Therapeutic Application of Novel Stat3 Inhibitors in Breast and Pancreatic Cancer

描述（由申请人提供）：项目概述许多人类癌症，包括乳腺癌和胰腺癌，都含有异常的Stat 3，其作为促进肿瘤形成和进展的事件的主要调节因子发挥作用。在小鼠模型中阻断异常Stat 3活性诱导癌细胞生长抑制和凋亡以及肿瘤消退。鉴于具有异常Stat 3活性的人类肿瘤的数量，Stat 3抑制剂作为新型抗癌药物具有很高的商业潜力。此外，有效的和选择性的Stat 3抑制剂将提供优良的分子探针来询问Stat 3信号，以推进我们对该蛋白介导致癌的分子机制的理解，并提供新的方向来阻止异常蛋白的功能。通过利用Stat 3激活的关键结构要求的计算建模，以及NCI多样性和平板集化学文库的计算机筛选，我们鉴定了作为Stat 3-SH 2结构域结合剂和Stat 3 DNA结合活性抑制剂的试剂NSC 42067、NSC 59263和NSC 74859（IC 50为65-86 μ M）。在初步工作中，代理人诱导选择性抗肿瘤细胞的影响和乳腺肿瘤异种移植物的消退，从而提供了探索它们作为分子探针和新型抗癌药物设计的基本原理。虽然预计药物与Stat 3-SH 2结构域相互作用，但Stat 3抑制的确切模式尚不清楚。我们的总体目标是应用综合的多学科方法来批判性地探索这些分子的结构，分子和生物学特性，并利用它们的结构特性来促进设计有效的，选择性的和有效的类似物。我们假设42067、59263、74859或类似物与Stat 3-SH 2结构域相互作用，抑制Stat 3功能，并诱导携带异常Stat 3的肿瘤消退。该假设将通过以下具体目的进行检验：（1）在体外探索42067、59263、74859或类似物与Stat 3的生物化学相互作用。进行与Stat 3相互作用的生物化学，生物物理和结构分析;（2）使用结构信息优化分子以增强效力和选择性。使用目标1的结构信息和建模，以促进更有效的，选择性的，和有效的类似物的设计;（3）定义在乳腺癌和胰腺癌细胞在体外的选择剂的生化，分子和生物学效应;和（4）测试选择剂对乳腺癌和胰腺癌的生长，转移和异种移植血管生成的影响。研究将测量抗肿瘤作用并研究体内潜在的分子机制。这些是重要的研究，将确定药物的分子和生物学特性，并确定具有抗肿瘤活性的强效Stat 3选择性抑制剂，用于开发新型抗癌药物。公共卫生相关性：许多人类癌症具有异常的Stat 3活性，其作为促进肿瘤形成和进展的事件的主要调节剂发挥作用。在小鼠模型中阻断异常Stat 3活性诱导癌细胞生长抑制、凋亡和肿瘤消退。有效的和选择性的Stat 3抑制剂是很好的研究工具，询问Stat 3信号，以促进我们对导致癌症的机制的理解，并代表潜在的新的抗癌药物。我们的提案将新型药物的分子和生物学特性定义为具有抗肿瘤活性并可能适合开发为新型抗癌药物的Stat 3选择性抑制剂。

DESCRIPTION (provided by applicant): Project Summary Many human cancers, including breast and pancreatic cancers, harbor aberrant Stat3 that functions as a master regulator of events that promote tumor formation and progression. Blocking aberrant Stat3 activity induces cancer cell growth inhibition and apoptosis, and tumor regression in mouse models. Given the number of human tumors with aberrant Stat3 activity, there is a high commercial potential for Stat3 inhibitors as novel anticancer drugs. Moreover, effective and selective Stat3 inhibitors will provide excellent molecular probes to interrogate Stat3 signaling to advance our understanding of the molecular mechanisms by which this protein mediates carcinogenesis, and provide new directions to thwart the functions of the aberrant protein. By computational modeling that exploited the key structural requirements for Stat3 activation, together with in silico screening of the NCI's Diversity and Plated sets chemical libraries, we identified agents, NSC 42067, NSC 59263 and NSC 74859, as binders of Stat3-SH2 domain and inhibitors of Stat3 DNA-binding activity (IC50 of 65-86 <M). In preliminary work, agents induced selective antitumor cell effects and breast tumor regression in xenografts, thereby providing the rationale for exploring them as molecular probes and for novel anticancer drug design. While agents are predicted to interact with the Stat3-SH2 domain, the exact mode of Stat3 inhibition is unknown. Our overall objective is to apply an integrated multi-disciplinary approach to critically explore the structural, molecular and biological properties of these molecules and to capitalize on their structural properties to facilitate the design of potent, selective and efficacious analogs. We hypothesize 42067, 59263, 74859, or analogs interact with the Stat3-SH2 domain, inhibit Stat3 function, and induce the regression of tumors harboring aberrant Stat3. The hypothesis will be tested by the following Specific Aims: (1) To probe the biochemical interactions of 42067, 59263, 74859, or analogs with Stat3 in vitro. Perform biochemical, biophysical, and structural analyses of interactions with Stat3; (2) To use structural information to optimize molecules for enhanced potency and selectivity. Use structural information from Aim 1 and modeling to facilitate the design of more potent, selective, and efficacious analogs; (3) To define the biochemical, molecular and biological effects of select agents in breast and pancreatic cancer cells in vitro; and (4) To test select agents for effects on breast and pancreatic tumor growth, metastasis, and angiogenesis in xenografts. Studies will measure antitumor effects and investigate underlying molecular mechanisms in vivo. These are important studies that will define the molecular and biological properties of agents, and identify potent Stat3-selective inhibitors with antitumor activity for development into novel anticancer drugs. PUBLIC HEALTH RELEVANCE: Many human cancers harbor abnormal Stat3 activity that functions as a master regulator of events that promote tumor formation and progression. Blocking abnormal Stat3 activity induces cancer cell growth inhibition, apoptosis, and tumor regression in mouse models. Effective and selective Stat3 inhibitors are excellent research tools to interrogate Stat3 signaling to advance our understanding of the mechanisms leading to cancer, and represent potential new anticancer agents. Our proposal defines the molecular and biological properties of novel agents as Stat3-selective inhibitors that possess antitumor activity and that may be suitable for development into novel anticancer drugs.