Serine protease 14 (Prss14)/epithin is a transmembrane serine protease that plays essential roles in tumor progression and metastasis and therefore is a promising target for managing cancer. Prss14/epithin shedding may underlie its activity in cancer and worsen outcomes; accordingly, a detailed understanding of the molecular mechanisms in Prss14/epithin shedding may inform the design of future cancer therapies. On the basis of our previous observation that an activator of PKC, phorbol 12-myristate 13-acetate (PMA), induces Prss14/epithin shedding, here we further investigated the intracellular signaling pathway involved in this process. While using mitogen-activated protein kinase inhibitors to investigate possible effectors of downstream PKC signaling, we unexpectedly found that an inhibitor of c-Jun N-terminal kinase (JNK), SP600125, induces Prss14/epithin shedding even in the absence of PMA. SP600125-induced shedding, like that stimulated by PMA, was mediated by tumor necrosis factor-α-converting enzyme. In contrast, a JNK activator, anisomycin, partially abolished the effects of SP600125 on Prss14/epithin shedding. Moreover, the results from loss-of-function experiments with specific inhibitors, short hairpin RNA-mediated knockdown, and overexpression of dominant-negative PKCβII variants indicated that PKCβII is a major player in JNK inhibition- and PMA-mediated Prss14/epithin shedding. SP600125 increased phosphorylation of PKCβII and tumor necrosis factor-α-converting enzyme and induced their translocation into the plasma membrane. Finally, in vitro cell invasion experiments and bioinformatics analysis of data in The Cancer Genome Atlas breast cancer database revealed that JNK and PKCβII are important for Prss14/epithin-mediated cancer progression. These results provide important information regarding strategies against tumor metastasis.

中文翻译：

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JUN N末端激酶抑制剂通过蛋白激酶CβII诱导癌症相关膜蛋白酶Prss14 / epithin的胞外域脱落。

丝氨酸蛋白酶14（Prss14）/上皮蛋白是一种跨膜丝氨酸蛋白酶，在肿瘤的进展和转移中起着至关重要的作用，因此是治疗癌症的有希望的靶标。Prss14 / epithin脱落可能是其抗癌活性的基础，并恶化了预后。因此，对Prss14 / epithin脱落的分子机制的详细了解可能会为将来的癌症治疗设计提供依据。基于我们先前的观察，PKC的一种活化剂，佛波醇12-肉豆蔻酸酯13-乙酸酯（PMA）诱导Prss14 /蛋白的脱落，在此我们进一步研究了参与该过程的细胞内信号通路。在使用促分裂原激活的蛋白激酶抑制剂研究下游PKC信号转导的可能效应子时，我们意外地发现c-Jun N末端激酶（JNK），SP600125，即使在没有PMA的情况下，也会诱导Prss14 / epithin脱落。像PMA刺激的那样，SP600125诱导的脱落是由肿瘤坏死因子-α转换酶介导的。相反，JNK激活剂茴香霉素可部分消除SP600125对Prss14 / epithin脱落的影响。此外，使用特定抑制剂进行功能丧失实验，短发夹RNA介导的敲除以及显性负性PKCβII变体过表达的结果表明，PKCβII是JNK抑制和PMA介导的Prss14 / epithin脱落的主要参与者。SP600125增加了PKCβII和肿瘤坏死因子-α转化酶的磷酸化，并诱导其向质膜的转运。最后，癌症基因组图谱乳腺癌数据库中数据的体外细胞入侵实验和生物信息学分析表明，JNK和PKCβII对于Prss14 /上皮蛋白介导的癌症进展至关重要。这些结果提供了有关抗肿瘤转移策略的重要信息。