USP35 promotes hepatocellular carcinoma progression by protecting PKM2 from ubiquitination‑mediated degradation

Inhibition of colorectal cancer cell growth by downregulation of M2-PK and reduction of aerobic glycolysis by clove active ingredients

Exploring the anti-tumor molecular mechanisms of traditional Chinese medicines has become an important strategy to develop novel anti-tumor drugs in the clinic. Several pharmacological studies have reported the antioxidant, antibacterial, anti-inflammatory, and anti-tumor effects of clove. Previously, we have shown that the active fraction from clove (AFC) can inhibit the growth of tumor cells, particularly colon cancer cells, in vitro. However, the mechanism of action regarding the anti-colon cancer activity of AFC, especially in aerobic glycolysis, has not been adequately investigated. In this study, we found that AFC significantly inhibited the growth of five types of colon cancer cells, downregulated the mRNA and protein levels of M2-type pyruvate kinase (PKM2), and reduced aerobic glycolysis capacity. Transfection of PKM2-siRNA mimicked the inhibitory effects of AFC on aerobic glycolysis in colon cancer cells. Furthermore, the highly expressed, tumor-specific targets c-myc and cyclin D1 in cells were also found to be downregulated following the action of AFC. In the HCT116 cell xenograft nude mice models, the results after AFC administration were consistent with those of the cellular experiments, while AFC caused less liver injury and weight loss than the conventional chemotherapeutic agent 5- fluorouracil (5-FU). In conclusion, AFC inhibits colon cancer growth by downregulating PKM2 to inhibit aerobic glycolysis and reduce the tumor-specific high expression of c-myc and cyclin D1. Future work should explore how it downregulates pyruvate kinase (PK) in the first place, along with the intrinsic mechanism between the downregulation of PKM2 and the downregulation of c-myc.

FAM50A as a novel prognostic marker modulates the proliferation of colorectal cancer cells via CylinA2/CDK2 pathway

OBJECTIVE

Colorectal cancer (CRC) is the third most prevalent malignant tumor type and the second leading cause of cancer-related death. Sequence similarity family 50 member A (FAM50A) plays a vital role in numerous disease processes, including tumor progression. This study aimed to evaluate the prognostic significance of FAM50A in CRC and to explore its role in CRC cell proliferation.

METHODS

TCGA and GTEX databases and immunohistochemical staining (IHC) was used to study the expression of FAM50A in CRC tissues. Patient survival data were used to assess the prognostic significance of FAM50A in CRC using Kaplan-Meier analysis and Cox regression analysis. The Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), and colony-formation assays were employed to assess the impact of FAM50A on tumor cell proliferation. Flow cytometry was used to detect the changes of cell cycle. The cell cycle and cycle-related proteins were measured via western blotting (WB) to explore the potential mechanisms involving in cancer progresses.

RESULTS

The results of IHC revealed a notable upregulation of FAM50A expression levels in CRC tissue compared with adjacent normal tissue. Moreover, FAM50A expression was positively correlated with N and TNM stages in 145 patients with CRC. Cox regression analysis and construction of a nomogram revealed that high FAM50A expression was a prognostic indicator for poor overall survival in patients with CRC. Knockdown of FAM50A decreased cell proliferation ability, the proportion of EdU positive cells, and the number of CRC cell colonies, whereas overexpressing FAM50A promoted proliferative phenotypes. Knocking down FAM50A induced a significant increase in the number of cells in the S phase. Meanwhile, CyclinA2 and CDK2 were significantly reduced after FAM50A knocking down.

CONCLUSION

FAM50A may be a novel prognostic marker for CRC, and may participate in regulating tumor progression by targeting the CyclinA2/CDK2 signal pathway.

USP35 promotes breast cancer progression by regulating PFK-1 ubiquitination to mediate glycolysis

Ubiquitin-specific protease 35 (USP35) was found to be involved in various tumor progression, but its role in breast cancer remains largely unknown. USP35 mRNA and protein expression in breast cancer tissues and cells were evaluated by quantitative real-time PCR and Western blot, respectively. Subsequently, flow cytometry and 5-ethynyl-2'-deoxyuridine labeling were used to evaluate breast cancer cell apoptosis and proliferation. Cellular glycolytic function was analyzed using the Seahorse assay and various kits. Furthermore, co-immunoprecipitation (Co-IP) and immunoprecipitation assays were utilized to validate the deubiquitylation mechanism of USP35. Finally, a subcutaneous human xenograft tumor model was established in nude mice to verify the effect of USP35 in vivo. By examining the clinical samples and cell lines, we found that USP35 expression was significantly upregulated in breast cancer. Further functional studies showed that knockdown USP35 expression inhibited cell proliferation and promoted apoptosis. In addition, knockdown of USP35 decreased phosphofructokinase1 (PFK-1) expression and was associated with lower extracellular acidification rate and oxygen consumption rate compared with sh-Control. Co-IP assays identified PFK-1 as a direct deubiquitiation target of USP35. Importantly, we demonstrated that PFK-1 is an essential mediator for USP35-induced cell proliferation and glycolysis in vitro and in vivo. This study identified that USP35 regulates the proliferation and glycolysis of breast cancer cells by mediating the ubiquitination level of PFK-1. The USP35/PFK-1 axis offers novel insight for the treatment of breast cancer.NEW & NOTEWORTHY This study identified that USP35 regulates the proliferation and glycolysis of breast cancer cells by mediating the ubiquitination level of PFK-1. The USP35/PFK-1 axis offers novel insight for the treatment of breast cancer.

A novel ubiquitination-related gene signature for overall survival prediction in patients with liver hepatocellular carcinoma

Liver hepatocellular carcinoma (LIHC) is a highly heterogeneous disease, necessitating the discovery of novel biomarkers to enhance individualized treatment approaches. Recent research has shown the significant involvement of ubiquitin-related genes (UbRGs) in the progression of LIHC. However, the prognostic value of UbRGs in LIHC has not been investigated. In this study, the mRNA expression profiles and clinical data were obtained from public databases of LIHC patients. The least absolute shrinkage and selection operator Cox regression model was employed to construct a multigene signature in the TCGA cohort. Our results showed that a twelve UbRGs signature was developed to categorize patients into two risk groups, with significant differences in expression between LIHC and normal tissues. Patients in the high-risk group exhibited significantly reduced overall survival (OS) and progression-free survival compared to those in the low-risk group. The risk score was identified as an independent predictor for OS in multivariate Cox regression analyses. Receiver operating characteristic curve analysis confirmed the predictive capacity of the signature. Functional analysis revealed enrichment of immune-related pathways and differences in immune status between the two risk groups. The risk score was correlated with 35 transcription factors and 26 eRNA enhancers, and positively associated with tumor mutation burden. Patients in the high-risk group demonstrated decreased sensitivity to targeted and chemotherapeutic drugs than those in the low-risk group. In conclusion, our study identified a twelve UbRGs signature that may serve as a prognostic predictor for LIHC patients and and provide valuable insights for cancer treatment.

USP31 Activates the Wnt/β-catenin Signaling Pathway and Promotes Gastric Cancer Cell Proliferation, Invasion and Migration

BACKGROUND

Gastric cancer (GC) has a poor prognosis because it is highly aggressive, yet there are currently few effective therapies available. Although protein ubiquitination has been shown to play a complex role in the development of gastric cancer, to date, no efficient ubiquitinating enzymes have been identified as treatment targets for GC.

METHODS

The TCGA database was used for bioinformatic investigation of ubiquitin-specific protease 31 (USP31) expression in GC, and experimental techniques, including Western blotting, qRT-PCR, and immunohistochemistry, were used to confirm the findings. We also analyzed the relationship between USP31 expression and clinical prognosis in patients with GC. We further investigated the effects of USP31 on the proliferation, invasion, migration, and glycolysis of GC cells in vitro and in vivo by using colony formation, CCK-8 assays, Transwell chamber assays, cell scratch assays, and cell-derived xenograft. Furthermore, we examined the molecular processes by which USP31 influences the biological development of GC.

RESULTS

Patients with high USP31 expression have a poor prognosis because USP31 is abundantly expressed in GC. Therefore, USP31 reduces the level of ubiquitination of the Wnt/β-catenin pathway by binding to β-catenin, thereby activating glycolysis, which ultimately promotes GC proliferation and aggressive metastasis.

CONCLUSION

USP31 inhibits ubiquitination of β-catenin by binding to it, stimulates the Wnt/β-- catenin pathway, activates glycolysis, and accelerates the biology of GCs, which are all demonstrated in this work.

Unveiling the anticancer potential of plumbagin: targeting pyruvate kinase M2 to induce oxidative stress and apoptosis in hepatoma cells

Pyruvate kinase M2 (PKM2), a crucial enzyme in the glycolysis pathway, is commonly documented as being overexpressed in cancer cells. Inhibiting PKM2, a strategy to mitigate cancer cell-dependent glycolysis, has demonstrated efficacy in anticancer treatment. In this study, plumbagin, which was originally extracted from the plant Plumbago zeylanica L., was discovered as a novel PKM2 inhibitor and it could bind to PKM2 to inhibit the enzymatic activity. Treatment with plumbagin in HepG2 cells resulted in the decrease of PKM2 expression, which in turn reduced the protein kinase function. The mRNA levels of its downstream genes, such as LDHA and MYC, were suppressed. Additionally, plumbagin downregulated the expression of intracellular antioxidant proteins, which induced oxidative stress and mitochondrial damage, ultimately triggering apoptosis. Moreover, plumbagin also reduced the migration and proliferation of HepG2 cells. This study offered valuable insights into the molecular mechanism of plumbagin and advocated for the exploration of PKM2 inhibitors as viable possibilities for anticancer therapeutics.

The Role of Pyruvate Kinase M2 Posttranslational Modification in the Occurrence and Development of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is one of the deadly malignant tumors that directly leads to the death of nearly one million people worldwide every year, causing a serious burden on society. In the presence of sufficient oxygen, HCC cells rapidly generate energy through aerobic glycolysis, which promotes tumor cell proliferation, immune evasion, metastasis, angiogenesis, and drug resistance. Pyruvate kinase M2 (PKM2) is a key rate-limiting enzyme in glycolysis. In recent years, studies have found that PKM2 not only exerts pyruvate kinase activity in the process of glucose metabolism, but also exerts protein kinase activity in non-metabolic pathways to affect tumor cell processes, and its activity is flexibly regulated by various posttranslational modifications such as acetylation, phosphorylation, lactylation, ubiquitination, SUMOylation, and so forth. This review summarizes the role of posttranslational modifications of PKM2-related sites in the development of HCC.

Ubiquitination and deubiquitination in cancer: from mechanisms to novel therapeutic approaches

Ubiquitination, a pivotal posttranslational modification of proteins, plays a fundamental role in regulating protein stability. The dysregulation of ubiquitinating and deubiquitinating enzymes is a common feature in various cancers, underscoring the imperative to investigate ubiquitin ligases and deubiquitinases (DUBs) for insights into oncogenic processes and the development of therapeutic interventions. In this review, we discuss the contributions of the ubiquitin-proteasome system (UPS) in all hallmarks of cancer and progress in drug discovery. We delve into the multiple functions of the UPS in oncology, including its regulation of multiple cancer-associated pathways, its role in metabolic reprogramming, its engagement with tumor immune responses, its function in phenotypic plasticity and polymorphic microbiomes, and other essential cellular functions. Furthermore, we provide a comprehensive overview of novel anticancer strategies that leverage the UPS, including the development and application of proteolysis targeting chimeras (PROTACs) and molecular glues.

A novel model based on ubiquitination-related gene to predict prognosis and immunotherapy response in hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is a common cancer that is increasingly becoming a global health problem and a major public health concern. In order to improve patient outcomes, additional biomarkers and targets must be explored. Ubiquitination-related genes (URGs), as tumor regulators, exhibit multiple functions in tumor development. Our objective was to examine the influence of URGs on the prognosis of patients with HCC.

Methods

By utilizing unsupervised cluster analysis, we were able to identify URGs in the database and create a risk score profile for predicting the prognosis of patients with HCC. The model's clinical application was explored using subject operating characteristic curves, survival analysis, and correlation analysis. We additionally examined the variances in clinical traits, immune infiltration, somatic genetic alterations, and responsiveness to treatment among high- and low-risk populations identified by the prognostic model. Scores for immune cell infiltration and immune-related pathway activity were determined by performing ssGSEA enrichment analysis. Additionally, to investigate potential mechanisms, we utilized GO, KEGG and GSVA analyses.

Results

We developed a risk scoring model that relies on genes associated with ubiquitination. As the risk score increased, the malignancy and prognosis of the tumor worsened. The high-risk and low-risk groups exhibited notable disparities in relation to the immune microenvironment, genes associated with immune checkpoints, sensitivity to drugs, and response to immunotherapy.

Conclusion

The utilization of a risk model that relies on genes associated with ubiquitination can serve as a biomarker to assess the prognosis of patients with HCC, and aid in the selection of suitable therapeutic agents.

Ubiquitin-specific proteases: From biological functions to potential therapeutic applications in gastric cancer

Deubiquitination, a post-translational modification regulated by deubiquitinases, is essential for cancer initiation and progression. Ubiquitin-specific proteases (USPs) are essential elements of the deubiquitinase family, and are overexpressed in gastric cancer (GC). Through the regulation of several signaling pathways, such as Wnt/β-Catenin and nuclear factor-κB signaling, and the promotion of the expression of deubiquitination- and stabilization-associated proteins, USPs promote the proliferation, metastasis, invasion, and epithelial-mesenchymal transition of GC. In addition, the expression of USPs is closely related to clinicopathological features, patient prognosis, and chemotherapy resistance. USPs therefore could be used as prognostic biomarkers. USP targeting small molecule inhibitors have demonstrated strong anticancer activity. However, they have not yet been tested in the clinic. This article provides an overview of the latest fundamental research on USPs in GC, aiming to enhance the understanding of how USPs contribute to GC progression, and identifying possible targets for GC treatment to improve patient survival.

The USP35-CXCR3 Axis plays an oncogenic role in JeKo-1 mantle cell lymphoma cells

In B cells, the chemokine receptor CXCR3 is expressed only by a subset of B cells. However, CXCR3 is highly expressed in a rare type of B-cell lymphoma known as Mantle Cell Lymphoma (MCL) and CXCR3 inhibitor impairs proliferation and induces apoptosis in the MCL cell line JeKo-1. Despite this, the mechanism responsible for maintaining high levels of CXCR3 in MCL cells remains unclear. In this study, we assessed CXCR3 expression and amplification in MCL samples and confirmed that CXCR3 is overexpressed in MCL tissues. We also observed that CXCR3 amplification is present in a small portion of MCL patients and is associated with MCL classification. We then screened ubiquitin-specific proteases (USPs) that might control the degradation of CXCR3 protein. Our investigation revealed that USP35 acts as a potent stabilizer of CXCR3 protein. Knockdown of USP35 substantially reduced the CXCR3 protein levels in JeKo-1 cells, resulting in reduced cell viability, cell cycle arrest, increased apoptosis, and mitigated migration and invasion in these cells. At the molecular level, USP35 deubiquitinates and stabilizes CXCR3. USP35 deficiency attenuated the activation of the JAK1/STAT1 pathway and reduced the expression of β-catenin and c-Myc in JeKo-1 cells. Furthermore, we observed that overexpression of CXCR3 rescued the impaired tumorigenicity of USP35-deficient JeKo-1 cells, and the mechanism may be related to the fact that USP35 promotes CXCR3 deubiquitination to stabilize its expression. These findings collectively demonstrate the oncogenic role of the USP35-CXCR3 axis in JeKo-1 MCL cells.