Normal Human Urothelial Cells Research Articles

Abstract 1552: Tumorigenesis of basal muscle invasive bladder cancer was mediated by PTEN protein degradation resulting from SNHG1 upregulation

Abstract hosphatase and tensin homolog deleted on chromosome ten (PTEN) serves as a powerful tumor suppressor, and has been found to be downregulated in human bladder cancer (BC) tissues. Despite this observation, the mechanisms contributing to PTEN’s downregulation have remained elusive. In this study, we discovered that mice exposed to N-butyl-N-(4-hydroxybu-tyl)nitrosamine (BBN), a specific bladder chemical carcinogen, exhibited primary basal muscle invasive BC (BMIBC) accompanied by a pronounced reduction in PTEN protein expression in vivo. Utilizing a lncRNA deep sequencing high-throughput platform, along with gain- and loss-of-function analyses, we identified small nucleolar RNA host gene 1 (SNHG1) as a critical lncRNA that might drive the formation of primary BMIBCs in BBN-treated mice. Cell culture results further demonstrated that BBN exposure significantly induced SNHG1 in normal human bladder urothelial cell UROtsa. Notably, the ectopic expression of SNHG1 alone was sufficient to induce malignant transformation in human urothelial cells, while SNHG1 knockdown effectively inhibited anchorage-independent growth of human BMIBCs. Our detailed investigation revealed that SNHG1 overexpression led to PTEN protein degradation through its direct interaction with HUR. This interaction reduced HUR binding to ubiquitin-specific peptidase 8 (USP8) mRNA, causing degradation of USP8 mRNA and a subsequent decrease in USP8 protein expression. The downregulation of USP8, in turn, increased PTEN poly-ubiquitination and degradation, culminating in cell malignant transformation and BMIBC anchorage-independent growth. In vivo studies confirmed the downregulation of PTEN and USP8, as well as their positive correlations in both BBN-treated mouse bladder urothelium and tumor tissues of bladder cancer in nude mice.Our findings, for the first time, demonstrate that overexpressed SNHG1 competes with USP8 for binding to HUR. This competition attenuates USP8 mRNA stability and protein expression, leading to PTEN protein degradation, consequently, this process drives urothelial cell malignant transformation and fosters BMIBC growth and primary BMIBC formation. Citation Format: Chuanshu Huang, Tengda Li, Honglei Jin. Tumorigenesis of basal muscle invasive bladder cancer was mediated by PTEN protein degradation resulting from SNHG1 upregulation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1552.

Tumorigenesis of basal muscle invasive bladder cancer was mediated by PTEN protein degradation resulting from SNHG1 upregulation

BackgroundPhosphatase and tensin homolog deleted on chromosome ten (PTEN) serves as a powerful tumor suppressor, and has been found to be downregulated in human bladder cancer (BC) tissues. Despite this observation, the mechanisms contributing to PTEN’s downregulation have remained elusive.MethodsWe established targeted genes’ knockdown or overexpressed cell lines to explore the mechanism how it drove the malignant transformation of urothelial cells or promoted anchorageindependent growth of human basal muscle invasive BC (BMIBC) cells. The mice model was used to validate the conclusion in vivo. The important findings were also extended to human studies.ResultsIn this study, we discovered that mice exposed to N-butyl-N-(4-hydroxybu-tyl)nitrosamine (BBN), a specific bladder chemical carcinogen, exhibited primary BMIBC accompanied by a pronounced reduction in PTEN protein expression in vivo. Utilizing a lncRNA deep sequencing high-throughput platform, along with gain- and loss-of-function analyses, we identified small nucleolar RNA host gene 1 (SNHG1) as a critical lncRNA that might drive the formation of primary BMIBCs in BBN-treated mice. Cell culture results further demonstrated that BBN exposure significantly induced SNHG1 in normal human bladder urothelial cell UROtsa. Notably, the ectopic expression of SNHG1 alone was sufficient to induce malignant transformation in human urothelial cells, while SNHG1 knockdown effectively inhibited anchorage-independent growth of human BMIBCs. Our detailed investigation revealed that SNHG1 overexpression led to PTEN protein degradation through its direct interaction with HUR. This interaction reduced HUR binding to ubiquitin-specific peptidase 8 (USP8) mRNA, causing degradation of USP8 mRNA and a subsequent decrease in USP8 protein expression. The downregulation of USP8, in turn, increased PTEN polyubiquitination and degradation, culminating in cell malignant transformation and BMIBC anchorageindependent growth. In vivo studies confirmed the downregulation of PTEN and USP8, as well as their positive correlations in both BBN-treated mouse bladder urothelium and tumor tissues of bladder cancer in nude mice.ConclusionsOur findings, for the first time, demonstrate that overexpressed SNHG1 competes with USP8 for binding to HUR. This competition attenuates USP8 mRNA stability and protein expression, leading to PTEN protein degradation, consequently, this process drives urothelial cell malignant transformation and fosters BMIBC growth and primary BMIBC formation.

Effect of Arsenate and p-Phenylenediamine on the Expression of Aquaporins in Cultured Human Urothelial Cells.

Exposure to arsenic (As) orp‑phenylenediamine (PPD) can lead to dysfunction, or even cancer, in various types of organs, including the urinary bladder, yet the underlying mechanisms remain unclear. Aquaporins (AQPs) are widely expressed small water channel proteins that provide the major route for the transport of water and other small molecules across plasma membranes in diverse cell types. Altered expression of AQPs has been associated with pathologies in all major organs, including the urinary bladder. The presentin vitrostudy was performed as a first step towards exploring the possible involvement of AQPs in As- and PPD‑induced bladder diseases. An immortalized normal human urothelial cell line was employed. Cells were exposed to different concentrations of sodium arsenate (0‑20 μM) or PPD (0‑200 μM) for 48 h. Cell viability was subsequently assessed. The mRNA and protein expression levels of AQPs (specifically, AQP3, 4, 7, 9, and 11) were analyzed using reverse transcription‑quantitative polymerase chain reaction and Western blot analyses, respectively. The viability of the cells was decreased in a concentration-dependent manner upon exposure to arsenate. The mRNA and protein expression levels of AQP3, 4, 7, and 9 were substantially reduced, whereas the expression of AQP11 was largely unchanged. As for the experiments with PPD, treatment with increasing concentrations of PPD induced a gradual decrease in cell viability. The mRNA and protein expression levels of AQP3, 4, and 11 were generally unaltered; however, a marked reduction in the expression levels of AQP7 was observed, contrasting with a gradual concentration-dependent decrease in the expression of AQP9. The importance of the differential expression profiles of the AQPs induced by arsenate and PPD requires further investigation; nevertheless, the findings of the present study suggest that AQPs have a role in As‑ and PPD‑induced bladder diseases.

TERT promoter mutations and methylation for telomerase activation in urothelial carcinomas: New mechanistic insights and clinical significance.

Telomerase, an RNA-dependent DNA polymerase synthesizing telomeric TTAGGG sequences, is primarily silent in normal human urothelial cells (NHUCs), but widely activated in urothelial cell-derived carcinomas or urothelial carcinomas (UCs) including UC of the bladder (UCB) and upper track UC (UTUC). Telomerase activation for telomere maintenance is required for the UC development and progression, and the key underlying mechanism is the transcriptional de-repression of the telomerase reverse transcriptase (TERT), a gene encoding the rate-limiting, telomerase catalytic component. Recent mechanistic explorations have revealed important roles for TERT promoter mutations and aberrant methylation in activation of TERT transcription and telomerase in UCs. Moreover, these TERT-featured genomic and epigenetic alterations have been evaluated for their usefulness in non-invasive UC diagnostics, recurrence monitoring, outcome prediction and response to treatments such as immunotherapy. Importantly, the detection of the mutated TERT promoter and TERT mRNA as urinary biomarkers holds great promise for urine-based UC liquid biopsy. In the present article, we review recent mechanistic insights into altered TERT promoter-mediated telomerase activation in UCs and discuss potential clinical implications. Specifically, we compare differences in senescence and transformation between NHUCs and other types of epithelial cells, address the interaction between TERT promoter mutations and other factors to affect UC progression and outcomes, evaluate the impact of TERT promoter mutations and TERT-mediated activation of human endogenous retrovirus genes on UC immunotherapy including Bacillus Calmette-Guérin therapy and immune checkpoint inhibitors. Finally, we suggest the standardization of a TERT assay and evaluation system for UC clinical practice.

Classification between Normal and Cancerous Human Urothelial Cells by Using Micro-Dimensional Electrochemical Impedance Spectroscopy Combined with Machine Learning.

Although the high incidence and recurrence rates of urothelial cancer of the bladder (UCB) are heavy burdens, a noninvasive tool for effectively detecting UCB as an alternative to voided urine cytology, which has low sensitivity, is yet to be reported. Herein, we propose an intelligent discrimination method between normal (SV-HUC-1) and cancerous (TCCSUP) urothelial cells by using a combination of micro-dimensional electrochemical impedance spectroscopy (µEIS) with machine learning (ML) for a noninvasive and high-accuracy UCB diagnostic tool. We developed a unique valved flow cytometry, equipped with a pneumatic valve to increase sensitivity without cell clogging. Since contact between a cell and electrodes is tight with a high volume fraction, the electric field can be effectively confined to the cell. This enables the proposed sensor to highly discriminate different cell types at frequencies of 10, 50, 100, 500 kHz, and 1 MHz. A total of 236 impedance spectra were applied to six ML models, and systematic comparisons of the ML models were carried out. The hyperparameters were estimated by conducting a grid search or Bayesian optimization. Among the ML models, random forest strongly discriminated between SV-HUC-1 and TCCSUP, with an accuracy of 91.7%, sensitivity of 92.9%, precision of 92.9%, specificity of 90%, and F1-score of 93.8%.

LINC00958 Inhibits Autophagy of Bladder Cancer Cells via Sponge Adsorption of miR-625-5p to Promote Tumor Angiogenesis and Oxidative Stress.

Objective This study further explored LINC00958's role in promoting tumor angiogenesis (AG) and oxidative stress (OS) development by inhibiting BC cell autophagy through sponge adsorption of miR-625-5p. Methods BC patients and healthy controls who visited our hospital between June 2017 and February 2019 were selected as the research group (RG) and the control group (CG), respectively, with a total of 133 study subjects. Peripheral blood LINC00958 and miR-625-5p in both cohorts of participants were detected. Additionally, human bladder transitional cell carcinoma cells (T24 and J82) and human normal urothelial cells (SV-HUC-1) were purchased. Alterations in cell biological behavior were observed after transfecting miR-625-5p-mimics, miR-625-5p-inhibition, and miR-625-5p-NC sequences into these cells, respectively. Besides, ELISA was performed to quantify inflammatory factors (IFs), AG indicators, and OS indexes in cells. Subsequently, a double luciferase reporter (DLR) assay was performed to verify the targeting relationship between LINC00958 and miR-625-5p. Finally, BALB/c-nu nude mice were purchased, and T24 cells transfected with silenced LINC00958 and miR-625-5p expression sequences were used to establish subcutaneous tumors to observe tumor growth and pathological changes. Results RG exhibited higher LINC00958 and lower miR-625-5p than CG. LINC00958 and miR-625-5p were strongly linked to myometrial invasion (MI), lymph node metastasis (LNM), distant metastasis (DM), and histology in BC patients, and the increase of LINC00958 and the decrease of miR-625-5p predicted an increased risk of prognostic death in such patients. After miR-625-5p inhibition, the capacity of BC cells to proliferate, invade, and migrate enhanced and the AG, inflammatory response, and OS injury increased, while the apoptosis rate and autophagy ability decreased. The DLR assay revealed inhibited LINC00958WT fluorescence activity by miR-625-5p-mimics, while the biological behavior of BC cells cotransfected with sh-LINC00958 and miR-625-5p-inhibition had no difference with the functions of sh-control and miR-625-5p-NC cotransfected cells. Finally, the nude mouse tumorigenesis experiment showed that the tumor mass, volume, and histopathological features of the sh-LINC00958 group were decreased compared with the sh-control group, while those of the miR-625-5p-inhibition group were increased versus miR-625-5p-NC. Conclusions In BC, LINC00958 is highly expressed while miR-625-5p is underexpressed. LINC00958 can inhibit cell autophagy to enhance cell activity; promote OS, inflammation, and AG; and regulate tumor immunity by targeting miR-625-5p, thus participating in the development of BC.

Highly Expressed LINC00958 Modulates the Growth and Epithelial-Mesenchymal Transition of Bladder Cancer Cells Through SAPK/JNK Signaling Pathway.

Objective: To determine the expression of LINC00958 (BLACAT2) in bladder cancer (BC), the most common malignancy in the urinary system, and to determine its exact mechanism of action, so as to provide novel references for future clinical diagnosis and treatment of BC and lay a foundation for the follow-up research on LINC00958. Materials and Methods: Human bladder transitional cell carcinoma cells (T24 and J82) and human normal urothelial cells (SV-HUC-1) were purchased to detect the expression of LINC00958 and SAPK/JNK signaling pathway-related proteins. sh-LINC00958 targeting to silence LINC00958 expression and corresponding negative blank (sh-Control) were transfected into T24 and J82. Additionally, BC cells cultured with SP600125 (SP600125 group), a specific inhibitor of SAPK/JNK signaling pathway, and those cultured with the same amount of normal saline (Blank group) were also constructed. Cell growth capacity, cell invasiveness, and expression of epithelial-mesenchymal transition (EMT)-associated proteins were determined using CCK-8 & clone formation assays, Transwell assay, and Western blot, respectively. Results: The online databases Gene Expression Profiling Interactive Analysis, European Bioinformatics Institute, and StarBase revealed elevated LINC00958 expression in BC, and a potential association between LINC00958 and patient prognosis and survival. PCR results showed that LINC00958 was increased in T24 and J82 compared with the sh-Control group (p < 0.05). The results of biological behavior test revealed that the proliferation and invasiveness capacity of the sh-LINC00958 group decreased, while that of the SP600125 group increased compared with the Blank group (both p < 0.05). In the rescue experiment, the influence of sh-LINC00958 on BC cells was completely reversed by SP600125 (p > 0.05); In addition, the expression of E-cadherin, an EMT marker protein, was lower compared with the SH-LINC0958 group, while the Vimentin expression was higher (p < 0.05). Similarly, the wound-healing assay determined reduced cell healing rate in the sh-LINC00958 group (p < 0.05), and there was no difference between the sh-LINC00958+SP600125 group and the sh-Control group (p > 0.05). Conclusion: LINC00958 shows elevated expression in BC and promotes the growth and EMT of BC cell via inhibiting the SAPK/JNK signaling pathway, which has important potential as a new clinical diagnostic marker and therapeutic target for BC.

Deglycosylation Does Not Affect the Cytotoxic Action of Adenoviral Interferon α‐Induced Bystander Proteins

We previously reported an indirect effect of adenoviral interferon α (Ad‐IFNα) that is mediated by secreting bystander proteins (BSPs) and causing cytotoxic responses in both interferon α (IFNα)‐sensitive and –resistant cancer cells. Here, we investigated whether glycosylation of BSPs is necessary for the inhibition of IFNα‐resistant human bladder cancer cell line (KU7). The condition medium (CM) from the normal human urothelial cell line, TERT‐NHUC, was collected as described previously and incubated with and without N‐glycosidase F at 37°C (overnight). The growth inhibition of KU7 was compared between the control and experimental conditions. The proliferation of KU7 cells treated with interferon a protein (Intron A) is comparable to the cells treated with control TERT‐NHUC‐CM (without Ad‐IFNα infection) after 72 hr incubation. The growth of KU7 was significantly inhibited by the CM from Ad‐IFNα–infected TERT‐NHUC culture. N‐glycosidase F incubation effectively deglycosylated the BSPs in the CM (Ad‐IFNα TERT‐NHUC) as demonstrated by the band shifting in the PAGE gel verification. The deglycosylated CM (Ad‐IFNα TERT‐NHUC) produced a same degree of inhibition on the proliferation of KU7 cells (Fig 1). In conclusion, the cytotoxic effects of BSPs is independent of its status of glycosylation.

Barrier-Forming Potential of Epithelial Cells from the Exstrophic Bladder

Bladder exstrophy (BEX) is a rare developmental abnormality resulting in an open, exposed bladder plate. Although normal bladder urothelium is a mitotically quiescent barrier epithelium, histologic studies of BEX epithelia report squamous and proliferative changes that can persist beyond surgical closure. The current study examined whether patient-derived BEX epithelial cells in vitro were capable of generating a barrier-forming epithelium under permissive conditions. Epithelial cells isolated from 11 BEX samples, classified histologically as transitional (n = 6) or squamous (n = 5), were propagated in vitro. In conditions conducive to differentiated tight barrier formation by normal human urothelial cell cultures, 8 of 11 BEX lines developed transepithelial electrical resistances of more than 1000 Ω.cm2, with 3 squamous lines failing to generate tight barriers. An inverse relationship was found between expression of squamous KRT14 transcript and barrier development. Transcriptional drivers of urothelial differentiation PPARG, GATA3, and FOXA1 showed reduced expression in squamous BEX cultures. These findings implicate developmental interruption of urothelial transcriptional programming in the spectrum of transitional to squamous epithelial phenotypes found in BEX. Assessment of BEX epithelial phenotype may inform management and treatment strategies, for which distinction between reversible versus intractably squamous epithelium could identify patients at risk of medical complications or those who are most appropriate for reconstructive tissue engineering strategies.

The Cytotoxicity Effect Study of Fosfomycin and Mecillinam Antibiotic on Multi-Drug Resistant Klebsiella pneumoniae from Infected Urothelial Tissue

Enterobacteriaceae bacteria are clinically important and lead to various diseases associated with high mortality and morbidity, including urinary tract infections, yet their treatment is a challenge due to increasing antibiotic resistance. This study examined the cytotoxicity effects and viability-inducing abilities of mecillinam and fosfomycin antibiotics in the extended-spectrum beta-lactamase Klebsiella pneumoniae strain. The immortalized normal human urothelial cell line was used and the urothelial cell line and bacteria using Klebsiella pneumoniae cultures were prepared. The bacterial association assays with the urothelial cell line were then conducted. The cytotoxic effects were examined using cytotoxicity assays of Klebsiella pneumoniae, cefotaxime-Munich, ampicillinase C, oxacillinase and transmission electron microscopy on the immortalized normal human urothelial cell line. The cytotoxicity of fosfomycin and mecillinam on cell line cytotoxic assays were measured by lactate dehydrogenase, a cell death marker and visualized by hematoxylin. Klebsiella pneumoniae strains showed significantly reduced association with urothelial cells than cefotaxime-Munich strains. The cefotaxime-Munich and ampicillinase C had a higher association with the urothelial cells than the oxacillinase and transmission electron microscopy strains. The cytotoxicity assays indicated that all Klebsiella pneumoniae strains had increased cytotoxicity after 24 or 12 h of incubation. Antibiotic resistance is increased by the bacterial strains that have genes encoding resistance, such as cefotaxime-Munich, ampicillinase C, transmission electron microscopy and oxacillinase.

Proteolytic activation of Growth-blocking peptides triggers calcium responses through the GPCR Mthl10 during epithelial wound detection.

The presence of a wound triggers surrounding cells to initiate repair mechanisms, but it is not clear how cells initially detect wounds. In epithelial cells, the earliest known wound response, occurring within seconds, is a dramatic increase in cytosolic calcium. Here, we show that wounds in the Drosophila notum trigger cytoplasmic calcium increase by activating extracellular cytokines, Growth-blocking peptides (Gbps), which initiate signaling in surrounding epithelial cells through the G-protein-coupled receptor Methuselah-like 10 (Mthl10). Latent Gbps are present in unwounded tissue and are activated by proteolytic cleavage. Using wing discs, we show that multiple protease families can activate Gbps, suggesting that they act as a generalized protease-detector system. We present experimental and computational evidence that proteases released during wound-induced cell damage and lysis serve as the instructive signal: these proteases liberate Gbp ligands, which bind to Mthl10 receptors on surrounding epithelial cells, and activate downstream release of calcium.

Berberine suppresses bladder cancer cell proliferation by inhibiting JAK1-STAT3 signaling via upregulation of miR-17-5p

Hyperactivation of signal transducer and activator of transcription 3 (STAT3) is strongly associated with cancer initiation, progression, metastasis, chemoresistance, and immune evasion; thus, STAT3 has been intensely studied as a therapeutic target for cancer treatment. Berberine (BBR), an active component extracted from Coptis chinensis, has shown anti-tumor effects in multiple tumors. However, its underlying mechanisms have not yet been fully elucidated. In this study, we investigated the effects and the underlying mechanisms of BBR on bladder cancer (BCa) cells. We found that BBR showed significant cytotoxic effects against BCa cell lines both in vivo and in vitro, with much lower cytotoxic effects on the human normal urothelial cell line SV-HUC-1. BBR treatment induced DNA replication defects and cell cycle arrest, resulting in apoptosis or cell senescence, depending on p53 status, in BCa cells. Mechanistically, BBR exerted anti-tumor effects on BCa cells by inhibiting Janus kinase 1 (JAK1)-STAT3 signaling through the upregulation of miR-17-5p, which directly binds to the 3′UTR of JAK1 and STAT3, downregulating their expressions. Collectively, our results demonstrate that BBR exerts anti-tumor effects by perturbing JAK1-STAT3 signaling through the upregulation of miR-17-5p in BCa cells, and that BBR may serve as a potential therapeutic option for BCa treatment.

Keratin 17 knockdown suppressed malignancy and cisplatin tolerance of bladder cancer cells, as well as the activation of AKT and ERK pathway.

Bladder cancer (BCa) is one the most common urinary system malignancies and approximately one quarter of diagnosis is invasive muscle-invasive BCa. Accumulating evidence revealed that keratin 17 (KRT17) is closely related to the prognosis and progression of various tumors including a recent study also implying the potential role of KRT17 in the diagnosis of BCa. However, the specific role of KRT17 in BCa remains to be elucidated. The expression of KRT17 in 5637 BCa cells and SV-HUC-1 normal human urothelial cells was detected using quantitative real-time PCR (qRT-PCR) and western blot. Short hairpin RNA targeting KRT17 was used to knockdown KRT17 in BCa cells. The colony formation was assessed and the proliferation of cells was studied by Cell Counting Kit-8 (CCK-8). Invasion and epithelial-mesenchymal transition (EMT) capacity of BCa cells were assessed using transwell assay and western blot, respectively. Cisplatin sensitivity of cancer cells was measured by evaluating the cell viability using CCK-8 assay. The downstream pathway of KRT17 was explored by western blot. The expression of KRT17 was elevated in BCa cells in comparison with the normal human urothelial cell at the mRNA and protein levels. The in vitro assays demonstrated that KRT17 interference affected the proliferation, colony formation and invasion capacity of BCa cells, as well as EMT. Furthermore, knockdown of KRT17 enhanced cisplatin sensitivity in BCa cells. Mechanically, KRT17 ablation led to the inactivation of both AKT and ERK pathways. Our results elucidate the vital role of KRT17 in the development of malignancy of BCa cells, probably by the activation of AKT and ERK pathways and suggest that it may represent a novel therapeutic target for BCa.

Grainyhead-Like 3 Influences Migration and Invasion of Urothelial Carcinoma Cells.

Invasive urothelial carcinomas of the bladder (UCB) characteristically show a loss of differentiation markers. The transcription factor Grainyhead-like 3 (GRHL3) plays an important role in the development and differentiation of normal urothelium. The contribution to UCB progression is still elusive. Differential expression of GRHL3 was assessed in normal human urothelium and in non-invasive and invasive bladder cancer cell lines. The contribution of GRHL3 to cell proliferation, viability and invasion in UCB cell lines was determined by gain- and loss-of-function assays in vitro and in an organ culture model using de-epithelialized porcine bladders. GRHL3 expression was detectable in normal human urothelial cells and showed significantly higher mRNA and protein levels in well-differentiated, non-invasive RT4 urothelial carcinoma cells compared to moderately differentiated RT112 cells. GRHL3 expression was absent in anaplastic and invasive T24 cells. Ectopic de novo expression of GRHL3 in T24 cells significantly impaired their migration and invasion properties in vitro and in organ culture. Its downregulation improved the invasive capacity of RT4 cells. The results indicate that GRHL3 may play a role in progression and metastasis in UCB. In addition, this work demonstrates that de-epithelialized porcine bladder organ culture can be a useful, standardized tool to assess the invasive capacity of cancer cells.

Mutational signature modelling in vitro recapitulates bladder cancer initiation

Smoking is the best established risk factor for bladder cancer and direct mutagenesis by smoke carcinogens on the cellular genome can be described in clonal populations as mutational signatures. A mutational signature summarises a lifetime of DNA-damage (caused by interaction between mutagenic processes, tissue-specific gene transcription, and the DNA-repair machinery) as mutational classes in the context of their local genomic chemistry. Our aim was to establish a novel experimental model for understanding carcinogenic initiation in normal human urothelium. Finite normal human urothelial cell cultures were established in vitro and differentiated to form functional barrier epithelia capable of activating the smoke-derived procarcinogen benzo[a]pyrene (BaP), via CYP1A1, into mutagenic metabolites. New in vitro approaches were developed allowing chronic BaP-exposure, subsequent clonal expansion of NHU cells for whole genome DNAseq and mutational signature derivation. This approach retains tissue heterogeneity during the carcinogenic exposure, modelling the early selection pressures in urothelium that lead to clonal expansion and cancer. The single-base (SBS) and double-base signatures (DBS) derived from BaP-exposed urothelial tissues were dominated by C>A and CC>AA transversions, respectively. The InDel (ID) signature described cytosine deletions in homopolymer regions. Comparison to the Catalogue of Somatic Mutations in Cancer (COSMIC) using the Signal pipeline showed homology with SBS4, DBS2 and ID3, respectively; which have been detected by others in bladder cancer patients. Mutation enrichment in specific genes (eg KMT2D and CDKN1A) mirrored in situ observations by others; effectively modelling the competitive advantage mutations convey in the carcinogenic tissue environment. BaP is detected in urine, metabolically activated by urothelial CYP1A1, and therefore may be a bladder mutagen. However, C>A transversions contribute a minor fraction of all mutations recorded in bladder tumours. Widespread DNA damage caused by chronic BaP exposure did not trigger any of the APOBEC-like mutational processes (SBS2/13) that dominate bladder tumour genomes, indicating a missing factor that the new model system is well positioned to identify.

Modulation of BAG3 expression in human normal urothelial cells by Diuron.

Diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea] is a substituted urea herbicide, carcinogenic for the rat urinary bladder. It has been hypothesized that Diuron cytotoxicity, resulting in regenerative proliferation, leads to urothelial hyperplasia and, finally, to bladder tumors, but molecular mechanisms of carcinogenesis have not still fully investigated. Here, we report the results of a study aimed at verifying the involvement of BAG3, an intracellular protein expressed in several tumors, in the Diuron-induced carcinogenesis. For this purpose, we analyzed the effect of Diuron on human primary urothelial cells and on human dermal fibroblasts. We found that while high concentrations of Diuron have a cytotoxic effect in human primary urothelial cells, in the same cells, noncytotoxic concentrations of the herbicide induce BAG3 expression. These findings show that BAG3 is a molecular target of Diuron and unravel the possible involvement of BAG3 protein in bladder carcinogenesis induced by the herbicide. In addition, these results suggest that BAG3 might be a potential early biomarker of damage induced by chronic exposure to Diuron.

Abstract 588: Characterization of oncolytic peptides for local bladder cancer therapy

Abstract Background: Bladder cancer is the sixth most common cancer in the United States, with over 80,000 new cases diagnosed each year. While patients often initially respond positively to treatment, it has been found that nearly 75% of patients diagnosed with high-grade non-muscle invasive bladder cancer (NMIBC) will develop a recurrence within ten years. Treatment options for recurrent NMIBC are severely lacking. Antimicrobial peptides (AMPs) are naturally occurring molecules that kill bacteria by forming membrane pores and lysing the cells. While these molecules have been explored for their use in oncology as oncolytic peptides, their low potency and limited therapeutic index have hindered further development. However, intravesical delivery of oncolytic peptides for NMIBC could minimize the current issues by enabling high concentrations at the site of action while limiting systemic exposure. The aim of this research project was to identify potent and selective oncolytic peptides and investigate their functional activity in vitro. Methods: T24 (bladder transitional cell carcinoma) and HUC (normal urothelial cells) were purchased from ATCC and ScienCell, respectively. Bladder cancer organoid models were acquired from Dr. Shen's laboratory (Columbia University). Proliferation and cytotoxicity measurements were conducted with alamarBlue (Thermo Fisher), CellTiter-Glo 3D (Promega) and xCELLigence RTCA (ACEA Biosciences). Results: We screened a library of ~40 known AMPs for antiproliferative activity in T24 bladder cancer cells, as well as normal human urothelial cells (HUCs). Based on the results of this experiment, six hits were identified and selected for further characterization. These hits were validated in two patient derived organoid models. While results from the phenotypic screen showed lack of selectivity against HUCs, we further investigated the kinetics of cell death to determine the utility of these molecules as intravesical therapies with short residence time within the bladder. It was determined that Temporin-L exhibited the most rapid kinetics of cell death of the six peptide hits analyzed. Furthermore, washout studies revealed that Temporin-L is capable of quickly killing cancer cells with a lasting effect. Conclusion: We identified several reference oncolytic peptides capable of killing bladder cancer cells. Of these peptides, Temporin-L exhibited unique characteristics in its kinetics of cell death and the potential for it to provide temporal selectivity over normal cells. These unique properties may be advantageous in local intravesical therapy for NMIBC due to the availability to control concentration and duration of exposure. Citation Format: Amy Klova, Hiroe Tariga, Suijin Yang, Anastasia Velentza, Jacek Stalewski, Adeela Kamal, Scott McDonnell. Characterization of oncolytic peptides for local bladder cancer therapy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 588.

Quantitative Proteomics of Urinary Bladder Cancer Cell Lines Identify UAP1 as a Potential Therapeutic Target.

Bladder carcinoma (BC) incidence and mortality rates are increasing worldwide. The development of novel therapeutic strategies is required to improve clinical management of this cancer. Aberrant protein expression may lead to cancer initiation and progression. Therefore, the identification of these potential protein targets and limiting their expression levels would provide alternative treatment options. In this study, we utilized a liquid-chromatography tandem mass spectrometry-based global proteomics approach to identify differentially expressed proteins in bladder cancer cell lines. A total of 3913 proteins were identified in this study, of which 479 proteins were overexpressed and 141 proteins were downregulated in 4 out of 6 BC cell lines when compared with normal human urothelial cell line (TERT-NHUC). We evaluated the role of UDP-N-acetylhexosamine pyrophosphorylase (UAP1) in bladder cancer pathogenesis. The silencing of UAP1 led to reduction in proliferation, invasion, colony formation and migration capability of bladder cancer cell lines. Thus, our study reveals UAP1 as a promising therapeutic target for bladder cancer.

Procarcinogen Activation and Mutational Signatures Model the Initiation of Carcinogenesis in Human Urothelial Tissues In Vitro

Disparity between genome-wide mutations in bladder and other cancers where smoking is a risk factor raises questions about carcinogenesis in different epithelia. To develop an experimental model of bladder carcinogenesis, we clonally expanded in vitro differentiated normal human urothelial (NHU) cells following exposure to an exemplar procarcinogen and used whole-genome DNA sequencing to derive mutational signatures. Benzo[a]pyrene (BaP) was activated by endogenous cytochrome P450 (cytochrome P450 family 1 subfamily A member 1 [CYP1A1]) to create genomically modified NHU cells. Comparison with the Catalogue of Somatic Mutations in Cancer (COSMIC) showed that mutations induced by BaP in NHU cells were similar to smoking-associated signatures in bladder and other cancers, including single- and doublet-base substitution signatures characterised by C > A transversions (COSMIC_SBS4 and COSMIC_DBS2, respectively), and an insertion/deletion signature of C deletions in homopolymer regions (COSMIC ID3). Our study provides the first direct evidence that BaP is activated locally in the urothelium, initiating the well-described smoking-associated mutational signatures. An absence of other common bladder cancer (BLCA)-associated genomic signatures points strongly to other primary causes of BLCA, which the new experimental approach described here is well placed to investigate. Mutational signatures ignore whether genes are affected, but tissue-specific drivers (KMT2D, KMT2C, and CDKN1A) were significantly overmutated in this model, providing insight on the emergent selection pressures. Patient summaryIn a carefully controlled laboratory setting, we exposed normal human urothelial tissues to a procarcinogen (benzo[a]pyrene) found in cigarette smoke. We show that the urothelial tissues activated the carcinogen and led to mutations forming across the genome in a characteristic pattern. This particular “mutational signature” is found in bladder tumours and other smoking-induced cancers (eg, lung); however, our study highlights that there are other unknown mutational processes in bladder cancer that is not the direct result of smoke carcinogens, and this will require further investigation.

CpG Oligodeoxynucleotides Induces Apoptosis of Human Bladder Cancer Cells via Caspase-3-Bax/Bcl-2-p53 Axis

To evaluate the anti-cancer effect of unmethylated cytosine-phosphorothioate-guanine (CpG)-containing oligodeoxynucleotides (ODNs) on human bladder cancer UM-UC-3cells, our study was carried out. The viability of cells (UM-UC-3, T24 and SV-HUC-1) with CpG ODN treatments was examined by cell counting kit-8 (CCK-8) assay. Apoptosis and cell cycle phase were determined by flow cytometry analysis. Pre-apoptosis factors of caspase-3, p53, B-cell lymphoma 2 associated X protein (Bax) and anti-apoptosis factor of B-cell lymphoma 2 (Bcl-2) were detected by western blot. Experimental results showed that the viability of human bladder cancer cells (UM-UC-3 and T24) with CpG ODN treatment was decreased and the viability of human normal urothelial cells (SV-HUC-1) with CpG ODN treatment was increased with time-dependance manner. Moreover, CpG ODN increased the apoptosis rate of UM-UC-3cells and arrested more cells in G0G1 phase. Furthermore, the expression of caspase-3, p53 and Bax were increased and the expression of Bcl-2 was decreased with CpG ODN treatment on UM-UC-3cells. CpG ODN promoted the proliferation of normal urinary transitional epithelial cells (SV-HUC-1) and inhibited the cell viability of human bladder cancer cells (UM-UC-3 and T24) invitro. CpG ODN induced the apoptosis of human bladder cancer (UM-UC-3) cells in a cascade progress via enhancing the expression of caspase-3, p53 and Bax, and inhibiting the expression of Bcl-2 with significant time-dependancy. CpG ODN inhibited cell cycle distribution of human bladder cancer (UM-UC-3) cells with more cells were arrested in G0G1 phase. This study suggested that the CpG ODN is the potential candidate on human bladder cancer.