Ubiquitin-specific peptidase 46 promotes tumor metastasis through stabilizing ENO1 in human esophageal squamous cell carcinoma

Transcriptional regulation and post-translational modifications in the glycolytic pathway for targeted cancer therapy

Cancer cells largely rely on aerobic glycolysis or the Warburg effect to generate essential biomolecules and energy for their rapid growth. The key modulators in glycolysis including glucose transporters and enzymes, e.g. hexokinase 2, enolase 1, pyruvate kinase M2, lactate dehydrogenase A, play indispensable roles in glucose uptake, glucose consumption, ATP generation, lactate production, etc. Transcriptional regulation and post-translational modifications (PTMs) of these critical modulators are important for signal transduction and metabolic reprogramming in the glycolytic pathway, which can provide energy advantages to cancer cell growth. In this review we recapitulate the recent advances in research on glycolytic modulators of cancer cells and analyze the strategies targeting these vital modulators including small-molecule inhibitors and microRNAs (miRNAs) for targeted cancer therapy. We focus on the regulation of the glycolytic pathway at the transcription level (e.g., hypoxia-inducible factor 1, c-MYC, p53, sine oculis homeobox homolog 1, N6-methyladenosine modification) and PTMs (including phosphorylation, methylation, acetylation, ubiquitination, etc.) of the key regulators in these processes. This review will provide a comprehensive understanding of the regulation of the key modulators in the glycolytic pathway and might shed light on the targeted cancer therapy at different molecular levels.

Clinical and genetic characteristics of patients with TRG 0 and TRG III in esophageal squamous cell carcinoma after neoadjuvant therapy

Neoadjuvant therapy (NAT) is an important treatment for patients with resectable locally advanced esophageal squamous cell carcinoma (ESCC), but neoadjuvant resistance affects the overall treatment outcome. Therefore, it is particularly important to accurately screen the population for NAT and explore the mechanism of resistance. Usually, different chemotherapy regimens cause different drug resistance mechanisms. Prior to combining immunotherapy with chemotherapy, extensive research has been conducted on previous drug resistance mechanisms. Currently, the mainstream NAT for ESCC involves chemotherapy combined with immunotherapy. We have witnessed the remarkable effect of this combination therapy; however, there are still a considerable number of patients whose tumor tissues show no change or even progress after NAT, and their drug resistance mechanisms remain unclear. Hence, we aim to identify relevant evidence that can distinguish and predict the effectiveness of NAT from a clinical perspective in order to provide a clinical basis for future screening of suitable populations for NAT and discovery of drug resistance mechanisms. This study is based in China's high incidence area of esophageal cancer, where enrolled patients all receive the current mainstream NAT regimen resulting in more reliable outcomes.

USP46 promotes the interferon antiviral signaling in black carp by deubiquitinating TBK1

Ubiquitin-specific peptidase 46 (USP46) functions as a deubiquitinating enzyme, facilitating the removal of ubiquitin molecules attached to substrate proteins and playing a critical role in cancer and neurodegenerative diseases. However, its function in innate antiviral immunity is unknown. In this study we cloned and identified bcUSP46, a homolog of USP46 from black carp. We discovered that overexpression of bcUSP46 enhanced the transcription of interferon (IFN) promoters and increased the expression of IFN, PKR, and Mx1. In addition, bcUSP46 knockdown significantly inhibited the expression of ISG genes, as well as the antiviral activity of the host cells. Interestingly, when bcUSP46 was co-expressed with the RLR factors, it significantly enhanced the activity of the IFN promoter mediated by these factors, especially TANK-binding kinase 1 (TBK1). The subsequent co-immunoprecipitation (co-IP) and immunofluorescence (IF) assay confirmed the association between bcUSP46 and bcTBK1. Noteworthily, co-expression of bcUSP46 with bcTBK1 led to an elevation of bcTBK1 protein level. Further analysis revealed that bcUSP46 stabilized bcTBK1 by eliminating the K48-linked ubiquitination of bcTBK1. Overall, our findings highlight the unique role of USP46 in modulating TBK1/IFN signaling and enrich our knowledge of the function of deubiquitination in regulating innate immunity in vertebrates.

USP46 enhances tamoxifen resistance in breast cancer cells by stabilizing PTBP1 to facilitate glycolysis

Tamoxifen (TAM) is the primary drug for treating estrogen receptor alpha-positive (ER+) breast cancer (BC). However, resistance to TAM can develop in some patients, limiting its therapeutic efficacy. The ubiquitin-specific protease (USP) family has been associated with the development, progression, and drug resistance of various cancers. To explore the role of USPs in TAM resistance in BC, we used qRT-PCR to compare USP expression between TAM-sensitive (MCF-7 and T47D) and TAM-resistant cells (MCF-7R and T47DR). We then modulated USP46 expression and examined its impact on cell proliferation, drug resistance (via CCK-8 and EdU experiments), glycolysis levels (using a glycolysis detection assay), protein interactions (confirmed by co-IP), and protein changes (analyzed through Western blotting). Our findings revealed that USP46 was significantly overexpressed in TAM-resistant BC cells, leading to the inhibition of the ubiquitin degradation of polypyrimidine tract-binding protein 1 (PTBP1). Overexpression of PTBP1 increased the PKM2/PKM1 ratio, promoted glycolysis, and intensified TAM resistance in BC cells. Knockdown of USP46 induced downregulation of PTBP1 protein by promoting its K48-linked ubiquitination, resulting in a decreased PKM2/PKM1 ratio, reduced glycolysis, and heightened TAM sensitivity in BC cells. In conclusion, this study highlights the critical role of the USP46/PTBP1/PKM2 axis in TAM resistance in BC. Targeted therapy against USP46 may represent a promising strategy to improve the prognosis of TAM-resistant patients.

Emerging roles of deubiquitinating enzymes in actin cytoskeleton and tumor metastasis

BACKGROUND

Metastasis accounts for the majority of cancer-related deaths. Actin dynamics and actin-based cell migration and invasion are important factors in cancer metastasis. Metastasis is characterized by actin polymerization and depolymerization, which are precisely regulated by molecular changes involving a plethora of actin regulators, including actin-binding proteins (ABPs) and signalling pathways, that enable cancer cell dissemination from the primary tumour. Research on deubiquitinating enzymes (DUBs) has revealed their vital roles in actin dynamics and actin-based migration and invasion during cancer metastasis.

CONCLUSION

Here, we review how DUBs drive tumour metastasis by participating in actin rearrangement and actin-based migration and invasion. We summarize the well-characterized and essential actin cytoskeleton signalling molecules related to DUBs, including Rho GTPases, Src kinases, and ABPs such as cofilin and cortactin. Other DUBs that modulate actin-based migration signalling pathways are also discussed. Finally, we discuss and address therapeutic opportunities and ongoing challenges related to DUBs with respect to actin dynamics.

Upregulation of miR-194-5p or silencing of PRC1 enhances radiotherapy sensitivity in esophageal squamous carcinoma cells

Background

To investigate the possible molecular mechanism of miR-194-5p/PRC1/Wnt/β-catenin signaling axis that regulates the invasive metastatic ability and radiotherapy sensitivity of esophageal squamous cell carcinoma (ESCC) cells.

Methods

ESCC-related differentially expressed miRNAs were identified by microarray analysis, followed by the identification of a putative target. The targeting relationship between miR-194-5p and PRC1 was assayed. A series of mimic and shRNA were transfected into ESCC cells to find out the mechanism of miR-194-5p in ESCC by regulating PRC1 through Wnt/β-catenin signaling pathway and their effect on cell proliferation, migration, invasion, and radiosensitivity as well as xenograft tumor growth and metastasis in nude mice.

Results

We demonstrated low miR-194-5p expression and high PRC1 expression in ESCC tissues and cells. PRC1 was confirmed as a putative target for miR-194-5p. High miR-194-5p or silenced PRC1 enhanced ESCC cell radiosensitivity but reduced proliferation, invasion, and migration via PRC1 through modulation of the Wnt/β-catenin signaling pathway. Animal experiments also validated that overexpression of miR-194-5p suppressed tumorigenesis and in vivo metastasis in nude mice.Conclusion: miR-194-5p can inhibit the Wnt/β-catenin signaling pathway through down-regulation of the PRC1 gene, thereby enhancing the sensitivity of ESCC cells to radiotherapy and attenuating the invasion and metastasis ability of ESCC cells.

Deubiquitylating Enzymes in Cancer and Immunity

Deubiquitylating enzymes (DUBs) maintain relative homeostasis of the cellular ubiquitome by removing the post-translational modification ubiquitin moiety from substrates. Numerous DUBs have been demonstrated specificity for cleaving a certain type of ubiquitin linkage or positions within ubiquitin chains. Moreover, several DUBs perform functions through specific protein-protein interactions in a catalytically independent manner, which further expands the versatility and complexity of DUBs' functions. Dysregulation of DUBs disrupts the dynamic equilibrium of ubiquitome and causes various diseases, especially cancer and immune disorders. This review summarizes the Janus-faced roles of DUBs in cancer including proteasomal degradation, DNA repair, apoptosis, and tumor metastasis, as well as in immunity involving innate immune receptor signaling and inflammatory and autoimmune disorders. The prospects and challenges for the clinical development of DUB inhibitors are further discussed. The review provides a comprehensive understanding of the multi-faced roles of DUBs in cancer and immunity.

USP32 deubiquitinase: cellular functions, regulatory mechanisms, and potential as a cancer therapy target

An essential protein regulatory system in cells is the ubiquitin-proteasome pathway. The substrate is modified by the ubiquitin ligase system (E1-E2-E3) in this pathway, which is a dynamic protein bidirectional modification regulation system. Deubiquitinating enzymes (DUBs) are tasked with specifically hydrolyzing ubiquitin molecules from ubiquitin-linked proteins or precursor proteins and inversely regulating protein degradation, which in turn affects protein function. The ubiquitin-specific peptidase 32 (USP32) protein level is associated with cell cycle progression, proliferation, migration, invasion, and other cellular biological processes. It is an important member of the ubiquitin-specific protease family. It is thought that USP32, a unique enzyme that controls the ubiquitin process, is closely linked to the onset and progression of many cancers, including small cell lung cancer, gastric cancer, breast cancer, epithelial ovarian cancer, glioblastoma, gastrointestinal stromal tumor, acute myeloid leukemia, and pancreatic adenocarcinoma. In this review, we focus on the multiple mechanisms of USP32 in various tumor types and show that USP32 controls the stability of many distinct proteins. Therefore, USP32 is a key and promising therapeutic target for tumor therapy, which could provide important new insights and avenues for antitumor drug development. The therapeutic importance of USP32 in cancer treatment remains to be further proven. In conclusion, there are many options for the future direction of USP32 research.

Ubiquitin specific protease 46 potentiates triple negative breast cancer development by stabilizing PGAM1-mediated glycolysis

Triple-negative breast cancer (TNBC) is a malignancy with high metastasis rate and poor prognosis. Limited drugs are effective for the treatment of TNBC patients. Ubiquitin specific proteases (USPs) are important posttranscription modulators that promote protein stability by reducing the ubiquitination of the proteins. Aberrant expression of USPs is involved in the development of numerous cancers. However, it remains poorly understood on the role of USP46 in TNBC growth and metastasis. In this study, we explored the clinical relevance, function and molecular mechanisms of USP46 in TNBC. USP46 expression was increased in breast cancer tissues. High expression of USP46 was associated with the poorer prognosis of the patients. Overexpression and knockdown experiments demonstrated that USP46 was critical for TNBC cell growth, migration, and tumorigenesis. Mechanistically, USP46 enhanced the protein stability of phosphoglycerate mutase 1 (PGAM1) via direct interaction. Importantly, USP46 stimulated the glycolysis and promoted the malignant growth of TNBC cells through upregulation of PGAM1. Our study reveals that USP46/PGAM1 axis contributes to TNBC progression and is a potential target for the treatment of TNBC patients.

MiR-27a-3p targets USP46 to inhibit the cell proliferation of hepatocellular carcinoma

Micro-RNAs are involved in the occurrence and development of hepatocellular carcinoma (HCC) as potential therapeutic targets for HCC. In this study, we found that miR-27a-3p was highly expressed in HCC, which was associated with lower survival rates of HCC patients. In vivo and in vitro functional experiments confirmed that over-expression or knock-down miR-27a-3p could significantly affect the proliferation ability of HCCLM3 and Huh-7, two HCC cell lines. Ubiquitin-specific protease 46 (USP46) was confirmed as the key target gene of miR-27a-3p in HCC via RNA-seq, quantitative polymerase chain reaction, Western blotting, and luciferase report. When knocking down USP46, the proliferation activity of HCC cells was significantly enhanced, while it was significantly inhibited after over-expressing USP4. Above results suggest that the abnormally over-expressed miR-27a-3p in liver promotes the proliferation of cancer cells and accelerates the development of HCC by targeting inhibition the expression of USP46. Targeting miR-27a-3p may be an effective strategy for prevention and treatment of HCC.

FAM126A interacted with ENO1 mediates proliferation and metastasis in pancreatic cancer via PI3K/AKT signaling pathway

Pancreatic cancer (PC) is a common digestive system carcinoma with high mortality rate mostly due to aberrant growth and distant metastasis. Current researches demonstrated that Family Sequence Similarities (FAMs) have been involving in tumor development, and which subfamily has the function of promoting or inhibiting tumors and its in-depth molecular mechanism remains unclear. Based on the Gene Expression Omnibus (GEO), the Gene Expression Profiling Interactive Analysis (GEPIA2), we observed that FAM126A is in high expressed level among PC tissues and contributes to worse progression of PC, which was validated by PC tissue microarray. Function assay indicated that overexpression of FAM126A accelerates PC cell proliferation, invasion and migration in vitro, as well as liver cancer metastasis in vivo. Further, we found that FAM126A induces epithelial-mesenchymal transition (EMT), including the downregulation of E-cadherin epithelial marker expression, and the upregulation of N-cadherin, Vimentin, and Snail, mesenchymal marker expression. By co-localization and co-immunoprecipitation assays, we confirmed that FAM126A directly interacts with ENO1, which was a key activator of the PI3K/AKT signaling pathway. Furthermore, ENO1 knockdown reversed cell proliferation, migration, and invasion of PC cells promoted by FAM126A overexpression in vitro and in vivo. In general, these results verified FAM126A is an oncogene interacting with ENO1 in PC by activating PI3K/AKT signaling pathway.

Knockdown of UCHL3 inhibits esophageal squamous cell carcinoma progression by reducing CRY2 methylation

UCHL3 (Ubiquitin carboxyl-terminal hydrolase L3), a member of deubiquitinating enzymes, has been implicated in various cancers. However, the role of UCHL3 in esophageal squamous cell carcinoma (ESCC) remains unknown. In the current study, we aimed to investigate the role of UCHL3 in ESCC growth and migration, and whether UCHL3 could modulate CRY2 methylation through FOXM1. The expression of UCHL3 and CRY2 in ESCC tissues was assessed using qRT-PCR, western blotting and immunohistochemistry (IHC). Cell viability was determined by CCK-8 and colony formation assays. Hoechst 33342 and flow cytometry were used to detect cell apoptosis. Transwell assay was performed to investigate cell migration and invasion. In vivo animal model was used to assess cell tumorigenesis. Methylation-Specific PCR (MSP) was applied to detect CRY2 methylation in the promoter region. The results showed that UCHL3 expression was elevated in ESCC tissues and cells, while CRY2 expression was decreased. UCHL3 silencing inhibited cell viability, invasion, migration and induced cell apoptosis in vitro, repressed tumor growth in vivo, and increased CRY2 expression and decreased FOXM1 expression. In addition, UCHL3 knockdown decreased CRY2 methylation through downregulating FOXM1, leading to an increase in the expression of CRY2. Moreover, CRY2 silencing abolished UCHL3 deficiency-mediated inhibition in cell growth and migration. In summary, this study reveals that knockdown of UCHL3 inhibits ESCC growth and migration by reducing CRY2 methylation through downregulation of FOXM1 expression.

Deubiquitinating enzyme USP46 suppresses the progression of hepatocellular carcinoma by stabilizing MST1

The deubiquitinating enzyme USP46 (ubiquitin-specific protease 46) is implicated in various cancers. However, its role and regulatory mechanism in HCC (hepatocellular carcinoma) are still unknown. In this study, we showed that USP46 is downregulated in HCC tissues and that low USP46 levels are associated with poor prognosis in HCC patients. In functional experiments, overexpression of USP46 impaired proliferation and metastasis of HCC cells, whereas knockdown of USP46 enhanced cell proliferation and invasiveness in vitro and in vivo. Furthermore, we found that USP46 suppresses HCC cell proliferation and metastasis by inhibiting YAP1. Ectopic expression of YAP1 rescued the inhibition of cell proliferation and metastasis caused by USP46 overexpression. Mechanistically, USP46 promotes the degradation of YAP1 by increasing expression of MST1, and the increase in MST1 protein antagonizes YAP1 to suppress HCC progression. Finally, we demonstrated that USP46 stabilizes the MST1 protein by directly binding to it and decreasing its ubiquitination. Taken together, our results demonstrated that USP46 may be a novel tumor suppressor in HCC. Moreover, USP46 acts as a deubiquitinating enzyme of MST1 to potentiate MST1 kinase activity to suppress tumor growth and metastasis, indicating that USP46 activation may represent a potential treatment strategy for HCC.

USP21 promotes cell proliferation by maintaining the EZH2 level in diffuse large B-cell lymphoma

BACKGROUND

Diffuse large B-cell lymphoma (DLBCL) is the most common category of non-Hodgkin lymphoma (NHL). However, the underlying molecular mechanism of DLBCL remains unclear.

METHODS

Real-time PCR and Western blot analysis were performed to assess the expression of ubiquitin-specific peptidase 21 (USP21) or enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2). CCK8 assay and cell death staining were carried out to examine the role of USP21 in cell proliferation and cell death, respectively.

RESULTS

We found that the deubiquitinase USP21 was highly expressed in the DLBCL lymphoid tissue. The expression of USP21 promoted DLBCL cell proliferation, while it had no obvious effect on cell death. In addition, we found that USP21 regulated cell proliferation via cysteine 221, the catalytic site of USP21. Furthermore, we identified that USP21 could stabilize EZH2, a protein required for germinal center formation and lymphoma formation.

CONCLUSION

The deubiquitinase USP21 promotes cell proliferation by maintaining the EZH2 protein level in DLBCL.

Krüppel-like factor 12 suppresses bladder cancer growth through transcriptionally inhibition of enolase 2

Krüppel-like factors (KLFs) are transcription factors and play important roles in bladder cancer (BC). Clarifying the function of KLFs will provide new strategies for clinical treatment of BC. In this study, we found that Krüppel-like factor 12 (KLF12) was decreased in BC tissues and cells. Knockdown of KLF12 by siRNA dramatically elevated the proliferation and colony formation of BC cells. By contrast, overexpressing KLF12 suppressed the cell viability and the number of clones. Overexpression of KLF12 also regulated cell cycle progression, apoptosis and migration of BC cells. Furthermore, KLF12 bound to the promoter of enolase 2 (ENO2) and transcriptionally inhibited the expression of ENO2, which was highly expressed in BC tissues. KLF12 suppressed, while ENO2 promoted glycolysis. Lastly, ENO2 overexpression and knockdown promoted and suppressed the proliferation and migration of BC cells, respectively. These results suggest that KLF12 acts as a tumor suppressor by negatively regulated ENO2. Targeting ENO2 is a promising treatment strategy for this malignancy.