Identification of novel spermine oxidase (SMOX) inhibitors as probes for an emerging chemoprevention target

炎症/感染与20-30%的上皮癌的起源有关，在许多情况下， 与活性氧（ROS）的产生增加同时发生。然而，精确 将感染/炎症与癌症联系起来的途径尚未明确。我们的数据表明， 多胺分解代谢酶精胺氧化酶（SMOX）通过感染/炎症产生DNA损伤 ROS并引起致癌作用中观察到的变化;抑制SMOX可降低 观察到致癌变化。重要的是，我们有令人信服的数据表明， 由ROS诱导的表观遗传转录沉默。这些数据确定了一种分子途径， 感染/炎症诱导的SMOX活性与致癌作用直接相关，并将SMOX定义为 有吸引力的化学预防目标。SMOX的选择性抑制剂作为研究的探针具有重要价值 炎症/感染诱导的致癌作用，并将保持作为化学预防剂的潜力，但是， 不幸的是，不存在这样的抑制剂。鉴于这些事实，本申请的总体目标是确定 并测试SMOX的选择性抑制剂，这些抑制剂可以作为工具化合物和用于鉴定 化学预防剂以下具体目标旨在实现这些目标。 目标1.利用类似物的化学合成、相似性搜索和 基于结构的设计技术。我们将使用多种药物化学方法来识别和 合成SMOX的潜在抑制剂，然后对所选化合物进行命中-先导优化， 治疗潜力 目标2.评价新合成的化合物选择性抑制SMOX和改变SMOX活性的能力。 细胞反应。这一特定目标的目标是鉴定具有选择性抑制活性的化合物 对密切相关的FAD依赖性胺氧化酶几乎没有或没有抑制活性， 包括MAO和LSD 1。在这个目标中，我们将确定酶抑制动力学曲线， 类似物，我们将确定这些类似物在体外抑制SMOX的细胞效应。 目标3。评价SMOX抑制剂在体内的有效性。由于本提案的主要目的是 确定有效的和选择性的SMOX抑制剂具有潜在的化学预防剂，这是至关重要的 它们在相关致癌模型中表现出有效性。我们将使用ETBF/Min鼠标 结肠肿瘤模型和长爪沙鼠H.幽门螺旋杆菌诱发的胃癌 先前发表的，以确定新鉴定的SMOX抑制剂的体内抗癌有效性。

Inflammation/infection has been implicated in the origin of 20-30% of epithelial cancers and, in many cases, occurs concurrently with increased production of reactive oxygen species (ROS). However, the precise pathways linking infection/inflammation to cancer are not well defined. Our data demonstrate that induction of the polyamine catabolic enzyme spermine oxidase (SMOX) by infection/inflammation produces DNA-damaging ROS and causes changes observed in carcinogenesis; inhibition of SMOX reduces the incidence of the observed carcinogenic changes. Importantly, we have compelling data indicating that the DNA damage induced by ROS leads to epigenetic transcriptional silencing. These data identify a molecular pathway in which infection/inflammation-induced SMOX activity is directly linked to carcinogenesis and define SMOX as an attractive target for chemoprevention. Selective inhibitors of SMOX would be of great value as probes to study inflammation/infection-induced carcinogenesis and would hold potential as chemopreventive agents, but, unfortunately, no such inhibitors exist. In light of these facts, the overall goals of this application are to identify and test selective inhibitors of SMOX that can serve as tool compounds and leads for the identification of chemopreventive agents. The following Specific Aims are designed to pursue these goals. Aim 1. To identify inhibitors of SMOX using chemical synthesis of analogues, similarity searching, and structure-based design techniques. We will use multiple medicinal chemistry approaches to identify and synthesize potential inhibitors of SMOX, followed by hit-to-lead optimization of selected compounds with therapeutic potential. Aim 2. To evaluate newly synthesized compounds for the ability to selectively inhibit SMOX and alter cellular response. The goal of this specific aim is to identify compounds that have selective inhibitory activity against SMOX with little or no inhibitory activity against closely related FAD-dependent amine oxidases, including the MAOs and LSD1. In this aim, we will determine the enzyme inhibitory kinetic profile for selected analogues, and we will determine the cellular effects of SMOX inhibition by these analogues in vitro. Aim 3. To evaluate the effectiveness of SMOX inhibitors in vivo. As the primary purpose of this proposal is to identify effective and selective inhibitors of SMOX that have potential as chemopreventive agents, it is critical that they demonstrate effectiveness in a relevant carcinogenesis model. We will use our ETBF/Min mouse colon tumorigenesis model and a Mongolian gerbil model for H. pylori-induced gastric cancer, as we have previously published, to determine the in vivo anticancer effectiveness of newly identified SMOX inhibitors.