄取可以通过正电子发射断层摄影术（PET）用2-[18F]氟脱氧葡萄糖（FDG）在体内研究， 由GLUT而非SGLT转运，以及甲基4-[18 F]氟脱氧葡萄糖（Me 4FDG），对SGLT具有特异性。 我们将研究LUAD中葡萄糖转运的异质性，以了解LUAD中葡萄糖转运的生物学机制。 目的探讨SGLT 2和GLUT 1表达的调控机制及其意义。在目标1中，我们 通过PET成像表征GEMM和PDX中Me 4FDG+与FDG+肿瘤中的葡萄糖代谢， 呼吸测量、代谢组学、代谢示踪、组织学和转录组学，有或没有CRISPR SGLT 2和GLUT 1敲除或过表达。在目标2中，我们将研究GSK 3激酶的作用， 我们将其鉴定为SGLT 2调节剂，在与细胞周期相关的代谢/分化程序的调节中， 从SGLT 2切换到GLUT 1。在目的3中，我们将研究缺氧在SGLT 2至SGLT 3的转换中的作用。 随着LUAD从高分化发展到低分化，GLUT 1表达，包括FDG 或Me 4FDG摄取与缺氧标志物（F-MISO，pimonidazole），并评估缺氧的影响- SGLT和GLUT依赖性摄取的诱导因子敲除。 这项研究的目的是阐明代谢重编程的新机制 在癌症中：在两种不同的葡萄糖转运蛋白之间切换，癌细胞可以重新定向葡萄糖的代谢命运。 葡萄糖对不同的途径;这一观察具有重要的意义，因为干扰瓦尔堡 已经提出了一种新的癌症治疗方法;癌细胞的能力， 通过转换葡萄糖转运蛋白来改变它们的代谢是一种潜在的靶向耐药机制， 因为存在SGLT 2和GLUT的特异性抑制剂。此外，PET示踪剂的可用性， 选择性测量体内SGLT或GLUT活性（分别为Me 4FDG和FDG）是一种有前途的工具， 表征体内癌症的代谢表型，以预测它们对治疗的反应。

Project Summary/Abstract Lung cancer is the leading cause of cancer-related death; lung adenocarcinoma (LUAD) is the most frequent type. The pathogenesis of LUAD is poorly understood. We recently discovered that sodium-glucose transporter 2 (SGLT2) is a previously unrecognized system of metabolic supply specifically active in early- stage LUAD and required for lung carcinogenesis. SGLT2 inhibition prolongs survival, delays cancer development, and slows tumor growth in genetically engineered murine models (GEMMs) and in patient- derived xenografts (PDXs) of LUAD. Pre-malignant lesions and early-stage LUADs express SGLT2 but not the well-known GLUT1 transporter, whereas more advanced tumors display heterogeneous expression of SGLT2 in low-grade and GLUT1 in high-grade areas of the same tumor. Why do tumors need to switch from SGLT2 to GLUT1 as they progress? Our data suggest that this switch is associated with a reprogramming of glucose metabolism: SGLT2+ tumors use oxidative glucose metabolism, GLUT1+ tumors use glycolysis. Glucose uptake can be studied in vivo by positron emission tomography (PET) with 2-[18F] fluorodeoxyglucose (FDG), transported by GLUTs and not SGLTs, and methyl 4-[18F]fluorodeoxyglucose (Me4FDG), specific for SGLTs. We will investigate the heterogeneity of glucose transport in LUAD, to understand the biological significance and the mechanisms that regulate the expression of SGLT2 and GLUT1. In Aim 1, we will characterize glucose metabolism in Me4FDG+ versus FDG+ tumors in GEMMs and in PDXs by PET imaging, respirometry, metabolomics, metabolic tracing, histology, and transcriptomics, with or without CRISPR knockout or overexpression of SGLT2 and GLUT1. In Aim 2, we will investigate the role of GSK3 kinase, which we identified as an SGLT2 regulator, in the regulation of metabolic/differentiation programs associated with the switch from SGLT2 to GLUT1. In Aim 3, we will investigate the role of hypoxia in the switch from SGLT2 to GLUT1 expression as LUAD progresses from well- to poorly differentiated, including correlation between FDG or Me4FDG uptake with markers of hypoxia (F-MISO, pimonidazole), and evaluation of the effect of hypoxia- inducible factors knockout on SGLT- and GLUT-dependent uptake. The goal of the proposed research is the elucidation of a novel mechanism of metabolic reprogramming in cancer: switching between two different glucose transporters, cancer cells can redirect the metabolic fate of glucose towards different pathways; this observation has important implications as interfering with the Warburg effect or with glucose transport has been proposed as a novel therapy for cancer; the ability of cancer cells to change their metabolism by switching glucose transporters is a potentially targetable mechanism of resistance, as there are specific inhibitors of both SGLT2 and GLUT. Moreover, the availability of PET tracers that can selectively measure SGLT or GLUT activity in vivo (Me4FDG and FDG, respectively) is a promising tool for characterizing the metabolic phenotype of cancers in vivo, in order to predict their response to treatments.