Kang Moon-Il, Henrich Curtis J, Bokesch Heidi R, Gustafson Kirk R, McMahon James B, Baker Alyson R, Young Matthew R, Colburn Nancy H
Laboratory of Cancer Prevention, Gene Regulation Section, Molecular Targets Development Program, National Cancer Institute-Frederick, Room 187, Building 567, Frederick, MD 21702, USA.
Mol Cancer Ther. 2009 Mar;8(3):571-81. doi: 10.1158/1535-7163.MCT-08-0811. Epub 2009 Mar 3.
NSC 676914 has been identified as a selective nuclear factor-kappaB (NF-kappaB) inhibitor that does not inhibit cell proliferation. This compound was originally identified in a high-throughput cell-based assay for activator protein-1 (AP-1) inhibitors using synthetic compound libraries and the National Cancer Institute natural product repository. NSC 676914 shows activity against NF-kappaB in luciferase reporter assays at concentrations much less than the IC50 for AP-1. A serum response element reporter used as a specificity control and indicator of cell proliferation was relatively insensitive to the compound. Pretreatment with NSC 676914 is here shown to repress 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced IkappaB-alpha phosphorylation and translocation of p65/50 to the nucleus but not the processing of p52 from p100, suggesting the inhibition of NF-kappaB regulator IKKbeta rather than IKKalpha. Inhibition of NF-kappaB activation occurred as a consequence of blocking phosphorylation of IKK. Induction of IkappaB-alpha phosphorylation by TPA was diminished by pretreatment of NSC 676914 even at 1.1 mumol/L. In contrast, kinases c-Jun-NH2-kinase and extracellular signal-regulated kinases 1 and 2, important for AP-1 activation, showed no significant repression by this compound. Furthermore, a Matrigel invasion assay with breast cancer cell lines and a transformation assay in mouse JB6 cells revealed that TPA-induced invasion and transformation responses were completely repressed by this compound. These results suggest that NSC 676914 could be a novel inhibitor having potential therapeutic activity to target NF-kappaB for cancer treatment or prevention.
NSC 676914已被鉴定为一种选择性核因子-κB（NF-κB）抑制剂，它不会抑制细胞增殖。该化合物最初是在一项基于细胞的高通量检测中被鉴定出来的，该检测使用合成化合物库和美国国立癌症研究所天然产物库来筛选激活蛋白-1（AP-1）抑制剂。在荧光素酶报告基因检测中，NSC 676914对NF-κB的活性浓度远低于其对AP-1的半数抑制浓度（IC50）。用作特异性对照和细胞增殖指标的血清反应元件报告基因对该化合物相对不敏感。本文显示，用NSC 676914预处理可抑制12-O-十四酰佛波醇-13-乙酸酯（TPA）诱导的IκB-α磷酸化以及p65/50向细胞核的转位，但不会抑制p100加工生成p52，这表明其抑制的是NF-κB调节因子IKKβ而非IKKα。NF-κB激活的抑制是由于IKK磷酸化受阻所致。即使在1.1 μmol/L的浓度下，NSC 676914预处理也能减弱TPA诱导的IκB-α磷酸化。相比之下，对AP-1激活很重要的激酶c-Jun氨基末端激酶以及细胞外信号调节激酶1和2，并未受到该化合物的显著抑制。此外，对乳腺癌细胞系进行的基质胶侵袭实验以及对小鼠JB6细胞进行的转化实验表明，该化合物可完全抑制TPA诱导的侵袭和转化反应。这些结果表明，NSC 676914可能是一种新型抑制剂，具有针对NF-κB进行癌症治疗或预防干预的潜在治疗活性。
