The deubiquitinating enzyme PSMD14 facilitates tumor growth and chemoresistance through stabilizing the ALK2 receptor in the initiation of BMP6 signaling pathway.

Although bone morphogenetic protein 6 (BMP6) signaling pathway has been implicated in many types of cancer, its role of tumorigenesis seems to be controversial and its ubiquitin-modifying mechanisms have not been fully addressed. Our study was designed to investigate how BMP6 signaling pathway is regulated by ubiquitin-modifying systems and to address molecular and clinical significance in colorectal cancers. Human deubiquitnase (DUB) siRNA library was used to screen the specific DUB, named PSMD14, involved in BMP6 signaling pathway. Immunoblot, immunoprecipitation and ubiquitination assays were used to analyze targets of the PSMD14. A role of PSMD14-mediated BMP6 signaling pathway for malignant cancer progression was investigated using in vitro and in vivo model of colorectal cancers as well as clinical samples of colorectal cancer patients. The deubiquitinase PSMD14 acts as a positive regulator for the initiation of the BMP6 signaling pathway through deubiquitinating K48-linked ALK2 type I receptor ubiquitination mediated by Smurf1 E3 ligase, resulting in increased stability of the ALK2. This role of PSMD14 is independent of its intrinsic role in the 26S proteasome system. Furthermore, either PSMD14 or ALK2 depletion significantly decreases tumorigenesis of HCT116 colorectal cancer cells in a xenograft model as well as cancer stemness/chemoresistance, and expression of the PSMD14 and ALK2 gene are correlated with malignant progression and the survival of colorectal cancer patients. These findings suggest that the PSMD14-ALK2 axis plays an essential role in initiation of the BMP6 signaling pathway and contributes to tumorigenesis and chemoresistance of colorectal cancers.

Seo D ，Jung SM ，Park JS ，Lee J ，Ha J ，Kim M ，Park SH ... -  《EBioMedicine》

Blockade of deubiquitinating enzyme PSMD14 overcomes chemoresistance in head and neck squamous cell carcinoma by antagonizing E2F1/Akt/SOX2-mediated stemness.

Increasing evidence reveals a close relationship between deubiquitinating enzymes (DUBs) and cancer progression. In this study, we attempted to identify the roles and mechanisms of critical DUBs in head and neck squamous cell carcinoma (HNSCC). Methods: Bioinformatics analysis was performed to screen differentially expressed novel DUBs in HNSCC. Immunohistochemistry assay was used to measure the expression of DUB PSMD14 in HNSCC specimens and adjacent normal tissues. The level of PSMD14 in HNSCC tumorigenesis was investigated using a 4-NQO-induced murine HNSCC model. The function of PSMD14 was determined through loss-of-function assays. Chromatin immunoprecipitation, immunoprecipitation and in vivo ubiquitination assay were conducted to explore the potential mechanism of PSMD14. The anti-tumor activity of PSMD14 inhibitor Thiolutin was assessed by in vitro and in vivo experiments. Results: We identified PSMD14 as one of significantly upregulated DUBs in HNSCC tissues. Aberrant expression of PSMD14 was associated with tumorigenesis and malignant progression of HNSCC and further indicated poor prognosis. The results of in vitro and in vivo experiments demonstrated PSMD14 depletion significantly undermined HNSCC growth, chemoresistance and stemness. Mechanically, PSMD14 inhibited the ubiquitination and degradation of E2F1 to improve the activation of Akt pathway and the transcription of SOX2. Furthermore, PSMD14 inhibitor Thiolutin exhibited a potent anti-tumor effect on HNSCC in vivo and in vitro by impairing DUB activity of PSMD14. Conclusion: Our findings demonstrate the role and mechanism of PSMD14 in HNSCC, and provide a novel and promising target for diagnosis and clinical therapy of HNSCC.

Jing C ，Duan Y ，Zhou M ，Yue K ，Zhuo S ，Li X ，Liu D ，Ye B ，Lai Q ，Li L ，Yao X ，Wei H ，Zhang W ，Wu Y ，Wang X ... -  《Theranostics》

The PSMD14 inhibitor Thiolutin as a novel therapeutic approach for esophageal squamous cell carcinoma through facilitating SNAIL degradation.

Jing C ，Li X ，Zhou M ，Zhang S ，Lai Q ，Liu D ，Ye B ，Li L ，Wu Y ，Li H ，Yue K ，Chen P ，Yao X ，Wu Y ，Duan Y ，Wang X ... -  《Theranostics》

Deubiquitinase PSMD14 enhances hepatocellular carcinoma growth and metastasis by stabilizing GRB2.

Hepatocellular carcinoma (HCC) has emerged as one of the most common malignancies worldwide. It is associated with a high mortality rate, as evident from its increasing incidence and extremely poor prognosis. The deubiquitinating enzyme 26S proteasome non-ATPase regulatory subunit 14 (PSMD14) has been reported to act as an oncogene in several human cancers. The present study aimed to reveal the functional significance of PSMD14 in HCC progression and the underlying mechanisms. We found that PSMD14 was significantly upregulated in HCC tissues. Overexpression of PSMD14 correlated with vascular invasion, tumor number, tumor recurrence, and poor tumor-free and overall survival of patients with HCC. Knockdown and overexpression experiments demonstrated that PSMD14 promoted proliferation, migration, and invasion in HCC cells in vitro, and facilitated tumor growth and metastasis in vivo. Mechanistically, we identified PSMD14 as a novel post-translational regulator of GRB2. PSMD14 inhibits degradation of GRB2 via deubiquitinating this oncoprotein in HCC cells. Furthermore, pharmacological inhibition of PSMD14 with O-phenanthroline (OPA) suppressed the malignant behavior of HCC cells in vitro and in vivo. In conclusion, our findings suggest that PSMD14 could serve as a novel promising therapeutic candidate for HCC.

Lv J ，Zhang S ，Wu H ，Lu J ，Lu Y ，Wang F ，Zhao W ，Zhan P ，Lu J ，Fang Q ，Xie C ，Yin Z ... -  《-》

PSMD14 stabilizes estrogen signaling and facilitates breast cancer progression via deubiquitinating ERα.

The over-activation of ERα signaling is regarded as the major driver for luminal breast cancers, which could be effective controlled via selective estrogen receptor modulators (SERM), such as tamoxifen. The endocrine resistance is still a challenge for breast cancer treatment, while recently studies implicate the post-translational modification on ERα play important roles in endocrine resistance. The stability of ERα protein and ERα transcriptome are subject to a balance between E3 ubiquitin ligases and deubiquitinases. Through deubiquitinases siRNA library screening, we discover PSMD14 as a critical deubiquitinase for ERα signaling and breast cancer progression. PSMD14 could facilitate breast cancer progression through ERα signaling in vitro and in vivo, while pharmaceutical inhibition of PSMD14 via Thiolutin could block the tumorigenesis in breast cancer. In endocrine resistant models, PSMD14 inhibition could de-stabilize the resistant form of ERα (Y537S) and restore tamoxifen sensitivity. Molecular studies reveal that PSMD14 could inhibition K48-linked poly-ubiquitination on ERα, facilitate ERα transcriptome. Interestingly, ChIP assay shows that ERα could bind to the promoter region of PSMD14 and facilitate its gene transcription, which indicates PSMD14 is both the upstream modulator and downstream target for ERα signaling in breast cancer. In general, we identified a novel positive feedback loop between PSMD14 and ERα signaling in breast cancer progression, while blockade of PSMD14 could be a plausible strategy for luminal breast cancer.

Yang P ，Yang X ，Wang D ，Yang H ，Li Z ，Zhang C ，Zhang S ，Zhu J ，Li X ，Su P ，Zhuang T ... -  《-》