Novel Targeted Anticancer Agents from Marine Cyanobacteria

描述（由申请人提供）：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，我们正在利用它来发现抗癌药物。我们过去的研究表明，海洋蓝藻含有具有特别有效活性的化合物和/或具有不寻常或一流的抑制剂，具有新的作用机制。然而，蓝藻也因产生有害人体健康的毒素和其他一般细胞毒素而臭名昭著。我们的提案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互补的体外细胞和体内有机检测集，对具有治疗潜力和癌症选择性的化合物进行适当的样品选择和优先排序。靶向通路与生长因子受体活性、血管生成、抵抗和转移有关，是癌症研究的主要领域。我们已经开发了新的化学、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剂。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，并结合细胞毒性试验。将培养优先的蓝藻，并生成分数库。其次，我们将利用各种合适的基于人类细胞的模型，通过评估部分文库的差异细胞毒性，实现对选择性细胞毒素的合理筛选策略。具体来说，我们将筛选

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.