The USP21/YY1/SNHG16 axis contributes to tumor proliferation, migration, and invasion of non-small-cell lung cancer

20-hydroxyecdysone suppresses bladder cancer progression via inhibiting USP21: A mechanism associated with deubiquitination and degradation of p65

Bladder cancer is one of the most common malignancies of the urinary tract and a prevalent cancer worldwide, still requiring efficient therapeutic agents and approaches. 20-Hydroxyecdysone (20-HE), a steroid hormone, can be found in insects and few plants and mediate numerous biological events to control the progression of varying diseases; however, its impacts on bladder cancer remain unclear. In the study, we found that 20-HE treatments effectively inhibited the viability and proliferation of bladder cancer cells and induced apoptosis by activating Caspase-3. The migratory and invasive potential of bladder cancer cells was markedly repressed by 20-HE in a dose-dependent manner. The inhibitory effects of 20-HE on bladder cancer were confirmed in an established xenograft mouse model, as indicated by the markedly reduced tumor growth rates and limited lung and lymph node metastasis. High-throughput RNA sequencing was performed to explore dysregulated genes in bladder cancer cells after 20-HE treatment. We identified ubiquitin-specific protease 21 (USP21) as a key deubiquitinating enzyme for bladder cancer progression and a positive correlation between USP21 and nuclear factor-κB (NF-κB)/p65 in patients. Furthermore, 20-HE treatments markedly reduced USP21 expression, NF-κB/p65 mRNA, stability and phosphorylated NF-κB/p65 expression levels in bladder cancer cells, which were validated in animal tumor tissues. Mechanistic studies showed that USP21 directly interacted with and stabilized p65 by deubiquitinating its K48-linked polyubiquitination in bladder cancer cells, which could be abolished by 20-HE treatment, contributing to p65 degradation. Finally, we found that USP21 overexpression could not only facilitate the proliferation, migration, and invasion of bladder cancer cells, but also significantly eliminated the suppressive effects of 20-HE on bladder cancer. Notably, 20-HE could still perform its anti-tumor role in bladder cancer when USP21 was knocked down with decreased NF-κB/p65 expression and activation, revealing that USP21 suppression might not be the only way for 20-HE during bladder cancer treatment. Collectively, all our results clearly demonstrated that 20-HE may function as a promising therapeutic strategy for bladder cancer treatment mainly through reducing USP21/p65 signaling expression.

The emerging role of deubiquitylating enzyme USP21 as a potential therapeutic target in cancer

Although certain members of the Ubiquitin-specific peptidases (USPs) have been recognized as promising therapeutic targets for various diseases, research progress regarding USP21 has been relatively sluggish in its early stages. USP21 is a crucial member of the USPs subfamily, involved in diverse cellular processes such as apoptosis, DNA repair, and signal transduction. Research findings from the past decade demonstrate that USP21 mediates the deubiquitination of multiple well-known target proteins associated with critical cellular processes relevant to both disease and homeostasis, particularly in various cancers.This reviewcomprehensively summarizes the structure and biological functions of USP21 with an emphasis on its role in tumorigenesis, and elucidates the advances on the discovery of tens of small-molecule inhibitors targeting USP21, which suggests that targeting USP21 may represent a potential strategy for cancer therapy.

Utilizing machine learning to identify nifuroxazide as an inhibitor of ubiquitin-specific protease 21 in a drug repositioning strategy

Ubiquitin-specific protease (USP), an enzyme catalyzing protein deubiquitination, is involved in biological processes related to metabolic disorders and cancer proliferation. We focused on constructing predictive models tailored to unveil compounds boasting USP21 inhibitory attributes. Six models, Extra Trees Classifier, Random Forest Classifier, LightGBM Classifier, XGBoost Classifier, Bagging Classifier, and a convolutional neural network harnessed from empirical data were selected for the screening process. These models guided our selection of 26 compounds from the FDA-approved drug library for further evaluation. Notably, nifuroxazide emerged as the most potent inhibitor, with a half-maximal inhibitory concentration of 14.9 ± 1.63 μM. The stability of protein-ligand complexes was confirmed using molecular modeling. Furthermore, nifuroxazide treatment of HepG2 cells not only inhibited USP21 and its established substrate ACLY but also elevated p-AMPKα, a downstream functional target of USP21. Intriguingly, we unveiled the previously unknown capacity of nifuroxazide to increase the levels of miR-4458, which was identified as downregulating USP21. This discovery was substantiated by manipulating miR-4458 levels in HepG2 cells, resulting in corresponding changes in USP21 protein levels in line with its predicted interaction with ACLY. Lastly, we confirmed the in vivo efficacy of nifuroxazide in inhibiting USP21 in mice livers, observing concurrent alterations in ACLY and p-AMPKα levels. Collectively, our study establishes nifuroxazide as a promising USP21 inhibitor with potential implications for addressing metabolic disorders and cancer proliferation. This multidimensional investigation sheds light on the intricate regulatory mechanisms involving USP21 and its downstream effects, paving the way for further exploration and therapeutic development.

GHITM regulates malignant phenotype and sensitivity to PD-1 blockade of renal cancer cells via Notch signalling

Growth hormone inducible transmembrane protein (GHITM), one member of Bax inhibitory protein-like family, has been rarely studied, and the clinical importance and biological functions of GHITM in kidney renal clear cell carcinoma (KIRC) still remain unknown. In the present study, we found that GHITM was downregulated in KIRC. Aberrant GHITM downregulation related to clinicopathological feature and unfavourable prognosis of KIRC patients. GHITM overexpression inhibited KIRC cell proliferation, migration and invasion in vitro and in vivo. Mechanistically, GHITM overexpression could induce the downregulation of Notch1, which acts as an oncogene in KIRC. Overexpression of Notch1 effectively rescued the inhibitory effect induced by GHITM upregulation. More importantly, GHITM could regulate PD-L1 protein abundance and ectopic overexpression of GHITM enhanced the antitumour efficiency of PD-1 blockade in KIRC, which provided new insights into antitumour therapy. Furthermore, we also showed that YY1 could decrease GHITM level via binding to its promoter. Taken together, our study revealed that GHITM was a promising therapeutic target for KIRC, which could modulate malignant phenotype and sensitivity to PD-1 blockade of renal cancer cells via Notch signalling pathway.

Programmed Death Ligand 1 Regulatory Crosstalk with Ubiquitination and Deubiquitination: Implications in Cancer Immunotherapy

Programmed death ligand 1 (PD-L1) plays a pivotal role in cancer immune evasion and is a critical target for cancer immunotherapy. This review focuses on the regulation of PD-L1 through the dynamic processes of ubiquitination and deubiquitination, which are crucial for its stability and function. Here, we explored the intricate mechanisms involving various E3 ubiquitin ligases and deubiquitinating enzymes (DUBs) that modulate PD-L1 expression in cancer cells. Specific ligases are discussed in detail, highlighting their roles in tagging PD-L1 for degradation. Furthermore, we discuss the actions of DUBs that stabilize PD-L1 by removing ubiquitin chains. The interplay of these enzymes not only dictates PD-L1 levels but also influences cancer progression and patient response to immunotherapies. Furthermore, we discuss the therapeutic implications of targeting these regulatory pathways and propose novel strategies to enhance the efficacy of PD-L1/PD-1-based therapies. Our review underscores the complexity of PD-L1 regulation and its significant impact on the tumor microenvironment and immunotherapy outcomes.

Phosphorylation-dependent deubiquitinase OTUD3 regulates YY1 stability and promotes colorectal cancer progression

Yin Yang 1 (YY1) is a key transcription factor that has been implicated in the development of several malignancies. The stability of YY1 is regulated by the ubiquitin-proteasome system. The role of deubiquitinases (DUBs) and their impact on YY1 remain to be fully elucidated. In this study, we screened for ubiquitin-specific proteases that interact with YY1, and identified OTUD3 as a DUB for YY1. Over-expressed OTUD3 inhibited YY1 degradation, thereby increasing YY1 protein levels, whereas OTUD3 knockdown or knockout promoted YY1 degradation, thereby decreasing the proliferation of colorectal cancer (CRC). Furthermore, PLK1 mediates OTUD3 S326 phosphorylation, which further enhances OTUD3 binding and deubiquitination of YY1. In CRC tissues, elevated the expression level of OTUD3 and YY1 were significantly associated with poor prognostic outcomes. These findings suggest that the OTUD3-YY1 pathway has therapeutic potential in CRC, and OTUD3 plays a critical role in regulating YY1.

Inhibition of USP21 leads to ovarian carcinoma cell death by suppressing MAPK signaling

Ovarian cancer is the most aggressive and lethal of all gynecologic malignancies. Although the overexpression (OE) of ubiquitin-specific peptidase 21 (USP21) has been observed in multiple cancers, its expression profile and biological function in ovarian cancer remain unknown. The expression levels of USP21 in ovarian cancer cells and tissues as well as adjacent normal tissues were assessed by qRT-PCR or Western blot assay. The biological function of USP21 in ovarian cancer cells was assessed by cell growth assay in vitro and a tumor growth model in vivo. Our study revealed that USP21 was markedly elevated in ovarian carcinoma tissues compared with adjacent normal tissues. Downregulation of USP21 attenuated the expression levels of MEK2 and p-ERK1/2. Depletion of USP21 resulted in suppressed cell growth of ovarian cancers in vitro and inhibited tumor growth in vivo. Conversely, OE of USP21 promoted the cell proliferation of ovarian cancers and conferred resistance to BAY 11-7082. These findings provide evidences supporting the notion of USP21 as a promising therapeutic target for the treatment of ovarian cancer.

Low-dose radiotherapy promotes the formation of tertiary lymphoid structures in lung adenocarcinoma

Purpose

A tertiary lymphoid structure (TLS) refers to an organized infiltration of immune cells that is linked to a positive prognosis and improved response to immunotherapy. However, methods that promote TLS formation are limited and challenging to implement in clinical settings. In this study, we aimed to promote the formation and maturation of TLSs in lung adenocarcinoma (LUAD) by combining low-dose radiotherapy (LDRT) with immunotherapy.

Methods

Tissue sections from 198 patients who had undergone surgery were examined. Risk factors for patient survival were assessed, and the relationship between TLSs and five-year survival was analyzed. The Kras-LSL-G12D spontaneous lung cancer mouse model was used to screen the optimal irradiation dose (0/1/2 Gy whole lung irradiation) for promoting TLS formation. LDRT combined with anti-PD-1 was used to promote the formation and maturation of TLSs.

Results

TLS+, TLSHigh, TLS+GC+ and CD8High within TLS+ were associated with a favorable prognosis. LDRT increased the formation of early TLSs in the Kras-LSL-G12D lung cancer mouse model. In addition, LDRT combined with anti-PD-1 treatment can significantly improve the maturity of TLSs in mouse LUAD, resulting in greater antitumor effects. This antitumor effect was strongly associated with the number of CD8+ T cells within the TLSs.

Conclusion

We successfully applied LDRT combined with PD-1 inhibitor therapy for the first time, which increased both the quantity and maturity of TLSs in lung cancer. This approach achieved a promising antitumor effect.

Synergistic effect of YOD1 and USP21 on the Hippo signaling pathway

BACKGROUND

Deubiquitinating enzymes (DUBs) comprise a family of proteases responsible for cleaving the peptide or isopeptide bond between ubiquitin and its substrate proteins. Ubiquitin is essential for regulating diverse cellular functions by attaching to target proteins. The Hippo signaling pathway plays a crucial role in controlling tissue size, cell proliferation, and apoptosis. In a previous study, we discovered that YOD1 regulates the Hippo signaling pathway by deubiquitinating the neural precursor cell expressed developmentally down-regulated protein 4 (NEDD4), an E3 ligase of large tumor suppressor kinase 1 (LATS1). Here, our aim was to investigate potential substrates of YOD1 implicated in the Hippo signaling pathway.

METHODS

We employed various bioinformatics tools (BioGRID, STRING, and Cytoscape) to identify novel potential substrates of YOD1. Furthermore, we used western blotting, co-immunoprecipitation (co-IP), glutathione S-transferase (GST) pull-down, immunocytochemistry (ICC) assays to investigate cellular interactions. To evaluate cell proliferation, we performed cell counting kit-8 (CCK-8), wound healing, colony forming, and flow cytometry assays using A549, HEK293T, and HeLa cells. Additionally, we assessed the expression levels of YAP and p-YAP in A549, HEK293T, and HeLa cells through western blotting.

RESULTS

Our investigations revealed that YOD1 interacts with ubiquitin-specific proteases 21 (USP21), a DUB involved in the Hippo signaling pathway, and deubiquitinates the microtubule-affinity regulating kinase (MARK). Intriguingly, YOD1 and USP21 mutually deubiquitinate each other; while YOD1 regulates the protein stability of USP21, USP21 does not exert a regulatory effect on YOD1. Moreover, we observed the synergistic effect of YOD1 and USP21 on cell proliferation through the modulation of the Hippo signaling pathway.

CONCLUSIONS

Our study revealed multiple cellular interactions between YOD1 and USP21. Moreover, our findings suggest that the combined activities of YOD1 and USP21 synergistically influence cell proliferation in A549 cells by regulating the Hippo signaling pathway.

A novel necroptosis related gene signature and regulatory network for overall survival prediction in lung adenocarcinoma

We downloaded the mRNA expression profiles of patients with LUAD and corresponding clinical data from The Cancer Genome Atlas (TCGA) database and used the Least Absolute Shrinkage and Selection Operator Cox regression model to construct a multigene signature in the TCGA cohort, which was validated with patient data from the GEO cohort. Results showed differences in the expression levels of 120 necroptosis-related genes between normal and tumor tissues. An eight-gene signature (CYLD, FADD, H2AX, RBCK1, PPIA, PPID, VDAC1, and VDAC2) was constructed through univariate Cox regression, and patients were divided into two risk groups. The overall survival of patients in the high-risk group was significantly lower than of the patients in the low-risk group in the TCGA and GEO cohorts, indicating that the signature has a good predictive effect. The time-ROC curves revealed that the signature had a reliable predictive role in both the TCGA and GEO cohorts. Enrichment analysis showed that differential genes in the risk subgroups were associated with tumor immunity and antitumor drug sensitivity. We then constructed an mRNA-miRNA-lncRNA regulatory network, which identified lncRNA AL590666. 2/let-7c-5p/PPIA as a regulatory axis for LUAD. Real-time quantitative PCR (RT-qPCR) was used to validate the expression of the 8-gene signature. In conclusion, necroptosis-related genes are important factors for predicting the prognosis of LUAD and potential therapeutic targets.

LncRNA-HOTAIRM1 promotes aerobic glycolysis and proliferation in osteosarcoma via the miR-664b-3p/Rheb/mTOR pathway

Osteosarcoma (OS), which is a common and aggressive primary bone malignancy, occurs mainly in children and adolescent. Long noncoding RNAs (lncRNAs) are reported to play a pivotal role in various cancers. Here, we found that the lncRNA HOTAIRM1 is upregulated in OS cells and tissues. A set of functional experiments suggested that HOTAIRM1 knockdown attenuated the proliferation and stimulated the apoptosis of OS cells. A subsequent mechanistic study revealed that HOTAIRM1 functions as a competing endogenous RNA to elevate ras homologue enriched in brain (Rheb) expression by sponging miR-664b-3p. Immediately afterward, upregulated Rheb facilitates proliferation and suppresses apoptosis by promoting the mTOR pathway-mediated Warburg effect in OS. In summary, our findings demonstrated that HOTAIRM1 promotes the proliferation and suppresses the apoptosis of OS cells by enhancing the Warburg effect via the miR-664b-3p/Rheb/mTOR axis. Understanding the underlying mechanisms and targeting the HOTAIRM1/miR-664b-3p/Rheb/mTOR axis are essential for OS clinical treatment.

Yin Yang 1 suppresses tumor invasion and metastasis in nasopharyngeal carcinoma by negatively regulating eIF4E transcriptional activity and expression

Tumor metastasis is a leading cause of death in nasopharyngeal carcinoma (NPC) patients. Previous research has identified that transcription factor Yin Yang 1 (YY1) acts as a tumor suppressor that inhibits cell proliferation and tumor growth in NPC; however, the role and the molecular mechanisms of YY1 in NPC invasion and metastasis remain unclear. In this study, we discovered that YY1 could inhibit the migration and invasion of NPC cells in vitro as well as NPC xenograft tumor metastasis in vivo. Furthermore, we identified eIF4E as a direct downstream target of YY1, and YY1 could negatively regulate the expression of eIF4E at transcriptional level. Moreover, we found that eIF4E promoted the migration and invasion of NPC cells as well as NPC lung metastasis, suggesting its potential as a pro-metastatic mediator in NPC. Importantly, restoring eIF4E expression could partially reverse the inhibitory effects of YY1 on NPC malignancy. In consistent with these findings, the expression of YY1 was downregulated while eIF4E was upregulated in NPC patients with metastasis, and there was a negative correlation between YY1 and eIF4E expression. Collectively, our results indicate that YY1 suppresses the invasion and metastasis of NPC by negatively regulating eIF4E transcription. Therefore, targeting the YY1/eIF4E transcriptional axis could be a potential therapeutic strategy for the treatment of patients with NPC.

A review of deubiquitinases and thier roles in tumorigenesis and development

Ubiquitin is a small protein that can be added onto target protein for inducing target degradation, thereby modulating the activity and stability of protein. Relatively, deubiquitinases (DUBs), a class catalase that can remove ubiquitin from substrate protein, provide a positive regulation of the protein amount at transcription level, post-translational modification, protein interaction, etc. The reversible and dynamic ubiquitination-deubiquitination process plays an essential role in maintaining protein homeostasis, which is critical to almost all the biological processes. Therefore, the metabolic dysregulation of deubiquitinases often lead to serious consequences, including the growth and metastasis of tumors. Accordingly, deubiquitinases can be served as key drug targets for the treatment of tumors. The small molecule inhibitors targeting deubiquitinases has become one of the hot spots of anti-tumor drug research areas. This review concentrated on the function and mechanism of deubiquitinase system in the proliferation, apoptosis, metastasis and autophagy of tumor cells. The research status of small molecule inhibitors of specific deubiquitinases in tumor treatment is introduced, aiming to provide reference for the development of clinical targeted drugs.

USP21 contributes to the aggressiveness of laryngeal cancer cells by deubiquitinating and stabilizing AURKA

Laryngeal cancer is a usual malignant tumor of the head and neck. The role and mechanism of deubiquitinase USP21 in laryngeal cancer are still unclear. We aimed to explore whether USP21 affected laryngeal cancer progress through deubiquitinating AURKA. USP21 and AURKA levels were evaluated by qRT-PCR and Western blot. Kaplan-Meier analysis was conducted by survival package. MTT was performed to detect cell proliferation. The wound healing assay was applied to evaluate cell migration. Transwell was used to measure cell invasion. Co-IP and GST-pull down determined the interaction between USP21 and AURKA. In addition, AURKA ubiquitination levels were analyzed. USP21 was signally elevated in laryngeal cancer tissues and cells. USP21 level in clinical stages III-IV was higher than that in clinical stages I-II, and high levels of USP21 were highly correlated with poor prognosis in laryngeal cancer. USP21 inhibition suppressed AMC-HN-8 and TU686 cell proliferation, migration and invasion. Co-IP and GST-pull down confirmed the interaction between USP21 and AURKA. Knockdown of USP21 markedly increased the ubiquitination level of AURKA, and USP21 restored AURKA activity through deubiquitination. In addition, overexpression of AURKA reversed the effects of USP21 knockdown on cell growth, migration, and invasion. USP21 stabilized AURKA through deubiquitination to promote laryngeal cancer progression.

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.

Discovery and Characterization of BAY-805, a Potent and Selective Inhibitor of Ubiquitin-Specific Protease USP21

USP21 belongs to the ubiquitin-specific protease (USP) subfamily of deubiquitinating enzymes (DUBs). Due to its relevance in tumor development and growth, USP21 has been reported as a promising novel therapeutic target for cancer treatment. Herein, we present the discovery of the first highly potent and selective USP21 inhibitor. Following high-throughput screening and subsequent structure-based optimization, we identified BAY-805 to be a non-covalent inhibitor with low nanomolar affinity for USP21 and high selectivity over other DUB targets as well as kinases, proteases, and other common off-targets. Furthermore, surface plasmon resonance (SPR) and cellular thermal shift assays (CETSA) demonstrated high-affinity target engagement of BAY-805, resulting in strong NF-κB activation in a cell-based reporter assay. To the best of our knowledge, BAY-805 is the first potent and selective USP21 inhibitor and represents a valuable high-quality in vitro chemical probe to further explore the complex biology of USP21.

Identifying Oxidized Lipid Metabolism-Related LncRNAs as Prognostic Biomarkers of Head and Neck Squamous Cell Carcinoma

The relationship between oxidized lipid metabolism and the immunological function of cancer is well known. However, the functions and regulatory mechanisms of lncRNAs associated with oxidized lipid metabolism in head and neck squamous cell carcinoma (HNSCC) remain to be fully elucidated. In this study, we established an oxidized lipid metabolism-related lncRNA prognostic signature to assess the prognosis and immune infiltration of HNSCC patients. The HNSCC transcriptome was obtained from The Cancer Genome Atlas. The choice of the target genes with a relevance score greater than 10 was performed via a correlation analysis by GeneCards. Patients were categorized by risk score and generated with multivariate Cox regression, which was then validated and evaluated using the Kaplan–Meier analysis and time-dependent receiver operating characteristics (ROC). A nomogram was constructed by combining the risk score with the clinical data. We constructed a risk score with 24 oxidized lipid metabolism-related lncRNAs. The areas’ 1-, 2-, and 3-year OS under the ROC curve (AUC) were 0.765, 0.724, and 0.724, respectively. Furthermore, the nomogram clearly distinguished the survival probabilities of patients in high- and low-risk groups, between which substantial variations were revealed by immune infiltration analysis. The results supported the fact that oxidized lipid metabolism-related lncRNAs might predict prognoses and assist with differentiating amid differences in immune infiltration in HNSCC.

Salt-like transcription factor 4 promotes laryngeal cancer progression through transcriptional activation of ubiquitin-specific protease 21 to stabilize Yin Yang 1

Laryngeal cancer (LC) is a rare and challenging clinical problem. Our aim was to investigate the mechanism of salt-like transcription factor 4 (SALL4) in LC. LC tissue and paracancerous tissue were collected. Relative mRNA or protein levels were measured by quantitative real-time polymerase chain reaction or Western blot. MTT, wound healing, and transwell assay were performed to evaluate cell proliferation, migration and invasion. The binding relationship between SALL4 and USP21 promoter was verified by dual-luciferase assay and ChIP. Co-IP and glutathione-S-transferase (GST)-pull down were performed to measure the protein interaction between USP21 and YY1. Additionally, YY1 ubiquitination level was analyzed. It was found that SALL4 mRNA and SALL4 protein levels were elevated in LC clinical tissues and various LC cells. Knockdown of SALL4 inhibited epithelial-mesenchymal transition (EMT) of LC cells. USP21 was transcriptionally activated by SALL4. Co-IP and GST-pull down confirmed USP21 interacted with YY1. USP21 protected YY1 from degradation through deubiquitination. Furthermore, overexpression of USP21 reversed the effect of knockdown of SALL4 on YY1 and EMT in LC cells. In general, SALL4 facilitated EMT of LC cells through modulating USP21/YY1 axis.

USP21 Promotes the Progression of Nasopharyngeal Carcinoma by Regulating FOXM1

The purpose of this work was to explore the molecular mechanisms by which USP21 regulates nasopharyngeal carcinoma tumor growth and cancer cell stemness. In this study, the USP21 transcript data was obtained from TCGA database. Then, qPCR and western blot tests revealed that, in contrast to normal tissue or normal nasopharyngeal epithelial cells, the expression of USP21 was greater in nasopharyngeal carcinoma tissues or cell lines, respectively. CCK-8 and EdU immunofluorescent staining assays revealed that USP21 promoted the proliferation of nasopharyngeal carcinoma cells. Meanwhile, scratch and transwell assays showed that USP21 facilitated migration and invasion of nasopharyngeal carcinoma cells. Sphere formation assay was performed on nasopharyngeal carcinoma cells after knockdown of USP21, which revealed that knockdown of USP21 inhibited the stemness profiles of nasopharyngeal carcinoma cells. Then, the western blot assays indicated that knockdown of USP21 in nasopharyngeal carcinoma cells would inhibit FOXM1 expression, and overexpression of FOXM1 could reverse the cell proliferation ability, cell migration and invasion ability, and cell stemness profiles. Finally, a nasopharyngeal xenograft model suggested that USP21 facilitated tumor growth in mice. These findings proved that USP21 promoted tumor growth and cancer cell stemness in nasopharyngeal carcinoma by regulating FOXM1.

The significance of the crosstalk between ubiquitination or deubiquitination and ncRNAs in non-small cell lung cancer

Lung cancer (LC) remains the leading cause of cancer-related deaths worldwide, with extremely high morbidity and mortality rates. Non-small cell lung cancer (NSCLC) is the most critical type of LC. It seriously threatens the life and health of patients because of its early metastasis, late clinical symptoms, limited early screening methods, and poor treatment outcomes. Non-coding RNAs (ncRNAs), including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), participate in cell proliferation, metastasis, and chemoresistance. Several previous studies have proven that ncRNAs are vital regulators of tumorigenesis. Ubiquitination plays the most crucial role in protein post-translational modification (PTM). Deubiquitination and ubiquitination form a homeostasis. In summary, ubiquitination and deubiquitination play essential roles in mediating the degradation or overexpression of a range of crucial proteins in various cancers. A growing number of researchers have found that interactions between ncRNAs and ubiquitination (or deubiquitination) play a crucial role in NSCLC. This review presents several typical examples of the important effects of ncRNAs and ubiquitination (or deubiquitination) in NSCLC, aiming to provide more creative ideas for exploring the diagnosis and treatment of NSCLC.

Tumour-derived exosomal lncRNA SNHG16 induces telocytes to promote metastasis of hepatocellular carcinoma via the miR-942-3p/MMP9 axis

BACKGROUND

Hepatocellular carcinoma (HCC) cell-derived exosomal LncRNA SNHG16 is highly expressed and associated with poor overall survival of patients. Telocytes (TCs), as novel interstitial cells, have been reported to promote HCC metastasis. Therefore, in our study, we investigated whether a molecular interaction occurred between exosomal LncSNHG16 and TCs in the tumor microenvironment.

METHODS

LncSNHG16 expression in HCC tissues and cell lines was measured, and bioinformatics analysis was performed. Exosomes were isolated and purified from HCC cells with LncSNHG16 overexpression/knockdown vectors and cocultured with TCs. Then, markers of the LncSNHG16/miR-942-3p/MMP9 axis were tested in TCs. Transwell assays and cell wound healing assays were designed to examine the invasion and migration of HCC cells after coincubation with TCs. RNA immunoprecipitation (RIP) assays and dual-luciferase gene reporter assays were performed to verify the binding effect of LncSNHG16, miR-942-3p, and MMP9 mRNA. In vivo, experimental animal models were established to confirm the effect of exosomal LncSNHG16-induced MMP9 expression on HCC metastasis.

RESULTS

Exosomal LncSNHG16 was phagocytized by TCs and downregulated miR-942-3p, which induced targeted MMP9 upregulation, and it had specific binding sites with miR-942-3p in TCs to facilitate the migration of HCC cells in vitro and in vivo. Exosomal LncSNHG16 was found to act as a competing endogenous RNA of the miR-942-3p/MMP9 axis in TCs.

CONCLUSION

Tumour-derived exosomal LncSNHG16 modulates MMP9 via competitively binding to miR-942-3p in TCs, thus promoting the metastasis of HCC.

LncRNA SNHG16 promotes development of oesophageal squamous cell carcinoma by interacting with EIF4A3 and modulating RhoU mRNA stability

Background

Numerous studies have revealed that long noncoding RNAs (lncRNAs) are closely related to the development of many diseases and carcinogenesis. However, their specific biological function and molecular mechanism in oesophageal squamous cell carcinoma (ESCC) remains unclear.

Methods

RNA-Seq was performed to determine the differential expressions of lncRNAs in ESCC, and the level of SNHG16 expression was detected in ESCC and intraepithelial neoplasia (IEN) samples. In vitro and in vivo experiments were performed to explore the role of SNHG16 and the interaction of EIF4A3 and Ras homologue family member U (RhoU) signalling.

Results

One hundred and seventy-five upregulated and 134 downregulated lncRNAs were identified by RNA-Seq. SNHG16 was highly expressed in ESCC and intraepithelial neoplasia (IEN) samples, and its expression level was correlated with tumour differentiation and T stage. Overexpression of SNHG16 can facilitate ESCC cell proliferation and metastasis. Mechanistically, we noticed that SNHG16 could bind RNA binding protein (RBP)-eukaryotic translation initiation factor (EIF4A3) and interact with it to form a complex. Importantly, the coalition of SNHG16 and EIF4A3 ultimately regulated Ras homologue family member U (RhoU). SNHG16 modulated RhoU expression by recruiting EIF4A3 to regulate the stability of RhoU mRNA. Knockdown of RhoU further alleviated the effect of the SNHG16 oncogene in ESCC cells.

Conclusions

The newly identified SNHG16–EIF4A3–RhoU signalling pathway directly coordinates the response in ESCC pathogenesis and suggests that SNHG16 is a promising target for potential ESCC treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-022-00386-w.

Long non-coding RNA SNHG16 silencing inhibits proliferation and inflammation in Mycobacterium tuberculosis-infected macrophages by targeting miR-140-5p expression

OBJECTIVE

The study investigated the clinical diagnostic value of long non-coding RNA (LncRNA) small nucleolar RNA host gene 16 (SNHG16) and explored its underlying molecular mechanism through Mycobacterium tuberculosis (M. tuberculosiinfection of macrophages.

METHODS

RT-qPCR analysis of the serum SNHG16 levels of the 66 healthy individuals, 67 latent TB (LTB) patients, and 67 active TB (ATB) patients. The receiver-operating characteristic (ROC) curve to detect the clinical diagnostic value of SNHG16 in TB patients. In vitro, M. tuberculosis-infected macrophages, CCK-8 and ELISA to detect cell proliferation and inflammatory factor levels. Luciferase reported assay was performed to analyze the targeting relationship between SNHG16 and miR-140-5p.

RESULTS

SNHG16 was significantly elevated in TB patients, and among them, ATB patients were higher than LTB patients. ROC confirmed that SNHG16 could distinguish LTB patients from healthy controls, and ATB patients from LTB patients, and can be used as a good diagnostic biomarker for TB. M. tuberculosis infection increased SNHG16 levels and promoted the proliferation and inflammation in macrophages. However, SNHG16 silencing significantly reversed the effect of infection. miR-140-5p, a direct target miRNA of SNHG16, was down-regulated in TB patients and was negatively correlated with SNHG16. When miR-140-5p was inhibited, the alleviating effect of SNHG16 silencing on M. tuberculosis infection proliferation and inflammation was significantly reversed.

CONCLUSION

The present results suggested that SNHG16 may be a new diagnostic biomarker for TB patients and SNHG16 silencing may alleviate TB by inhibiting the proliferation of macrophages in TB by regulation miR-140-5p.

USP21 promotes self-renewal and tumorigenicity of mesenchymal glioblastoma stem cells by deubiquitinating and stabilizing FOXD1

Recent studies suggest that Forkhead box D1 (FOXD1) plays an indispensable role in maintaining the mesenchymal (MES) properties of glioblastoma (GBM) stem cells (GSCs). Thus, understanding the mechanisms that control FOXD1 protein expression is critical for guiding GBM treatment, particularly in patients with therapy-resistant MES subtypes. In this study, we identify the ubiquitin-specific peptidase 21 (USP21) as a critical FOXD1 deubiquitinase in MES GSCs. We find that USP21 directly interacts with and stabilizes FOXD1 by reverting its proteolytic ubiquitination. Silencing of USP21 enhances polyubiquitination of FOXD1, promotes its proteasomal degradation, and ultimately attenuates MES identity in GSCs, while these effects could be largely restored by reintroduction of FOXD1. Remarkably, we show that disulfiram, a repurposed drug that could block the enzymatic activities of USP21, suppresses GSC tumorigenicity in MES GSC-derived GBM xenograft model. Additionally, we demonstrate that USP21 is overexpressed and positively correlated with FOXD1 protein levels in GBM tissues, and its expression is inversely correlated with patient survival. Collectively, our work reveals that USP21 maintains MES identity by antagonizing FOXD1 ubiquitination and degradation, suggesting that USP21 is a potential therapeutic target for the MES subtype of GBM.

Deubiquitinases in Cancers: Aspects of Proliferation, Metastasis, and Apoptosis

Simple Summary

This review summarizes the current DUBs findings that correlate with the most common cancers in the world (liver, breast, prostate, colorectal, pancreatic, and lung cancers). The DUBs were further classified by their biological functions in terms of proliferation, metastasis, and apoptosis. The work provides an updated of the current findings, and could be used as a quick guide for researchers to identify target DUBs in cancers.

Abstract

Deubiquitinases (DUBs) deconjugate ubiquitin (UBQ) from ubiquitylated substrates to regulate its activity and stability. They are involved in several cellular functions. In addition to the general biological regulation of normal cells, studies have demonstrated their critical roles in various cancers. In this review, we evaluated and grouped the biological roles of DUBs, including proliferation, metastasis, and apoptosis, in the most common cancers in the world (liver, breast, prostate, colorectal, pancreatic, and lung cancers). The current findings in these cancers are summarized, and the relevant mechanisms and relationship between DUBs and cancers are discussed. In addition to highlighting the importance of DUBs in cancer biology, this study also provides updated information on the roles of DUBs in different types of cancers.

Insights Into the Properties, Biological Functions, and Regulation of USP21

Deubiquitylating enzymes (DUBs) antagonize ubiquitination by removing ubiquitin from their substrates. The role of DUBs in controlling various physiological and pathological processes has been extensively studied, and some members of DUBs have been identified as potential therapeutic targets in diseases ranging from tumors to neurodegeneration. Ubiquitin-specific protease 21 (USP21) is a member of the ubiquitin-specific protease family, the largest subfamily of DUBs. Although USP21 was discovered late and early research progress was slow, numerous studies in the last decade have gradually revealed the importance of USP21 in a wide variety of biological processes. In particular, the pro-carcinogenic effect of USP21 has been well elucidated in the last 2 years. In the present review, we provide a comprehensive overview of the current knowledge on USP21, including its properties, biological functions, pathophysiological roles, and cellular regulation. Limited pharmacological interventions for USP21 have also been introduced, highlighting the importance of developing novel and specific inhibitors targeting USP21.

Long Noncoding RNA SNHG16 Regulates the Growth of Human Lung Cancer Cells by Modulating the Expression of Aldehyde Dehydrogenase 2 (ALDH2)

The involvement of long noncoding RNA (lncRNA) SNHG16 has been reported in several human cancers. Notwithstanding, the role of lncRNA SNHG16 is yet largely unknown in human lung cancer. Consequently, this study was undertaken to investigate the role and therapeutic potential of SNHG16 in human lung cancer. The results showed a significant (P < 0.05) transcriptional upregulation of SNHG16 in lung cancer tissues and cell lines. However, downregulation of SNHG16 resulted in significant (P < 0.05) inhibition of lung cancer A549 and SK-LU-1 cell proliferation. DAPI and annexin V/PI assays revealed apoptosis to be responsible for inhibition of cell proliferation and colony formation observed upon SNHG16 knockdown. This was accompanied by enhancement of Bax and suppression of Bcl-2 expression in A549 and SK-LU-1 cells. Transwell assays revealed that silencing of SNHG16 also significantly (P < 0.05) inhibited migration and invasion of A549 and SK-LU-1 cells. Bioinformatic analysis revealed that SNHG16 interacted with ALDH2 to exert its effects in human lung cancer cells. The expression of ALDH2 was found to be significantly (P < 0.05) suppressed in human lung cancer tissues and cell lines. Overexpression of ALDH2 inhibited the proliferation and colony formation of the A549 and SK-LU-1 cells. However, silencing of ALDH2 could avoid the tumor-suppressive effects of SNHG16 knockdown. Finally, SNHG16 silencing was also found to inhibit in vivo tumor growth. Collectively, the study unveils the molecular role of SNHG16 in regulating the development of lung cancer by interacting with ALDH2.

The emerging role of ubiquitin-specific protease 20 in tumorigenesis and cancer therapeutics

As a critical member of the ubiquitin-specific proteolytic enzyme family, ubiquitin-specific peptidase 20 (USP20) regulates the stability of proteins via multiple signaling pathways. In addition, USP20 upregulation is associated with various cellular biological processes, such as cell cycle progression, proliferation, migration, and invasion. Emerging studies have revealed the pivotal role of USP20 in the tumorigenesis of various cancer types, such as breast cancer, colon cancer, lung cancer, gastric cancer and adult T cell leukemia. In our review, we highlight the different mechanisms of USP20 in various tumor types and demonstrate that USP20 regulates the stability of multiple proteins. Therefore, regulating the activity of USP20 is a novel tumor treatment. However, the clinical significance of USP20 in cancer treatment merits more evidence. Finally, different prospects exist for the continued research focus of USP20.

Computational Analyses of YY1 and Its Target RKIP Reveal Their Diagnostic and Prognostic Roles in Lung Cancer

Simple Summary

Lung cancer (LC) is the tumor with the highest global mortality rate. Novel personalized therapies are currently being tested (e.g., targeted inhibitors, the immune-checkpoint inhibitors), but they cannot yet prevent the very frequent relapse and generalized metastases observed in a large population of LC patients. Currently, there is an urgent need for novel reliable biomarkers for the prognosis and diagnosis of LC. Through the systematic analysis of multiple deposited expression datasets, this report aims to explore the role of the Yin-Yang 1 (YY1) transcription factor and its target the Raf Kinase Inhibitory Protein (RKIP) in LC. The computational analysis suggested the predictive diagnostic and prognostic roles for both YY1 and RKIP stimulating further studies for proving their implication as novel biomarkers, as well as therapeutically druggable targets in LC.

Abstract

Lung cancer (LC) represents a global threat, being the tumor with the highest mortality rate. Despite the introduction of novel therapies (e.g., targeted inhibitors, immune-checkpoint inhibitors), relapses are still very frequent. Accordingly, there is an urgent need for reliable predictive biomarkers and therapeutically druggable targets. Yin-Yang 1 (YY1) is a transcription factor that may work either as an oncogene or a tumor suppressor, depending on the genotype and the phenotype of the tumor. The Raf Kinase Inhibitory Protein (RKIP), is a tumor suppressor and immune enhancer often found downregulated in the majority of the examined cancers. In the present report, the role of both YY1 and RKIP in LC is thoroughly explored through the analysis of several deposited RNA and protein expression datasets. The computational analyses revealed that YY1 negatively regulates RKIP expression in LC, as corroborated by the deposited YY1-ChIP-Seq experiments and validated by their robust negative correlation. Additionally, YY1 expression is significantly higher in LC samples compared to normal matching ones, whereas RKIP expression is lower in LC and high in normal matching tissues. These observed differences, unlike many current biomarkers, bear a diagnostic significance, as proven by the ROC analyses. Finally, the survival data support the notion that both YY1 and RKIP might represent strong prognostic biomarkers. Overall, the reported findings indicate that YY1 and RKIP expression levels may play a role in LC as potential biomarkers and therapeutic targets. However, further studies will be necessary to validate the in silico results.

RNF144A exerts tumor suppressor function in breast cancer through targeting YY1 for proteasomal degradation to downregulate GMFG expression

Ring finger protein 144A (RNF144A), a poorly characterized member of the RING-in-between-RING family of E3 ubiquitin ligases, is an emerging tumor suppressor, but its underlying mechanism remains largely elusive. To address this issue, we used Affymetrix GeneChip Human Transcriptome Array 2.0 to profile gene expression in MDA-MB-231 cells stably expressing empty vector pCDH and Flag-RNF144A, and found that 128 genes were differentially expressed between pCDH- and RNF144A-expressing cells with fold change over 1.5. We further demonstrated that RNF144A negatively regulated the protein and mRNA levels of glial maturation factor γ (GMFG). Mechanistical investigations revealed that transcription factor YY1 transcriptionally activated GMFG expression, and RNF144A interacted with YY1 and promoted its ubiquitination-dependent degradation, thus blocking YY1-induced GMFG expression. Functional rescue assays showed that ectopic expression of RNF144A suppressed the proliferative, migratory, and invasive potential of breast cancer cells, and the noted effects were partially restored by re-expression of GMFG in RNF144A-overexpressing breast cancer cells. Collectively, these findings reveal that RNF144A negatively regulates GMFG expression by targeting YY1 for proteasomal degradation, thus inhibiting the proliferation, migration, and invasion of breast cancer cells.

The deubiquitinase OTUD1 inhibits non‐small cell lung cancer progression by deubiquitinating and stabilizing KLF4

Background

Lung cancer results in the highest mortality associated with cancer worldwide. Non‐small cell cancer (NSCLC) is the leading subtype of lung cancer. Ovarian tumor protease (OTU) domain‐containing protein 1 (OTUD1) is a member of the OTU subfamily of DUBs, and its function in NSCLC remains unclear.

Methods

GEPIA database was employed to reveal the expression level of OTUD1 in addition to Krüppel‐ like factor 4 (KLF4) in NSCLC tissue samples and prove the correlation between OTUD1 and KLF4. The protein level was estimated using western blot. Cell counting kit‐8 (CCK‐8) assay was used to detect cell viability and transwell assay was utilized to observe cell migration and invasion. Cycloheximide (CHX) was introduced to measure half‐lives of KLF4 and deubiquitination assay was used to detect deubiquitination ability of OTUD1.

Results

OTUD1 expression was downregulated in NSCLC tissues and cells. Overexpression of OTUD1 inhibited NSCLC cell progression and it was promoted by knockdown of OTUD1. OTUD1 was positively correlated with KLF4 and stabilized KLF4 at protein level by deubiquitinating KLF4. Overexpressing KLF4 dramatically eliminated the effects of OTUD1 on the development of NSCLC cells.

Conclusions

Our study revealed that OTUD1 suppresses NSCLC progression by mediating KLF4 stabilization, which suggests a potential gene target for the future treatment of NSCLC.

USP21 regulates Hippo signaling to promote radioresistance by deubiquitinating FOXM1 in cervical cancer

The ectopic expression of ubiquitin-specific peptidase 21 (USP21) is common in different types of cancer. However, its relationship with radio-sensitivity in cervical cancer (CC) remains unclear. In this study, we aimed to uncover the effect of USP21 on CC radio-resistance and its underlying mechanism. Our results showed that the expression of USP21 was markedly increased in CC tissues of radio-resistant patients and CC cells treated with radiation. Besides, knockdown of USP21 restrained the survival fractions, and facilitated apoptosis of CC cells in the absence or presence of radiation. Additionally, USP21 in combination with FOXM1 regulated the stability and ubiquitination of FOXM1. However, FOXM1 reversed the effects of USP21 knockdown on the radio-resistance of CC cells. Furthermore, FOXM1 knockdown activated the Hippo pathway by inhibiting the nuclear translocation of Yes-associated protein 1 (YAP1), and FOXM1 knockdown attenuated the radio-resistance of CC cells via inhibiting the Hippo-YAP1 pathway. USP21 activated the Hippo pathway by mediating FOXM1. Knockdown of USP21 enhanced the radio-sensitivity of CC cells in vivo. In summary, USP21 contributed to the radio-resistance of CC cells via FOXM1/Hippo signaling, and may serve as a promising target for radio-sensitizers in the radiotherapy of CC.

PR-619, a General Inhibitor of Deubiquitylating Enzymes, Diminishes Cisplatin Resistance in Urothelial Carcinoma Cells through the Suppression of c-Myc: An In Vitro and In Vivo Study

Cisplatin-based chemotherapy is the standard treatment for bladder urothelial carcinoma (UC). Most patients experience chemoresistance, the primary cause of treatment failure, which leads to disease relapse. The underlying mechanism of chemoresistance involves reduced apoptosis. In this study, we investigated the antitumor effect of the deubiquitylating enzyme inhibitor PR-619 in cisplatin-resistant bladder UC. Deubiquitinase (ubiquitin-specific protease 14 (USP14) and USP21) immunohistochemical staining demonstrated that deubiquitination is related to chemoresistance in patients with metastatic UC and may be a target for overcoming chemoresistance. Cytotoxicity and apoptosis were assessed using fluorescence-activated flow cytometry and a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium assay, and PR-619 was found to enhance the cytotoxic and apoptotic effects of cisplatin in cisplatin-resistant T24/R cells. Mitigated cisplatin chemoresistance was associated with the concurrent suppression of c-Myc expression in T24/R cells. Moreover, the expression of c-Myc was upregulated in human bladder UC specimens from patients with chemoresistance. Experiments in a xenograft nude mouse model confirmed that PR-619 enhanced the antitumor effects of cisplatin. These results are promising for the development of therapeutic strategies to prevent UC chemoresistance through the combined use of chemotherapeutic agents/deubiquitination inhibitors (PR-619) by targeting the c-Myc pathway.

A Review on the Role of Small Nucleolar RNA Host Gene 6 Long Non-coding RNAs in the Carcinogenic Processes

Being located on 17q25.1, small nucleolar RNA host gene 6 (SNHG16) is a member of SNHG family of long non-coding RNAs (lncRNA) with 4 exons and 13 splice variants. This lncRNA serves as a sponge for a variety of miRNAs, namely miR-520a-3p, miR-4500, miR-146a miR-16–5p, miR-98, let-7a-5p, hsa-miR-93, miR-17-5p, miR-186, miR-302a-3p, miR-605-3p, miR-140-5p, miR-195, let-7b-5p, miR-16, miR-340, miR-1301, miR-205, miR-488, miR-1285-3p, miR-146a-5p, and miR-124-3p. This lncRNA can affect activity of TGF-β1/SMAD5, mTOR, NF-κB, Wnt, RAS/RAF/MEK/ERK and PI3K/AKT pathways. Almost all studies have reported oncogenic effect of SNHG16 in diverse cell types. Here, we explain the results of studies about the oncogenic role of SNHG16 according to three distinct sets of evidence, i.e., in vitro, animal, and clinical evidence.

Long non-coding RNA SNHG16 as a potential biomarker in hepatocellular carcinoma: A meta-analysis

Small nucleolar RNA host gene 16 (SNHG16) has recently been reported as a potential biomarker in various cancers. However, the prognostic value of SNHG16 in hepatocellular carcinoma (HCC) has not been investigated yet. Therefore, the purpose of this study was to reveal the association between SNHG16 expression and clinicopathological characteristics of HCC.Standards-compliant literature was retrieved from multiple public databases, and data on overall survival, disease-free survival, and clinicopathological characteristics related to SNGH16 were extracted and meta-analysis was performed. Additionally, the Cancer Genome Atlas data were analyzed through the gene expression profiling interactive analysis database to verify previous results.A total of 5 reports involving 410 patients with HCC were enrolled. The high expression of SNHG16 indicated worse overall survival (hazard ratio, 2.10; 95% CI, 1.22-3.60; P = .007) and disease-free survival (hazard ratio, 3.38; 95% CI, 1.10-10.40; P = .03). Additionally, the high expression of SNHG16 predicted a larger tumor size, metastasis, and advanced TNM stage.SNHG16 could serve as a potential biomarker of poor prognosis in HCC.

Advances in deubiquitinating enzymes in lung adenocarcinoma

The process of ubiquitination and deubiquitination is widely present in the human body's protein reactions and plays versatile roles in multiple diseases. Deubiquitinating enzymes (DUBs) are significant regulators of this process, which cleave the ubiquitin (Ub) moiety from various substrates and maintain protein stability. Lung adenocarcinoma (LUAD) is the most common type of non-small cell lung cancer (NSCLC) and remains refractory to treatment. To elucidate the mechanism of LUAD and advance new therapeutic targets, we review the latest research progress on DUBs in LUAD. We summarize the biological capabilities of these DUBs and further highlight those DUBs that may serve as anticancer target candidates for precision treatment. We also discuss deubiquitinase inhibitors, which are expected to play a role in targeted LUAD therapy.

Circular RNA circβ-catenin aggravates the malignant phenotype of non-small-cell lung cancer via encoding a peptide

Background

More and more evidences demonstrate that circular RNAs (circNRAs) can encode protein. As a circRNA with translation capabilities, outcomes of circβ‐catenin in non‐small cell lung cancer (NSCLC) still need to be explored.

Method

The research methods of circβ‐catenin in the article include qRT‐PCR, wound healing assay, CCK‐8, colony formation, and Transwell assay. Western blotting and immunofluorescence were provided to detect protein expression levels and peptide encoded by circβ‐catenin, respectively.

Results

A prominently higher circβ‐catenin expression was found in NSCLC tissues. Silencing of circβ‐catenin was able to inhibit NSCLC cell migrating, invasive, and proliferative phenotypes. Overexpression of circβ‐catenin could enhance the migrating, invasive, and proliferative phenotypes of NSCLC cells. Importantly, circβ‐catenin was found to encode a peptide in NSCLC cells. Silencing or overexpression of circβ‐catenin could reduce or increase β‐catenin protein expression via suppressing the degradation of β‐catenin.

Conclusion

Circβ‐catenin could promote NSCLC cell malignant phenotypes via peptide‐regulated β‐catenin pathway. Our study provided a new understanding for the mechanisms of NSCLC.

JOSD1 promotes proliferation and chemoresistance of head and neck squamous cell carcinoma under the epigenetic regulation of BRD4

Background

Deubiquitinating enzymes (DUBs) play critical roles in various cancers by modulating functional proteins post-translationally. Previous studies have demonstrated that DUB Josephin Domain Containing 1 (JOSD1) is implicated in tumor progression, however, the role and mechanism of JOSD1 in head and neck squamous cell carcinoma (HNSCC) remain to be explored. In this study, we aimed to identify the clinical significance and function of JOSD1 in HNSCC.

Methods

The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were analyzed to find novel DUBs in HNSCC. Immunohistochemistry assay was performed to determine the expression of JOSD1 in our cohort of 42 patients suffered with HNSCC. Kaplan–Meier analysis was used to identify the correlation between JOSD1 and the prognosis of HNSCC patients. The regulation of BRD4 on JOSD1 was determined by using pharmacological inhibition and gene depletion. The in vitro and in vivo experiments were conducted to elucidate the role of JOSD1 in HNSCC.

Results

The results of IHC showed that JOSD1 was aberrantly expressed in HNSCC specimens, especially in the chemoresistant ones. The overexpression of JOSD1 indicated poor clinical outcome of HNSCC patients. Moreover, JOSD1 depletion dramatically impaired cell proliferation and colony formation, and promoted cisplatin-induced apoptosis of HNSCC cells in vitro. Additionally, JOSD1 suppression inhibited the tumor growth and improved chemosensitivity in vivo. The epigenetic regulator BRD4 contributed to the upregulation of JOSD1 in HNSCC.

Conclusions

These results demonstrate that JOSD1 functions as an oncogene in HNSCC progression, and provide a promising target for clinical diagnosis and therapy of HNSCC.

The Association of microRNA-34a With High Incidence and Metastasis of Lung Cancer in Gejiu and Xuanwei Yunnan

The incidence and associated mortality of lung cancer in tin miners in Gejiu County and farmers in Xuanwei Country, Yunnan Province have been very high in the world. Current published literatures on the molecular mechanisms of lung cancer initiation and progression in Gejiu and Xuanwei County are still controversial. Studies confirmed that microRNA-34a (miR-34a) functioned as a vital tumor suppressor in tumorigenesis and progression. However, the role and precise mechanisms of miR-34a and its regulatory gene network in initiation and progression of lung cancer in Gejiu and Xuanwei County, Yunnan Province, have not been elucidated. In the current study, we first found that miR-34a was downregulated in Gejiu lung squamous carcinoma YTMLC-90, Xuanwei lung adenocarcinoma XWLC-05, and other non-small cell lung carcinoma (NSCLC) cell lines, and miR-34a overexpression inhibited cell proliferation, migration and invasion, as well as induced cell apoptosis in YTMLC-90 and XWLC-05 cells. Our findings revealed that miR-34a is critical and cannot be considered as the area-specific non-coding RNA in initiation and progression of lung cancer in Gejiu and Xuanwei County. Next we revealed that miR-34a overexpression suppressed lung cancer growth and metastasis partially via increasing PTEN but reducing CDK6 expression that might lead to subsequent inactivation of PI3K/AKT pathway. Furthermore, our findings demonstrated that YY1 functioned as a tumor suppressor gene in initiation and progression of lung cancer in Gejiu and Xuanwei County. In conclusion, our findings in the study confirmed that miR-34a overexpression could simultaneously suppress tumor growth and metastasis and play a vital role in tumorigenesis and progression of NSCLC via increasing PTEN and YY1 expression, but decreasing CDK6. Most interestingly, our findings also raised doubts about the current ideas about these area-specific diseases.

De-Ubiquitinating Enzymes USP21 Regulate MAPK1 Expression by Binding to Transcription Factor GATA3 to Regulate Tumor Growth and Cell Stemness of Gastric Cancer

USP21 is a kind of deubiquitinating enzymes involved in the malignant progression of various cancers, while its role in gastric cancer (GC) and the specific molecular mechanism are still unclear. This study probed into the function of USP21 in vitro and in vivo, and discussed the regulatory mechanism of USP21 in GC in vitro. We reported that USP21 promoted GC cell proliferation, migration, invasion, and stemness in vitro, and regulated GC tumor growth and cell stemness in mice in vivo. USP21 stabilized the expression of GATA3 by binding to GATA3. Besides, GATA3 also regulated the expression of MAPK1 at the transcriptional level. A series of in vitro experiments testified that USP21 regulated the expression of MAPK1 by binding to transcription factor GATA3, thereby regulating the tumor growth and cell stemness of GC. Overall, this study identified a new USP21/GATA3/MAPK1 axis, which plays a pivotal role in promoting the malignant progression of GC and might provide a potential target for treatment.

LncRNA SNHG16 promotes pulmonary fibrosis by targeting miR-455-3p to regulate the Notch2 pathway

Background

Idiopathic pulmonary fibrosis (IPF) is the most common interstitial lung diseases with a poor prognosis. Long non-coding RNAs (lncRNAs) have been reported to be involved in IPF in several studies. However, the role of lncRNA SNHG16 in IPF is largely unknown.

Methods

Firstly, experimental pulmonary fibrosis model was established by using bleomycin (BML). Histology and Western blotting assays were used to determine the different stages of fibrosis and expression of several fibrosis biomarkers. The expression of SNHG16 was detected by quantitative real-time polymerase chain reaction (qRT‐PCR). EdU staining and wound-healing assay were utilized to analyze proliferation and migration of lung fibroblast cells. Molecular mechanism of SNHG16 was explored by bioinformatics, dual-luciferase reporter assay, RNA immunoprecipitation assay (RIP), and qRT-PCR.

Results

The expression of SNHG16 was significantly up-regulated in bleomycin-(BLM) induced lung fibrosis and transforming growth factor-β (TGF-β)-induced fibroblast. Knockdown of SNHG16 could attenuate fibrogenesis. Mechanistically, SNHG16 was able to bind and regulate the expression of miR-455-3p. Moreover, SNHG16 also regulated the expression of Notch2 by targeting miR-455-3p. Finally, SNHG16 could promote fibrogenesis by regulating the expression of Notch2.

Conclusion

Taken together, our study demonstrated that SNHG16 promoted pulmonary fibrosis by targeting miR-455-3p to regulate the Notch2 pathway. These findings might provide a novel insight into pathologic process of lung fibrosis and may provide prevention strategies in the future.

Transcription factor YY1 enhances the stemness of lung cancer cells by stabilizing hypoxia factor HIF-1α under a hypoxic microenvironment

The hypoxic microenvironment can facilitate the tumor progression, and transcription factor YY1 holds promoting effects in various tumors. This work aims to investigate whether YY1 is involved in hypoxia-induced stemness of lung cancer cells. We showed that hypoxic microenvironment induced the expression of HIF-1α and YY1, and the stemness of lung cancer cells, which was attenuated by YY1 knockdown. Additionally, we found that YY1 regulates the hypoxia-induced stemness in a HIF-1α-dependent manner, but independent on p53 expression. Further analysis revealed that YY1 physically interacted with HIF-1α protein and stabilized HIF-1α protein. Our work indicates a novel YY1/HIF-1α axis regulating the stemness of lung cancer cells.

Identification of hsa_circ_0039053 as an up-regulated and oncogenic circRNA in hepatocellular carcinoma via the miR-637-mediated USP21 activation

Accumulating evidence indicated that circular RNAs (circRNAs) are crucial regulators in tumorigenesis of hepatocellular carcinoma (HCC), but it is still unclear how hsa_circ_0039053 causes HCC. Herein, hsa_circ_0039053 was upregulated in HCC tissues and cell lines. The upregulation of hsa_circ_0039053 was linked to the advanced clinical characteristics of patients. Downregulation of hsa_circ_0039053 decreased the invasion and proliferative ability of tumors in vitro and as well as tumor growth in vivo. Mechanically, hsa_circ_0039053 positively regulated USP21 expression through interacting with miR-637. Moreover, overexpression of USP21 or silencing of miR-637 restored the inhibitory impacts of hsa_circ_0039053 silencing on HCC progression. Collectively, our study confirmed that hsa_circ_0039053 could be regarded as a competing endogenous RNA (ceRNA) to positively modulate the expression of USP21 combining with miR-637, which provided a potential target in HCC treatment.

Genomic Analysis of Localized High-Risk Prostate Cancer Circulating Tumor Cells at the Single-Cell Level

Accurate risk classification of men with localized high-risk prostate cancer directly affects treatment management decisions and patient outcomes. A wide range of risk assessments and classifications are available. However, each one has significant limitations to distinguish between indolent and aggressive prostate cancers. Circulating tumor cells (CTCs) may provide an alternate additional source, beyond tissue biopsies, to enable individual patient-specific clinical assessment, simply because CTCs can reveal both tumor-derived and germline-specific genetic information more precisely than that gained from a single diagnostic biopsy. In this study, we combined a filtration-based CTC isolation technology with prostate cancer CTC immunophenotyping to identify prostate cancer CTCs. Next, we performed 3-D telomere profiling prior to laser microdissection and single-cell whole-exome sequencing (WES) of 21 CTCs and 4 lymphocytes derived from 10 localized high-risk prostate cancer patient samples. Localized high-risk prostate cancer patient CTCs present a high number of telomere signals with lower signal intensities (short telomeres). To capture the genetic diversity/heterogeneity of high-risk prostate cancer CTCs, we carried out whole-exome sequencing. We identified 202,241 single nucleotide variants (SNVs) and 137,407 insertion-deletions (indels), where less than 10% of these genetic variations were within coding regions. The genetic variation (SNVs + indels) and copy number alteration (CNAs) profiles were highly heterogeneous and intra-patient CTC variation was observed. The pathway enrichment analysis showed the presence of genetic variation in nine telomere maintenance pathways (patients 3, 5, 6, and 7), including an important gene for telomere maintenance called telomeric repeat-binding factor 2 (TRF2). Using the PharmGKB database, we identified nine genetic variations associated with response to docetaxel. A total of 48 SNVs can affect drug response for 24 known cancer drugs. Gene Set Enrichment Analysis (GSEA) (patients 1, 3, 6, and 8) identified the presence of CNAs in 11 different pathways, including the DNA damage repair (DDR) pathway. In conclusion, single-cell approaches (WES and 3-D telomere profiling) showed to be useful in unmasking CTC heterogeneity. DDR pathway mutations have been well-established as a target pathway for cancer therapy. However, the frequent CNA amplifications found in localized high-risk patients may play critical roles in the therapeutic resistance in prostate cancer.