Moores Cancer Center, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0695, USA.
J Med Chem. 2013 Jun 13;56(11):4206-23. doi: 10.1021/jm301694x. Epub 2013 May 24.
A cell-based high-throughput screen to identify small molecular weight stimulators of the innate immune system revealed substituted pyrimido[5,4-b]indoles as potent NFκB activators. The most potent hit compound selectively stimulated Toll-like receptor 4 (TLR4) in human and mouse cells. Synthetic modifications of the pyrimido[5,4-b]indole scaffold at the carboxamide, N-3, and N-5 positions revealed differential TLR4 dependent production of NFκB and type I interferon associated cytokines, IL-6 and interferon γ-induced protein 10 (IP-10) respectively. Specifically, a subset of compounds bearing phenyl and substituted phenyl carboxamides induced lower IL-6 release while maintaining higher IP-10 production, skewing toward the type I interferon pathway. Substitution at N-5 with short alkyl substituents reduced the cytotoxicity of the leading hit compound. Computational studies supported that active compounds appeared to bind primarily to MD-2 in the TLR4/MD-2 complex. These small molecules, which stimulate innate immune cells with minimal toxicity, could potentially be used as adjuvants or immune modulators.
一种基于细胞的高通量筛选方法，用于鉴定小分子的先天免疫系统刺激物，结果发现取代的嘧啶并[5,4-b]吲哚是有效的 NFκB 激活剂。最有效的先导化合物选择性地刺激人源和鼠源细胞中的 Toll 样受体 4（TLR4）。对嘧啶并[5,4-b]吲哚骨架的羧酰胺、N-3 和 N-5 位进行的合成修饰，揭示了 TLR4 依赖性 NFκB 和 I 型干扰素相关细胞因子的差异产生，分别为白细胞介素 6（IL-6）和干扰素 γ 诱导蛋白 10（IP-10）。具体而言，一组带有苯基和取代苯基羧酰胺的化合物诱导较低的 IL-6 释放，同时保持较高的 IP-10 产生，偏向于 I 型干扰素途径。用短链烷基取代 N-5 降低了主要先导化合物的细胞毒性。计算研究支持活性化合物似乎主要与 TLR4/MD-2 复合物中的 MD-2 结合。这些具有最小毒性的刺激先天免疫细胞的小分子，可能被用作佐剂或免疫调节剂。
