Liu Ge, Bao Yantao, Liu Chaohua, Zhu Qinchang, Zhao Lin, Lu Xiaopeng, Zhu Qian, Lv Yafei, Bai Feng, Wen He, Sun Yujie, Zhu Wei-Guo
Guangdong Key Laboratory of Genome Instability and Human Disease Prevention, Department of Biochemistry and Molecular Biology, Shenzhen University School of Medicine, Shenzhen 518055, China.
Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education, Beijing Key Laboratory of Protein Posttranslational Modifications and Cell Function, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.
Theranostics. 2020 Jan 16;10(5):2358-2373. doi: 10.7150/thno.40397. eCollection 2020.
Invadopodia formation is a key driver of cancer metastasis. The noncanonical IkB-related kinase IKKε has been implicated in cancer metastasis, but its roles in invadopodia formation and colorectal cancer (CRC) metastasis are unclear. : Immunofluorescence, gelatin-degradation assay, wound healing assay and transwell invasion assay were used to determine the influence of IKKε over-expression, knockdown and pharmacological inhibition on invadopodia formation and the migratory and invasive capacity of CRC cells . Effects of IKKε knockdown or pharmacological inhibition on CRC metastasis were examined in mice. Immunohistochemistry staining was used to detect expression levels of IKKε in CRC patient tissues, and its association with prognosis in CRC patients was also analyzed. Immunoprecipitation, western blotting and kinase assay were constructed to investigate the molecular mechanisms. : IKKε co-localizes with F-actin and the invadopodia marker Tks5 at the gelatin-degrading sites of CRC cells. Genetic over-expression/knockdown or pharmacological inhibition of IKKε altered invadopodia formation and the migratory and invasive capacity of CRC cells . , knockdown or pharmacological inhibition of IKKε significantly suppressed metastasis of CRC cells in mice. IKKε knockdown also inhibited invadopodia formation . Clinical investigation of tumor specimens from 191 patients with CRC revealed that high IKKε expression correlates with metastasis and poor prognosis of CRC. Mechanistically, IKKε directly binds to and phosphorylates kindlin-2 at serine 159; this effect mediates the IKKε-induced invadopodia formation and promotion of CRC metastasis. : We identify IKKε as a novel regulator of invadopodia formation and a unique mechanism by which IKKε promotes the metastasis of CRC. Our study suggests that IKKε is a potential target to suppress CRC metastasis.
侵袭伪足的形成是癌症转移的关键驱动因素。非经典的 IkB 相关激酶 IKKε 与癌症转移有关，但其在侵袭伪足形成和结直肠癌（CRC）转移中的作用尚不清楚。采用免疫荧光、明胶降解试验、伤口愈合试验和 Transwell 侵袭试验来确定 IKKε 过表达、敲低和药理抑制对侵袭伪足形成以及 CRC 细胞迁移和侵袭能力的影响。在小鼠中检测 IKKε 敲低或药理抑制对 CRC 转移的影响。采用免疫组织化学染色检测 CRC 患者组织中 IKKε 的表达水平，并分析其与 CRC 患者预后的关系。构建免疫沉淀、蛋白质印迹和激酶试验来研究分子机制。IKKε 与 F-肌动蛋白和侵袭伪足标志物 Tks5 在 CRC 细胞的明胶降解位点共定位。IKKε 的基因过表达/敲低或药理抑制改变了侵袭伪足的形成以及 CRC 细胞的迁移和侵袭能力。此外，IKKε 的敲低或药理抑制显著抑制了 CRC 细胞在小鼠中的转移。IKKε 敲低也抑制了侵袭伪足的形成。对 191 例 CRC 患者的肿瘤标本进行临床研究发现，IKKε 高表达与 CRC 的转移和不良预后相关。机制上，IKKε 直接结合并在丝氨酸 159 位点磷酸化桩蛋白-2；这种作用介导了 IKKε 诱导的侵袭伪足形成和 CRC 转移的促进。我们确定 IKKε 是侵袭伪足形成的新型调节因子，以及 IKKε 促进 CRC 转移的独特机制。我们的研究表明，IKKε 是抑制 CRC 转移的潜在靶点。
