Therapeutic Target For Bladder Cancer Research Articles

Antisense lncRNA-RP11-498C9.13 promotes bladder cancer progression by enhancing reactive oxygen species-induced mitophagy.

Urinary system's most prevalent malignant tumor is bladder cancer. The enzyme pyrroline-5-carboxylate reductase 1 (PYCR1) has pro-tumorigenic characteristics. In the present study, the upstream and downstream regulatory mechanisms of PYCR1 in bladder cancer were investigated. The relationship between the expression of PYCR1 in bladder cancer and its prognosis was analyzed using a bioinformatics technique. Plasmid transfection and small interfering RNA were utilized to overexpress and silence genes, respectively. Utilizing MTT, colony formation, EdU, and transwell assays, the proliferation and invasiveness of bladder cancer cells were evaluated. Employing an RNA pull-down experiment and RNA immunoprecipitation, the relationship between RNAs was analyzed. Fluorescence in situ hybridization, immunohistochemistry, and western blotting were used to detect protein expression and localization. Flow cytometry was used to identify reactive species (ROS) expression in cells. Mitophagy was detected using immunofluorescence. PYCR1 was highly expressed in bladder cancer tissue and was related with a poor prognosis for the patient. By binding to PYCR1, the antisense RNA lncRNA-RP11-498C9.13 prevented the degradation of PYCR1 and promoted its production. Down-regulation of lncRNA-RP11-498C9.13 and PYCR1 inhibited the proliferation and invasiveness of bladder cancer cells and decreased tumorigenesis. In addition, it was found that the lncRNA-RP11-498C9.13/PYCR1 axis promoted ROS generation and induced mitophagy in bladder cancer cells. We demonstrated that lncRNA-RP11-498C9.13 promoted bladder cancer tumorigenesis by stabilizing the mRNA of PYCR1 and promoted ROS-induced mitophagy. The lncRNA-RP11-498C9.13/PYCR1/mitophagy axis was anticipated to be a significant therapeutic target for bladder cancer.

Androgen dihydrotestosterone promotes bladder cancer cell proliferation and invasion via EPPK1-mediated MAPK/JUP signalling

The incidence of bladder cancer (BLCA) in men is higher than that in women. Differences in androgen levels between men and women are considered the main causes of incidence rate differences. In this study, dihydrotestosterone (DHT) significantly increased the proliferation and invasion of BLCA cells. In addition, BLCA formation and metastatic rates were higher in N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)-treated male mice than in female and castrated male mice in vivo. However, immunohistochemistry showed that androgen receptor (AR) was expressed at low levels in normal and BLCA tissues of men and women. The classical AR pathway considers that DHT binds to AR and induces it to enter the nucleus, where it functions as a transcription factor. Here, a non-AR combination pathway of androgen that promoted BLCA development was investigated. The EPPK1 protein was bombarded with DHT, as determined by biotinylated DHT-binding pull-down experiments. EPPK1 was highly expressed in BLCA tissues, and EPPK1 knockdown significantly inhibited BLCA cell proliferation and invasion promoted by DHT. Moreover, JUP expression was elevated in DHT-treated high-EPPK1 expressing cells, and JUP knockdown inhibited cell proliferation and invasion. EPPK1 overexpression increased tumour growth and JUP expression in nude mice. Furthermore, DHT increased the expression of the MAPK signals p38, p-p38, and c-Jun, and c-Jun could bind to the JUP promoter. However, the promotion of p38, p-p38, and c-Jun expression by DHT was not observed in EPPK1 knockdown cells, and a p38 inhibitor suppressed the DHT-induced effects, indicating that p38 MAPK may be involved in the regulation of DHT-dependent EPPK1-JUP-promoted BLCA cell proliferation and invasion. The growth of bladder tumours in BBN-treated mice was inhibited by the addition of the hormone inhibitor goserelin. Our findings indicated the potential oncogenic role and mechanism of DHT in BLCA pathogenesis through a non-AR pathway, which may serve as a novel therapeutic target for BLCA.

Monoamine oxidase as a potential target for the development of new therapeutic strategies for bladder cancer.

e16611 Background: Bladder cancer (BC) is the most common malignancy of the urinary tract and one of the most prevalent cancers worldwide. As the overall prognosis of BC has not changed over the past 30 years, there is a pressing medical need to develop new diagnostic and therapeutic approaches. At present, efforts to deeply understand the pathogenic mechanisms that support urothelial carcinogenesis could help in identifying new therapeutic targets. Monoamine oxidases (MAOs) A and B are oxidative isoenzymes that catalyze the conversion of biogenic amines into their corresponding aldehydes and ketones through oxidative deamination. Recently, MAOs expression have been associated with metastasis and decreased overall survival in various types of cancer. However, the role of MAOs in BC is still poorly explored. This study characterized and compared the molecular profiles of MAO-A and MAO-B isoenzymes in the different histological stages of non-muscle (NMIBC) and muscle (MIBC) invasive bladder cancer, aiming the adaptation of these biomarkers as a criterion of clinical response, risk stratification and outcome prognosis. Methods: Sixty formalin-fixed paraffin-embedded samples of bladder were obtained from 34 to 96-year-old patients (mean 65 years) with BC diagnosis in University of Campinas and Paulinia Municipal Hospital/ Brazil. Subsequently, the samples were divided into 6 groups: pTis group, low-grade pTa group, high-grade pTa group, pT1 group and pT2 group; and submitted to immunohistochemistry analysis for MAO-A and MAO-B. The retrospective anonymous study was approved by the local ethics committee (Clinical Trial: RBR-6swqd2). Results: All stages and grades of NMIBC and pT2 (MIBC) showed positive immunoreactivity for both MAO-A and MAO-B. MAO-A immunoreactivities were significantly higher (p < 0.01) in the high-grade pTa, pTis and pT2 groups in relation to low-grade pTa and pT1. Likewise, MAO-B immunoreactivities were remarkably higher (p < 0.01) in the high-grade pTa and pT2 groups. No statistical differences were found between pTis and low-grade pTa for MAO-B. Interestingly, pT1 group showed the lowest (p < 0.01) MAO-A and MAO-B immunoreactivities in relation to other stages and grades of BC, probably due to disruption of the extracellular matrix, with consequent reduction in O2 delivery (hypoxia). Conclusions: These findings collectively characterize the contribution of MAOs in BC pathogenesis and suggest that MAOs have potential as a therapeutic target in BC.

EIF4A3 serves as a prognostic and immunosuppressive microenvironment factor and inhibits cell apoptosis in bladder cancer.

EIF4A3 (Eukaryotic translation initiation factor 4A3 (EIF4A3) was recently recognized as an oncogene; however, its role in BLCA (bladder cancer) remains unclear. We explored EIF4A3 expression and its prognostic value in BLCA in public datasets, including the TCGA (The Cancer Genome Atlas) and GEO (Gene Expression Omnibus). Thereafter, the association between EIF4A3 expression and the infiltration of immune cells and immune-checkpoint expression was determined using TIMER2 (Tumor Immune Estimation Resource 2) tool. Additionally, the impact of EIF4A3 on cellular proliferation and apoptosis events in BLCA cell lines was determined by siRNA technology. In this study, EIF4A3 was found to be significantly upregulated in BLCA, upregulated expression of EIF4A3 was related to poor prognosis, advanced histologic grade, subtype, pathological stage, white race, and poor primary therapy outcome. The immune infiltration analysis revealed that EIF4A3 expression was negatively associated with CD8+ and CD4+ T cells and positively with myeloid-derived suppressor cells, macrophage M2, cancer-associated fibroblasts, and Treg cells. Moreover, EIF4A3 was coexpressed with PD-L1 (programmed cell death 1-ligand 1) and its expression was higher in patients responding to anti-PD-L1 therapy. EIF4A3 knockdown significantly inhibited proliferation and promoted apoptosis in 5,637 and T24 cells. In summary, BLCA patients with elevated EIF4A3 expression had an unfavorable prognosis and immunosuppressive microenvironment, and EIF4A3 may facilitate BLCA progression by promoting cell proliferation and inhibiting apoptosis. Furthermore, our study suggests that EIF4A3 is a potential biomarker and therapeutic target for BLCA.

LDL receptor related protein 1 is an adverse prognostic biomarker that correlates with stromal remodeling and macrophages infiltration in bladder cancer.

Bladder cancer (BLCA) is a highly heterogeneous disease influenced by the tumor microenvironment, which may affect patients' response to immune checkpoint blockade therapy. Therefore, identifying molecular markers and therapeutic targets to improve treatment is essential. In this study, we aimed to investigate the prognostic significance of LRP1 in BLCA. We analyzed TCGA and IMvigor210 cohorts to investigate the relationship of LRP1 with BLCA prognosis. We utilized gene mutation analysis and enrichment to identify LRP1-associated mutated genes and biological processes. Deconvolution algorithms and single-cell analysis were used to understand the tumor-infiltrated cells and biological pathways associated with LRP1 expression. Immunohistochemistry was conducted to validate the bioinformatics analysis. Our study revealed that LRP1 was an independent risk factor for overall survival in BLCA patients and was associated with clinicopathological features and FGFR3 mutation frequency. Enrichment analysis demonstrated that LRP1 was involved in extracellular matrix remodeling and tumor metabolic processes. Furthermore, the ssGSEA algorithm revealed that LRP1 was positively correlated with the activities of tumor-associated pathways. Our study also found that high LRP1 expression impaired patients' responsiveness to ICB therapy in BLCA, which was predicted by TIDE prediction and validated by IMvigor210 cohort. Immunohistochemistry confirmed the expression of LRP1 in Cancer-Associated Fibroblasts (CAFs) and macrophages in the tumor microenvironment of BLCA. Our study suggests that LRP1 may be a potential prognostic biomarker and therapeutic target in BLCA. Further research on LRP1 may improve BLCA precision medicine and enhance the efficacy of immune checkpoint blockade therapy.

Abstract 1583: Bcl-6 as a potential therapeutic target for bladder cancer

Abstract Introduction and Objectives: B-cell lymphoma 6 (Bcl-6) is known to be a nuclear protein and a master transcription factor for regulation of T follicular helper cells (TFH cells) proliferation. Previously, we reported on the increased angiogenic potential of human prostate cancer cells that overexpressed the Bcl-2. Comparative genomic profiling of the endothelial cells treated with/without conditioned media from Bcl-2-overexpressing human prostate cancer cells revealed approximately 250 differentially expressed genes. Interestingly, bioinformatics analysis identified Bcl-6 as one of several secreted proteins on the list. In this study, we first confirmed that Bcl-6 exists in liquid biopsy, and secondly evaluate the effect of Bcl-6 neutralization on angiogenesis and tumor growth in in vitro and in vivo models. Methods: We first analyzed Bcl-6 levels in serum and urine by ELISA. Then we tested the effect of Bcl-6 antibody for the following: ability to inhibit in vitro and in vivo angiogenesis, ability to inhibit cellular proliferation, and tumor growth in cell line-derived xenograft model. Results: First, we found that Bcl-6 exists in urine and serum. Interestingly, Bcl-6 level was significantly higher in cancer patients than healthy subjects. Next, we identified the effective clone tube formation assay. Then we further tested the effect of the antibody and exogenous Bcl-6 on cell proliferation, tube formation, and tube disruption in HUVEC. The exogenous Bcl-6 did not enhance cell proliferation of HUVEC. On the other hand, the Bcl-6 antibody significantly inhibited tube formation in HUVEC, but not tube disruption. Subsequently, we performed Matrigel plug assay to evaluate the effect on angiogenesis in vivo. The CD31 positive cells in Matrigel plug were significantly reduced by the Bcl-6 antibody treatment. To evaluate the effect on tumor growth, we first performed the cell proliferation assay to evaluate the effect on tumor growth in vitro. The Bcl-6 antibody significantly inhibited the cell proliferation of T24 and UM-UC-3 cell lines highly expressing Bcl-6. Finally, we tested the effect of the Bcl-6 antibody on tumor growth in an animal model. Intratumoral injection of Bcl-6 antibody (15 μg/tumor, twice weekly) significantly inhibited the tumor growth. Conclusions: This is the first time to identify that Bcl-6 may be a secreted protein and found that neutralization of Bcl-6 by antibody inhibits angiogenesis and tumor growth in both in vitro and in vivo. The results suggest that neutralizing Bcl-6 by antibody could be a promising therapeutic agent in bladder cancer. Citation Format: Hideki Furuya, Kaoru Murakami, Nari Kim, Charles J. Rosser. Bcl-6 as a potential therapeutic target for bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1583.

Abstract 472: HER2 as a therapeutic target in bladder cancer

Abstract Introduction: HER2 (encoded by the ERBB2 gene) is a member of the epidermal growth factor receptor (EGFR) family that exerts its activity through homo- or hetero-dimerization with other HER proteins. While multiple HER2-targeted therapies are FDA-approved for breast cancer, the clinical utility of targeting HER2 in bladder cancer patients remains undefined. We leveraged a prospective sequencing initiative and a new collection of patient-derived organoid (PDO) and xenograft (PDX) models to explore the prevalence of HER2 alterations in bladder cancers, its biologic role in bladder cancer pathogenesis and the potential clinical utility of HER2-targeted therapies. Methods: To define the landscape of HER2 alterations in bladder cancer patients, we analyzed data generated by The Cancer Genome Atlas (TCGA) and patients enrolled in the prospective MSK-IMPACT sequencing cohort. To study the biology of HER2 alterations in a bladder cancer context, we generated PDO and PDX bladder cancer models, including ERBB2 amplified, ERBB2 hotspot mutated and ERBB2 wildtype models. Patient-derived models were characterized using a multiplatform approach and were used to study HER2 oncogenic dependence and sensitivity to multiple anti-HER2 targeted agents. Results: The MSK-IMPACT assay revealed that ERBB2 alteration is common in bladder cancer, with a mutation frequency of 10.4% (breast cancer: 2.8%) and amplification frequency of 7.8% (breast cancer: 11.8%). ERBB2 alterations were more common in higher grade and stage bladder cancers. Among the HER2-altered PDOs, we identified some models with HER2 pathway dependence, similar to that observed in HER2 amplified breast cancer cell lines. However, most models had less dependence of downstream effector pathways such as AKT and ERK on HER2 signaling as compared to breast cancers. HER2-altered PDX models were significantly more sensitive to the HER2-targeted antibody-drug conjugate (ADC) trastuzumab deruxtecan (T-DXd) than to HER kinase inhibitor neratinib. We also observed a complete response of a HER2+ bladder cancer patient treated with T-DXd (based on PET at 7 weeks). Sensitivity to the T-DXd payload, an exatecan derivative (DXd), was found to play a key role in determining sensitivity of bladder cancer models to T-DXd. Conclusion: Bladder cancer has higher ERBB2 mutation frequency than breast cancer, and HER2 alterations are more common in high grade and stage bladder cancers than in low-grade and non-invasive tumors, suggesting a role for HER2 in invasion and metastatic progression. The greater sensitivity of HER2 altered bladder cancer models to HER2-targeted ADC T-DXd and the complete response to T-DXd in a HER2+ bladder cancer patient provide justification for further clinical trials of HER2-targeted ADCs in bladder cancer. The sensitivity to ADC cytotoxic payload may be an important factor in determining patient response. Citation Format: Xinran Tang, Ziyu Chen, Jasmine Thomas, Karan Nagar, John Christin, Naryan Rustgi, Sizhi Gao, Carissa Chu, Elisa De Stanchina, Michael F. Berger, Jonathan A. Coleman, Michael M. Shen, Hikmat A. Al-Ahmadie, Gopakumar V. Iyer, Kwanghee Kim, David B. Solit. HER2 as a therapeutic target in bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 472.

High expression of ABCF1 is an independent predictor of poor prognosis in bladder cancer

ABCF1, a member of the ATP-binding cassette (ABC) transporter family, is involved in the malignant progression of tumors. However, the role of ABCF1 in bladder cancer is poorly understood. In our study, we explored the differential expression of ABCF1 in bladder cancer and normal bladder tissues based on bioinformatic analysis and immunohistochemical results. GSEA was performed to ascertain the potential related signaling pathways of ABCF1. The relationship between ABCF1 expression and bladder cancer progression was analyzed using the GSE13507 dataset. In addition, the differential expression of ABCF1 in the cell lines was verified by quantitative real-time polymerase chain reaction (qRT‒PCR) and Western blotting. ABCF1 was upregulated in bladder cancer, and the high expression of ABCF1 was closely related to sex (P = 0.00056), grade (P = 0.00049), T stage (P = 0.00007), and N stage (P = 0.0076). High expression of ABCF1 was correlated with poor overall survival in bladder cancer patients (P < 0.001). In addition, univariate and multivariate Cox regression analyses showed that high ABCF1 expression was an independent factor for poor prognosis in bladder cancer patients. Therefore, ABCF1 expression is closely related to the progression of bladder cancer and can be used as a potential indicator of poor prognosis and a therapeutic target for bladder cancer.

Ubiquitin-Specific Proteases as Potential Therapeutic Targets in Bladder Cancer—In Vitro Evaluation of Degrasyn and PR-619 Activity Using Human and Canine Models

The inhibition of ubiquitin-specific proteases (USPs) is a novel and promising direction in the development of molecularly targeted therapies in oncology. The aim of the present study was to examine whether Degrasyn could be a potential therapeutic agent against bladder cancer (BC). Also, we aimed to determine whether Degrasyn is more effective in terms of anti-cancer activity compared to the non-selective DUB inhibitor PR-619. To facilitate the translational value of the obtained results, our experiments were performed using both human and canine in vitro models of BC. Human T24 (urothelial grade III BC) and SV-HUC-1 (non-tumorigenic urothelial cell line), as well as canine K9TCC-PU-NK and RDSVS-TCC1 (both derived from invasive grade III urothelial bladder tumors) cell lines, were used in the present study. Cell proliferation was determined using the MTT assay and Ki-67 proliferation assay, and the level of apoptosis induced by Degrasyn and PR-619 was evaluated by Annexin V-FITC staining and caspase 3/7 activation assay. Western blot was used to assess DNA damage and key proteins involved in apoptosis. Degrasyn inhibited the proliferation of all BC cell lines in a concentration- and time-dependent manner. Lower concentrations of Degrasyn were more potent against human and canine BC cell lines compared to PR-619. Degrasyn induced caspase-dependent apoptosis and triggered DNA damage. PR-619 did not show a significant pro-apoptotic effect. Our results demonstrate that Degrasyn significantly impairs the growth of in vitro models of human and canine BC. Selective USP inhibition with Degrasyn seems to be more effective in reducing BC cell proliferation and inducing apoptosis and DNA damage than non-selective USP inhibition with PR-619.

Inhibitor of apoptosis proteins as therapeutic targets in bladder cancer.

Evasion from apoptosis is a hallmark of cancer. Inhibitor of apoptosis proteins (IAPs) contribute to this hallmark by suppressing the induction of cell death. IAPs were found to be overexpressed in cancerous tissues and to contribute to therapeutic resistance. The present review focuses on the IAP members cIAP1, cIAP2, XIAP, Survivin and Livin and their importance as potential therapeutic targets in bladder cancer.

Exosomal miR-93-5p as an important driver of bladder cancer progression.

Tumor-derived exosomes are involved in the process of tumor metastasis and angiogenesis. MicroRNAs (miRNAs) are the most widely investigated factors in exosomes. Therefore, we hope to find a new therapeutic target in bladder cancer (BLCA), which has high incidence rate and mortality. Exosomal microRNA(miR)-93-5p expression level, downstream target molecules, and biological functions were examined with bioinformatics technology. Exosomes were extracted by sequential differential centrifugation and verified by transmission electron microscopy. The exosomal miR-93-5p on cell proliferation, invasion, and angiogenesis abilities in 5637 and T24 cells was determined by Cell Counting Kit 8 (CCK-8), colony-forming assay, Transwell assay, and vascular ring formation assay. A mouse xenograft model with intratumor injection was adopted to evaluate the correlation between BLCA-derived exosomes and tumor growth in vivo. The results revealed that exosomes play an important role in the biological progression of BLCA, with miR-93-5p being a particularly important molecule. Compared to normal cells, more malignant cells release more exosomal miR-93-5p, and tumor-derived exosomal miR-93-5p could significantly promote cell proliferation, invasion, and angiogenesis in vitro and in vivo. We identified phosphatase and tensin homolog (PTEN) as the most significant target of miR-93-5p in BLCA and human umbilical vein endothelial cells. Our study successfully revealed the biological role and mechanism of BLCA-derived exosomes in tumor progression. Target at tumor exosomes and exosomal miR-93-5p may be an effective treatment in BLCA.

Alternative splicing event associated with immunological features in bladder cancer.

Bladder cancer (BLCA) is the most prevalent urinary tumor with few treatments. Alternative splicing (AS) is closely related to tumor development and tumor immune microenvironment. However, the comprehensive analysis of AS and prognosis and immunological features in BLCA is still lacking. In this study, we downloaded RNA-Seq data and clinical information from The Cancer Genome Atlas (TCGA) database, and AS events were acquired from the TCGA Splice-seq. A total of eight prognostic AS events (C19orf57|47943|ES, ANK3|11845|AP, AK9|77203|AT, GRIK2|77096|AT, DYM|45472|ES, PTGER3|3415|AT, ACTG1|44120|RI, and TRMU|62711|AA) were identified by univariate analysis and least absolute shrinkage and selection operator (LASSO) regression analysis to construct a risk score model. The Kaplan-Meier analysis revealed that the high-risk group had a worse prognosis compared with the low-risk group. The area under the receiver operating characteristic (ROC) curves (AUCs) for this risk score model in 1, 3, and 5 years were 0.698, 0.742, and 0.772, respectively. One of the prognostic AS event-related genes, TRMU, was differentially expressed between tumor and normal tissues in BLCA. The single-sample gene set enrichment analysis (ssGSEA) and CIBERSORT algorithm showed that both the risk score model and TRMU were significantly associated with tumor immune microenvironment and immune status (immune cells, immune-related pathway, and immune checkpoint) in BLCA patients. The TIMER database confirmed the relationship between the expression of TRMU and immune cells and checkpoint genes. Furthermore, Cytoscape software 3.8.0 was used to construct the regulatory network between AS and splicing factors (SFs). Our study demonstrated that AS events were powerful biomarkers to predict the prognosis and immune status in BLCA, which may be potential therapeutic targets in BLCA.

Urine micro-RNA signature as a potential non-invasive diagnostic biomarker in bladder cancer.

Background: Bladder cancer (BC) is one of the most prevalent malignancies worldwide, 70% of patients initially diagnosed with superficial BC. In addition, 20% of BC patients with recurrence experience disease progression. Thus, identification of novel biomarkers for diagnosis, prognosis and therapeutic targets of BC will help to advance clinical diagnosis and treatment of this disease. MicroRNAs (miRNAs) are single stranded, non coding RNAs that are hypothesized to regulate gene expression at the post transcriptional level. This study aimed to assess the urine and tissue expression levels of miR-200, miR-145 and miR-21 in BC patients o evaluate their potential as noninvasive biomarkers. Subjects and methods: Urine and their corresponding tissue samples were collected from 111 BC patients and from 25 healthy controls. A quantitative real-time polymerase chain reaction method based on a TaqMan probe was used to evaluate the expression levels of miR‑200, miR‑145 and miR-21, the correlations between these miRNA expression levels in urine and tissues and certain clinicopathological parameters were investigated. Results: The expression of the 3 studied miRNAs was significantly higher in urine of low and high tumor grade BC patients compared to the controls and the expression were increased in BC tissues compared with those in normal bladder tissues, the results proved that the 3 miRNAs function as oncogenes. A marked positive correlation was observed between the mRNA expression of miR-200 and miR 21, with a coefficient of 0.511 and P value of 0.02. Conclusion: The results of the present study indicated that miR-200, miR-145 and miR-21 may function as oncogenes and have a potential to serve as an early noninvasive diagnostic biomarkers and therapeutic targets for treatment of BC.

Tumour microenvironment landscape and immunotherapy response in bladder cancer decoded by stromal MOXD1 based on copper-related genes signature.

We aimed to develop a copper-related gene (CRG) signature that can be used to evaluate prognosis and guide therapeutic management in bladder cancer patients. The raw transcriptome profiles and clinical data of 405 bladder samples were downloaded from The Cancer Genome Atlas (TCGA) database, and differentially expressed copper-related genes were identifified using the Molecular Signatures Database (MSigDB) database and univariate and multivariate Cox regression analysis. A multigene prognostic signature based on 14 CRGs was developed by least absolute shrinkage and selection operation (LASSO) analysis in the TCGA cohort and validated in the Gene Expression Omnibus (GEO) cohort. Multiple analyses were then conducted in which the nomograms, clinicopathological features, immune-related cell infifiltration characteristics, and therapy responses of the high- and low-risk score groups were compared. A 14 CRGs signature was constructed and used to classify patients into high-risk and low-risk groups. Compared to patients classifified as high-risk, low-risk patients in both the TCGA cohort and the GEO cohort had better overall survival. Patients in high-risk groups had more aggressive clinical features, immunologically "cold" infifiltrating characteristics, and experienced lower therapeutic effificacy. We identifified a CRG signature of bladder cancer and validated it using unsupervised clustering analysis. Monooxygenase DBH-like 1 (MOXD1) was further identifified, and its potential for evaluating the tumor immune microenvironment and predicting the immunotherapy response was explored. These results suggest a novel research direction for precision therapy of bladder cancer and demonstrate that copper-related genes can play a promising role in predicting prognosis and may serve as therapeutic targets for bladder cancer.

Fibronectin 1 as a Key Gene in the Genesis and Progression of Cadmium-Related Bladder Cancer.

Exposure to cadmium (Cd), a non-essential heavy metal, leads to the malignant transformation of urothelial cells and promotes bladder cancer (BC) development, but the mechanisms are unclear. Therefore, we aimed to explore the possible molecules associated with Cd-related BC. By analyzing and mining biological big data in public databases, we screened genes associated with the malignant transformation of uroepithelial cells caused by Cd and further screened the key gene associated with BC prognosis from these genes. The possible roles of the key gene in BC progression were then further explored through biological big data analysis and cellular experiments. Data mining yielded a total of 387 malignant transformation-related genes, which were enriched in multiple cancer-related signaling pathways, such as cytokine-cytokine receptor interaction, Toll-like receptor signaling pathway, and Jak-STAT signaling pathway. Further screening identified Fibronectin 1 (FN1) as the key gene. High expression of FN1 was associated with the advanced pathologic stage, T stage, N stage, and M stage and predicted an unfavorable outcome in BC patients. FN1 expression was positively associated with the infiltration of several types of immune cells, particularly tumor-associated macrophages and cancer-associated fibroblasts. Overexpression of FN1 could be detected in Cd-treated urothelial cells and BC cell lines. Interestingly, silencing of FN1 impaired the proliferation and invasive capacity of BC cells. In conclusion, the present study provides new insight into the mechanism of Cd-related BC. FN1 might be a prognostic marker and therapeutic target for BC. Future studies are needed to confirm these results.

Abstract B030: Combined inhibition of BET proteins and PARP promotes impaired DNA damage repair response and cell cycle dysregulation in preclinical models of bladder cancer

Abstract Background: Bladder cancer (BC) remains a common and deadly malignancy, with a projected 81,180 new diagnoses and 17,100 deaths in the United States in 2022. According to the MSK/TCGA Bladder Cancer dataset, mutations in DNA damage response (DDR) genes that are part of the homologous recombination (HR) pathway occurred in up to 55% of patients, representing a potential therapeutic target in BC. In previous work, we used UNC’s EpiG Diamond compound library to show that, as a class, inhibition of the methyl-lysine reader bromodomain and extra-terminal domain (BET) proteins potently abrogate BC cell line viability. Here, we evaluated mechanisms related to HR inhibition that could explain pan-BET inhibitor OTX-015’s potency in BC. Methods: 5637 and J82 BC cells were treated with 1 µM OTX-015 or 0.1% DMSO control for 48-hours, total RNA was extracted, and then bulk RNA-sequencing (RNA-seq) was performed on an Illumina NovaSeq 6000 (Novogene, Sacramento, CA). Expression data was analyzed using Geneious Prime v2022.2.1 (Biomatters, San Diego, CA). Cells were then treated with 1 μM OTX-015, 5 μM of the PARP inhibitor olaparib, or combination for gene and protein expression analysis. Gene expression changes in BRCA1, BRCA2, PALB2, and RAD51, as well as MYC as a positive control, were confirmed by RT-PCR in biological triplicates after 48-hour incubation, normalized to an SDHA housekeeper and compared to a 0.1% DMSO control. Western blotting evaluated OTX-015 and olaparib effects on BRCA1, BRCA2, c-MYC, PALB2, and RAD51 protein expression after 72-hour incubation, using a GAPDH loading control and compared to a 0.1% DMSO control. Last, cells were treated with the same treatment schema for 24-72 hours, fixed with methanol, stained with propidium iodide (25 μg/mL), and flow cytometry evaluated effects on cell cycle using a ThermoFisher Attune NxT and FlowJo v10.8.1 (BD Life Sciences, Ashland, OR). Results: Bulk RNA-seq analyses revealed significantly altered expression of HR pathway genes in 5637 and J82 cells treated with OTX-015±olaparib. In 5637 cells, OTX-015 alone significantly reduced BRCA1, BRCA2, PALB2 and RAD51 expression, (n=3; P&amp;lt;0.001 for all), but only PALB2 and RAD51 expression was significantly reduced after combination treatment (n=3; P&amp;lt;0.001 for both). In J82 cells, OTX-015 alone and combination treatment significantly reduced BRCA1, PALB2 and RAD51 expression, (n=3; P&amp;lt;0.001 for all). Similarly, both OTX-015 and combination treatment resulted in reduced BRCA1, c-MYC, PALB2 and RAD51 protein expression in both cell lines. In both cell lines, combination treatment resulted in a substantially increased G2/M fraction at 48 hours compared to 0.1% DMSO (5637 cells: 62.9% vs 12.6% G2/M; J82 cells: 28.2% vs 17.8% G2/M). Conclusions: These data indicate that OTX-015-mediated inhibition of RAD51 and PALB2 could be responsible for impaired HR. Cell cycle data revealed a G2/M stall, rather than an S phase stall, suggesting mechanisms independent from impaired HR could be responsible for cell cycle dysregulation. Citation Format: Ryan M. Kemper, Manfred Meng, Daniel J. Crona. Combined inhibition of BET proteins and PARP promotes impaired DNA damage repair response and cell cycle dysregulation in preclinical models of bladder cancer. [abstract]. In: Proceedings of the AACR Special Conference: Cancer Epigenomics; 2022 Oct 6-8; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_2):Abstract nr B030.

Ferroptosis: A new therapeutic target for bladder cancer.

Bladder cancer (BC) is the most frequent type of urinary system cancer. The prognosis of BC is poor due to high metastasis rates and multidrug resistance. Hence, development of novel therapies targeting BC cell death is urgently needed. As a novel cell death type with strong antitumor potential, ferroptosis has been investigated by many groups for its potential in BC treatment. As an iron-dependent cell death process, ferroptosis is characterized by excessive oxidative phospholipids. The molecular mechanisms of ferroptosis include iron overload and the system Xc-GSH-GPX4 signaling pathway. A recent study revealed that ferroptosis is involved in the metastasis, treatment, and prognosis of BC. Herein, in this review, we comprehensively summarize the mechanism of ferroptosis, address newly identified targets involved in ferroptosis, and discuss the potential of new clinical therapies targeting ferroptosis in BC.

Circ_0002099 is a novel molecular therapeutic target for bladder cancer.

Bladder cancer (BLCA) acts as one of the most common malignant tumors in the urinary system without ideal therapy. We performed the present study to explore the role and mechanism of Circ_0002099 in BLCA progression. RNase R treatment assay and actinomycin D treatment assay were used to confirm the circular structure of Circ_0002099. Nuclear-cytoplasmic fractionation assay and fluorescence in situ hybridization (FISH) were used to indicatethe subcellular localization of Circ_0002099. The CCK-8 assay, colony formation assay, wound-healing assay, Transwell assay, and animal experiment were used to reveal the facilitative effect of Circ_0002099 on BLCA both in vitro and in vivo. Furthermore, bioinformatic analysis, western blot analysis, FISH,and dual-luciferase reporter assay were conducted to demonstrate the role of Circ_0002099 in BLCA progression. The results indicated that Circ_0002099 was significantly upregulated in BLCA and could enhance the progression of BLCA in vivo and in vitro. Furthermore, dual-luciferase reporter assay and FISHassay revealed that Circ_0002099 could regulate miR-217-5p/miR-103a-3p/Kirsten RAS (KRAS) axis in BLCA. In addition, rescue experiments confirmed that miR-217-5p/miR-103a-3p could rescue the facilitative effect of Circ_0002099 on BLCA progression. Moreover, FUS(FUSed in sarcoma)was identified to regulate the Circ_0002099-miR-217-5p/miR-103a-3p/KRAS axis in BLCA progression. The present study suggested that FUS-medicated Circ_0002099 could promote the epithelial-mesenchymal transitionprocess in BLCA progression via miR-217-5p/miR-103a-3p/KRAS axis-WNT/β-catenin axis. It could be a promising prognostic biomarker and therapeutic target for BLCA.

Prognostic Signature GXYLT2 Is Correlated with Immune Infiltration in Bladder Cancer.

Background GXYLT2 (glucoside xylosyltransferase 2) was known as an important gene that regulates classical Notch signaling and is involved in progression in human tumors. However, the correlation between GXYLT2 expression and bladder cancer remains unclear. Methods GXYLT2 expression was analyzed by ONCOMINE database, GEPIA database, and TIMER database. The Cancer Genome Atlas (TCGA) was utilized to confirm relationships between GXYLT2 and molecular subtypes of BLCA (bladder cancer). We discovered prognostic value of GXYLT2 in BLCA using GEPIA, LinkedOmics database, and Kaplan-Meier Plotter database. Subsequently, correlations between GXYLT2 and tumor immune infiltration were investigated through TIMER and TISIDB website. We then downloaded data of patients with BLCA from TCGA website, to conduct functional annotations and to construct protein-protein interaction network through STRING and Enrich web servers. Results Significant differences were observed between GXYLT2 expression of bladder cancer and normal tissues. GXYLT2 was a poor prognostic biomarker in BLCA with impact on diverse clinical characteristics. We found that GXYLT2 was closely related to tumor immune infiltrated cells and immune genes. Functional annotations indicated that GXYLT2 was linked to immune-related pathways. Conclusions The results suggested that GXYLT2 was associated with a poor prognosis and tumor immune cell infiltration of BLCA. GXYLT2 could be a promising therapeutic target in bladder cancer.

Flavokawain A is a natural inhibitor of PRMT5 in bladder cancer

BackgroundProtein arginine methyltransferases (PRMTs) regulate protein biological activity by modulating arginine methylation in cancer and are increasingly recognized as potential drug targets. Inhibitors targeting PRMTs are currently in the early phases of clinical trials and more candidate drugs are needed. Flavokawain A (FKA), extracted from kava plant, has been recognized as a potential chemotherapy drug in bladder cancer (BC), but its action mechanism remains unclear.MethodsWe first determined the role of a type II PRMT, PRMT5, in BC tissue samples and performed cytological experiments. We then utilized bioinformatics tools, including computational simulation, virtual screening, molecular docking, and energy analysis, to identify the potential use of PRMT5 inhibitors for BC treatment. In vitro and in vivo co-IP and mutation assays were performed to elucidate the molecular mechanism of PRMT5 inhibitor. Pharmacology experiments like bio-layer interferometry, CETSA, and pull-down assays were further used to provide direct evidence of the complex binding process.ResultsAmong PRMTs, PRMT5 was identified as a therapeutic target for BC. PRMT5 expression in BC was correlated with poor prognosis and manipulating its expression could affect cancer cell growth. Through screening and extensive experimental validation, we recognized that a natural product, FKA, was a small new inhibitor molecule for PRMT5. We noticed that the product could inhibit the action of BC, in vitro and in vivo, by inhibiting PRMT5. We further demonstrated that FKA blocks the symmetric arginine dimethylation of histone H2A and H4 by binding to Y304 and F580 of PRMT5.ConclusionsIn summary, our research strongly suggests that PRMT5 is a potential epigenetic therapeutic target in bladder cancer, and that FKA can be used as a targeted inhibitor of PRMT5 for the treatment of bladder cancer.