Diez-Cecilia Elena, Carson Robert, Kelly Brendan, van Schaeybroeck Sandra, Murray James T, Rozas Isabel
School of Chemistry, Trinity Biomedical Sciences Institute, Trinity College Dublin, 152-160 Pearse Street, Dublin 2, Ireland.
Drug Resistance Group, Centre for Cancer Research and Cell Biology, 97 Lisburn Road, Belfast BT9 7BL, UK.
Bioorg Med Chem Lett. 2015 Oct 1;25(19):4287-92. doi: 10.1016/j.bmcl.2015.07.082. Epub 2015 Aug 18.
Mutations in the Ras-pathway occur in 40-45% of colorectal cancer patients and these are refractory to treatment with anti-EGFR-targeted therapies. With this in mind, we have studied novel guanidinium-based compounds with demonstrated ability to inhibit protein kinases. We have performed docking studies with several proteins involved in the Ras-pathway and evaluated 3,4'-bis-guanidinium derivatives as inhibitors of B-Raf. Compound 3, the most potent in this series, demonstrated strong cytotoxicity in (WT)B-Raf colorectal cancer cells and also cells with (V600E)B-Raf mutations. Cell death was induced by apoptosis, detected by cleavage of PARP. Compound 3 also potently inhibited ERK1/2 signalling, inhibited EGFR activation, as well as Src, STAT3 and AKT phosphorylation. Mechanistically, compound 3 did not inhibit ATP binding to B-Raf, but direct assay of B-Raf activity was inhibited in vitro. Summarizing, we have identified a novel B-Raf type-III inhibitor that exhibits potent cellular cytotoxicity.
40%-45%的结直肠癌患者存在Ras通路突变，这些患者对抗表皮生长因子受体（EGFR）靶向治疗耐药。鉴于此，我们研究了具有蛋白激酶抑制能力的新型胍基化合物。我们对几种参与Ras通路的蛋白质进行了对接研究，并评估了3,4'-双胍基衍生物作为B-Raf抑制剂的效果。该系列中活性最强的化合物3在野生型（WT）B-Raf结直肠癌细胞以及携带（V600E）B-Raf突变的细胞中均表现出强大的细胞毒性。通过聚ADP核糖聚合酶（PARP）裂解检测发现，细胞死亡是由凋亡诱导的。化合物3还能有效抑制细胞外信号调节激酶1/2（ERK1/2）信号传导、EGFR激活以及Src、信号转导和转录激活因子3（STAT3）和蛋白激酶B（AKT）磷酸化。从机制上讲，化合物3不抑制ATP与B-Raf的结合，但在体外直接检测时其对B-Raf活性有抑制作用。综上所述，我们鉴定出一种新型的B-Raf III型抑制剂，它具有强大的细胞毒性。
