BRCC3 Promotes Tumorigenesis of Bladder Cancer by Activating the NF-κB Signaling Pathway Through Targeting TRAF2

Deubiquitinase BRCC3 promotes the migration, invasion and EMT progression of colon adenocarcinoma by stabilizing MET expression

BACKGROUND

Breast cancer type 1 susceptibility protein/breast cancer type 2 susceptibility protein-containing complex subunit 3 (BRCC3), a deubiquitinase (DUBs), is overexpressed in various cancers. However, the underlying biological roles of BRCC3 in adenocarcinoma colon (COAD) have yet to be decrypted.

OBJECTIVE

In this work, we explored the potential biological function of BRCC3 in the natural process of COAD cells.

METHODS

The expression levels of BRCC3 in COAD tissues and cell lines were investigated via quantitative real time polymerase chain reaction and western blotting analyses. Meanwhile, short hairpin RNAs targeting BRCC3 (sh-BRCC3) or mesenchymal-epithelial transition factor (MET) (sh-MET) were used to investigate the biological function, including proliferation, apoptosis, migration, invasion, and epithelial-mesenchymal transition (EMT) progression in COAD cells. Furthermore, the expression levels of EMT-related biomarkers were detected with western blotting analysis. Furthermore, we also performed Co-IP assay to identify the correlation between BRCC3 and MET.

RESULTS

BRCC3 expression was increased in COAD tissues and cell lines. ShRNA-mediated downmodulation of BRCC3 in COAD cell lines induced EMT progression. BRCC3 knockdown resulted in decreased migration as well as invasion and increased apoptosis of SW480 and Lovo cells. Besides, MET was regulated by BRCC3 and involved in the migration, invasion, and EMT in SW480 and Lovo cells. Finally, we uncovered that the overexpressed MET reversed the effects of BRCC3 knockdown in COAD cell development.

CONCLUSIONS

BRCC3 acted as a critical factor in the development of COAD by deubiquitinating and stabilizing MET, which might provide an emerging biomarker for the therapeutic and diagnosis strategy of COAD.

High expression of PPP1CC promotes NHEJ-mediated DNA repair leading to radioresistance and poor prognosis in nasopharyngeal carcinoma

Protein phosphatase 1 catalytic subunit gamma (PPP1CC) promotes DNA repair and tumor development and progression, however, its underlying mechanisms remain unclear. This study investigated the molecular mechanism of PPP1CC's involvement in DNA repair and the potential clinical implications. High expression of PPP1CC was significantly correlated with radioresistance and poor prognosis in human nasopharyngeal carcinoma (NPC) patients. The mechanistic study revealed that PPP1CC bound to Ku70/Ku80 heterodimers and activated DNA-PKcs by promoting DNA-PK holoenzyme formation, which enhanced nonhomologous end junction (NHEJ) -mediated DNA repair and led to radioresistance. Importantly, BRCA1-BRCA2-containing complex subunit 3 (BRCC3) interacted with PPP1CC to enhance its stability by removing the K48-linked polyubiquitin chain at Lys234 to prevent PPP1CC degradation. Therefore, BRCC3 helped the overexpressed PPP1CC to maintain its high protein level, thereby sustaining the elevation of DNA repair capacity and radioresistance. Our study identified the molecular mechanism by which PPP1CC promotes NHEJ-mediated DNA repair and radioresistance, suggesting that the BRCC3-PPP1CC-Ku70 axis is a potential therapeutic target to improve the efficacy of radiotherapy.

USP15 facilitates the progression of bladder cancer by amplifying the activation of the NF-κB signaling pathway

USP15, a pivotal member of the deubiquitinase family, plays a crucial role in orchestrating numerous vital biological processes, including the regulation of NF-κB signaling pathway and deubiquitination of proto-oncogenes. In various cancers, USP15 has been validated to exhibit up-regulated expression, impacting the initiation and progression of cancer. However, its precise mechanism in bladder cancer remains elusive. Our study shed light on the significant overexpression of USP15 in bladder cancer cells compared to normal bladder cells, correlating with a poorer prognosis for bladder cancer patients. Strikingly, attenuation of USP15 expression greatly attenuated the proliferation, migration, and invasion of bladder cancer cells. Moreover, upregulation of USP15 was found to drive cancer progression through the activation of the NF-κB signaling pathway. Notably, USP15 directly deubiquitinates BRCC3, heightening its expression level, and subsequent overexpression of BRCC3 counteracted the antitumoral efficacy of USP15 downregulation. Overall, our findings elucidated the carcinogenic effects of USP15 in bladder cancer, primarily mediated by the excessive activation of the NF-κB signaling pathway, thereby promoting tumor development. These results underscore the potential of USP15 as a promising therapeutic target for bladder cancer in the future.

Body Weight Correlates with Molecular Variances in Patients with Cancer

Overweight and obesity are identified by a high body mass index (BMI) and carry significant health risks due to associated comorbidities. Although epidemiologic data connect overweight/obesity with 13 cancer types, a better understanding of the molecular mechanisms underlying this correlation is needed to improve prevention and treatment strategies. In this study, we conducted a comprehensive analysis of molecular differences between overweight or obese patients and normal weight patients across 14 different cancer types from The Cancer Genome Atlas. Using the propensity score weighting algorithm to control for confounding factors, obesity-specific mutational features were identified, such as higher mutation burden in rectal cancer and biased mutational signatures in other cancers. Differentially expressed genes (DEG) in tumors from patients with overweight/obesity were predominantly upregulated and enriched in inflammatory and hormone-related pathways. These DEGs were significantly associated with survival rates in various cancer types, highlighting the impact of elevated body fat on gene expression profiles and clinical outcomes in patients with cancer. Interestingly, while high BMI seemed to have a negative impact on most cancer types, the normal weight-biased mutational and gene expression patterns indicated overweight/obesity may be beneficial in endometrial cancer, suggesting the presence of an "obesity paradox" in this context. Body fat also significantly impacted the tumor microenvironment by modulating immune cell infiltration, underscoring the importance of understanding the interplay between weight and immune response in cancer progression. Together, this study systematically elucidates the molecular differences corresponding to body weight in multiple cancer types, offering potentially critical insights for developing precision therapy for patients with cancer.

SIGNIFICANCE

Elucidation of the complex interplay between body weight and the molecular landscape of cancer could potentially guide tailored therapies and improve patient management amid the global obesity crisis.

BRCC3 mediates inflammation and pyroptosis in cerebral ischemia/reperfusion injury by activating the NLRP6 inflammasome

AIMS

Neuroinflammation and pyroptosis are key mediators of cerebral ischemia/reperfusion (I/R) injury-induced pathogenic cascades. BRCC3, the human homolog of BRCC36, is implicated in neurological disorders and plays a crucial role in neuroinflammation and pyroptosis. However, its effects and potential mechanisms in cerebral I/R injury in mice are unclear.

METHODS

Cellular localization of BRCC3 and the interaction between BRCC3 and NLRP6 were assessed. Middle cerebral artery occlusion/reperfusion (MCAO) and oxygen-glucose deprivation/reoxygenation (OGD/R) models were established in mice and HT22 cells, respectively, to simulate cerebral I/R injury in vivo and in vitro.

RESULTS

BRCC3 protein expression peaked 24 h after MCAO and OGD/R. BRCC3 knockdown reduced the inflammation and pyroptosis caused by cerebral I/R injury and ameliorated neurological deficits in mice after MCAO. The effects of BRCC3 on inflammation and pyroptosis may be mediated by NLRP6 inflammasome activation. Moreover, both BRCC3 and its N- and C-terminals interacted with NLRP6, and both BRCC3 and its terminals reduced NLRP6 ubiquitination. Additionally, BRCC3 affected the interaction between NLRP6 and ASC, which may be related to inflammasome activation.

CONCLUSION

BRCC3 shows promise as a novel target to enhance neurological recovery and attenuate the inflammatory responses and pyroptosis caused by NLRP6 activation in cerebral I/R injury.

Friend or foe? Reciprocal regulation between E3 ubiquitin ligases and deubiquitinases

Protein ubiquitination is a post-translational modification that entails the covalent attachment of the small protein ubiquitin (Ub), which acts as a signal to direct protein stability, localization, or interactions. The Ub code is written by a family of enzymes called E3 Ub ligases (∼600 members in humans), which can catalyze the transfer of either a single ubiquitin or the formation of a diverse array of polyubiquitin chains. This code can be edited or erased by a different set of enzymes termed deubiquitinases (DUBs; ∼100 members in humans). While enzymes from these distinct families have seemingly opposing activities, certain E3-DUB pairings can also synergize to regulate vital cellular processes like gene expression, autophagy, innate immunity, and cell proliferation. In this review, we highlight recent studies describing Ub ligase-DUB interactions and focus on their relationships.

Unlocking hepatocellular carcinoma aggression: STAMBPL1-mediated TRAF2 deubiquitination activates WNT/PI3K/NF-kb signaling pathway

STAM Binding Protein Like 1 (STAMBPL1), functions as a deubiquitinase (DUB) and plays a significant role in various types of cancers. However, its effect as a DUB participating in the HCC tumorigenesis and progression still unknown. In the study, the upregulation and strong prognosis value of STAMBPL1 were identified in HCC patients. Functionally, STAMBPL1 significantly promoted HCC cells proliferation and metastasis, and it interacts with TRAF2 and stabilize it via the deubiquitination at the K63 residue. The TRAF2 upregulation stabilized by STAMBPL1 overexpression transfers of P65 protein into the nucleus and activates the WNT/PI3K/ NF-kb signaling pathway. The 251-436 sites of STAMBPL1 particularly interact with the 294-496 sites of TRAF2, thereby exerting the function of DUB and removing the ubiquitin molecules attached to TRAF2. Our research unveiled a new function of STAMBPL1 in mediating TRAF2 deubiquitination and stabilization, thereby activating the WNT/PI3K/NF-kb signaling pathway, suggesting its potential as a novel biomarker and therapeutic target for HCC.

Downregulated RBM5 Enhances CARM1 Expression and Activates the PRKACA/GSK3β Signaling Pathway through Alternative Splicing-Coupled Nonsense-Mediated Decay

Downregulated RNA-binding motif protein 5 (RBM5) promotes the development and progression of various tumors, including bladder cancer (BC). Alternative splicing (AS) plays a crucial role in the progression of cancer by producing protein isomers with different functions or by promoting nonsense-mediated mRNA decay (NMD). However, whether RBM5 modulates the progression of BC through AS-NMD remains unexplored. In this study, we revealed that the downregulation of RBM5 expression promoted the expression of coactivator-associated arginine methyltransferase 1 (CARM1) in BC cells and tissues. Increased expression of CARM1 facilitated the activation of the Wnt/β-catenin axis and cell proliferation, which then contributed to the poor prognosis of patients with BC. Interestingly, RBM5 bound directly to CARM1 mRNA and participated in AS-NMD, downregulating the expression of CARM1. In addition, we revealed that protein kinase catalytic subunit alpha (PRKACA) functioned as a phosphorylated kinase of GSK3β, was regulated by CARM1 at the transcription level, and promoted the growth and progression of BC cells. Furthermore, in this study, we demonstrated a regulatory mechanism of Wnt/β-catenin activation through the RBM5/CARM1/PRKACA axis and identified a novel potential target for treating BC.

The function of Foxp1 represses β-adrenergic receptor transcription in the occurrence and development of bladder cancer through STAT3 activity

Bladder cancer is a common malignant tumor. FOXP1 has been found to be abnormally expressed in tumors such as renal cell carcinoma and endometrial cancer. Here, this investigated the biological roles of Foxp1 in the occurrence and development of bladder cancer. Patients with bladder cancer were obtained from China-Japan Friendship Hospital. Bladder cancer cell lines (5637, UMUC3, J82, and T24 cell) were used in this experiment. Foxp1 mRNA and protein expression levels in patients with bladder cancer were increased, compared with paracancerous tissue (normal). OS and DFS of Foxp1 low expression in patients with bladder cancer were higher than those of Foxp1 high expression. Foxp1 promoted bladder cancer cell growth in vitro model. Foxp1 increased the Warburg effect of bladder cancer. Foxp1 suppressed β-adrenoceptor (β-AR) expression in vitro model. ChIP-seq showed that Foxp1 binding site (E1, TTATTTAT) was detected at -2,251 bp upstream of the β-AR promoter. β-AR Reduced the effects of Foxp1 on cell growth in vitro model. β-AR reduced the effects of Foxp1 on the Warburg effect in vitro model by STAT3 activity. Taken together, our findings reveal that Foxp1 promoted the occurrence and development of bladder cancer through the Warburg effect by the activation of STAT3 activity and repressing β-AR transcription, and which might serve as an important clue for its targeting and treatment of bladder cancer.

UCA1 executes an oncogenic role in pancreatic cancer by regulating miR-582-5p/BRCC3

Background

As a fatal disease, the mechanism of pancreatic cancer is unclear. Urothelial carcinoma antigen 1(UCA1), a long noncoding RNA (lncRNA) that was first reported in bladder cancer, acts as an oncogene. However, the regulatory role and mechanism of UCA1 in pancreatic cancer remain unknown. This study aims to investigate the expression level and prognostic value of UCA1 in pancreatic cancer tissues, the effects and mechanism of UCA1 in regulating cell proliferation, apoptosis and metastasis.

Methods

UCA1 expression levels in tissues were detected by in situ hybridization (ISH) and the prognostic value was evaluated by univariate and multivariate survival analysis. For in vitro experiments, proliferation was evaluated by a cell count kit assay, Edu experiments, and a clone formation assay. Apoptosis was evaluated by fluorescence-activated cell sorting flow-cytometry. Cell migration and invasion capacities were detected by wound healing and transwell assays. Western blots were performed to detect apoptotic associated molecules and epithelial-mesenchymal transition (EMT) markers. For the in vivo experiment, subcutaneous transplantation models of pancreatic cancer in nude mice were established to observe the tumor growth. The regulatory mechanism of UCA1 was explored by proteomics, bioinformatic analysis, luciferase reporter assays, and rescue experiments.

Results

ISH staining revealed that UCA1 levels between cancer tissues (n=94) and tumor-adjacent tissues (n=73) did not show significant differences. Survival analysis indicated that high expression of UCA1 was an unfavorable prognosis factor for pancreatic cancer. Downregulation of UCA1 by siRNA significantly inhibited cell proliferation, decreased the capacities of cell migration and invasion, induced cell apoptosis, and inhibited EMT. Furthermore, we demonstrated that UCA1 positively regulated the expression of BRCC3 by inhibiting miR-582-5p. Rescue experiments indicated that either inhibiting the expression of miR-582-5p or enhancing expression of BRCC3 could partly attenuate the antitumor effects of downregulation of UCA1.

Conclusion

UCA1 acted as an oncogene in pancreatic cancer by partly regulating miR-582-5p/BRCC3, which could be a new therapeutic target for pancreatic cancer.

XTP1 facilitates the growth and development of gastric cancer by activating CDK6

Background

Hepatitis B virus X protein (XTP1) is overexpressed in tumor tissues and regulates cancer progression. However, the molecular mechanism of XTP1 in gastric cancer (GC) is poorly understood. Hence, we aimed to dissect the underlying role of XTP1 in the development of GC.

Methods

Lentiviruses were constructed and transfected into GC cells to upregulate or downregulate gene expression. The expressions of proteins in GC cells or tumor tissues were assessed by quantitative reverse transcription polymerase chain reaction (RT-qPCR), Western blotting, immunohistochemistry (IHC) assay, or the Gene Expression Profiling Interactive Analysis (GEPIA) database. Cell proliferation was assessed via methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay, Celigo cell counting assay, cell cycle analysis, and colony formation assay. Cell apoptosis was assessed by flow cytometry. The apoptosis-related proteins were evaluated using the human apoptosis antibody array. GC cell migration was detected by scratch wound-healing assays and Transwell migration assays. Potential downstream molecules were identified by the human GeneChip assay combined with bioinformatics analysis.

Results

We found that XTP1 is overexpressed in GC tissues and is positively related to its pathological grade. XTP1 knockdown restrained the growth and migration of GC cells, while XTP1 overexpression promoted cell proliferation and suppressed apoptosis. A mechanistic study indicated that XTP1 knockdown inhibited cyclin-dependent kinase 6 (CDK6) expression and that CDK6 might be a potential downstream molecule of XTP1. Further study confirmed that CDK6 depletion also suppressed GC cell proliferation and migration and increased GC cell apoptosis. Moreover, rescue experiments verified that CDK6 knockdown abated the promotion of XTP1 overexpression on GC progression.

Conclusions

XTP1 facilitated the development and progression of GC cells by activating CDK6. Therefore, the XTP1-CDK6 axis might be a potential therapeutic target for GC.

UCHL5 Promotes Proliferation and Migration of Bladder Cancer Cells by Activating c-Myc via AKT/mTOR Signaling

Ubiquitin C-terminal hydrolase L5 (UCHL5) is a deubiquitinating enzyme (DUB) that removes ubiquitin from its substrates. Associations between UCHL5 and cancer have been reported in various tissues, but the effect of UCHL5 on bladder cancer has not been thoroughly investigated. This study investigates the expression and function of UCHL5 in bladder cancer. UCHL5 was shown to be abnormally expressed using IHC of tissue microarray and Western blotting. Several procedures were performed to assess the effect of UCHL5 overexpression or knockdown on bladder cancer, such as cell proliferation, colony formation, wound-healing, and Transwell assays. In addition, RNA-Seq and Western blotting experiments were used to verify the status of downstream signaling pathways. Finally, bladder cancers with knockdown or overexpression of UCHL5 were treated with either SC79 or LY294002 to examine the participation of the AKT/mTOR signaling pathway and the expression of downstream targets c-Myc, SLC25A19, and ICAM5. In contrast to adjacent tissue samples, we discovered that UCHL5 was substantially expressed in bladder cancer samples. We also found that UCHL5 downregulation significantly suppressed both tumor growth in vivo and cell proliferation and migration in vitro. According to RNA-Seq analyses and Western blotting experiments, the expression of c-Myc, SLC25A19, and ICAM5 was modified as a result of UCHL5 activating AKT/mTOR signaling in bladder cancer cells. All things considered, our findings show that increased UCHL5 expression stimulates AKT/mTOR signaling, subsequently triggering the expression of c-Myc, SLC25A19, and ICAM5, which in turn promotes carcinogenesis in bladder cancer. UCHL5 is therefore a potential target for therapy in bladder cancer patients.

NCAPG promotes tumorigenesis of bladder cancer through NF-κB signaling pathway

The non-SMC condensin I complex subunit G (NCAPG) is a subunit of the condensin complex, many studies have shown that NCAPG is aberrantly expressed in different tumors and closely associated with poor prognosis, but its role in bladder cancer is unclear. In this paper, we found that NCAPG expression was upregulated in bladder cancer in tumor-related databases, and further verified the expression of NCAPG in bladder cancer tissues as well as bladder cancer cell lines by tissue microarray, qPCR, and WB. Next, we explored the changes in bladder cancer cell proliferation as well as migration after NCAPG knockdown by cell growth curve, colony formation, soft agar assay, and xenograft model. Finally, we examined the changes in downstream signaling pathways after NCAPG knockdown using RNA-Seq, and we found that the NF-κB signaling pathway was inhibited with NCAPG gene knockdown, which was verified by luciferase reporter assay as well as WB. In conclusion, our results illustrate that NCAPG knockdown can inhibit the proliferation of bladder cancer cells through the NF-κB signaling pathway. This finding demonstrates that NCAPG could be a potential target for the treatment of bladder cancer.