Department of Pathology, School of Basic Medical Sciences & Sir Run Run Hospital & State Key Laboratory of Reproductive Medicine & Key Laboratory of Antibody Technique of National Health Commission, Nanjing Medical University, Nanjing 211166, Jiangsu, China.
Jiangsu Cancer Hospital, The Affiliated Cancer Hospital of Nanjing Medical University, Jiangsu Institute of Cancer Research, Nanjing 210009, Jiangsu, China.
Theranostics. 2021 Jan 1;11(5):2108-2122. doi: 10.7150/thno.48112. eCollection 2021.
Protein kinases are critical therapeutic targets for curing hepatocellular carcinoma (HCC). As a serine/threonine kinase, the potential roles of serine/threonine kinase 39 (STK39) in HCC remain to be explored. The expression of STK39 was examined by RT-qPCR, western blotting and immunohistochemistry. Cell proliferation and apoptosis were detected by CCK8 and TUNEL kit. Cell migration and invasion assays were performed using a transwell system with or without Matrigel. RNA-seq, mass spectrometry and luciferase reporter assays were used to identify STK39 binding proteins. Here, we firstly report that STK39 was highly overexpressed in clinical HCC tissues compared with adjacent tissues, high expression of STK39 was induced by transcription factor SP1 and correlated with poor patient survival. Gain and loss of function assays revealed that overexpression of STK39 promoted HCC cell proliferation, migration and invasion. In contrast, the depletion of STK39 attenuated the growth and metastasis of HCC cells. Moreover, knockdown of STK39 induced the HCC cell cycle arrested in the G2/M phase and promoted apoptosis. In mechanistic studies, RNA-seq revealed that STK39 positively regulated the ERK signaling pathway. Mass spectrometry identified that STK39 bound to PLK1 and STK39 promoted HCC progression and activated ERK signaling pathway dependent on PLK1. Thus, our study uncovers a novel role of STK39/PLK1/ERK signaling axis in the progress of HCC and suggests STK39 as an indicator for prognosis and a potential drug target of HCC.
蛋白激酶是治疗肝细胞癌（HCC）的关键治疗靶点。丝氨酸/苏氨酸激酶 39（STK39）作为一种丝氨酸/苏氨酸激酶，其在 HCC 中的潜在作用仍有待探索。通过 RT-qPCR、western blot 和免疫组织化学检测 STK39 的表达。通过 CCK8 和 TUNEL 试剂盒检测细胞增殖和凋亡。使用带有或不带有 Matrigel 的 Transwell 系统进行细胞迁移和侵袭实验。RNA-seq、质谱和荧光素酶报告基因实验用于鉴定 STK39 结合蛋白。 在这里，我们首先报告 STK39 在临床 HCC 组织中的表达明显高于相邻组织，高表达 STK39 由转录因子 SP1 诱导，并与患者预后不良相关。获得和缺失功能实验表明，STK39 的过表达促进了 HCC 细胞的增殖、迁移和侵袭。相比之下，STK39 的耗竭减弱了 HCC 细胞的生长和转移。此外，STK39 的敲低诱导 HCC 细胞周期停滞在 G2/M 期并促进凋亡。在机制研究中，RNA-seq 显示 STK39 正向调节 ERK 信号通路。质谱鉴定出 STK39 与 PLK1 结合，STK39 通过 PLK1 促进 HCC 进展并激活 ERK 信号通路。 因此，我们的研究揭示了 STK39/PLK1/ERK 信号轴在 HCC 进展中的新作用，并表明 STK39 可作为预后标志物和 HCC 的潜在药物靶点。
