Prognostic significance of USP10 as a tumor-associated marker in gastric carcinoma

The deubiquitination-PARylation positive feedback loop of the USP10-PARP1 axis promotes DNA damage repair and affects therapeutic efficacy of PARP1 inhibitor

PARP1 initiates DNA repair pathways including single-strand break repair (SSBR) by recruiting multiple DNA repair factors via poly ADP-ribosylation (PARylation) of target proteins. However, how PARP1 is stabilized and activated to promote DNA damage repair remains unclear. Here we report that DNA damage generates a ROS signal, which triggers USP10 to interact with and stabilize PARP1 by deubiquitinating the K418 site in an ATM-dependent manner. In turn, PARP1 mediates PARylation of USP10 at amino acid residues D634, D645, and E648, which further promotes the deubiquitination activity of USP10 and DNA damage response to form a positive feedback loop. PARP1 is highly expressed in breast cancer tissues and positively correlates with USP10 protein levels. Moreover, breast cancer cells treated with a USP10 inhibitor show increased sensitivity to PARP1 inhibitor both in vivo and in vitro. Overall, our results unravel that the deubiquitination-PARylation positive feedback loop of the USP10-PARP1 axis promotes DNA damage repair, which might contribute to the improvement of PARP1 inhibitor efficacy in breast cancer treatment.

Recent advances in small molecule inhibitors of deubiquitinating enzymes

Proteins play a pivotal role in maintaining cellular homeostasis. Their degradation primarily orchestrated through the ubiquitin-proteasome system (UPS) and cellular autophagy. Dysfunction of the UPS is associated with various human diseases, including cancer, autoimmune disorders, and neurodegenerative conditions. Consequently, the UPS has emerged as a promising therapeutic target. Deubiquitinases (DUBs) have garnered significant attention as potential targets for therapeutic intervention due to their role in modulating protein stability and function. This review focuses on recent advancements of DUBs, particularly their relevance in the UPS and their potential as drug targets. Notably, inhibitors targeting specific DUBs, such as USP1, USP7, USP14, and USP30 have shown promise in preclinical and clinical studies for cancer therapy. Additionally, DUB inhibitors have been involved in novel therapeutic approaches lately, including as targets for proteolysis-targeting chimeras (PROTACs) or as tools in deubiquitinase-targeting chimeras (DUBTACs).

Ubiquitin-specific peptidase 10 promotes renal interstitial fibrosis progression through deubiquitinating and stabilizing P53 protein

Renal interstitial fibrosis is the main factor determining chronic kidney disease (CKD) progression, and renal tubular epithelial cells are the key drivers of this pathological process. Herein, we revealed significantly increased ubiquitin-specific peptidase 10 (USP10) expression in the kidney tissues of both patients with CKD and mice induced by unilateral ureteral obstruction, as well as in transforming growth factor-beta 1 (TGFβ1)-induced renal tubular epithelial cells. In vivo, treatment with the USP10 small molecule inhibitor Spautin-1, which inhibits its deubiquitinating activity, weakened renal interstitial fibrosis progression and alleviated the subsequent inflammatory response and oxidative stress in male mice. In vitro, knocking down USP10 or inhibiting its deubiquitinating activity through Spautin-1 significantly reduced fibronectin expression and ameliorated TGFβ1-induced renal tubular epithelial cell dedifferentiation. Additionally, our results revealed that USP10 directly binds to P53 and removes the K48-linked polyubiquitin chains from P53, thereby affecting its ubiquitination, stability, and nuclear translocation, which subsequently leads to the upregulation of P21 and promotes fibrotic gene expression in injured renal tubular epithelial cells, ultimately exacerbating renal interstitial fibrosis. In conclusion, USP10 is inhibited through the P53 signaling pathway to alleviate the progression of renal interstitial fibrosis and serve as a potential target for treating CKD.

Roles of deubiquitinases in urologic cancers (Review)

Human health is endangered by the occurrence and progression of urological cancers, including renal cell carcinoma, prostate cancer and bladder cancer, which are usually associated with the activation of oncogenic factors and inhibition of cancer suppressors. The primary mechanism for protein breakdown in cells is the ubiquitin-proteasome system, whilst deubiquitinases contribute to the reversal of this process. However, both are important for protein homeostasis. Deubiquitination may also be involved in the control of the cell cycle, proliferation and apoptosis, and dysregulated deubiquitination is associated with the malignant transformation, invasion and metastasis of urologic malignancies. Therefore, a comprehensive summary of the mechanisms underlying deubiquitination in urological cancers may provide novel strategies and insights for diagnosis and treatment. The present review aimed to methodically clarify the role of deubiquitinating enzymes in urinary system cancers as well as their prospective application prospects for clinical treatment.

Loss of USP10 promotes hepatocellular carcinoma proliferation by regulating the serine synthesis pathway through inhibition of LKB1 activity

Metabolic dysregulation is emerging as a critical factor in tumorigenesis, and reprogramming of serine metabolism has been identified as an essential factor in the progression of hepatocellular carcinoma (HCC). Studies have shown that LKB1 deficiency can activate mTOR to upregulate the serine synthesis pathway (SSP) and promote tumor progression. Our team discovered that ubiquitin-specific protease 10 (USP10) can inhibit HCC proliferation through mTOR, but its relationship with SSP needs further investigation. The metabolite assays revealed a significant increase in serine content in HCC tissues. Through the LKB1/mTOR/activating transcription factor 4 (ATF4) axis, loss of USP10 may increase serine biosynthesis and promote the proliferation of HCC in vitro and in vivo. Furthermore, it was found that USP10 could activate LKB1 through deubiquitination. Analyzing clinical HCC tissues revealed a positive correlation between USP10 and LKB1. Additionally, those with high expression of USP10 in HCC tissues showed a better degree of tumor differentiation and longer overall survival time. Moreover, we found increased expression of both serine and its synthase in liver tumor tissues of USP10 liver-specific KO mice. Loss of USP10 inhibits the activity of LKB1, contributing to the stimulation of the mTOR/ATF4 axis and SSP and then promoting the proliferation of HCC. This work presents a novel approach for serine-targeted treatment in HCC.

Dysregulation of deubiquitinases in gastric cancer progression

Gastric cancer (GC), characterized by a high incidence rate, poses significant clinical challenges owing to its poor prognosis despite advancements in diagnostic and therapeutic approaches. Therefore, a comprehensive understanding of the molecular mechanisms driving GC progression is crucial for identifying predictive markers and defining treatment targets. Deubiquitinating enzymes (DUBs), also called deubiquitinases, function as reverse transcriptases within the ubiquitin-proteasome system to counteract protein degradation. Recent findings suggest that DUB dysregulation could be a crucial factor in GC pathogenesis. In this review, we examined recent research findings on DUBs in the context of GC, elucidating their molecular characteristics, categorizations, and roles while also exploring the potential mechanisms underlying their dysregulation in GC. Furthermore, we assessed the therapeutic efficacy of DUB inhibitors in treating malignancies and evaluated the prevalence of aberrant DUB expression in GC.

Ubiquitin-specific protease 10 determines colorectal cancer outcome by modulating epidermal growth factor signaling via inositol polyphosphate-4-phosphatase type IIB

Although there have been advances in understanding colorectal cancer (CRC) pathogenesis, significant gaps still exist, highlighting the need for deeper insights. Dysregulated protein homeostasis, including perturbations in the epidermal growth factor receptor (EGFR) pathway, remains a focal point in CRC pathogenesis. Within this context, the roles of ubiquitin ligases and deubiquitinases have attracted attention, but exploration of their precise contributions is still in its early stages. To address this gap, we investigated the involvement of the deubiquitinase USP10 in CRC. Our in vitro and in vivo study reveals a new paradigm in CRC biology and unravels a novel mechanistic axis, demonstrating for the first time the involvement of inositol polyphosphate 4-phosphatase type II B (INPP4B) in USP10-mediated CRC modulation. Specifically, our study demonstrates that the loss of USP10 results in reduced sensitivity to the EGFR tyrosine kinase inhibitors gefitinib and osimertinib. This is accompanied by a decrease in the activation of the AKT1/PKB pathway upon EGF stimulation, which is mediated by INPP4B. Importantly, in vivo xenograft experiments validate these findings and highlight the crucial role of USP10, particularly in conjunction with INPP4B, in driving CRC progression. The findings enhance our understanding of CRC pathobiology and reveal a new regulatory axis involving USP10 and INPP4B in CRC progression. This unique insight identifies USP10 and INPP4B as potential therapeutic targets in CRC.

USP10 promotes cell proliferation, migration, and invasion in NSCLC through deubiquitination and stabilization of EIF4G1

Lung cancer is one of the most common types of malignant cancer worldwide, causing a serious social and economic burden. It is classified into non-small cell lung cancer (NSCLC) and small cell lung cancer, with NSCLC accounting for 80-85% of cases. Eukaryotic translation initiation factor 4 gamma 1 (EIF4G1) is highly expressed in NSCLC, playing an important role in regulating tumor growth, angiogenesis, malignant transformation, and phagocytosis. Ubiquitin-specific protease 10 (USP10) functions as a deubiquitinating enzyme to regulate substrate protein deubiquitination and reverse the ubiquitin proteasome degradation pathway. Our previous study identified an interaction between EIF4G1 and USP10; however, their regulatory mechanism remains unclear. Herein, we found that USP10 positively regulates EIF4G1 in NSCLC cells. An in vivo ubiquitination assay demonstrated deubiquitination of EIF4G1 by USP10, which reversed the ubiquitin proteasomal degradation of EIF4G1, thereby increasing its stability. Upregulation of EIF4G1 promoted cell proliferation, migration, and invasion in NSCLC cells. The current study not only reveals a novel mechanism through which USP10 positively regulates EIF4G1 in NSCLC, but also demonstrates the potential of USP10 as a therapeutic target to treat NSCLC.

System-wide identification of novel de-ubiquitination targets for USP10 in gastric cancer metastasis through multi-omics screening

OBJECTIVE

Ubiquitin-specific peptidase 10 (USP10), a typical de-ubiquitinase, has been found to play a double-edged role in human cancers. Previously, we reported that the expression of USP10 was negatively correlated with the depth of gastric wall invasion, lymph node metastasis, and prognosis in gastric cancer (GC) patients. However, it remains unclear whether USP10 can regulate the metastasis of GC cells through its de-ubiquitination function.

METHODS

In this study, proteome, ubiquitinome, and transcriptome analyses were conducted to comprehensively identify novel de-ubiquitination targets for USP10 in GC cells. Subsequently, a series of validation experiments, including in vitro cell culture studies, in vivo metastatic tumor models, and clinical sample analyses, were performed to elucidate the regulatory mechanism of USP10 and its de-ubiquitination targets in GC metastasis.

RESULTS

After overexpression of USP10 in GC cells, 146 proteins, 489 ubiquitin sites, and 61 mRNAs exhibited differential expression. By integrating the results of multi-omics, we ultimately screened 9 potential substrates of USP10, including TNFRSF10B, SLC2A3, CD44, CSTF2, RPS27, TPD52, GPS1, RNF185, and MED16. Among them, TNFRSF10B was further verified as a direct de-ubiquitination target for USP10 by Co-IP and protein stabilization assays. The dysregulation of USP10 or TNFRSF10B affected the migration and invasion of GC cells in vitro and in vivo models. Molecular mechanism studies showed that USP10 inhibited the epithelial-mesenchymal transition (EMT) process by increasing the stability of TNFRSF10B protein, thereby regulating the migration and invasion of GC cells. Finally, the retrospective clinical sample studies demonstrated that the downregulation of TNFRSF10B expression was associated with poor survival among 4 of 7 GC cohorts, and the expression of TNFRSF10B protein was significantly negatively correlated with the incidence of distant metastasis, diffuse type, and poorly cohesive carcinoma.

CONCLUSIONS

Our study established a high-throughput strategy for screening de-ubiquitination targets for USP10 and further confirmed that inhibiting the ubiquitination of TNFRSF10B might be a promising therapeutic strategy for GC metastasis.

USP10 promotes migration and cisplatin resistance in esophageal squamous cell carcinoma cells

Cisplatin-based chemotherapy is the main treatment option for advanced or metastatic esophageal squamous cell carcinoma (ESCC). However, most ESCC patients develop drug resistance within 2 years after receiving cisplatin chemotherapy. Ubiquitin-specific protease 10 (USP10) is abnormally expressed in a variety of cancers, but the mechanistic roles of USP10 in ESCC are still obscure. Here, the effects of USP10 on the migration and cisplatin resistance of ESCC in vivo and in vitro and the underlying mechanisms have been investigated by bioinformatics analysis, RT-PCR, western blotting, immunoprecipitation, immunohistochemistry, cell migration and MTS cell proliferation assays, deubiquitination assay, and mouse tail vein injection model. USP10 was significantly up-regulated in ESCC tissues compared with adjacent normal tissues in both public databases and clinical samples and was closely associated with overall survival. Subsequent results revealed that USP10 contributed to the migration and cisplatin resistance of ESCC cells, while knocking down USP10 in cisplatin-resistant cells exhibited opposite effects in vitro and in vivo. Further Co-IP experiments showed that integrin β1 and YAP might be targets for USP10 deubiquitination. Moreover, deficiency of USP10 significantly inhibited the migrative and chemo-resistant abilities of ESCC cells, which could be majorly reversed by integrin β1 or YAP reconstitution. Altogether, USP10 was required for migration and cisplatin resistance in ESCC through deubiquinating and stabilizing integrin β1/YAP, highlighting that inhibition of USP10 may be a potential therapeutic strategy for ESCC.

USP10 suppresses ABCG2-induced malignant characteristics of doxorubicin-resistant thyroid cancer by inhibiting PI3K/AKT pathway

Doxorubicin (DOX) is the most extensively used drug in the chemotherapy of thyroid cancer (TC). However, the existence of DOX resistance is not conducive to TC treatment. Here, we investigated the role of USP10 in DOX-resistant TC and explored the underlying molecular mechanism. CCK-8 assay was used to measure cell viability in thyroid cancer FTC133 and DOX-resistant FTC133-DOX cells. RT-qPCR and western blot were used to evaluate USP10 expression. Cell migration, invasion, and apoptotic assays were conducted. Western blot was used to detect cellular signaling proteins, EMT-related proteins, and apoptosis-related proteins. We found a lower expression of USP10 in the human TC cell line FTC133 as compared to the normal human thyroid Htori-3 cells. Notably, USP10 expression was further reduced in DOX-resistant (FTC133-DOX) cells compared to the FTC133 cells. FTC133-DOX cells had increased invasion, migration, and EMT properties while less apoptosis by activating the PI3K/AKT pathway. Interestingly, overexpressing USP10 increased the chemosensitivity of FTC133 cells to DOX therapy. Overexpressing USP10 inhibited invasion, migration, and EMT properties of FTC133-DOX cells and promoted apoptosis. Mechanistically, overexpressing USP10 inhibited PI3K/AKT pathway by activating PTEN. Furthermore, overexpressed USP10 controlled all these processes by downregulating ABCG2. This study demonstrates that USP10 could reduce DOX-induced resistance of TC cells to DOX therapy and could suppress TC malignant behavior by inhibiting the PI3K/AKT pathway. Furthermore, USP10 targeted ABCG2 to inhibit all these malignant processes, therefore, either increasing USP10 expression or inhibiting ABCG2 could be used as novel targets for treating DOX-resistant thyroid cancer.

Deubiquitinating enzyme USP10 promotes osteosarcoma metastasis and epithelial-mesenchymal transition by stabilizing YAP1

BACKGROUND

Osteosarcoma (OS) is a fatal adolescent tumor, which is susceptible to remote metastases at an early stage, and its treatment remains a major challenge. ubiquitin-specific protease 10 (USP10) is primarily located in the cytoplasm and can therefore deubiquitinate various cytoplasmic proteins. However, the expression and mechanism of USP10 in OS remain ambiguous. The aim of this study was to explore how USP10 affects Yes-associated protein1 (YAP1) to influence the metastasis and epithelial-mesenchymal transition (EMT).

METHODS

Western blotting, qRT-PCR, and immunohistochemical (IHC) analyses were performed to evaluate USP10 and YAP1 levels. Using wound healing and transwell tests, the roles and molecular pathways of USP10 and YAP1 ability to migrate and invade of OS were investigated, and cell morphological alterations were examined using phalloidin staining.

RESULTS

Our results indicated that USP10, a new type of deubiquitinating protease, is increased in OS tissues and cells contrasted with adjacent healthy tissues. Overexpression of USP10 correlated with tumor size, distant metastasis, and TNM stage, and was an independent factor of poor prognosis in OS patients. Also, USP10 expression is closely connected with the incident of OS metastasis and tumor size. Functional assays revealed that USP10 knockdown suppressed cell migrating and invading ability and inhibited the EMT of OS cells in vivo and in vitro. In addition, we showed that USP10 knockdown decreased the levels of YAP1, which is an important positive regulator of migration and invasion in many cancers. We also found a significant positive correlation between USP10 and YAP1 levels, further demonstrating that USP10-induced migration and EMT are based on YAP1 in OS cells. In a mechanistic way, USP10 stabilizes the expression of YAP1 by mediating its deubiquitination in OS cells.

CONCLUSION

Together, this study showed that USP10 can directly interact with YAP1 to reduce ubiquitinated YAP1, thereby stabilizing its protein levels and affecting EMT and distant metastasis in OS cells.

USP10 deubiquitinates RUNX1 and promotes proneural-to-mesenchymal transition in glioblastoma

The mesenchymal (MES) subtype of glioblastoma (GBM) is a highly aggressive, malignant and proliferative cancer that is resistant to chemotherapy. Runt-related transcription factor 1 (RUNX1) was shown to support MES GBM, however, its underlying mechanisms are unclear. Here, we identified USP10 as a deubiquitinating enzyme that regulates RUNX1 stabilization and is mainly expressed in MES GBM. Overexpression of USP10 upregulated RUNX1 and induced proneural-to-mesenchymal transition (PMT), thus maintaining MES properties in GBM. Conversely, USP10 knockdown inhibited RUNX1 and resulted in the loss of MES properties. USP10 was shown to interact with RUNX1, with RUNX1 being stabilized upon deubiquitylation. Moreover, we found that USP10 inhibitor Spautin-1 induced RUNX1 degradation and inhibited MES properties in vitro and in vivo. Furthermore, USP10 was strongly correlated with RUNX1 expression in samples of different subtypes of human GBM and had prognostic value for GBM patients. We identified USP10 as a key deubiquitinase for RUNX1 protein stabilization. USP10 maintains MES properties of GBM, and promotes PMT of GBM cells. Our study indicates that the USP10/RUNX1 axis may be a potential target for novel GBM treatments.

Targeted therapy based on ubiquitin-specific proteases, signalling pathways and E3 ligases in non-small-cell lung cancer

Lung cancer is one of the most common malignant tumours worldwide, with the highest mortality rate. Approximately 1.6 million deaths owing to lung cancer are reported annually; of which, 85% of deaths occur owing to non-small-cell lung cancer (NSCLC). At present, the conventional treatment methods for NSCLC include radiotherapy, chemotherapy, targeted therapy and surgery. However, drug resistance and tumour invasion or metastasis often lead to treatment failure. The ubiquitin–proteasome pathway (UPP) plays an important role in the occurrence and development of tumours. Upregulation or inhibition of proteins or enzymes involved in UPP can promote or inhibit the occurrence and development of tumours, respectively. As regulators of UPP, ubiquitin-specific proteases (USPs) primarily inhibit the degradation of target proteins by proteasomes through deubiquitination and hence play a carcinogenic or anticancer role. This review focuses on the role of USPs in the occurrence and development of NSCLC and the potential of corresponding targeted drugs, PROTACs and small-molecule inhibitors in the treatment of NSCLC.

The deubiquitinase USP10 protects pancreatic cancer cells from endoplasmic reticulum stress

The ubiquitin-specific peptidase 10 (USP10) plays a context-specific, pro or anti-tumorigenic role in different malignancies. However, the role of USP10 in pancreatic cancer remains unclear. Our protein and RNA level analysis from archived specimens and public databases show that USP10 is overexpressed in pancreatic ductal adenocarcinoma (PDAC) and expression correlates with poor overall patient survival. Phenotypically, silencing USP10 decreased viability, clonal growth and invasive properties of pancreatic cancer cells. Mechanistically, silencing USP10 upregulated BiP and induced endoplasmic reticulum (ER) stress that led to an unfolded protein response (UPR) and upregulation of PERK, IRE1α. Decreased cell viability of USP10 silenced cells could be rescued by a chemical chaperone that promotes protein folding. Our studies suggest that USP10 by protecting pancreatic cancer cells from ER stress may support tumor progression.

Research Progress for Targeting Deubiquitinases in Gastric Cancers

Gastric cancers (GCs) are malignant tumors with a high incidence that threaten global public health. Despite advances in GC diagnosis and treatment, the prognosis remains poor. Therefore, the mechanisms underlying GC progression need to be identified to develop prognostic biomarkers and therapeutic targets. Ubiquitination, a post-translational modification that regulates the stability, activity, localization, and interactions of target proteins, can be reversed by deubiquitinases (DUBs), which can remove ubiquitin monomers or polymers from modified proteins. The dysfunction of DUBs has been closely linked to tumorigenesis in various cancer types, and targeting certain DUBs may provide a potential option for cancer therapy. Multiple DUBs have been demonstrated to function as oncogenes or tumor suppressors in GC. In this review, we summarize the DUBs involved in GC and their associated upstream regulation and downstream mechanisms and present the benefits of targeting DUBs for GC treatment, which could provide new insights for GC diagnosis and therapy.

Ubiquitin-specific peptidase 10, a deubiquitinating enzyme: Assessing its role in tumor prognosis and immune response

Ubiquitin-specific peptidase 10 (USP10) is a member of the ubiquitin-specific protease family that removes the ubiquitin chain from ubiquitin-conjugated protein substrates. We performed a literature search to evaluate the structure and biological activity of USP10, summarize its role in tumorigenesis and tumor progression, and discuss how USP10 may act as a tumor suppressor or a tumor-promoting gene depending on its mechanism of action. Subsequently, we elaborated further on these results through bioinformatics analysis. We demonstrated that abnormal expression of USP10 is related to tumorigenesis in various types of cancer, including liver, lung, ovarian, breast, prostate, and gastric cancers and acute myeloid leukemia. Meanwhile, in certain cancers, increased USP10 expression is associated with tumor suppression. USP10 was downregulated in kidney renal clear cell carcinoma (KIRC) and associated with reduced overall survival in patients with KIRC. In contrast, USP10 upregulation was associated with poor prognosis in head and neck squamous cell carcinoma (HNSC). In addition, we elucidated the novel role of USP10 in the regulation of tumor immunity in KIRC and HNSC through bioinformatics analysis. We identified several signaling pathways to be significantly associated with USP10 expression, such as ferroptosis, PI3K/AKT/mTOR, TGF-β, and G2/M checkpoint. In summary, this review outlines the role of USP10 in various forms of cancer, discusses the relevance of USP10 inhibitors in anti-tumor therapies, and highlights the potential function of USP10 in regulating the immune responses of tumors.

CircCOL1A2 Sponges MiR-1286 to Promote Cell Invasion and Migration of Gastric Cancer by Elevating Expression of USP10 to Downregulate RFC2 Ubiquitination Level

Gastric cancers (GC) are generally malignant tumors, occurring with high incidence and threatening public health around the world. Circular RNAs (circRNAs) play crucial roles in modulating various cancers, including GC. However, the functions of circRNAs and their regulatory mechanism in colorectal cancer (CRC) remain largely unknown. This study focuses on both the role of circCOL1A2 in CRC progression as well as its downstream molecular mechanism. Quantitative polymerase chain reaction (qPCR) and western blot were adopted for gene expression analysis. Functional experiments were performed to study the biological functions. Fluorescence in situ hybridization (FISH) and subcellular fraction assays were employed to detect the subcellular distribution. Luciferase reporter, RNA-binding protein immunoprecipitation (RIP), co-immunoprecipitation (Co-IP), RNA pull-down, and immunofluorescence (IF) and immunoprecipitation (IP) assays were used to explore the underlying mechanisms. Our results found circCOL1A2 to be not only upregulated in GC cells, but that it also propels the migration and invasion of GC cells. CircCOL1A2 functions as a competing endogenous RNA (ceRNA) by sequestering microRNA-1286 (miR-1286) to modulate ubiquitin-specific peptidase 10 (USP10), which in turn spurs the migration and invasion of GC cells by regulating RFC2. In sum, CircCOL1A2 sponges miR-1286 to promote cell invasion and migration of GC by elevating the expression of USP10 to downregulate the level of RFC2 ubiquitination. Our study offers a potential novel target for the early diagnosis and treatment of GC.

USP10 as a Potential Therapeutic Target in Human Cancers

Deubiquitination is a major form of post-translational protein modification involved in the regulation of protein homeostasis and various cellular processes. Deubiquitinating enzymes (DUBs), comprising about five subfamily members, are key players in deubiquitination. USP10 is a USP-family DUB featuring the classic USP domain, which performs deubiquitination. Emerging evidence has demonstrated that USP10 is a double-edged sword in human cancers. However, the precise molecular mechanisms underlying its different effects in tumorigenesis remain elusive. A possible reason is dependence on the cell context. In this review, we summarize the downstream substrates and upstream regulators of USP10 as well as its dual role as an oncogene and tumor suppressor in various human cancers. Furthermore, we summarize multiple pharmacological USP10 inhibitors, including small-molecule inhibitors, such as spautin-1, and traditional Chinese medicines. Taken together, the development of specific and efficient USP10 inhibitors based on USP10’s oncogenic role and for different cancer types could be a promising therapeutic strategy.

High Ubiquitin-Specific Protease 2a Expression Level Predicts Poor Prognosis in Upper Tract Urothelial Carcinoma

BACKGROUND

Ubiquitin-mediated protein degradation has been reported to be involved in regulating the activity of oncoproteins and tumor suppressors. Dysfunction or dysregulation of the ubiquitin-proteasome system may induce tumorigenesis. Deubiquitinase ubiquitin-specific protease 2a (USP2a) has been reported to regulate cell growth or death and is involved in the pathogenesis of various diseases, including cancers. However, the role of USP2a in upper tract urothelial carcinoma (UTUC) has not been investigated yet. The goal of this study was to evaluate the clinical significance of USP2a expression in UTUC.

MATERIALS AND METHODS

A total of 110 UTUC cases were included in this study. USP2a expression level was evaluated through immunohistochemistry staining, and the correlation of USP2a expression level with both clinical and pathologic variables was analyzed.

RESULTS

High USP2a expression level was observed in 48 (43.6%) cancer specimens. USP2a expression level was significantly correlated with tumor stage (P=0.001), grade (P=0.033), and tumor recurrence (P=0.008). High USP2a expression level was correlated with poor disease-free survival (P=0.005) and cancer-specific survival (P<0.001). In addition, high USP2a expression level was an independent predictor of poor disease-free survival (hazard ratio=2.31; P=0.007) and cancer-specific survival (hazard ratio=5.49; P=0.009).

CONCLUSIONS

This study indicated that USP2a protein expression level may be a potential biomarker for predicting UTUC patient survival. Further prospective studies are needed to investigate the role of USP2a in UTUC progression.

The Prognostic Value and Immune Infiltration of USP10 in Pan-Cancer: A Potential Therapeutic Target

Ubiquitin-specific peptidase 10 (USP10) can sustain cellular functions and regulate cellular processes. It plays an essential role in cancer inhibition or facilitation by reversing ubiquitin-proteasome degradation. Studies have identified USP10 to be involved in tumor progression in various cancers. However, the pan-cancer expression pattern of USP10, its prognostic value, and the association between tumor immune cell infiltration and USP10 expression remain to be discussed and thus comprised the aims of the present study. Based on clinical samples and bioinformatic analyses, high USP10 expression was observed in most cancer tissues except for ovarian cancer. High USP10 expression correlated with pathological stage and node metastasis and predicted poor patient prognosis. In addition, further analyses at the TIMER and GEPIA databases showed that USP10 is involved in the infiltration of multiple immune cells and regulated the infiltration levels of specific immune cell subpopulations, particularly in pancreatic adenocarcinoma (PAAD) and liver hepatocellular carcinoma (LIHC). Importantly, USP10 might influence survival by modulating immune infiltration in patients with PAAD and LIHC. These results identified USP10 as a potential biomarker for pan-cancer prognosis, and in certain cancers, USP10 could identify clinical prognosis linked to tumor immune infiltration.

Loss of Ras GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) inhibits the progression of ovarian cancer in coordination with ubiquitin-specific protease 10 (USP10)

Ovarian cancer (OC) is one of the most lethal gynecological malignancies. However, the molecular mechanisms underlying the development of OC remain unclear. Here, we report that loss of Ras GTPase-activating protein SH3 domain-binding protein 1 (G3BP1) inhibits the progression of OC cells. Analysis of databases and clinical specimens showed that G3BP1 is upregulated in OC. The Kaplan-Meier plot results showed that G3BP1 is highly expressed in OC with a poor clinical outcome. Moreover, loss-of-G3BP1 suppresses the proliferation, migration, and invasion of OC cells. Protein-protein interaction network analysis and immunoprecipitation assay showed that ubiquitin-specific protease 10 (USP10) interacts with G3BP1. We next found that USP10 coordinately promotes tumor progression with G3BP1. Moreover, loss of USP10could restore the G3BP1-induced proliferation, migration, and invasion of OC cells. These data indicate that G3BP1 coordinated with USP10 to facilitate the progression of OC cells, and that G3BP1 may become a treatment target for OC.

Prognostic Signature of Osteosarcoma Based on 14 Autophagy-Related Genes

Background: Osteosarcoma is a common malignancy of bone with inferior survival outcome. Autophagy can exert multifactorial influence on tumorigenesis and tumor progression. However, the specific function of genes related to autophagy in the prognosis of osteosarcoma patients remains unclear. Herein, we aimed to explore the association of genes related to autophagy with the survival outcome of osteosarcoma patients.

Methods: The autophagy-associated genes that were related to the prognosis of osteosarcoma were optimized by LASSO Cox regression analysis. The survival of osteosarcoma patients was forecasted by multivariate Cox regression analysis. The immune infiltration status of 22 immune cell types in osteosarcoma patients with high and low risk scores was compared by using the CIBERSORT tool.

Results: The risk score model constructed according to 14 autophagy-related genes (ATG4A, BAK1, BNIP3, CALCOCO2, CCL2, DAPK1, EGFR, FAS, GRID2, ITGA3, MYC, RAB33B, USP10, and WIPI1) could effectively predict the prognosis of patients with osteosarcoma. A nomogram model was established based on risk score and metastasis.

Conclusion: Autophagy-related genes were identified as pivotal prognostic signatures, which could guide the clinical decision making in the treatment of osteosarcoma.

When the chains do not break: the role of USP10 in physiology and pathology

Deubiquitination is now understood to be as important as its partner ubiquitination for the maintenance of protein half-life, activity, and localization under both normal and pathological conditions. The enzymes that remove ubiquitin from target proteins are called deubiquitinases (DUBs) and they regulate a plethora of cellular processes. DUBs are essential enzymes that maintain intracellular protein homeostasis by recycling ubiquitin. Ubiquitination is a post-translational modification where ubiquitin molecules are added to proteins thus influencing activation, localization, and complex formation. Ubiquitin also acts as a tag for protein degradation, especially by proteasomal or lysosomal degradation systems. With ~100 members, DUBs are a large enzyme family; the ubiquitin-specific peptidases (USPs) being the largest group. USP10, an important member of this family, has enormous significance in diverse cellular processes and many human diseases. In this review, we discuss recent studies that define the roles of USP10 in maintaining cellular function, its involvement in human pathologies, and the molecular mechanisms underlying its association with cancer and neurodegenerative diseases. We also discuss efforts to modulate USPs as therapy in these diseases.

Ubiquitin-Specific Peptidase 10 Protects Against Hepatic Ischaemic/Reperfusion Injury via TAK1 Signalling

Ubiquitin-specific peptidase 10 (USP10) protein is a deubiquitination enzyme involved in many important biological processes. However, the function of USP10 in hepatic ischaemic/reperfusion (I/R) injury remains unknown. The aim of this study was to explore the role of USP10 in hepatic I/R injury. USP10 Heterozygote mice and primary hepatocytes were used to construct hepatic I/R models. The effect of USP10 on hepatic I/R injury was examined via pathological and molecular analyses. Our results indicated that USP10 was significantly downregulated in the livers of mice after hepatic I/R injury and in hepatocytes subjected to hypoxia/reoxygenation stimulation. USP10 Heterozygote mice exhibited exacerbated hepatic I/R injury, as evidenced by enhanced liver inflammation via the NF-κB signalling pathway and increased hepatocyte apoptosis. Additionally, USP10 overexpression inhibited hepatocyte inflammation and apoptosis in hepatic I/R injury in vitro and in vivo. Mechanistically, our study demonstrated that USP10 knockdown exerted its detrimental effects on hepatic I/R injury by inducing activation of the transforming growth factor β-activated kinase 1 (TAK1)-JNK/p38 signalling pathways. TAK1 was required for USP10 function in hepatic I/R injury as TAK1 inhibition abolished USP10 function in vitro. In conclusion, our study demonstrated that USP10 plays a protective role in hepatic I/R injury by inhibiting the activation of the TAK1-JNK/p38 signalling pathways. Modulation of USP10/TAK1 might be a promising strategy to prevent this pathological process.

Revisiting the Concept of Stress in the Prognosis of Solid Tumors: A Role for Stress Granules Proteins?

Simple Summary

Stress Granules (SGs) were discovered in 1999 and while the first decade of research has focused on some fundamental questions, the field is now investigating their role in human pathogenesis. Since then, evidences of a link between SGs and cancerology are accumulating in vitro and in vivo. In this work we summarized the role of SGs proteins in cancer development and their prognostic values. We find that level of expression of protein involved in SGs formation (and not mRNA level) could serve a prognostic marker in cancer. With this review we strongly suggest that SGs (proteins) could be targets of choice to block cancer development and counteract resistance to improve patients care.

Abstract

Cancer treatments are constantly evolving with new approaches to improve patient outcomes. Despite progresses, too many patients remain refractory to treatment due to either the development of resistance to therapeutic drugs and/or metastasis occurrence. Growing evidence suggests that these two barriers are due to transient survival mechanisms that are similar to those observed during stress response. We review the literature and current available open databases to study the potential role of stress response and, most particularly, the involvement of Stress Granules (proteins) in cancer. We propose that Stress Granule proteins may have prognostic value for patients.

The USP10-HDAC6 axis confers cisplatin resistance in non-small cell lung cancer lacking wild-type p53

Ubiquitin-specific peptidase 10 (USP10) stabilizes both tumor suppressors and oncogenes in a context-dependent manner. However, the nature of USP10’s role in non-small cell lung cancer (NSCLC) remains unclear. By analyzing The Cancer Genome Atlas (TCGA) database, we have shown that high levels of USP10 are associated with poor overall survival in NSCLC with mutant p53, but not with wild-type p53. Consistently, genetic depletion or pharmacological inhibition of USP10 dramatically reduces the growth of lung cancer xenografts lacking wild-type p53 and sensitizes them to cisplatin. Mechanistically, USP10 interacts with, deubiquitinates, and stabilizes oncogenic protein histone deacetylase 6 (HDAC6). Furthermore, reintroducing either USP10 or HDAC6 into a USP10-knockdown NSCLC H1299 cell line with null-p53 renders cisplatin resistance. This result suggests the existence of a “USP10-HDAC6-cisplatin resistance” axis. Clinically, we have found a positive correlation between USP10 and HDAC6 expression in a cohort of NSCLC patient samples. Moreover, we have shown that high levels of USP10 mRNA correlate with poor overall survival in a cohort of advanced NSCLC patients who received platinum-based chemotherapy. Overall, our studies suggest that USP10 could be a potential biomarker for predicting patient response to platinum, and that targeting USP10 could sensitize lung cancer patients lacking wild-type p53 to platinum-based therapy.

Prognostic significance of USP10 and p14ARF expression in patients with colorectal cancer

Ubiquitin-specific proteases (USPs) play an important role in fundamental cellular processes. Among these, USP10 is known for its association with tumor development and progression of multiple cancers. We aimed to investigate the clinical significance of USP10 expression in colorectal cancer and examined the potential link between USP10 and p14ARF in patients with colorectal cancer. USP10 and p14ARF protein expression was assessed via immunohistochemistry (IHC) on a tissue microarray from 280 colorectal cancer cases. IHC scores were evaluated by digital image analysis and compared with patients' outcomes. In addition, we examined DNA hypermethylation in colorectal cancer cell lines and tissues, which were matched with adjacent normal colon samples. USP10 expression was lost (USP10^loss) in 18.6% of samples (52/280 cases), which was linked to lymphovascular invasion (p = 0.019) and distant metastases (p < 0.001). Similarly, loss of p14ARF expression (p14ARF^loss) was associated with more advanced tumors. USP10 expression correlated positively with p14ARF expression (r = 0.617, p < 0.001). USP10^loss, p14ARF^loss, and dual loss of USP10 and p14ARF were significantly associated with shorter disease-free survival and overall survival in comparison to USP10^intact, p14ARF^intact, and dual loss of USP10 and p14ARF, respectively. Multivariate analysis revealed that USP10^loss (p = 0.030) and dual loss of USP10 and p14ARF (p = 0.014) are independent prognostic factors for poor disease-free survival in colorectal cancer patients. Furthermore, aberrant hypermethylation of the USP10 promoter region was found in colorectal cancer cell lines and tissues. The present results suggest that USP10^loss is a potential prognostic marker for colorectal cancer.

Loss of Both USP10 and p14ARF Protein Expression Is an Independent Prognostic Biomarker for Poor Prognosis in Patients With Epithelial Ovarian Cancer

BACKGROUND/AIM

The prognostic role of USP10 in epithelial ovarian cancer has been studied in various human cancers. Our aim was to evaluate the clinical and pathological significance of USP10 in epithelial ovarian cancer.

MATERIALS AND METHODS

Immunohistochemical analyses of the expression of USP10 and p14ARF by using tissue microarrays were performed in 336 ovarian tumours and the data were compared with clinicopathological variables. We examined their level of DNA methylation around the putative transcriptional start site in 5' CpG islands in fresh frozen tissues and ovarian cancer cells.

RESULTS

Expression of USP10 and p14ARF was significantly lower in cancer tissues than in normal epithelium. Low USP10 expression and a combined USP10/p14ARF low expression were revealed to be independent prognostic factors. A high degree of methylation in USP10 and p14ARF CpG islands was found by methylation specific PCR analysis in cancer than in normal tissues and cells.

CONCLUSION

Decreased expression of USP10 or combined USP10/p14ARF decreased expression is a strong indicator of poor prognosis in patients with ovarian cancer.

The role of deubiquitinating enzymes in gastric cancer

The epigenetic regulation of gene expression (via DNA methylation, histone modification and microRNA interference) contributes to a variety of diseases, particularly cancer. Protein deubiquitination serves a key role in the mechanism underlying histone modification, and consequently influences tumor development and progression. Improved characterization of the role of ubiquitinating enzymes has led to the identification of numerous deubiquitinating enzymes (DUBs) with various functions. Gastric cancer (GC) is a highly prevalent cancer type that exhibits a high mortality rate. Latest analysis about cancer patient revealed that GC is sixth deadliest cancer type, which frequently occur in male (7.2%) than female (4.1%). Complex associations between DUBs and GC progression have been revealed in multiple studies; however, the molecular mechanism underpinning the metastasis and recurrence of GC is yet to be elucidated. Generally, DUBs were upregulated in gastric cancer. The relation of DUBs and tumor size, classification and staging was observed in GC. Besides, 5-yar survival rate of patients with GC is effeccted by expression level of DUBs. Among the highly expressed DUBs, specifically six DUBs namely UCHs, USPs, OTUs, MJDs, JAMMs and MCPIPs effect on this survival rate. Consequently, the association between GC and DUBs has received increasing attention in recent years. Therefore, in the present review, literature investigating the association between DUBs and GC pathophysiology was analyzed and critically appraised.

DUBs, Hypoxia, and Cancer

Alterations in protein ubiquitylation and hypoxia are commonly associated with cancer. Ubiquitylation is carried out by three sequentially acting ubiquitylating enzymes and can be opposed by deubiquitinases (DUBs), which have emerged as promising drug targets. Apart from protein localization and activity, ubiquitylation regulates degradation of proteins, among them hypoxia-inducible factors (HIFs). Thereby, various E3 ubiquitin ligases and DUBs regulate HIF abundance. Conversely, several E3s and DUBs are regulated by hypoxia. While hypoxia is a powerful HIF regulator, less is known about hypoxia-regulated DUBs and their impact on HIFs. Here, we review current knowledge about the relationship of E3s, DUBs, and hypoxia signaling. We also discuss the reciprocal regulation of DUBs by hypoxia and use of DUB-specific drugs in cancer.

Deubiquitinating enzymes as cancer biomarkers: new therapeutic opportunities?

Cancer remains a life-threatening disease and accounts for the major mortality rates worldwide. The practice of using biomarkers for early detection, staging, and customized therapy may increase cancer patients’ survival. Deubiquitinating enzymes (DUBs) are a family of proteases that remove ubiquitin tags from proteins of interest undergoing proteasomal degradation. DUBs play several functional roles other than deubiquitination. One of the important roles of DUBs is regulation of tumor progression. Several reports have suggested that the DUB family members were highly-elevated in various cancer cells and tissues in different stages of cancer. These findings suggest that the DUBs could be used as drug targets in cancer therapeutics. In this review, we recapitulate the role of the DUB family members, including ubiquitin-specific protease, otubain protease, and important candidates from other family members. Our aim was to better understand the connection between DUB expression profiles and cancers to allow researchers to design inhibitors or gene therapies to improve diagnosis and prognosis of cancers.

The role of ubiquitin-specific peptidases in cancer progression

Protein ubiquitination is an important mechanism for regulating the activity and levels of proteins under physiological conditions. Loss of regulation by protein ubiquitination leads to various diseases, such as cancer. Two types of enzymes, namely, E1/E2/E3 ligases and deubiquitinases, are responsible for controlling protein ubiquitination. The ubiquitin-specific peptidases (USPs) are the main members of the deubiquitinase family. Many studies have addressed the roles of USPs in various diseases. An increasing number of studies have indicated that USPs are critical for cancer progression, and some USPs have been used as targets to develop inhibitors for cancer prevention. Herein we collect and organize most of the recent studies on the roles of USPs in cancer progression and discuss the development of USP inhibitors for cancer therapy in the future.

Association and clinical implication of the USP10 and MSH2 proteins in non-small cell lung cancer

Ubiquitin-specific protease 10 (USP10) is involved in a number of biological processes by stabilizing several proteins, which have been implicated in multiple stages of tumorigenesis and progression. Previous studies have indicated that USP10 stabilizes and deubiquitinates MutS homolog 2 (MSH2) in in vitro and in vivo models. The level of MSH2 protein has been positively correlated with that of the USP10 protein in a panel of lung cancer cell lines. Furthermore, depletion of USP10 in lung cancer cells causes decreased apoptosis and increased cell survival upon treatment with DNA-damaging agents. However, the expression and clinical implication of USP10 protein in lung cancer tissues is not clear. Additionally, whether the level of MSH2 protein is positively correlated with that of the USP10 protein in lung cancer tissues also remains unresolved. Therefore, USP10 protein expression was detected in 148 human non-small cell lung cancer (NSCLC) and 139 non-cancerous lung tissues using immunohistochemistry, whereas mRNA was investigated by Gene Expression Omnibus dataset and The Cancer Genome Atlas database analyses. It was identified that USP10 protein expression was significantly downregulated in NSCLC tissues compared with in normal lung tissues (P<0.05). However, no significant difference in USP10 mRNA expression between the two tissues was identified. In addition, a positive correlation was observed between the USP10 and MSH2 proteins in NSCLC tissues (P<0.05). However, the clinicopathological features and survival analysis indicated that the USP10 and MSH2 proteins were not associated with clinical features, including age, sex, tumor size, Tumor-Node-Metastasis stage and tumor cell differentiation, along with the prognosis of NSCLC. Collectively, these results suggest that downregulation of USP10 protein serves an important function in the tumorigenesis of NSCLC, and the level of USP10 protein is positively correlated with that of MSH2 protein in NSCLC tissues, which may indicate that USP10 also stabilizes the MSH2 protein in patients with lung cancer.

Dual loss of USP10 and p14ARF protein expression is associated with poor prognosis in patients with small intestinal adenocarcinoma

Oncogene-induced senescence occurs following oncogene activation in normal cells and is considered as a critical tumor-suppressing mechanism. Ubiquitin-specific protease 10 (USP10) has been reported to play a vital role in oncogene-induced senescence via the deubiquitination-dependent stabilization of p14ARF. However, knowledge of the clinical significance of USP10 and p14ARF expression in patients with small intestinal adenocarcinoma is limited. To study the clinical significance of USP10 and p14ARF expression, we performed immunohistochemistry for USP10 and p14ARF on 195 surgically resected small intestinal adenocarcinoma specimens. Furthermore, we performed methylation analysis on five small intestinal adenocarcinoma samples and matched adjacent normal intestinal tissue samples. UPS10 ( p = 0.023) and p14ARF ( p = 0.007) expression were significantly decreased in adenocarcinoma in comparison with normal tissue. The loss of USP10 was observed in 124/194 (63.9%) of small intestinal adenocarcinoma samples and was correlated with a higher pT stage ( p = 0.044), lymphatic invasion ( p = 0.033), and the absence of sporadic adenoma ( p = 0.024) and peritumoral dysplasia ( p = 0.019). p14ARF expression was downregulated in 75/195 (38.5%) of small intestinal adenocarcinoma samples and was associated with vascular ( p = 0.011) and lymphatic ( p = 0.013) invasions. The loss of USP10 expression was associated with the loss of p14ARF expression ( r = 0.342, p < 0.001). Multivariate survival analysis revealed that the combined loss of USP10 and p14ARF expression could be an independent prognostic factor for overall survival in small intestinal adenocarcinoma. Furthermore, the aberrant hypermethylation of the USP10 and p14ARF promoter could be a key mechanism for the downregulation of USP10 and p14ARF proteins in small intestinal adenocarcinoma. These findings suggest that the dual loss of USP10 and p14ARF could be used as a prognostic indicator of small intestinal adenocarcinoma.

USP10 promotes proliferation and migration and inhibits apoptosis of endometrial stromal cells in endometriosis through activating the Raf-1/MEK/ERK pathway

Endometriosis has been initially described as endometrial-like tissue outside of the uterine cavity. The mitogen-activated protein kinase/ERK kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway playing an important role in the regulation of cell proliferation, apoptosis, and migration has been found to be activated in endometriosis. However, regulation of the MEK/ERK signaling pathway in endometriosis has not been fully understood. In this study, primary-cultured endometrial stromal cells were collected from patients with endometriosis and healthy controls, and the proliferation, apoptosis, and migration of ectopic endometrial stromal cells transfected with ubiquitin-specific protease 10 (USP10)-small-interfering RNA (siRNA) or pLVX-Puro-USP10 with or without MEK inhibitor PD-98059 or exogenous signaling stimulation such as epidermal growth factor (EGF) were measured by CCK-8, flow cytometry, and Transwell, respectively. The gene and protein expressions were measured by real-time PCR or Western blot. USP10 overexpression promoted ectopic endometrial stromal cell migration and proliferation, suppressed cell apoptosis, and activated MEK/ERK signaling that is a critical downstream target of the serine/threonine protein kinase Raf-1, which was significantly blocked by PD-98059. USP10 silencing demonstrated the inverse effects, and these effects induced by USP10 silencing were significantly blocked by EGF. USP10 overexpression promoted Raf-1 protein expression, but not mRNA expression, through deubiquitination. In conclusion, these results suggest that USP10 promotes proliferation and migration and inhibits apoptosis of endometrial stromal cells in endometriosis through activating the Raf-1/MEK/ERK pathway.

Ubiquitin-specific protease 3 overexpression promotes gastric carcinogenesis and is predictive of poor patient prognosis

Although gastric cancer (GC) is one of the most common cancers, knowledge of its development and carcinogenesis is limited. To date, expression of ubiquitin-specific protease 3 (USP3) in all types of cancer, including GC, is still unknown. The present study explored the involvement of USP3 in the carcinogenesis and prognosis of GC. We measured USP3 expression in normal and GC tissues and cell lines. Correlations between USP3 protein level and clinicopathological parameters, as well as the significance of USP3 protein level for disease-free survival were assessed. Small hairpin RNA technology and transfection were used to investigate the effect of USP3 manipulation on cell proliferation and spreading. Moreover, xenograft proliferation and metastasis were used to explore the influence of USP3 on tumor growth and metastasis in animals. An increase in USP3 expression was observed in GC cells and tissues. The overexpression of USP3 was significantly correlated with several clinicopathological parameters and poor disease-free survival. Multivariate Cox regression analysis showed that the overexpression of USP3 was an independent prognostic biomarker. Silencing of USP3 suppressed GC cell proliferation and spreading in vitro as well as xenograft proliferation and metastasis in vivo; however, opposite results were obtained when USP3 was overexpressed. Further studies showed that USP3 influenced cell proliferation and spreading by regulating the cell cycle control- and epithelial-mesenchymal transition-related molecules. This study suggests that USP3 overexpression can be a useful biomarker for predicting the outcomes of GC patients and that USP3 targeting represents a potential modality for treating GC.

A case of pediatric acute myeloid leukemia with t(11;16)(q23;q24) leading to a novel KMT2A-USP10 fusion gene

We present a leukemia case that exhibits a chromosomal translocation t(11;16)(q23;q23), which results in the expression of a novel KMT2A fusion gene. This novel fusion, KMT2A-USP10, was found in a relapse of acute myeloid leukaemia M5a. USP10 belongs to a protein family that deubiquitinates a distinct set of target proteins, and thus, increases the steady state protein levels of its target subproteome. One of the USP10 targets is TP53. Wildtype TP53 is usually rescued from proteasomal degradation by USP10. As most KMT2A leukemias display wildtype p53 alleles, one might argue that the disruption of an USP10 allele can be classified as a pro-oncogenic event.

Clinical significance of TM4SF1 as a tumor suppressor gene in gastric cancer

Transmembrane‐4‐L‐six‐family member‐1 (TM4SF1), a tumor‐associated antigen, is overexpressed in most epithelial cell carcinomas and a potential target for antibody‐mediated therapy. However, the role of TM4SF1 in gastric cancer has not been elucidated. The aim of this study was to investigate the clinical significance of TM4SF1 expression in gastric carcinoma (GC) tissues using 152 GC tissue samples and matched adjacent nontumor tissue samples analyzed by immunohistochemistry, and 13 fresh GC tissue samples analyzed by Western blotting. The results showed that TM4SF1 was heterogeneously expressed in normal gastric mucosa, with a high expression rate in fundus mucosa. Higher levels and strong expression rate of TM4SF1 were associated with GC tissues of higher‐grade differentiation. TM4SF1 levels were lower in gastric cancer tissues than gastric noncancerous tissues. Expression of TM4SF1 was not correlated with USP10 (P = 0.157), S100A12 (P = 0.479), p53 (P = 0.249), or Ki67 (P = 0.166) in GC. The expression of TM4SF1 was significantly and negatively correlated with depth of invasion (P = 0.031), nodal metastasis (P = 0.042), TNM stage (P = 0.030), and Lauren classification (P = 0.026). There was no significant correlation between TM4SF1 expression and age, gender, tumor size, or distant metastasis (P > 0.05). The expression of TM4SF1 was associated with well overall survival (P = 0.0164). The 5‐year survival rate for patients with GC showing TM4SF1 positive was 58.82% (10/17), and the median survival time was 78 months, higher than that (12.90%, 12/93) of patients who were TM4SF1 negative, whose median survival time was 62 months. These data suggested that low expression of TM4SF1 is associated with carcinogenesis and development, tumor progression and invasion of gastric cancer, and poor overall survival of patients with GC. TM4SF1 is a tumor suppressor for GC and a novel prognostic marker for patients with GC.

Clinicopathological significance of G9A expression in colorectal carcinoma

G9A, the primary histone methyltransferase (HMTase) for histone H3 lysine 9, is upregulated in numerous types of cancer and is critical for tumor cell proliferation. The present study aimed to investigate the G9A expression level in colorectal carcinoma (CRC) to evaluate the clinical significance of G9A in CRC. First, the present study detected the expression of G9A protein in 100 pairs of CRC specimens by immunohistochemistry staining and analyzed the correlations between G9A expression and pathological tumor features. It was found that G9A expression was increased markedly in CRC tumor specimens and the high expression was associated with tumor distant metastasis. Oncomine database analysis demonstrated an elevated expression level of G9A in various types of CRC. In total, 6 public available data sets from the Gene Expression Omnibus (GEO) were used and Gene set enrichment analysis (GSEA) was conducted. The results of the bioinformatics analysis demonstrated that high G9A expression was associated with American Joint Committee on Cancer staging, tumor differentiation, tumor relapse of CRC, and may serve a role in CRC cell proliferation. These findings suggested that G9A was overexpressed in CRC and involved in the tumorigenesis and distant metastasis of CRC. The expression level may also serve as a potential indicator for tumor recurrence in CRC. The present findings aided in the understanding of the crucial role of G9A in tumorigenesis and also offered novel ideas for CRC therapy.

Functional role of eukaryotic translation initiation factor 4 gamma 1 (EIF4G1) in NSCLC

Eukaryotic translation initiation factor 4 gamma 1(EIF4G1) is related to tumorigenesis and tumor progression. However, its role and the underlying mechanisms in the regulation of tumor development in non-small cell lung cancers (NSCLC) remain largely unknown. Here we report that the levels of EIF4G1 expression are much higher in NSCLC cell lines and tumor tissues than those in the normal lung cells and adjacent normal tissues from the same patients. Using shRNA to knock down EIF4G1 expression stably, we found EIF4G1 required for NSCLC cell proliferation, anchorage-independent growth, migration and invasion. Furthermore, silencing of EIF4G1 induces NSCLC cell apoptosis and causes G0/G1 cell cycle arrest. To identify the partner protein network of EIF4G1 in NSCLC cells, we found that Ubiquitin-specific protease 10 (USP10) can directly interacts with EIF4G1, while acting as a negative regulator for EIF4G1-mediated functions. Together, our results indicate that EIF4G1 functions as an oncoprotein during NSCLC development, which may represent a novel and promising therapeutic target in lung cancer.

Targeting Deubiquitinating Enzymes in Glioblastoma Multiforme: Expectations and Challenges

Glioblastoma (GBM) is regarded as the most common primary intracranial neoplasm. Despite standard treatment with tumor resection and radiochemotherapy, the outcome remains gloomy. It is evident that a combination of oncogenic gain of function and tumor-suppressive loss of function has been attributed to glioma initiation and progression. The ubiquitin-proteasome system is a well-orchestrated system that controls the fate of most proteins by striking a dynamic balance between ubiquitination and deubiquitination of substrates, having a profound influence on the modulation of oncoproteins, tumor suppressors, and cellular signaling pathways. In recent years, deubiquitinating enzymes (DUBs) have emerged as potential anti-cancer targets due to their targeting several key proteins involved in the regulation of tumorigenesis, apoptosis, senescence, and autophagy. This review attempts to summarize recent studies of GBM-associated DUBs, their roles in various cellular processes, and discuss the relation between DUBs deregulation and gliomagenesis, especially how DUBs regulate glioma stem cells pluripotency, microenvironment, and resistance of radiation and chemotherapy through core stem-cell transcriptional factors. We also review recent achievements and progress in the development of potent and selective reversible inhibitors of DUBs, and attempted to find a potential GBM treatment by DUBs intervention.

Functional characterization of AMP-activated protein kinase signaling in tumorigenesis

AMP-activated protein kinase (AMPK) is a ubiquitously expressed metabolic sensor among various species. Specifically, cellular AMPK is phosphorylated and activated under certain stressful conditions, such as energy deprivation, in turn to activate diversified downstream substrates to modulate the adaptive changes and maintain metabolic homeostasis. Recently, emerging evidences have implicated the potential roles of AMPK signaling in tumor initiation and progression. Nevertheless, a comprehensive description on such topic is still in scarcity, especially in combination of its biochemical features with mouse modeling results to elucidate the physiological role of AMPK signaling in tumorigenesis. Hence, we performed this thorough review by summarizing the tumorigenic role of each component along the AMPK signaling, comprising of both its upstream and downstream effectors. Moreover, their functional interplay with the AMPK heterotrimer and exclusive efficacies in carcinogenesis were chiefly explained among genetically altered mice models. Importantly, the pharmaceutical investigations of AMPK relevant medications have also been highlighted. In summary, in this review, we not only elucidate the potential functions of AMPK signaling pathway in governing tumorigenesis, but also potentiate the future targeted strategy aiming for better treatment of aberrant metabolism-associated diseases, including cancer.

Deubiquitinases in cancer

Deubiquitinases are deubiquitinating enzymes (DUBs), which remove ubiquitin from proteins, thus regulating their proteasomal degradation, localization and activity. Here, we discuss DUBs as anti-cancer drug targets.

Overexpression and Biological Function of Ubiquitin-Specific Protease 42 in Gastric Cancer

Ubiquitin-specific protease 42 (USP42) is a member of deubiquitinating enzymes (DUBs). The alterations of DUBs are implicated in the pathogenesis of a wide variety of tumors. However, there are few studies on the expression and biological function of USP42 in gastric cancer (GC). Here, the expression levels of USP42 were significantly higher in GC tissues than in non-tumorous tissues. USP42 expression was significantly correlated with tumor size, TNM stage, lymph node metastasis and overall survival of patients with GC. Moreover, USP42 silencing in two GC cell lines, AGS and MKN-45, notably inhibited cell proliferation, but stimulated G1 phase arrest. The proteins promoting cell cycle progression (Cyclin D1, Cyclin E1 and PCNA) were down-regulated in USP42-suppressed cells. Moreover, inhibition of USP42 in GC cells impaired cell invasion via affecting the expression of matrix metalloproteinases (MMPs) and epithelial-mesenchymal transition (EMT) regulators. In conclusion, USP42 overexpression could be a potential prognostic marker for GC, regulate the survival and invasive properties of GC, and may represent a novel therapeutic molecular target for this tumor.