Department of Neurosurgery, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China.
Institute of Translational Medicine, Nanhai Hospital, Southern Medical University, Foshan, Guangdong 528244, China.
Cytokine. 2019 Apr;116:78-87. doi: 10.1016/j.cyto.2019.01.005. Epub 2019 Jan 24.
The serine/threonine kinase IKBKE is frequently overexpressed or activated in a variety of human cancers. Ectopic expression of IKBKE induces malignant transformation, cell migration, invasion and chemoresistance. Thus, IKBKE is an attractive target for anti-cancer drug development.
By screening of NCI Diversity Set and Clinical Collection I and II compound libraries using cell-based assay, we identified several candidates of IKBKE inhibitors, which directly inhibited IKBKE kinase activity in vitro and in vivo. One of them, malachite green oxalate (MCCK1), was further characterized. The mechanism was examined by western blot, immunoprecipitation (IP) and Immunofluorescence. We also evaluated in a mouse xenograft model. In vitro kinase assay and luciferase reporter assay were also performed in our experiments.
MCCK1 inhibits IKBKE kinase as well as its downstream targets such as IκBα, p65 and IRF3. MCCK1 is a selective inhibitor for IKBKE, with moderate effect on TBK1, but does not inhibit the activation of IKKα/β, STAT3, Erk-1/2, p38 or JNK. The inhibition of IKBKE by MCCK1 resulted in induction of cell growth arrest and apoptosis selectively in human cancer cells that harbor aberrant expression of IKBKE. Furthermore, MCCK1 inhibits tumor growth in nude mice of human cancer cells in which IKBKE is elevated but not of those cancer cells in which it is not.
These data indicate that MCCK1 is an IKBKE inhibitor with anti-tumor activity in vitro and in vivo and could be a potential anti-cancer agent for patients with tumors over expressing IKBKE.
丝氨酸/苏氨酸激酶 IKBKE 在多种人类癌症中经常过表达或激活。IKBKE 的异位表达诱导恶性转化、细胞迁移、侵袭和化疗耐药。因此，IKBKE 是抗癌药物开发的一个有吸引力的靶点。
通过使用基于细胞的测定法筛选 NCI 多样性集和临床收集 I 和 II 化合物文库，我们鉴定了几种 IKBKE 抑制剂的候选物，这些抑制剂可直接在体外和体内抑制 IKBKE 激酶活性。其中之一，孔雀石绿草酸盐（MCCK1），进一步进行了表征。通过 Western blot、免疫沉淀（IP）和免疫荧光检测来研究其机制。我们还在小鼠异种移植模型中进行了评估。在我们的实验中还进行了体外激酶测定和荧光素酶报告基因测定。
MCCK1 抑制 IKBKE 激酶及其下游靶标，如 IκBα、p65 和 IRF3。MCCK1 是 IKBKE 的选择性抑制剂，对 TBK1 有中等抑制作用，但不抑制 IKKα/β、STAT3、Erk-1/2、p38 或 JNK 的激活。MCCK1 对 IKBKE 的抑制导致在异常表达 IKBKE 的人类癌细胞中选择性诱导细胞生长停滞和凋亡。此外，MCCK1 抑制裸鼠中 IKBKE 升高的人类癌细胞的肿瘤生长，但不抑制其不升高的癌细胞的肿瘤生长。
这些数据表明，MCCK1 是一种具有体内外抗肿瘤活性的 IKBKE 抑制剂，可能是表达 IKBKE 的肿瘤患者的潜在抗癌药物。
