Molecular mechanisms and therapeutic targeting of activated NRF2 signaling in MiT/TFE translocation renal cell carcinoma

项目摘要 肾细胞癌（RCC）是全球十大最常见的癌症之一，由多种肿瘤组成。 不同的组织学RCC的一种特别侵袭性的亚型是易位肾细胞癌（tRCC）， 一种破坏性和侵袭性肿瘤，由涉及转录因子的基因融合定义， MiT/TFE基因家族，最常见的是TFE 3。目前，还没有批准的治疗剂， 专门针对tRCC的生物学。此外，我们对TFE 3是如何 融合驱动这种癌症，这代表了一个主要的未满足的医疗需求。我们最近将基因组发现 方法来鉴定可能代表tRCC中新的治疗靶点的基因和/或途径。这些 研究表明，核因子红细胞2相关因子2（NRF 2）通路的激活-一个主要的调节因子 细胞对氧化应激的反应是tRCC的一个定义性特征。有趣的是，在tRCC中，NRF 2激活 发生在没有激活体细胞改变的情况下，这种改变通常在其他癌症中发现， NFE 2L 2（编码NRF 2的基因）的扩增或KEAP 1（NRF 2的负调节子）的失活， 提示tRCC中NRF 2调节的新模式。在这个项目中，我们将探索分子机制， 通过这种方法，NRF 2信号在tRCC中被激活，并且还将建立靶向肿瘤细胞的治疗潜力。 NRF 2在癌症中的作用在目标1中，我们将剖析TFE 3融合体调节细胞凋亡的分子机制。 tRCC中的NRF 2信号传导。我们将检验TFE 3融合蛋白和NRF 2协同调节细胞凋亡的假设。 关键抗氧化基因的表达和功能。我们还将使用无偏见的功能遗传和化学 蛋白质组学方法来鉴定tRCC中TFE 3融合的关键氧化还原敏感效应物。在目标2中，我们将测试 tRCC中NRF 2通路抑制的功能后果和治疗潜力。我们将评估 tRCC肿瘤组织中NRF 2通路活化的蛋白标志物。然后我们将使用遗传和小 分子方法来确定NRF 2抑制是否代表tRCC细胞中的依赖性， 和体内。该项目利用创新的生物化学和功能遗传学方法来阐明 NRF 2信号传导受TFE 3融合调节的机制。更广泛地说，这些研究可能 这对理解NRF 2通路在其他癌症中的调节具有重要意义。该项目还旨在 证明NRF 2通路作为tRCC的治疗靶点，从而推进机制驱动的 有可能改善代表未满足医疗要求的癌症结局的治疗假设 没有既定的护理标准。

PROJECT SUMMARY Renal cell carcinoma (RCC) is one of the top ten most common cancers worldwide and is comprised of multiple distinct histologies. One particularly aggressive subtype of RCC is translocation renal cell carcinoma (tRCC), a devastating and aggressive neoplasm that is defined by a gene fusion involving a transcription factor in the MiT/TFE gene family, most commonly TFE3. Currently, there are no approved therapeutic agents that are specifically targeted to the biology of tRCC. In addition, we have an incomplete understanding of how TFE3 fusions drive this cancer, which represents a major unmet medical need. We recently applied genomic discovery approaches to identify genes and/or pathways that may represent novel therapeutic targets in tRCC. These studies revealed activation of the nuclear factor erythroid 2–related factor 2 (NRF2) pathway – a master regulator of a cell’s response to oxidative stress – to be a defining feature of tRCC. Interestingly, in tRCC, NRF2 activation occurs without the activating somatic alterations in this pathway that are usually found in other cancers, such as amplification of NFE2L2 (the gene encoding NRF2) or inactivation of KEAP1 (a negative regulator of NRF2), suggesting a novel mode of NRF2 regulation in tRCC. In this project, we will explore the molecular mechanisms by which NRF2 signaling is activated in tRCC and will also establish the therapeutic potential of targeting the NRF2 pathway in this cancer. In Aim 1, we will dissect the molecular mechanisms by which TFE3 fusions regulate NRF2 signaling in tRCC. We will test the hypothesis that TFE3 fusions and NRF2 coordinately regulate the expression and function of critical antioxidant genes. We will also use unbiased functional genetic and chemical proteomic approaches to identify critical redox-sensitive effectors of TFE3 fusions in tRCC. In Aim 2, we will test the functional consequences and therapeutic potential of NRF2 pathway inhibition in tRCC. We will assess protein markers of NRF2 pathway activation in tRCC tumor tissue. We will then use both genetic and small molecule approaches to determine whether NRF2 inhibition represents a dependency in tRCC cells both in vitro and in vivo. This project leverages innovative biochemical and functional genetic approaches to clarify the basic mechanisms by which NRF2 signaling is regulated by TFE3 fusions. More broadly, these studies may have implications for understanding how the NRF2 pathway is regulated in other cancers. This project also seeks to credential the NRF2 pathway as a therapeutic target in tRCC, thereby advancing a mechanism-driven therapeutic hypothesis with the potential to improve outcomes in a cancer that represents an unmet medical need with no established standard of care.