Carmody Leigh, Germain Andrew, Morgan Barbara, VerPlank Lynn, Fernandez Cristina, Feng Yuxiong, Perez Jose, Dandapani Sivaraman, Munoz Benito, Palmer Michelle, Lander Eric S., Gupta Piyush B., Schreiber Stuart L.
The Broad Institute Probe Development Center, Cambridge, MA
The Whitehead Institute, Cambridge, MA
Cancer stem cells (CSCs), which drive tumor growth, are known to be resistant to standard chemotherapy and radiation treatment. This raises a significant unmet need to find therapies that can target CSCs within tumors because these cells are responsible for recurrence, the primary cause of patient mortality. However, one of the technical challenges of working with CSCs is that they are not stable outside the tumor environment and are not easy to grow in culture media. Hence, stable sibling cell lines that were induced into epithelial-to-mesenchymal transdifferentiation (EMT) to stably propagate CSC-enriched populations were used to screen a library of 300,718 compounds from the Molecular Libraries Small Molecule Repository (MLSMR). Several classes of selective inhibitors of CSCs were identified. The use of isogenic control cell lines for the secondary validation assays minimized the probability of false hits advancing along the critical path to probe development. Of these, 19 compounds were chosen based on their selectivity, potency, and chemical tractability and were retested in the primary screen and secondary assays. Three scaffolds were prioritized to develop potential probes. One of these compounds (ML243) displayed greater than 32-fold selective inhibition of the breast CSC-like cell line (HMLE_shECad) over the control cell line (HMLE_shGFP). The probe (ML243) was screened against a panel of 68 targets that are commonly used in drug discovery for lead profiling and found active in only one assay.
癌症干细胞（CSCs）驱动肿瘤生长，已知其对标准化疗和放射治疗具有抗性。这引发了一个重大的未满足需求，即需要找到能够靶向肿瘤内CSCs的疗法，因为这些细胞是复发的原因，而复发是患者死亡的主要原因。然而，研究CSCs的技术挑战之一是它们在肿瘤环境之外不稳定，并且在培养基中不易生长。因此，利用诱导上皮-间质转化（EMT）以稳定增殖富含CSC的群体的稳定同基因细胞系，对来自分子文库小分子储存库（MLSMR）的300,718种化合物文库进行筛选。鉴定出了几类CSCs的选择性抑制剂。在二级验证试验中使用同基因对照细胞系，将沿着关键路径推进到探针开发的假阳性命中概率降至最低。其中，根据其选择性、效力和化学可处理性选择了19种化合物，并在初次筛选和二级试验中重新测试。确定了三种支架以开发潜在的探针。这些化合物之一（ML243）对乳腺CSC样细胞系（HMLE_shECad）的选择性抑制作用比对对照细胞系（HMLE_shGFP）高32倍以上。针对药物发现中常用于先导物分析的一组68个靶点对该探针（ML243）进行筛选，发现其仅在一项试验中有活性。
