Madoux F, Koenig M, Sessions H, Nelson E, Mercer BA, Cameron M, Roush W, Frank D, Hodder P
Lead Identification Division, Translational Research Institute, Scripps Florida, C130 Scripps Way, Jupiter, Fl, 33458
Department of Chemistry, Scripps Florida, C130 Scripps Way, Jupiter, Fl, 33458
The transcription factor STAT3 (signal transducer and activator of transcription 3) mediates the effects of growth factors and cytokines by regulating gene expression. In many human cancers, including breast and prostate, STAT3 is constitutively active. This leads to increased expression of genes regulating survival and proliferation, and drives the malignant behavior of these cells. As a result, the identification of novel compounds that selectively inhibit STAT3 activity may lead to useful tools to reduce cancer-associated cell proliferation, inflammation, and chemotherapeutic resistance. In this report we describe the identification of a potent and selective STAT3 inhibitor through the use of high throughput screening, synthetic medicinal chemistry, and molecular assays. The novel inhibitor (PubChem CID-2100018) belongs to the thienopyrimidine scaffold and is assigned probe number ML116 within the NIH Molecular Libraries Probe Production Center Network. Probe ML116 exhibits a STAT3 IC50 value of approximately 4 micromolar and does not inhibit the STAT1, STAT5, or NFkB signaling pathways (IC50 values greater than 56 micromolar), as determined using cell-based luciferase reporter assays. Quantitative PCR experiments demonstrated that probe ML116 inhibits transcription of the STAT3-regulated gene BCL3. In contrast, the gene A20 which is regulated by the unrelated transcription factor NF-kB, was not inhibited, further supporting the STAT3 selectivity of this probe. Whereas this compound can induce loss of viability of breast cancer cell lines such as MDA-MB-468 cells that are dependent on STAT3 activity, it displays essentially no toxicity to STAT3-independent SKBR3 breast cancer cells. Similar results were found in ovarian cancer cell lines and multiple myeloma cell lines. Due to the central role of aberrant STAT3 signaling in cancer pathogenesis, this compound may provide a useful starting point for the development of chemical scaffolds to block STAT3 signaling for cancer therapy.
转录因子STAT3（信号转导及转录激活因子3）通过调节基因表达介导生长因子和细胞因子的作用。在包括乳腺癌和前列腺癌在内的许多人类癌症中，STAT3呈组成型激活。这导致调节生存和增殖的基因表达增加，并驱动这些细胞的恶性行为。因此，鉴定选择性抑制STAT3活性的新型化合物可能会带来减少癌症相关细胞增殖、炎症和化疗耐药性的有用工具。在本报告中，我们描述了通过高通量筛选、合成药物化学和分子分析鉴定出一种强效且选择性的STAT3抑制剂。这种新型抑制剂（PubChem CID - 2100018）属于噻吩并嘧啶支架，在国立卫生研究院分子文库探针生产中心网络中被赋予探针编号ML116。使用基于细胞的荧光素酶报告基因检测确定，探针ML116的STAT3 IC50值约为4微摩尔，且不抑制STAT1、STAT5或NFkB信号通路（IC50值大于56微摩尔）。定量PCR实验表明，探针ML116抑制STAT3调节基因BCL3的转录。相比之下，由不相关转录因子NF - kB调节的基因A20未受抑制，进一步支持了该探针的STAT3选择性。虽然这种化合物可诱导依赖STAT3活性的乳腺癌细胞系（如MDA - MB - 468细胞）的活力丧失，但对不依赖STAT3的SKBR3乳腺癌细胞基本无毒性。在卵巢癌细胞系和多发性骨髓瘤细胞系中也发现了类似结果。由于异常的STAT3信号在癌症发病机制中起核心作用，这种化合物可能为开发用于癌症治疗的阻断STAT3信号的化学支架提供有用的起点。
