Identification of Novel Cancer Selective Compounds in 3D Tumor Organoid Assays

描述（由申请人提供）：乳腺癌是一种病理和遗传异质性疾病，反映了负责癌症进展的多种信号通路。乳腺癌的体外模型必须将疾病的复杂性与培养方法结合起来，以密切模仿患者所见的不同临床类型的癌症。2007年，乳腺癌新发病例超过178 000例，死亡人数超过40 000人，使其成为妇女癌症相关死亡的第二大原因，这些统计数字表明需要开发更有效的治疗方法（美国癌症协会；http://www.cancer.org）。在过去的十年中，乳腺癌化疗治疗的大多数进展都涉及到剂量的优化和标准治疗方案的安排。一些新的靶向疗法和生物制剂已被批准用于治疗乳腺癌；然而，即使使用理想的药物治疗方案，许多癌症也没有反应或复发。由于特定的分子特征可以将乳腺癌分为具有不同临床特征的多种亚型，我们现在可以追求针对每种肿瘤类型的选择性治疗方法的发展。因此，乳腺癌必须被认为是一种多方面的疾病，每种亚型都为化疗干预提供了独特的机会。我们已经开发了一种新的抗癌药物发现屏幕，包括乳腺癌的细胞和遗传多样性。这种筛选方法的独特之处在于，它使用的小鼠原发肿瘤类器官的分子分类与在患者中观察到的实际乳腺癌亚型相似。利用化学文库对亚型特异性肿瘤类器官进行筛选，以鉴定新的小分子抗癌化合物。同时，这些化合物也被筛选对正常初级类器官的影响。通过这种筛选，我们发现了一种新的小分子C-6，它可以杀死来自小鼠和人类的原发肿瘤组织，随后的结构活性关系分析揭示了该分子的基本药效团。重要的是，C-6对从小鼠和人类患者中分离的基底样和腔内肿瘤类器官具有选择性细胞毒性，但对从正常小鼠和人类组织中分离的类器官没有选择性细胞毒性。该化合物结构新颖，可能通过独特的作用机制杀死肿瘤细胞。我们观察到C-6延缓了正常乳腺类器官腔内上皮细胞的凋亡；但不影响乳腺类器官的分支形态发生。C-6的选择性细胞毒性及其对正常生物过程的最小影响表明，该化合物靶向对乳腺癌细胞稳态至关重要的分子途径。因此，本提案的目标将是建立C-6的最佳药效团结构，确定分子靶点，并评估其在肿瘤和正常细胞中的生物学效应。公共卫生相关性：拟议研究的目标是确定一种名为C-6的新型抗乳腺癌化合物的最佳药效团结构，确定其分子靶点，并使用一种新的肿瘤-类器官测定法评估其在肿瘤和正常细胞中的生物活性。我们的合作研究计划包括C-6的化学和生物学评估，并可能确定一种独特的分子途径，选择性地调节癌症稳态。

DESCRIPTION (provided by applicant): Breast cancer is a pathologically and genetically heterogeneous disease, reflecting diverse signaling pathways responsible for cancer progression. In vitro models of breast cancer must integrate the complex nature of the disease with culturing methods that closely mimic different clinical types of cancer seen in patients. In 2007, there were more than 178,000 new cases and 40,000 deaths from breast cancer, making it the second leading cause of cancer related death in women and these statistics suggest the need for the development of more effective treatments (American Cancer Society; http://www.cancer.org). Over the past ten years, most advances in chemotherapeutic treatment of breast cancer have involved the optimization of doses and scheduling of standard therapeutics. Several new targeted therapies and biologics have been approved for the treatment of breast cancer; however, many cancers do not respond to or recur even with the ideal drug regimens. Because specific molecular signatures can classify breast cancer into multiple subtypes with distinct clinical characteristics, we can now pursue the development of therapeutics with selectiveness against each individual tumor type. Thus, breast cancer must be considered a multifaceted disease with each subtype offering unique opportunities for chemotherapeutic intervention. We have developed a novel anti-cancer drug discovery screen that encompasses the cellular and genetic diversity of breast cancer. This screen is unique in that it uses murine primary tumor organoids molecularly classified as similar to actual breast cancer subtypes observed in patients. The subtype-specific tumor organoids are screened against a chemical library to identify novel small-molecule anti-cancer compounds. In parallel, the compounds are also screened for their effect on normal primary organoids. Using this screen, we identified a novel small molecule, C-6, that kills primary tumor tissue derived from both mice and humans, and subsequent structure activity relationship analyses revealed the basic pharmacophore of the molecule. Importantly, C-6 exhibits selective cytotoxicity against both basal-like and luminal cancer organoids isolated from mice and human patients, but not organoids isolated from normal mice and human tissue. This compound is structurally novel and may kill tumor cells through a unique mechanism of action. We observed that C-6 delays epithelial cell apoptosis within the lumens of normal mammary organoids; however, it did not affect branching morphogenesis of mammary organoids. The selective cytotoxicity of C-6 combined with its minimal affect on normal biological processes suggests that this compound targets a molecular pathway vital to the homeostasis of breast cancer cells. Thus, the objectives outlined in this proposal will establish the optimal pharmacophore structure of C-6, identify the molecular target(s), and evaluate its biological effects in both tumor and normal cells. PUBLIC HEALTH RELEVANCE: The goal of the proposed research is to determine the optimal pharmacophore structure of a novel anti breast cancer compound called C-6, identify its molecular target, and evaluate its biological activity in both tumor and normal cells using a novel tumor-organoid assay. Our collaborative research plan encompasses both the chemical and biological evaluation of C-6, and may identify a unique molecular pathway that selectively regulates cancer homeostasis.