Deubiquitinating Enzyme USP9X Suppresses Tumor Growth via LATS Kinase and Core Components of the Hippo Pathway.
Deubiquitinating Enzyme USP9X Suppresses Tumor Growth via LATS Kinase and Core Components of the Hippo Pathway.
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DOI：
10.1158/0008-5472.can-16-3413
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发表时间：
2017-09-15
期刊：
影响因子：
11.2
通讯作者：
Chan SW
中科院分区：
文献类型：
--
作者：
Toloczko A;Guo F;Yuen HF;Wen Q;Wood SA;Ong YS;Chan PY;Shaik AA;Gunaratne J;Dunne MJ;Hong W;Chan SW
Hippo肿瘤抑制途径的核心LATS激酶磷酸化并抑制下游转录共激活因子雅普和TAZ，其涉及各种癌症。最近的研究已经确定了各种E3泛素连接酶，通过泛素化负调控Hippo途径，但很少有去泛素化酶（DUB）已经牵连。在这项研究中，我们报告DUB USP 9 X是该途径的核心激酶的重要调节因子。USP 9 X与LATS激酶强烈相互作用，并且在较小程度上与WW 45、KIBRA和血管动蛋白相互作用，并且在凝胶过滤色谱分析期间，LATS仅与USP 9 X共迁移。USP 9 X的敲低显著下调LATS并使其不稳定，导致雅普和TAZ的核转位增强，并伴随其靶基因的激活。在不存在USP 9 X的情况下，细胞表现出上皮向间充质转化的表型，在软琼脂中获得非贴壁依赖性生长，并导致扩大、紊乱的三维腺泡。响应于USP 9 X敲低的雅普/TAZ靶基因激活被雅普、TAZ和TEAD 2的敲低抑制。小鼠胚胎成纤维细胞中USP 9 X的缺失导致LATS的显著下调。此外，在胰腺癌组织以及胰腺癌和乳腺癌细胞系中，USP 9 X蛋白表达与LATS正相关，而与雅普/TAZ负相关。总之，这些结果强烈表明USP 9 X增强LATS激酶以抑制肿瘤生长。
The core LATS kinases of the Hippo tumor suppressor pathway phosphorylate and inhibit the downstream transcriptional co-activators YAP and TAZ, which are implicated in various cancers. Recent studies have identified various E3 ubiquitin ligases that negatively regulate the Hippo pathway via ubiquitination, yet few deubiquitinating enzymes (DUB) have been implicated. In this study, we report the DUB USP9X is an important regulator of the core kinases of this pathway. USP9X interacted strongly with LATS kinase and to a lesser extent with WW45, KIBRA, and Angiomotin, and LATS co-migrated exclusively with USP9X during gel filtration chromatography analysis. Knockdown of USP9X significantly downregulated and destabilized LATS and resulted in enhanced nuclear translocation of YAP and TAZ, accompanied with activation of their target genes. In the absence of USP9X, cells exhibited an epithelial-to-mesenchymal transition phenotype, acquired anchorage-independent growth in soft agar, and led to enlarged, disorganized, three-dimensional acini. YAP/TAZ target gene activation in response to USP9X knockdown was suppressed by knockdown of YAP, TAZ, and TEAD2. Deletion of USP9X in mouse embryonic fibroblasts resulted in significant downregulation of LATS. Furthermore, USP9X protein expression correlated positively with LATS but negatively with YAP/TAZ in pancreatic cancer tissues as well as pancreatic and breast cancer cell lines. Overall, these results strongly indicate that USP9X potentiates LATS kinase to suppress tumor growth.