Deciphering Mechanisms of Tumor-Stromal Interactions in Prostate Cancer

项目总结/摘要 前列腺癌（PC）影响九分之一的男性，在美国每年造成近30，000人死亡。 了解PC肿瘤微环境（TME）对于优化癌症预防和护理至关重要。 与高度突变的肿瘤细胞不同，TME中的非癌性基质细胞主要由癌细胞组成， 相关成纤维细胞（CAFs）是PC中遗传稳定且有吸引力的治疗靶点， 从基因变化中获得的抵抗力。我们的长期目标是阐明 控制PC生长和进展的基质支持，并确定潜在的药物治疗靶点 破坏肿瘤间质的相互作用。我们最近发现单胺氧化酶B MAOB是一种负责降解单胺神经递质的线粒体氧化酶， 与患者的正常前列腺基质细胞相比，饮食胺在PC基质细胞中高度诱导 样品、PTEN敲除（KO）转基因小鼠和患者来源的CAF的原代培养物。基质MAOB 在疾病向去势抵抗和神经内分泌抵抗的进展过程中， 与初治疾病相比，我们的流行病学研究显示， 用于神经系统疾病如抑郁症的MAOB抑制剂往往具有较低的PC发生率。 功能研究表明，前列腺基质细胞中的MAOB消融显著抑制了共培养的PC 细胞增殖/侵袭和共接种的异种移植物/同种异体移植物前列腺肿瘤生长。机械地说， 基因分析、生物信息学和表型分析表明，基质MAOB增强了细胞反应性， 氧种类（ROS）水平和趋化性/趋化因子分泌，特别是CXCL 13。基于这些新 研究结果，我们假设PC基质细胞中MAOB表达的升高促进了邻近的细胞增殖， 上皮PC的发生和发展，以及基质中靶向MAOB及其下游效应物 细胞是治疗PC的有效策略。在目的1中，我们将确定MAOB在基质中的功能作用。 组织重组异种移植物中的活化及其对肿瘤生长和进展的贡献 免疫受损小鼠和MAOB-KO免疫活性小鼠。在目标2中，我们将研究分子 MAOB介导PC中肿瘤间质通讯的机制，特别是解剖Twist 1 ROS与TGFβ1/Smad 3/4协同激活CXCL 13，以及CXCL 13/CXCR 5旁分泌轴如何参与CXCL 13的表达 影响PC细胞的行为和相关的新的信号通路在MAOB的背景下。我们还将 在大量的人类PC样本中建立我们的机制发现的相关性，并评估 与疾病状态的相关性。在目标3中，我们将评估MAOB抑制剂治疗PC的功效， 包括去势抵抗性PC，在异种移植和同基因小鼠前列腺肿瘤模型中。这些研究 对临床MAOB的未来应用具有巨大的生物学、病理学和临床意义 抑制剂和TME靶向治疗的发展，以补充现有的肿瘤细胞为中心的PC治疗。

Project Summary/Abstract Prostate cancer (PC) affects 1 in 9 men and causes nearly 30,000 yearly deaths in the United States. Understanding the PC tumor microenvironment (TME) is essential for optimizing cancer prevention and care. Unlike highly mutable tumor cells, non-cancerous stromal cells in the TME, consisting primarily of cancer associated fibroblasts (CAFs), are a genetically stable and attractive therapeutic target in PC, with reduced risk of acquired resistance from genetic changes. Our long-term goals are to elucidate the molecular mechanisms governing stromal support of PC growth and progression, and identify potential druggable therapeutic targets in the stromal compartment to disrupt tumor-stromal interactions. We recently found that monoamine oxidase B (MAOB), a mitochondrial oxidative enzyme responsible for degrading monoamine neurotransmitters and dietary amines, is highly induced in PC stromal cells compared to normal prostate stromal cells in patient samples, PTEN-knockout (KO) transgenic mice and primary cultures of patient-derived CAFs. Stromal MAOB expression further increases during disease progression toward castration resistance and neuroendocrine differentiation, compared to hormone-naïve disease. Our epidemiological studies revealed that men taking MAOB inhibitors for neurological disorders such as depression tend to have a lower incidence of PC. Functional studies showed that MAOB ablation in prostate stromal cells profoundly suppressed co-cultured PC cell proliferation/invasion and co-inoculated xenograft/allograft prostate tumor growth in mice. Mechanistically, gene profiling, bioinformatics and phenotypic analyses indicate that stromal MAOB heightens cellular reactive oxygen species (ROS) levels and chemotaxis/chemokine secretion, particularly CXCL13. Based on these new findings, we hypothesize that the elevated expression of MAOB in PC stromal cells promotes adjacent epithelial PC development and progression, and that targeting MAOB and its downstream effectors in stromal cells is an effective strategy to treat PC. In Aim 1, we will determine the functional role of MAOB in stromal activation and its contribution to tumor growth and progression in tissue recombinant xenograft immunocompromised mice and MAOB-KO immunocompetent mice. In Aim 2, we will investigate the molecular mechanism by which MAOB mediates tumor-stromal communication in PC, specifically dissecting how Twist1 cooperates with TGFβ1/Smad3/4 by ROS to activate CXCL13 and how the CXCL13/CXCR5 paracrine axis impacts PC cell behaviors and associated novel signaling pathways in the context of MAOB. We will also establish the relevance of our mechanistic findings in a large collection of human PC samples and assess correlations with disease status. In Aim 3, we will evaluate the efficacy of MAOB inhibitors for treating PC, including castration-resistant PC, in xenograft and syngeneic mouse prostate tumor models. These studies have tremendous biological, pathological and clinical implications for the future application of clinical MAOB inhibitors and development of TME-targeted therapies to complement existing tumor cell-centric PC therapies.