Cdc2-like kinase 1 (CLK1) has dual-specificity kinase ability to phosphorylate tyrosine and serine/threonine protein residues. CLK1 regulates many physiological processes and has been shown to contribute to multiple types of cancer. Here, we investigated the functional role of CLK1 during intrahepatic cholangiocarcinoma (ICC) development. The expression of CLK1 was elevated in ICC tumors, and patients with high expression of CLK1 demonstrated poor prognosis. In hydrodynamically transfected mouse models, CLK1 alone was insufficient to induce ICC, whereas CLK1 cooperated with AKT (AKT/CLK1) to trigger ICC initiation. In addition, overexpression of CLK1 in ICC cells facilitated proliferation in vitro and tumor growth in vivo, while loss of CLK1 elicited the opposite effects. Moreover, RNAseq analysis indicated that high levels of CLK1 corresponded with activation of the Hippo-YAP signaling pathway. Consistently, the AKT/CLK1 murine tumors displayed upregulation of YAP as well as its downstream targets. Furthermore, loss or pharmacological inhibition YAP in ICC cells inhibited CLK1-induced growth, and deletion of Yap completely retarded the induction of AKT/CLK1 tumors. Mechanistically, 4D-label free mass spectrometry and co-immunoprecipitation assays revealed WWC2 as a potential mediator of CLK1-YAP cascade. Collectively, the current findings identify a critical role for CLK1 in promoting ICC development and indicate that inhibiting YAP might be an effective approach for perturbing CLK1-mediated tumorigenesis.

中文翻译：

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CLK1 激活 YAP 促进肝内胆管癌生成


Cdc2 样激酶 1 （CLK1） 具有磷酸化酪氨酸和丝氨酸/苏氨酸蛋白残基的双特异性激酶能力。CLK1 调节许多生理过程，并已被证明会导致多种类型的癌症。在这里，我们研究了 CLK1 在肝内胆管癌 （ICC） 发展过程中的功能作用。CLK1 在 ICC 肿瘤中的表达升高，CLK1 高表达的患者预后不良。在流体动力学转染小鼠模型中，单独的 CLK1 不足以诱导 ICC，而 CLK1 与 AKT （AKT/CLK1） 配合触发 ICC 起始。此外，在 ICC 细胞中过表达 CLK1 促进体外增殖和体内肿瘤生长，而 CLK1 缺失则引起相反的作用。此外，RNAseq 分析表明，高水平的 CLK1 与 Hippo-YAP 信号通路的激活相对应。一致地，AKT/CLK1 小鼠肿瘤显示 YAP 及其下游靶标的上调。此外，ICC 细胞中 YAP 的缺失或药理学抑制抑制了 CLK1 诱导的生长，而 Yap 的缺失完全延缓了 AKT/CLK1 肿瘤的诱导。从机制上讲，无 4D 标记质谱和免疫共沉淀测定显示 WWC2 是 CLK1-YAP 级联反应的潜在介质。总的来说，目前的研究结果确定了 CLK1 在促进 ICC 发展中的关键作用，并表明抑制 YAP 可能是扰乱 CLK1 介导的肿瘤发生的有效方法。