The cholesterol esterification inhibitor avasimibe suppresses tumour proliferation and metastasis via the E2F-1 signalling pathway in prostate cancer.

BACKGROUND: New effective drugs for prostate cancer (PCa) treatment are urgently needed. Avasimibe was recently identified as a promising drug for anticancer therapies. The main purpose of this study was to explore the effects and the underlying mechanisms of avasimibe in prostate cancer. METHODS: In this study, MTT and clonogenic survival assays were performed to detect cell proliferation after avasimibe treatment. The effect of avasimibe on cell migration was measured by wound healing and transwell migration assays. Cell cycle distribution and apoptosis were detected by flow cytometry. Immunofluorescence staining and western blot analysis were used to detect the expression of cell cycle-related proteins and epithelial-mesenchymal transition (EMT)-related proteins. In vivo, the antitumour effects of avasimibe were evaluated using a xenograft model and pulmonary metastasis model. RESULTS: The study found that avasimibe suppresses tumour growth and triggers G1 phase arrest. Moreover, the expression of the cell cycle-related proteins CDK2/4/6, Cyclin D1 and Cyclin A1 + A2 was significantly increased and p21 expression was decreased after avasimibe treatment. The migration of PCa cells was attenuated after treatment with avasimibe, followed by the downregulation of the expression of the EMT-related proteins N-cadherin, ß-catenin, vimentin, Snail and MMP9 and upregulation of E-cadherin expression. Moreover, E2F-1 was elevated after treatment with avasimibe. After knockdown of E2F-1 expression, the inhibition of cell proliferation and migration caused by avasimibe was significantly recovered. The results of the xenograft model showed that avasimibe suppressed tumour growth in vivo. Immunofluorescence staining revealed lower levels of Ki67 and higher levels of E2F-1 in tumour tissues of the avasimibe group than those of the control group. A pulmonary metastasis model also confirmed the inhibition of PCa metastasis by avasimibe. The number of lung metastatic foci in the avasimibe group was significantly decreased compared with that in the control group. CONCLUSIONS: Our results suggest that avasimibe can suppress tumour proliferation and metastasis via the E2F-1 signalling pathway. These findings demonstrate the potential of avasimibe as a new effective drug for PCa treatment.

The inhibitory effect of silencing CDCA3 on migration and proliferation in bladder urothelial carcinoma.

BACKGROUND: CDCA3 is an important component of the E3 ligase complex with SKP1 and CUL1, which could regulate the progress of cell mitosis. CDCA3 has been widely identified as a proto-oncogene in multiple human cancers, however, its role in promoting human bladder urothelial carcinoma has not been fully elucidated. METHODS: Bioinformatic methods were used to analyze the expression level of CDCA3 in human bladder urothelial carcinoma tissues and the relationship between its expression level and key clinical characteristics. In vitro studies were performed to validate the specific functions of CDCA3 in regulating cell proliferation, cell migration and cell cycle process. Alterations of related proteins was investigated by western blot assays. In vivo studies were constructed to validate whether silencing CDCA3 could inhibit the proliferation rate in mice model. RESULTS: Bioinformatic analysis revealed that CDCA3 was significantly up-regulated in bladder urothelial carcinoma samples and was related to key clinical characteristics, such as tumor grade and metastasis. Moreover, patients who had higher expression level of CDCA3 tend to show a shorter life span. In vitro studies revealed that silencing CDCA3 could impair the migration ability of tumor cells via down-regulating EMT-related proteins such as MMP9 and Vimentin and inhibit tumor cell growth via arresting cells in the G1 cell cycle phase through regulating cell cycle related proteins like p21. In vivo study confirmed that silencing CDCA3 could inhibit the proliferation of bladder urothelial carcinoma cells. CONCLUSIONS: CDCA3 is an important oncogene that could strengthen the migration ability of bladder urothelial carcinoma cells and accelerate tumor cell growth via regulating cell cycle progress and is a potential biomarker of bladder urothelial carcinoma.

The inhibitory effect of melatonin on human prostate cancer.

Prostate cancer (PCa) is one of the most commonly diagnosed human cancers in males. Nearly 191,930 new cases and 33,330 new deaths of PCa are estimated in 2020. Androgen and androgen receptor pathways played essential roles in the pathogenesis of PCa. Androgen depletion therapy is the most used therapies for primary PCa patients. However, due to the high relapse and mortality of PCa, developing novel noninvasive therapies have become the focus of research. Melatonin is an indole-like neurohormone mainly produced in the human pineal gland with a prominent anti-oxidant property. The anti-tumor ability of melatonin has been substantially confirmed and several related articles have also reported the inhibitory effect of melatonin on PCa, while reviews of this inhibitory effect of melatonin on PCa in recent 10 years are absent. Therefore, we systematically discuss the relationship between melatonin disruption and the risk of PCa, the mechanism of how melatonin inhibited PCa, and the synergistic benefits of melatonin and other drugs to summarize current understandings about the function of melatonin in suppressing human prostate cancer. We also raise several unsolved issues that need to be resolved to translate currently non-clinical trials of melatonin for clinic use. We hope this literature review could provide a solid theoretical basis for the future utilization of melatonin in preventing, diagnosing and treating human prostate cancer. Video abstract.

Quantitative proteomics identified 3 oxidative phosphorylation genes with clinical prognostic significance in gastric cancer.

The aim of the present study was to explore the underlying mechanisms involved in gastric cancer (GC) formation using data-independent acquisition (DIA) quantitative proteomics analysis. We identified the differences in protein expression and related functions involved in biological metabolic processes in GC. Totally, 745 differentially expressed proteins (DEPs) were found in GC tissues vs. gastric normal tissues. Despite enormous complexity in the details of the underlying regulatory network, we find that clusters of proteins from the DEPs were mainly involved in 38 pathways. All of the identified DEPs involved in oxidative phosphorylation were down-regulated. Moreover, GC possesses significantly altered biological metabolic processes, such as NADH dehydrogenase complex assembly and tricarboxylic acid cycle, which is mostly consistent with that in KEGG analysis. Furthermore the higher expression of UQCRQ, NDUFB7 and UQCRC2 were positively correlated with a better prognosis, implicating these proteins may as novel candidate diagnostic and prognostic biomarkers.

BORA regulates cell proliferation and migration in bladder cancer.

BACKGROUND: Bladder cancer is having a gradually increasing incidence in China. Except for the traditional chemotherapy drugs, there are no emerging new drugs for almost 30 years in bladder cancer. New potential therapeutic targets and biomarkers are urgently needed. METHODS: BORA is the activator of kinase Aurora A and plays an important role in cell cycle progression. To investigate the function of BORA in BCa, we established BORA knockdown and overexpression cell models for in vitro studies, xenograft and pulmonary metastasis mouse models for in vivo studies. RESULTS: Our results indicated that BORA was upregulated in human bladder cancer (BCa) compared to the normal bladder and paracancerous tissues at transcriptional and translational levels. We found that BORA was positively related to BCa cell proliferation. Furthermore, BORA knockdown induced cell cycle arrest in G2/M phase while BORA overexpression decreased the proportion of cells in G2/M, associated with PLK1-CDC25C-CDK1 alteration. Interestingly, we observed that knockdown of BORA inhibited BCa cell migration and invasion, accompanied with alterations of epithelial-mesenchymal transition (EMT) pathway related proteins. In vivo studies confirmed the inhibition effect of BORA knockdown on BCa cell growth and migration. CONCLUSIONS: Our study indicates that BORA regulates BCa cell cycle and growth, meanwhile influences cell motility by EMT, and could be a novel biomarker and potential therapeutic target in BCa.

DLGAP5 triggers proliferation and metastasis of bladder cancer by stabilizing E2F1 via USP11.

Bladder cancer (BLCA) is one of the most widespread malignancies worldwide, and displays significant tumor heterogeneity. Understanding the molecular mechanisms exploitable for treating aggressive BLCA represents a crucial objective. Despite the involvement of DLGAP5 in tumors, its precise molecular role in BLCA remains unclear. BLCA tissues exhibit a substantial increase in DLGAP5 expression compared with normal bladder tissues. This heightened DLGAP5 expression positively correlated with the tumor's clinical stage and significantly affected prognosis negatively. Additionally, experiments conducted in vitro and in vivo revealed that alterations in DLGAP5 expression notably influence cell proliferation and migration. Mechanistically, the findings demonstrated that DLGAP5 was a direct binding partner of E2F1 and that DLGAP5 stabilized E2F1 by preventing the ubiquitination of E2F1 through USP11. Furthermore, as a pivotal transcription factor, E2F1 fosters the transcription of DLGAP5, establishing a positive feedback loop between DLGAP5 and E2F1 that accelerates BLCA development. In summary, this study identified DLGAP5 as an oncogene in BLCA. Our research unveils a novel oncogenic mechanism in BLCA and offers a potential target for both diagnosing and treating BLCA.

Parkin inhibits proliferation and migration of bladder cancer via ubiquitinating Catalase.

PRKN is a key gene involved in mitophagy in Parkinson's disease. However, recent studies have demonstrated that it also plays a role in the development and metastasis of several types of cancers, both in a mitophagy-dependent and mitophagy-independent manner. Despite this, the potential effects and underlying mechanisms of Parkin on bladder cancer (BLCA) remain unknown. Therefore, in this study, we investigated the expression of Parkin in various BLCA cohorts derived from human. Here we show that PRKN expression was low and that PRKN acts as a tumor suppressor by inhibiting the proliferation and migration of BLCA cells in a mitophagy-independent manner. We further identified Catalase as a binding partner and substrate of Parkin, which is an important antioxidant enzyme that regulates intracellular ROS levels during cancer progression. Our data showed that knockdown of CAT led to increased intracellular ROS levels, which suppressed cell proliferation and migration. Conversely, upregulation of Catalase decreased intracellular ROS levels, promoting cell growth and migration. Importantly, we found that Parkin upregulation partially restored these effects. Moreover, we discovered that USP30, a known Parkin substrate, could deubiquitinate and stabilize Catalase. Overall, our study reveals a novel function of Parkin and identifies a potential therapeutic target in BLCA.

ACAT1 promotes proliferation and metastasis of bladder cancer via AKT/GSK3ß/c-Myc signaling pathway.

Acetyl-CoA acetyltransferase 1 (ACAT1) plays a significant role in the regulation of gene expression and tumorigenesis. However, the biological role of ACAT1 in bladder cancer (BLCA) has yet to be elucidated. This research aimed to elucidate the bioinformatics features and biological functions of ACAT1 in BLCA. Here, we demonstrate that ACAT1 is elevated in BLCA tissues and is correlated with specific clinicopathological features and an unfavorable prognosis for survival in BLCA patients. ACAT1 was identified as an independent risk factor in BLCA. Phenotypically, both in vitro and in vivo, ACAT1 knockdown suppressed BLCA cell proliferation and migration, while ACAT1 overexpression had the opposite effect. Mechanistic assays revealed that ACAT1 enhances BLCA cell proliferation and metastasis through the AKT/GSK3ß/c-Myc signaling pathway by modulating the cell cycle and EMT. Taken together, the results of our study reveal that ACAT1 is an oncogenic driver in BLCA that enhances tumor proliferation and metastasis, indicating its potential as a diagnostic and therapeutic target for this disease.

UPP1 enhances bladder cancer progression and gemcitabine resistance through AKT.

UPP1, a crucial pyrimidine metabolism-related enzyme, catalyzes the reversible phosphorylation of uridine to uracil and ribose-1-phosphate. However, the effects of UPP1 in bladder cancer (BLCA) have not been elucidated. AKT, which is activated mainly through dual phosphorylation (Thr308 and Ser473), promotes tumorigenesis by phosphorylating downstream substrates. This study demonstrated that UPP1 promotes BLCA cell proliferation, migration, invasion, and gemcitabine resistance by activating the AKT signaling pathway in vitro and in vivo. Additionally, UPP1 promoted AKT activation by facilitating the binding of AKT to PDK1 and PDK2 and the recruitment of phosphatidylinositol 3,4,5-triphosphate to AKT. Moreover, the beneficial effects of UPP1 on BLCA tumorigenesis were mitigated upon UPP1 mutation with Arg94 or MK2206 treatment (AKT-specific inhibitor). AKT overexpression or SC79 (AKT-specific activator) treatment restored tumor malignancy and drug resistance. Thus, this study revealed that UPP1 is a crucial oncogene and a potential therapeutic target for BLCA and that UPP1 activates the AKT signaling pathway and enhances tumorigenesis and drug resistance to gemcitabine.

TRAIP suppresses bladder cancer progression by catalyzing K48-linked polyubiquitination of MYC.

TRAF-interacting protein (TRAIP), an E3 ligase containing a RING domain, has emerged as a significant contributor to maintaining genome integrity and is closely associated with cancer. Our study reveals that TRAIP shows reduced expression in bladder cancer (BLCA), which correlates with an unfavorable prognosis. In vitro and in vivo, TRAIP inhibits proliferation and migration of BLCA cells. MYC has been identified as a novel target for TRAIP, wherein direct interaction promotes K48-linked polyubiquitination at neighboring K428 and K430 residues, ultimately resulting in proteasome-dependent degradation and downregulation of MYC transcriptional activity. This mechanism effectively impedes the progression of BLCA. Restoring MYC expression reverses suppressed proliferation and migration of BLCA cells induced by TRAIP. Moreover, our results suggest that MYC may bind to the transcriptional start region of TRAIP, thereby exerting regulatory control over TRAIP transcription. Consequently, this interaction establishes a negative feedback loop that regulates MYC expression, preventing excessive levels. Taken together, this study reveals a mechanism that TRAIP inhibits proliferation and migration of BLCA by promoting ubiquitin-mediated degradation of MYC.

Integrated analysis of the roles of oxidative stress related genes and prognostic value in clear cell renal cell carcinoma.

BACKGROUND: Patients with clear cell renal cell carcinoma (ccRCC), which is the most commonly diagnosed subtype of renal cell carcinoma, are at risk of tumor metastasis and recrudescence. Previous research has shown that oxidative stress can induce tumorigenesis in many cancers and can be a target of cancer treatment. Despite these findings, little progress has been made understanding in the association of oxidative stress-related genes (OSRGs) with ccRCC. METHODS: In vitro experiments were conducted with MTT survival assays, qRT‒PCR, apoptosis assays, cell cycle assays, ROS assays, and IHC staining. RESULTS: In our study, 12 differentially expressed oxidative stress-related genes (DEOSGs) and related transcription factors (TFs) that are relevant to overall survival (OS) were screened, and their mutual regulatory networks were constructed with data from the TCGA database. Moreover, we constructed a risk model of these OSRGs and performed clinical prognostic analysis and validation. Next, we performed protein-protein interaction (PPI) network analysis and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of MELK, PYCR1, and PML. A tissue microarray also verified the high expression of MELK and PYCR1 in ccRCC. Finally, in vitro cellular experiments demonstrated that knockdown of MELK or PYCR1 significantly inhibited ccRCC cell proliferation by causing cell apoptosis and inducing cell cycle arrest in the G1 phase. Intracellular ROS levels were elevated after these two genes were knocked down. CONCLUSION: Our results revealed the potential DEORGs to be used in ccRCC prognostic prediction and identified two biomarkers, named PYCR1 and MELK, which regulated the proliferation of ccRCC cells by affecting ROS levels. Furthermore, PYCR1 and MELK could be promising targets for predicting the progression and prognosis of ccRCC, thereby serving as new targets for medical treatments.

NRP1 promotes prostate cancer progression via modulating EGFR-dependent AKT pathway activation.

Prostate cancer (PCa) is the most common malignant tumor with a high global incidence in males. The mechanism underlying PCa progression is still not clear. This study observed that NRP1 was highly expressed in PCa and associated with poor prognosis in PCa patients. Functionally, NRP1 depletion attenuated the proliferation and migration ability of PCa cells in vitro and in vivo, while NRP1 overexpression promoted PCa cell proliferation and migration. Moreover, it was observed that NRP1 depletion induced G1 phase arrest in PCa cells. Mechanistically, HIF1α is bound to the specific promoter region of NRP1, thereby regulating its transcriptional activation. Subsequently, NRP1 interacted with EGFR, leading to EGFR phosphorylation. This study also provided evidence that the b1/b2 domain of NRP1 was responsible for the interaction with the extracellular domain of EGFR. Moreover, EGFR mediated NRP1-induced activation of the AKT signaling pathway, which promoted the malignant progression of PCa. In addition, the administration of NRP1 inhibitor EG01377 significantly inactivated the EGFR/AKT signaling axis, thereby suppressing PCa progression. In conclusion, the findings from this study highlighted the molecular mechanism underlying NRP1 expression in PCa and provide a potential predictor and therapeutic target for clinical prognosis and treatment of PCa.

Decreased Nrf2 protein level and low sperm quality in intractable spermatocystitis.

ABSTRACT: To investigate the molecular etiology of low sperm quality in patients with intractable spermatocystitis, spermatozoa samples from patients with persistent hematospermia undergoing transurethral seminal vesiculoscopy and healthy volunteers were utilized. Spermatozoa samples were collected from the seminal vesicles through transurethral seminal vesiculoscopy or by masturbation ejaculation. Sperm quality was analyzed by a WLJY-9000 color semen analysis system. Measurement of tumor necrosis factor alpha (TNFα) and interleukin-6 (IL-6) in the seminal plasma was performed using enzyme-linked immunosorbent assay (ELISA). Measurement of H2O2 in the seminal plasma was performed with a hydrogen peroxide kit. The protein levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and phosphorylated-Nrf2 (p-Nrf2) were measured by western blot analysis and immunofluorescence assays. Low sperm quality parameters and increased levels of inflammatory cytokines (TNFα, IL-6, and H2O2) in the seminal plasma were detected among the semen samples from the patients with persistent hematospermia. Nrf2 and p-Nrf2 were strongly expressed in the nucleus and periphery of human sperm cells, according to the results of the immunofluorescence assays. The protein levels of Nrf2 and p-Nrf2 were significantly lower in the spermatozoa samples from patients with persistent hematospermia than in those from healthy volunteers with normal sperm motility. The results suggested that Nrf2 signaling might play a role in the low sperm quality of patients with intractable spermatocystitis.

Hypoxia-induced PLOD2 promotes clear cell renal cell carcinoma progression via modulating EGFR-dependent AKT pathway activation.

Clear cell renal cell carcinoma (ccRCC) is a type of kidney cancer that is both common and aggressive, with a rising incidence in recent decades. Hypoxia is a key factor that plays a vital role in the tumorigenesis and metastasis of malignancy. However, the precise mechanisms of hypoxia driving ccRCC progression were not totally uncovered. Our study found that hypoxia level was elevated in ccRCC and might be an independent risk factor of prognosis in ccRCC patients. We identified a key protein PLOD2 was induced under hypoxic conditions and strongly associated with poor prognosis in ccRCC patients. When PLOD2 was depleted, the proliferation and migration of ccRCC cells were reduced in vitro and in vivo, while overexpression of PLOD2 had the opposite effect. Mechanically, the study further revealed that PLOD2 was transcriptionally activated by HIF1A, which binds to a specific promoter region of the PLOD2 gene. PLOD2 was also shown to interact with EGFR, leading to the phosphorylation of the receptor. Furthermore, PLOD2 was responsible for binding to the extracellular domain of EGFR, which ultimately activated the AKT signaling pathway, thus promoting the malignant progression of ccRCC. Treatment with the PLOD2 inhibitor Minoxidil significantly suppressed ccRCC progression by inactivating the EGFR/AKT signaling axis. In summary, the findings of this study shed light on the molecular mechanisms behind PLOD2 expression in ccRCC and suggest that it may serve as a potential predictor and therapeutic target for the clinical prognosis and treatment of ccRCC.

Pectolinarigenin inhibits bladder urothelial carcinoma cell proliferation by regulating DNA damage/autophagy pathways.

Pectolinarigenin (PEC), an active compound isolated from traditional herbal medicine, has shown potential anti-tumor properties against various types of cancer cells. However, its mechanism of action in bladder cancer (BLCA), which is one of the fatal human carcinomas, remains unexplored. In this study, we first revealed that PEC, as a potential DNA topoisomerase II alpha (TOP2A) poison, can target TOP2A and cause significant DNA damage. PEC induced G2/M phase cell cycle arrest via p53 pathway. Simultaneously, PEC can perform its unique function by inhibiting the late autophagic flux. The blocking of autophagy caused proliferation inhibition of BLCA and further enhanced the DNA damage effect of PEC. In addition, we proved that PEC could intensify the cytotoxic effect of gemcitabine (GEM) on BLCA cells in vivo and in vitro. Summarily, we first systematically revealed that PEC had great potential as a novel TOP2A poison and an inhibitor of late autophagic flux in treating BLCA.

Melatonin inhibits bladder tumorigenesis by suppressing PPARγ/ENO1-mediated glycolysis.

Melatonin is a well-known natural hormone, which shows a potential anticancer effect in many human cancers. Bladder cancer (BLCA) is one of the most malignant human cancers in the world. Chemoresistance is an increasingly prominent phenomenon that presents an obstacle to the clinical treatment of BLCA. There is an urgent need to investigate novel drugs to improve the current clinical status. In our study, we comprehensively explored the inhibitory effect of melatonin on BLCA and found that it could suppress glycolysis process. Moreover, we discovered that ENO1, a glycolytic enzyme involved in the ninth step of glycolysis, was the downstream effector of melatonin and could be a predictive biomarker of BLCA. We also proved that enhanced glycolysis simulated by adding exogenous pyruvate could induce gemcitabine resistance, and melatonin treatment or silencing of ENO1 could intensify the cytotoxic effect of gemcitabine on BLCA cells. Excessive accumulation of reactive oxygen species (ROS) mediated the inhibitory effect of melatonin on BLCA cells. Additionally, we uncovered that PPARγ was a novel upstream regulator of ENO1, which mediated the downregulation of ENO1 caused by melatonin. Our study offers a fresh perspective on the anticancer effect of melatonin and encourages further studies on clinical chemoresistance.

DTL Is a Prognostic Biomarker and Promotes Bladder Cancer Progression through Regulating the AKT/mTOR axis.

BACKGROUND: Denticleless E3 ubiquitin protein ligase homolog (DTL) has been reported to be an important regulator for tumorigenesis and progression. Nonetheless, the biological functions and molecular mechanisms of DTL in BCa remain elusive. METHODS: We implemented integrative bioinformatics analysis to explore the diagnostic and prognostic values of DTL based on The Cancer Genome Atlas (TCGA), ArrayExpress, and Gene Expression Omnibus (GEO) databases. Then, we utilized qRT-PCR and immunohistochemistry to verify the clinical significance of DTL expression according to clinical specimens and tissue microarray (TMA). Moreover, the biological functions and underlying mechanisms of DTL in BCa were investigated through in vitro and in vivo experiments. RESULTS: Integrative bioinformatics analysis revealed that DTL was a key gene associated with BCa progression, and increased DTL expression was correlated with malignant biological behavior and poor prognosis. Experiments on clinical specimens and tissue microarray (TMA) further confirmed our findings. Bioinformatics analysis demonstrated that DTL could be associated with cell cycle- and DNA replication-associated pathways in BCa. The suppression of DTL inhibited BCa cell proliferation, migration, and invasion in vivo and in vitro. Mechanistically, DTL may promote BCa progression through the AKT/mTOR pathway. CONCLUSIONS: Increased DTL expression was correlated with malignant biological behavior and poor prognosis of BCa patients, and it may promote BCa progression through the AKT/mTOR pathway. Our research provided a potential predictor and therapeutic target for BCa.

PRR11 promotes ccRCC tumorigenesis by regulating E2F1 stability.

Proline rich 11 (PRR11), a novel tumor-related gene, has been identified in different tumors. However, the relevant biological functions of PRR11 in human clear cell renal cell carcinoma (ccRCC) have not been studied. In this study, we first identified PRR11 as a biomarker of ccRCC and predictor of poor prognosis by bioinformatics. Then, we showed that PRR11 silencing substantially reduced ccRCC cell proliferation and migration in vitro and in vivo. Importantly, we found that PRR11 induced the degradation of the E2F1 protein through its interaction with E2F1, and PRR11 reduced the stability of the E2F1 protein in ccRCC cells, thereby affecting cell cycle progression. Further results indicated that the downregulation of E2F1 expression partially reversed the changes in ccRCC cell biology caused by PRR11 deletion. In addition, we showed that PRR11 was a target gene of c-Myc. The transcription factor c-Myc may have promoted the expression of PRR11 in ccRCC cells by binding to the PRR11 promoter region, thereby accelerating the progression of ccRCC. In summary, we found that PRR11 served as an oncogene in ccRCC, and PRR11 reduced the protein stability of E2F1 and could be activated by c-Myc.

E3 ubiquitin ligase RNF126 affects bladder cancer progression through regulation of PTEN stability.

E3 ubiquitin ligase RNF126 (ring finger protein 126) is highly expressed in various cancers and strongly associated with tumorigenesis. However, its specific function in bladder cancer (BCa) is still debatable. Here, we found that RNF126 was significantly upregulated in BCa tissue by TCGA database, and our studies indicated that downregulation of RNF126 significantly inhibited cell proliferation and metastasis through the EGFR/PI3K/AKT signaling pathway in BCa cells. Furthermore, we identified PTEN, an inhibitor of the PI3K/AKT signaling pathway, as a novel substrate for RNF126. By co-immunoprecipitation assays, we proved that RNF126 directly interacts with PTEN. Predominantly, PTEN binds to the C-terminal containing the RING domain of RNF126. The in vivo ubiquitination assay showed that RNF126 specifically regulates PTEN stability through poly-ubiquitination. Furthermore, PTEN knockdown restored cell proliferation, metastasis, and tumor formation of BCa cells inhibited by RNF126 silencing in vitro and in vivo. In conclusion, these results identified RNF126 as an oncogene that functions through ubiquitination and degradation of PTEN in BCa.

CTHRC1 Is a Prognostic Biomarker and Correlated With Immune Infiltrates in Kidney Renal Papillary Cell Carcinoma and Kidney Renal Clear Cell Carcinoma.

Kidney renal clear cell carcinoma (KIRC) and kidney renal papillary cell carcinoma (KIRP) are the most common RCC types. RCC has high immune infiltration levels, and immunotherapy is currently one of the most promising treatments for RCC. Collagen triple helix repeat containing 1 (CTHRC1) is an extracellular matrix protein that regulates tumor invasion and modulates the tumor microenvironment. However, the association of CTHRC1 with the prognosis and tumor-infiltrating lymphocytes of KIRP and KIRC has not been reported. We examined the CTHRC1 expression differences in multiple tumor tissues and normal tissues via exploring TIMER, Oncomine, and UALCAN databases. Then, we searched the Kaplan-Meier plotter database to evaluate the correlation of CTHRC1 mRNA level with clinical outcomes. Subsequently, the TIMER platform and TISIDB website were chosen to assess the correlation of CTHRC1 with tumor immune cell infiltration level. We further explored the causes of aberrant CTHRC1 expression in tumorigenesis. We found that CTHRC1 level was significantly elevated in KIRP and KIRC tissues relative to normal tissues. CTHRC1 expression associates with tumor stage, histology, lymph node metastasis, and poor clinical prognosis in KIRP. The CTHRC1 level correlates to tumor grade, stage, nodal metastasis, and worse survival prognosis. Additionally, CTHRC1 is positively related to different tumor-infiltrating immune cells in KIRP and KIRC. Moreover, CTHRC1 was closely correlated with the gene markers of diverse immune cells. Also, high CTHRC1 expression predicted a worse prognosis in KIRP and KIRC based on immune cells. Copy number variations (CNV) and DNA methylation might contribute to the abnormal upregulation of CTHRC1 in KIRP and KIRC. In conclusion, CTHRC1 can serve as a biomarker to predict the prognosis and immune infiltration in KIRP and KIRC.