Novel Targeted Anticancer Agents from Marine Cyanobacteria

描述(申请人提供)：蓝藻是地球上最古老的生物之一，已经进化出用于防御目的的化学武器，我们正在利用这些武器来发现抗癌药物。我们过去的研究表明，海洋蓝藻包含具有异常有效活性的化合物和/或具有新作用机制的不寻常或一流的抑制剂。然而，蓝藻也因产生危害人类健康的毒素和其他一般细胞毒素而臭名昭著。我们的建议解决了天然产物药物发现中的主要问题，包括通过创新的去复制策略和针对关键癌症相关途径的独特的体外细胞和体内生物补充分析集，对那些具有潜在治疗潜力和癌症选择性的化合物进行适当的样本选择和优先排序。靶向通路与生长因子受体活性、血管生成、耐药和转移有关，所有这些都是癌症研究中关注的主要领域。我们开发了新的化学、生化和遗传工具，专门探索我们最近发现的新的作用机制，并确定这些途径的调节器。首先，我们将进行海洋蓝藻的野外采集，并将其提取物进行基于分类学和LC-MS/MS的去复制策略，结合细胞毒性分析。将优先培养蓝藻并建立组分文库。其次，我们将通过使用各种合适的基于人类细胞的模型来评估组分文库的不同细胞毒性，从而实施合理的选择性细胞毒素筛选策略。具体地说，我们将筛选 对结肠癌细胞具有选择性活性的药物，而不是相应的正常细胞，采用机械无偏见的方法。更有针对性的是，我们将筛选通过我们最近验证的机制发挥活性的抗血管生成药物，包括同时下调受体和生长因子。通过使用我们新创建的独特的等基因筛选系统，我们的目标是发现新的转录因子HIF-1和HIF-2的双重抑制物，它们有望与抗血管生成药物联合治疗。按优先顺序排列的部分将接受生物测定指导的分离，结构将 下定决心。第三，我们发现并表征了一种防止转移的新机制，并开发了合适的斑马鱼体内模型，以筛选当作为单一药物或与我们已发现的协同蓝藻化合物联合应用时，调节肿瘤抑制基因E-钙粘附素表达和细胞膜定位的抗侵袭剂。在一种新的斑马鱼肿瘤模型中，将通过监测细胞的扩散、侵袭和转移来评估化合物的抗侵袭特性。第四，我们将对已识别的选择性药物进行机械表征，以确定在癌细胞中诱导的分子变化，并确定潜在的直接靶点。

DESCRIPTION (provided by applicant): Cyanobacteria are among the most ancient organisms on Earth and have evolved chemical weapons for defensive purposes, which we are exploiting for anticancer drug discovery. Our past research has exemplified that marine cyanobacteria contain compounds with exceptionally potent activity and/or possess unusual or first-in-class inhibitors with novel mechanisms of action. However, cyanobacteria are also notorious for producing toxins detrimental to human health and other general cytotoxins. Our proposal addresses main issues in natural products drug discovery, including appropriate sample selection and prioritization for those compounds with promising therapeutic potential and cancer selectivity through innovative dereplication strategies and unique complementary in vitro cellular and in vivo organismal assay sets directed towards key cancer-related pathways. Targeted pathways are related to growth factor receptor activity and angiogenesis, resistance and metastasis, all of which are major areas of concern in cancer research. We have developed new chemical, biochemical and genetic tools to specifically probe novel mechanisms of action that we recently discovered and to identify modulators of these pathways. First, we will carry out field collections of marine cyanobacteria and will subject their extracts to taxonomy- and LC-MS/MS based dereplication strategies in combination with cytotoxicity assays. Prioritized cyanobacteria will be cultured and fraction libraries generated. Second, we will implement a rational screening strategy for selective cytotoxins by assessing differential cytotoxicity of fraction libraries using various suitable human cell-based models. Specifically, we will screen for agents with selective activity against colon cancer cells over the corresponding normal cells, in a mechanistically-unbiased approach. More targeted, we will screen for antiangiogenic agents that exert their activity through a mechanism we recently validated, involving simultaneous downregulation of receptors and growth factors. Through the use of our newly created unique isogenic screening system we then aim to discover novel dual inhibitors of the transcription factors HIF-1 and HIF-2, which have promise for combination therapy with anti-angiogenic agents. Prioritized fractions will be subjected to bioassay-guided isolation and structures will be determined. Third, we have discovered and characterized a novel mechanism to prevent metastasis and developed suitable zebrafish in vivo models to screen for anti-invasive agents that modulate tumor suppressor E-cadherin expression and localization to the cell membrane when applied as single agents or in combination with a synergizing cyanobacterial compound we already discovered. Anti-invasive properties of compounds will be assessed in a new zebrafish tumor model at the single-cell level by monitoring cell dissemination, invasion and metastasis. Fourth, we will mechanistically characterize the identified selective agents to pinpoint the molecular changes induced in the cancer cell and to determine potential direct targets.