Molecular biomarkers to predict response to neoadjuvant chemotherapy for bladder cancer

Targeting the KAT8/YEATS4 Axis Represses Tumor Growth and Increases Cisplatin Sensitivity in Bladder Cancer

Bladder cancer (BC) is one of the most common tumors characterized by a high rate of relapse and a lack of targeted therapy. Here, YEATS domain-containing protein 4 (YEATS4) is an essential gene for BC cell viability using CRISPR-Cas9 library screening is reported, and that HUWE1 is an E3 ligase responsible for YEATS4 ubiquitination and proteasomal degradation by the Protein Stability Regulators Screening Assay. KAT8-mediated acetylation of YEATS4 impaired its interaction with HUWE1 and consequently prevented its ubiquitination and degradation. The protein levels of YEATS4 and KAT8 are positively correlated and high levels of these two proteins are associated with poor overall survival in BC patients. Importantly, suppression of YEATS4 acetylation with the KAT8 inhibitor MG149 decreased YEATS4 acetylation, reduced cell viability, and sensitized BC cells to cisplatin treatment. The findings reveal a critical role of the KAT8/YEATS4 axis in both tumor growth and cisplatin sensitivity in BC cells, potentially generating a novel therapeutic strategy for BC patients.

Predictors of Response Following Neoadjuvant Cisplatin-Based Chemotherapy for Muscle Invasive Urothelial Bladder Cancer Using Molecular Profile: A Prospective Clinical Study

OBJECTIVES

To predict response of patients with muscle invasive bladder cancer (MIBC) to neoadjuvant chemotherapy (NAC) through analysis of molecular profile assessed clinically (radiologically and by pathological examination of transurethral resection biopsy [TURBT] specimens) and definitively with histopathological examination after radical cystectomy (RC).

METHODS

In a prospective study, tumor biopsies were obtained from patients with urothelial MIBC (T2-4a N0-2 M0) during TURBT. Patients were eligible for RC received 4 cycles of cisplatin-based NAC. DNA repair genes (BRACA1, ERCC1) & CTR gene m-RNA expression levels were assessed in resected tissue. The response to chemotherapy was assessed clinically (radiologically & TURBT) following NAC. Response was re-assessed for 64 patients who underwent RC and predictors of cancer-free survival (CFS) were calculated. Receiver operating characteristic (ROC) curve was used to delineate cutoff value copes with the best sensitivity and specificity for prediction of response to NAC.

RESULTS

The study included 104 patients, 42 (40.4%) responded well to NAC clinically. Out of 64 patients who underwent RC, 26 (40.6%) showed good response to NAC. CFS at 18 months for patients who underwent RC was 60%. Statistical analysis showed that molecular profile was an independent predictor of good response to NAC both clinically and pathologically and also predicted better CFS.

CONCLUSION

Molecular profile could play a decisive role in early detection of patients with MIBC who will get benefit from preoperative NAC.

Comprehensive analysis of scRNA-seq and bulk RNA-seq reveal the characteristics of disulfidptosis and a prognostic signature in BLCA

Disulfidptosis is a newly discovered mode of cell death. However, its biological mechanism in bladder cancer (BLCA) is still uncharacterized. In this investigation, we firstly examined the expression and mutation of disulfidptosis-related genes (DRGs) in BLCA. Two disulfidptosis phenotypes associated with DRGs expression patterns and immune cell infiltration were built. A disulfidptosis risk score signature was constructed based on ten differentially expressed genes (DEGs) between the disulfidptosis subtypes, which allowed patients to be stratified into high- and low-risk groups. We further confirmed that the disulfidptosis risk score signature has great power to predict prognosis, immune cell infiltration, and immunotherapy efficacy in BLCA. Additionally, we analyzed the differences in therapeutic sensitivities between high- and low-risk groups concerning targeted inhibitor therapy and immunotherapy. Analysis of single-cell RNA sequencing was conducted of the ten hub DRGs. Of the ten genes, we found that DUSP2 and SLCO1B3 were differentially expressed in BLCA tissues and adjacent normal tissues, and were markedly associated with patients' prognosis. Functional experiments revealed that overexpression of DUSP2 or knockdown of SLCO1B3 significantly inhibited cell proliferation, migration, and invasion in BLCA cells. In all, we present a fresh disulfidptosis-related prognostic signature, which has a remarkable capacity to characterize the immunological landscape and prognosis of BLCA patients.

A bibliometric insight into neoadjuvant chemotherapy in bladder cancer: trends, collaborations, and future avenues

Background

Neoadjuvant chemotherapy (NAC) followed by radical cystectomy (RC) remains the cornerstone of treatment for muscle-invasive bladder cancer (MIBC). While platinum-based regimens have demonstrated benefits in tumor downstaging and improved long-term survival for selected patients, they may pose risks for those who are ineligible or unresponsive to chemotherapy.

Objective

We undertook a bibliometric analysis to elucidate the breadth of literature on NAC in bladder cancer, discern research trajectories, and underscore emerging avenues of investigation.

Methods

A systematic search of the Web of Science Core Collection (WoSCC) was conducted to identify articles pertaining to NAC in bladder cancer from 1999 to 2022. Advanced bibliometric tools, such as VOSviewer, CiteSpace, and SCImago Graphica, facilitated the examination and depicted the publication trends, geographic contributions, institutional affiliations, journal prominence, author collaborations, and salient keywords, emphasizing the top 25 citation bursts.

Results

Our analysis included 1836 publications spanning 1999 to 2022, indicating a growing trend in both annual publications and citations related to NAC in bladder cancer. The United States emerged as the predominant contributor in terms of publications, citations, and international collaborations. The University of Texas was the leading institution in publication output. "Urologic Oncology Seminars and Original Investigations" was the primary publishing journal, while "European Urology" boasted the highest impact factor. Shariat, Shahrokh F., and Grossman, H.B., were identified as the most prolific and co-cited authors, respectively. Keyword analysis revealed both frequency of occurrence and citation bursts, highlighting areas of concentrated study. Notably, the integration of immunochemotherapy is projected to experience substantial growth in forthcoming research.

Conclusions

Our bibliometric assessment provides a panoramic view of the research milieu surrounding neoadjuvant chemotherapy for bladder cancer, encapsulating the present state, evolving trends, and potential future directions, with a particular emphasis on the promise of immunochemotherapy.

A risk signature of necroptosis-related lncRNA to predict prognosis and probe molecular characteristics for male with bladder cancer

Bladder cancer (BC) is a frequently diagnosed cancer with high mortality. Male patients have a higher risk of developing BC than female patients. As a type of caspase-independent cell death, necroptosis plays a significant role in the occurrence and progression of BC. The aberrant function of long non-coding RNAs (lncRNAs) plays an indispensable role in GI. However, the relationship between lncRNA and necroptosis in male patients with BC remains unclear. The clinical information and RNA-sequencing profiles of all BC patients were retrieved from The Cancer Genome Atlas Program. A total of 300 male participants were selected for the study. We conducted to identify the necroptosis-related lncRNAs (NRLs) by Pearson correlation analysis. Subsequently, least absolute shrinkage and selection operator Cox regression were conducted to establish a risk signature with overall survival-related NRLs in the training set and to validate it in the testing set. Finally, we verified the effectiveness of the 15-NRLs signature in prognostic prediction and therapy via survival analysis, receiver operating characteristic curve analysis, and Cox regression. Furthermore, we analyzed the correlation between the signature risk score and pathway enrichment analysis, immune cell infiltration, anticancer drug sensitivity, and somatic gene mutations. We developed 15-NRLs (AC009974.1, AC140118.2, LINC00323, LINC02872, PCAT19, AC017104.1, AC134312.5, AC147067.2, AL139351.1, AL355922.1, LINC00844, AC069503.1, AP003721.1, DUBR, LINC02863) signature, and divided patients into a high-risk group and low-risk group through the median risk score. Kaplan-Meier and receiver operating characteristic curves showed that the prognosis prediction had satisfactory accuracy. Cox regression analysis indicated that the 15-NRLs signature was a risk factor independent of various clinical parameters. Additionally, immune cell infiltration, half-maximal inhibitory concentration, and somatic gene mutations differed significantly among different risk subsets, implying that the signature could assess the clinical efficacy of chemotherapy and immunotherapy. This 15-NRLs risk signature may be helpful in assessing the prognosis and molecular features of male patients with BC and improve treatment modalities, thus can be further applied clinically.

BCAT2 Shapes a Noninflamed Tumor Microenvironment and Induces Resistance to Anti-PD-1/PD-L1 Immunotherapy by Negatively Regulating Proinflammatory Chemokines and Anticancer Immunity

To improve response rate of monotherapy of immune checkpoint blockade (ICB), it is necessary to find an emerging target in combination therapy. Through analyzing tumor microenvironment (TME)-related indicators, it is validated that BCAT2 shapes a noninflamed TME in bladder cancer. The outcomes of multiomics indicate that BCAT2 has an inhibitory effect on cytotoxic lymphocyte recruitment by restraining activities of proinflammatory cytokine/chemokine-related pathways and T-cell-chemotaxis pathway. Immunoassays reveal that secretion of CD8⁺ T-cell-related chemokines keeps a robust negative correlation with BCAT2, generating a decreasing tendency of CD8⁺ T cells around BCAT2⁺ tumor cells from far to near. Cotreatment of BCAT2 deficiency and anti-PD-1 antibody has a synergistic effect in vivo, implying the potential of BCAT2 in combination therapy. Moreover, the value of BCAT2 in predicting efficacy of immunotherapy is validated in multiple immunotherapy cohorts. Together, as a key molecule in TME, BCAT2 is an emerging target in combination with ICB and a biomarker of guiding precision therapy.

Regulation of cisplatin resistance in bladder cancer by epigenetic mechanisms

Bladder cancer is one of the most common malignancies in the world. Cisplatin is one of the most potent and widely used anticancer drugs and has been employed in several malignancies. Cisplatin-based combination chemotherapies have become important adjuvant therapies for bladder cancer patients. Cisplatin-based treatment often results in the development of chemoresistance, leading to therapeutic failure and limiting its application and effectiveness in bladder cancer. To develop improved and more effective cancer therapy, research has been conducted to elucidate the underlying mechanism of cisplatin resistance. Epigenetic modifications have been demonstrated involved in drug resistance to chemotherapy, and epigenetic biomarkers, such as urine tumor DNA methylation assay, have been applied in patients screening or monitoring. Here, we provide a systematic description of epigenetic mechanisms, including DNA methylation, noncoding RNA regulation, m6A modification and posttranslational modifications, related to cisplatin resistance in bladder cancer.

Systemic therapy in bladder preservation

Bladder cancer is an aggressive and lethal disease. Even when presenting as localized muscle-invasive disease, the 5-year survival rate is about 70%, and the recurrence rate after radical cystectomy is approximately 50%. Neoadjuvant chemotherapy (NAC) has the potential to downstage the primary tumor and treat micrometastases, leading to a decrease in recurrence rates and an increase in cure rates. There is level 1 evidence in favor of neoadjuvant cisplatin-based chemotherapy prior to radical cystectomy. However, data from clinical trials evaluating NAC for patients undergoing bladder-sparing treatments are less robust, so this strategy remains controversial. The response to NAC is prognostic and patients with favorable pathological response have better overall survival. Strategies to select patients based on molecular biomarkers have the potential to guide treatment decisions and even de-intensify treatment, avoiding local treatment for those with complete responses to systemic therapy. This review outlines the current literature on the use of NAC in the context of bladder preservation for muscle-invasive bladder cancer, highlights neoadjuvant studies in patients ineligible for cisplatin-based NAC, and discusses novel bladder-preservation strategies, including multimodality combinations and biomarker-driven studies of definitive chemotherapy.

Stepwise molecular mechanisms responsible for chemoresistance in bladder cancer cells

Chemotherapy resistance is an obstacle to cancer therapy and is considered a major cause of recurrence. Thus, understanding the mechanisms of chemoresistance is critical to improving the prognosis of patients. Here, we have established a stepwise gemcitabine-resistant T24 bladder cancer cell line to understand the molecular mechanisms of chemoresistance within cancer cells. The characteristics of the stepwise chemoresistance cell line were divided into 4 phases (parental, early, intermediate, and late phases). These four phase cells showed increasingly aggressive phenotypes in vitro and in vivo experiments with increasing phases and revealed the molecular properties of the biological process from parent cells to phased gemcitabine-resistant cell line (GRC). Taken together, through the analysis of gene expression profile data, we have characterized gene set of each phase indicating the response to anticancer drug treatment. Specifically, we identified a multigene signature (23 genes including GATA3, APOBEC3G, NT5E, MYC, STC1, FOXD1, SMAD9) and developed a chemoresistance score consisting of that could predict eventual responsiveness to gemcitabine treatment. Our data will contribute to predicting chemoresistance and improving the prognosis of bladder cancer patients.

A novel signature to predict the neoadjuvant chemotherapy response of bladder carcinoma: Results from a territory multicenter real-world study

Background: Although neoadjuvant chemotherapy (NAC) has become the standard treatment option for muscle invasive bladder carcinoma (MIBC), its application is still limited because of the lack of biomarkers for NAC prediction.

Methods: We conducted a territory multicenter real-world study to summarize NAC practice in China and its associated clinicopathologic variables with NAC response. Then, we developed and validated a robust gene-based signature for accurate NAC prediction using weighted correlation network analysis (WGCNA), the least absolute shrinkage and selector operation (LASSO) algorithm, a multivariable binary logistic regression model, and immunohistochemistry (IHC).

Results: In total, we collected 69 consecutive MIBC patients treated with NAC from four clinical centers. The application of NAC in the real world was relatively safe, with only two grade Ⅳ and seven grade Ⅲ AEs and no treatment-related deaths being reported. Among these patients, 16 patients gave up surgery after NAC, leaving 53 patients for further analysis. We divided them into pathological response and non-response groups and found that there were more patients with a higher grade and stage in the non-response group. Patients with a pathological response could benefit from a significant overall survival (OS) improvement. In addition, univariate and multivariate logistic analyses indicated that tumor grade and clinical T stage were both independent factors for predicting NAC response. Importantly, we developed and validated a five-gene-based risk score for extremely high predictive accuracy for NAC response.

Conclusion: NAC was relatively safe and could significantly improve OS for MIBC patients in the real-world practice. Our five-gene-based risk score could guide personalized therapy and promote the application of NAC.

Distinct immune and inflammatory response patterns contribute to the identification of poor prognosis and advanced clinical characters in bladder cancer patients

Due to the molecular heterogeneity, most bladder cancer (BLCA) patients show no pathological responses to immunotherapy and chemotherapy yet suffer from their toxicity. This study identified and validated three distinct and stable molecular clusters of BLCA in cross-platform databases based on personalized immune and inflammatory characteristics. H&E-stained histopathology images confirmed the distinct infiltration of immune and inflammatory cells among clusters. Cluster-A was characterized by a favorable prognosis and low immune and inflammatory infiltration but showed the highest abundance of prognosis-related favorable immune cell and inflammatory activity. Cluster-B featured the worst prognosis and high immune infiltration, but numerous unfavorable immune cells exist. Cluster-C had a favorable prognosis and the highest immune and inflammatory infiltration. Based on machine learning, a highly precise predictive model (immune and inflammatory responses signature, IIRS), including FN1, IL10, MYC, CD247, and TLR2, was developed and validated to identify the high IIRS-score group that had a poor prognosis and advanced clinical characteristics. Compared to other published models, IIRS showed the highest AUC in 5 years of overall survival (OS) and a favorable predictive value in predicting 1- and 3- year OS. Moreover, IIRS showed an excellent performance in predicting immunotherapy and chemotherapy's response. According to immunohistochemistry and qRT-PCR, IIRS genes were differentially expressed between tumor tissues with corresponding normal or adjacent tissues. Finally, immunohistochemical and H&E-stained analyses were performed on the bladder tissues of 13 BLCA patients to further demonstrate that the IIRS score is a valid substitute for IIR patterns and can contribute to identifying patients with poor clinical and histopathology characteristics. In conclusion, we established a novel IIRS depicting an IIR pattern that could independently predict OS and acts as a highly precise predictive biomarker for advanced clinical characters and the responses to immunotherapy and chemotherapy.

Analysis of prognostic oncogene filaggrin (FLG) wild-type subtype and its implications for immune checkpoint blockade therapy in bladder urothelial carcinoma

BACKGROUND

Bladder urothelial carcinoma (BLCA) is one of the most common urinary tract malignant tumors. Immune checkpoint blockade (ICB) therapy has significantly progressed the treatment of BLCA. This study aimed to investigate the role of specific genetic mutations that may serve as immune biomarkers for ICB therapy in BLCA.

METHODS

Mutation information and expression profiles were acquired from The Cancer Genome Atlas (TCGA) database. Integrated bioinformatics analysis was carried out to explore the subtypes with poor prognosis of BLCA. Functional enrichment analysis was also conducted. The infiltrating immune cells and the prediction of ICB response between different subtypes were explored using the immuCellAI algorithm. Cell Counting Kit-8 (CCK-8) and flow cytometry assays were conducted to explore the effect of filaggrin (FLG) knockdown in BLCA 5637 and T24 cell lines.

RESULTS

An overview of mutation information in BLCA patients was shown. FLG was identified to be strongly associated with the prognosis of BLCA patients and FLG wild-type was associated with poorer outcome. Prognostic FLG wild-type was divided into 2 subtypes (Sub1 and Sub2). Following an investigation of the subtypes, Sub2 of FLG wild-type was found to be associated with poorer outcome in BLCA. The differentially expressed genes (DEGs) between Sub1 and Sub2 were screened out and the DEGs were enriched in malignant tumor proliferation, DNA damage repair, and immune-related pathways. Furthermore, Sub2 of FLG wild-type was associated with infiltrated immune cells, and responded worse to ICB. Sub2 of FLG wild-type may be used as a biomarker to predict the prognosis of BLCA patients receiving ICB. The cellular experiments revealed that knockdown of FLG could suppress BLCA cell proliferation and promote apoptosis.

CONCLUSIONS

FLG is an oncogene that may affect the prognosis of BLCA patients through mutation. Sub2 of FLG wild-type is associated with poor prognosis and can be used to predict ICB response for BLCA treatment. This research provides a new basis and ideas for guiding the clinical application of BLCA immunotherapy.

A Preclinical Study to Repurpose Spironolactone for Enhancing Chemotherapy Response in Bladder Cancer

Neoadjuvant chemotherapy (NAC) followed by radical cystectomy is the standard-of-care for patients with muscle-invasive bladder cancer (MIBC). Defects in nucleotide excision repair (NER) are associated with improved responses to NAC. Excision Repair Cross-Complementation group 3 (ERCC3) is a key component of NER process. No NER inhibitors are available for treating patients with bladder cancer. We have developed an ex vivo cell-based assay of 6-4 pyrimidine-pyrimidinone (6-4PP) removal as a surrogate measure of NER capacity in human bladder cancer cell lines. The protein expression of ERCC3 was examined in human MIBC specimens and cell lines. Small molecule inhibitors were screened for NER inhibition in bladder cancer cell lines. Spironolactone was identified as a potent NER inhibitor. Combined effects of spironolactone with chemo-drugs were evaluated in vitro and in vivo. The efficacy between platinum and spironolactone on cytotoxicity was determined by combination index. A correlation between NER capacity and cisplatin sensitivity was demonstrated in a series of bladder cancer cell lines. Further, siRNA-mediated knockdown of ERCC3 abrogated NER capacity and enhanced cisplatin cytotoxicity. Spironolactone inhibited ERCC3 protein expression, abrogated NER capacity, and increased platinum-induced cytotoxicity in bladder cancer cells in vivo and in patient-derived organoids. Moreover, spironolactone exhibited the potential synergism effects with other clinical chemotherapy regimens in bladder cancer cell lines. Our data support the notion of repurposing spironolactone for improving the chemotherapy response of NAC in patients with MIBC. Further clinical trials are warranted to determine the safety and efficacy of spironolactone in combination with chemotherapy.

The role of tumour microenvironment-driven miRNAs in the chemoresistance of muscle-invasive bladder cancer-a review

Successful treatment for muscle-invasive bladder cancer is challenged by the ability of cancer cells to resist chemotherapy. While enormous progress has been made toward understanding the divergent molecular mechanisms underlying chemoresistance, the heterogenous interplay between the bladder tumour and its microenvironment presents significant challenges in comprehending the occurrence of chemoresistance. The last decade has seen exponential interest in the exploration of microRNA (miRNA) as a tool in the management of chemoresistance. In this review, we highlight the miRNAs involved in the tumour microenvironment crosstalk that contributes to the chemoresistance in bladder cancer. Decrypting the role of miRNAs in the interplay beholds scope for future clinical translational application in managing the long-standing concerns of chemoresistance in muscle-invasive bladder cancer.

Molecular Subtypes as a Basis for Stratified Use of Neoadjuvant Chemotherapy for Muscle-Invasive Bladder Cancer—A Narrative Review

Simple Summary

Although it is one disease, cancer of the urinary bladder occurs in several molecular subtypes that can be identified by laboratory tests. Tumors of advanced stages are treated with surgical removal of the urinary bladder with or without addition of chemotherapy. About 50% of patients are cured by surgery and this proportion is increased slightly by the addition of chemotherapy. Still, many patients do not benefit from chemotherapy, which also comes with significant toxicity. Recent advances in the field suggest that molecular subtypes can help identify patient categories that do or do not benefit from adding chemotherapy to surgery. In this article, we review the literature and conclude that molecular subtypes are likely to have such a role in the future but that there are differences between studies that make them challenging to compare. The current evidence is insufficient to guide clinical practice.

Abstract

There are no established biomarkers to guide patient selection for neoadjuvant chemotherapy prior to radical cystectomy for muscle-invasive bladder cancer. Recent studies suggest that molecular subtype classification holds promise for predicting chemotherapy response and/or survival benefit in this setting. Here, we summarize and discuss the scientific literature examining transcriptomic or panel-based molecular subtyping applied to neoadjuvant chemotherapy-treated patient cohorts. We find that there is not sufficient evidence to conclude that the basal subtype of muscle-invasive bladder cancer responds well to chemotherapy, since only a minority of studies support this conclusion. More evidence indicates that luminal-like subtypes may have the most improved outcomes after neoadjuvant chemotherapy. There are also conflicting data concerning the association between biopsy stromal content and response. Subtypes indicative of high stromal infiltration responded well in some studies and poorly in others. Uncertainties when interpreting the current literature include a lack of reporting both response and survival outcomes and the inherent risk of bias in retrospective study designs. Taken together, available studies suggest a role for molecular subtyping in stratifying patients for receiving neoadjuvant chemotherapy. The precise classification system that best captures such a predictive effect, and the exact subtypes for which other treatment options are more beneficial remains to be established, preferably in prospective studies.

Targeting HNRNPU to overcome cisplatin resistance in bladder cancer

Purpose

The overall response of cisplatin-based chemotherapy in bladder urothelial carcinoma (BUC) remains unsatisfactory due to the complex pathological subtypes, genomic difference, and drug resistance. The genes that associated with cisplatin resistance remain unclear. Herein, we aimed to identify the cisplatin resistance associated genes in BUC.

Experimental design

The cytotoxicity of cisplatin was evaluated in six bladder cancer cell lines to compare their responses to cisplatin. The T24 cancer cells exhibited the lowest sensitivity to cisplatin and was therefore selected to explore the mechanisms of drug resistance. We performed genome-wide CRISPR screening in T24 cancer cells in vitro, and identified that the gene heterogeneous nuclear ribonucleoprotein U (HNRNPU) was the top candidate gene related to cisplatin resistance. Epigenetic and transcriptional profiles of HNRNPU-depleted cells after cisplatin treatment were analyzed to investigate the relationship between HNRNPU and cisplatin resistance. In vivo experiments were also performed to demonstrate the function of HNRNPU depletion in cisplatin sensitivity.

Results

Significant correlation was found between HNRNPU expression level and sensitivity to cisplatin in bladder cancer cell lines. In the high HNRNPU expressing T24 cancer cells, knockout of HNRNPU inhibited cell proliferation, invasion, and migration. In addition, loss of HNRNPU promoted apoptosis and S-phase arrest in the T24 cells treated with cisplatin. Data from The Cancer Genome Atlas (TCGA) demonstrated that HNRNPU expression was significantly higher in tumor tissues than in normal tissues. High HNRNPU level was negatively correlated with patient survival. Transcriptomic profiling analysis showed that knockout of HNRNPU enhanced cisplatin sensitivity by regulating DNA damage repair genes. Furthermore, it was found that HNRNPU regulates chemosensitivity by affecting the expression of neurofibromin 1 (NF1).

Conclusions

Our study demonstrated that HNRNPU expression is associated with cisplatin sensitivity in bladder urothelial carcinoma cells. Inhibition of HNRNPU could be a potential therapy for cisplatin-resistant bladder cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12943-022-01517-9.

Circ_0002623 promotes bladder cancer progression by regulating the miR-1276/SMAD2 axis

Circular RNAs (circRNAs) are key regulatory factors in the development of multiple cancers. This study is targeted at exploring the effect of circ_0002623 on bladder cancer (BCa) progression and its mechanism. Circ_0002623 was screened out by analyzing the expression profile of circRNAs in BCa tissues. Circ_0002623, miR-1276 and SMAD2 mRNA expression levels in clinical sample tissues and cell lines were detected through quantitative real-time polymerase chain reaction (qRT-PCR). After circ_0002623 was overexpressed or silenced in BCa cells, the cell proliferation, migration and cell cycle were evaluated by CCK-8, BrdU, Transwell assay and flow cytometry. Tumor xenograft model was used to validate the biological function of circ_0002623 in vivo. Bioinformatics analysis and dual-luciferase reporter gene assay were conducted for analyzing and confirming, respectively, the targeted relationship between circ_0002623 and miR-1276, as well as between miR-1276 and SMAD2. The regulatory effects of circ_0002623 and miR-1276 on the expression levels of TGF-β, WNT1 and SMAD2 in BCa cells were detected by Western blot. We reported that, in BCa tissues and cell lines, circ_0002623 was up-regulated, whereas miR-1276 was down-regulated. Circ_0002623 positively regulated BCa cell proliferation, migration and cell cycle progression. Additionally, circ_0002623 could competitively bind with miR-1276 to increase the expression of SMAD2, the target gene of miR-1276. Furthermore, circ_0002623 could regulate the expression of TGF-β and WNT1 via modulating miR-1276 and SMAD2. This study helps to better understand the molecular mechanism underlying BCa progression.

Identification of Neoadjuvant Chemotherapy Response in Muscle-Invasive Bladder Cancer by Fourier-Transform Infrared Micro-Imaging

Simple Summary

Assessing the tumor response to chemotherapy is a paramount predictive step to improve patient care. Infrared spectroscopy probes the chemical composition of samples, and in combination with statistical multivariate processing, presents the capacity to highlight subtle molecular alterations associated with malignancy characteristics. Microscopic infrared imaging of tissue samples reveals spectral heterogeneity within histological structures, providing a new approach to characterize tumoral heterogeneity. We have taken advantage of the analytical capabilities of mid-infrared spectral imaging to implement a classification model to predict the response of a tumor to chemotherapy. Our development was demonstrated in muscle-invasive bladder cancer (MIBC) by comparing samples from responders and non-responders to neoadjuvant chemotherapy.

Abstract

Background: Neoadjuvant chemotherapy (NAC) improves survival in responder patients. However, for non-responders, the treatment represents an ineffective exposure to chemotherapy and its potential adverse events. Predicting the response to treatment is a major issue in the therapeutic management of patients, particularly for patients with muscle-invasive bladder cancer. Methods: Tissue samples of trans-urethral resection of bladder tumor collected at the diagnosis time, were analyzed by mid-infrared imaging. A sequence of spectral data processing was implemented for automatic recognition of informative pixels and scoring each pixel according to a continuous scale (from 0 to 10) associated with the response to NAC. The ground truth status of the responder or non-responder was based on histopathological examination of the samples. Results: Although the TMA spots of tumors appeared histologically homogeneous, the infrared approach highlighted spectral heterogeneity. Both the quantification of this heterogeneity and the scoring of the NAC response at the pixel level were used to construct sensitivity and specificity maps from which decision criteria can be extracted to classify cancerous samples. Conclusions: This proof-of-concept appears as the first to evaluate the potential of the mid-infrared approach for the prediction of response to neoadjuvant chemotherapy in MIBC tissues.

Tumor mutation burden is correlated with response and prognosis in microsatellite-stable (MSS) gastric cancer patients undergoing neoadjuvant chemotherapy

BACKGROUND

Neoadjuvant chemotherapy (NACT) before radical gastrectomy is preferred for locally advanced gastric cancer (GC). However, clinical practices demonstrate that a considerable proportion of GC patients do not benefit from NACT, largely due to the lack of biomarkers for patient selection and prognosis prediction. A recent study revealed that patients with microsatellite instability-high (MSI-H) may be resistant to NACT, however, most tumors in Chinese GC patients (~ 95%) are characterized by microsatellite stability (MSS). Here, we aimed to discover new molecular biomarkers for this larger population.

METHODS

We performed whole-exome sequencing on 46 clinical samples (pre- and post-treatment) from 30 stage II/III MSS GC patients whose response to NACT was rigorously defined. Serum tumor markers (TMs), including AFP, CEA, CA199, CA724 and CA242 were measured during the course.

RESULTS

High tumor mutation burden (TMB-H) and 19q12 amplification (19q12 +) were positively associated with the NACT response. When TMB and 19q12 amplification were jointly analyzed, those with TMB-H or 19q12 + showed favorable response to NACT (p = 0.035). Further, TMB-H was negatively correlated with ypN stage, lymph node metastasis, and macrophage infiltration. Patients with TMB-H showed better disease-free survival (DFS) than those with TMB-L (P = 0.025, HR = 0.1331), and this was further validated using two larger GC datasets: TCGA-STAD (p = 0.004) and ICGC-CN (p = 0.045).

CONCLUSION

The combination of TMB-H and 19q12 + can serve as an early indicator of response to NACT. Superior to traditional clinical indicators, TMB-H is a robust and easily accessible candidate biomarker associated with better DFS, and can be evaluated at the time of diagnosis.

Prognostic blood-based biomarkers in patients treated with neoadjuvant chemotherapy for urothelial carcinoma of the bladder: A systematic review

PURPOSE

The present systematic review aimed to identify prognostic values of blood-based biomarkers in patients treated with neoadjuvant chemotherapy (NAC) for urothelial carcinoma of the bladder (UCB).

MATERIAL AND METHODS

The PubMed, Web of Science, and Scopus databases were searched in August 2020 according to the PRISMA statement. Studies were deemed eligible if they compared oncological outcomes in patients treated with NAC for UCB with and without pretreatment laboratory abnormalities.

RESULTS

Overall, ten studies, including 966 patients who underwent NAC, met our eligibility criteria. Six studies provided data on pretreatment neutrophil to lymphocyte ratio (NLR) with contradicting results on its association with pathologic response (PR) and complete pathologic response (pCR); some studies reported a strong association between a high level of pretreatment NLR and worse survival outcomes. Two studies reported that higher pretreatment platelet-lymphocyte ratio (PLR) is associated with a lower likelihood of achieving PR and/or pCR, while lymphocyte count alone had the opposite association. One study reported a negative association between pretreatment blood-based myeloid-derived suppressors cells and pCR. Patients who experienced a remission have been reported to have higher level of lymphocyte subsets (CD3+, CD4+, CD57+ cells, the ratio of CD4+/CD8+) compared to those who had progression. One study found that low pretreatment blood-based human chorionic gonadotrophin b subunit (hCGβ) was associated with improved overall survival (OS). High levels of epithelial tumor markers (CA-125, CA 19-9) were also associated with worse OS and recurrence-free survival in the NAC setting.

CONCLUSION

Current evidence suggests that several readily available, easy measurable blood-based biomarkers hold promise to improve our selection of UCB patients who are likely benefit from NAC. However, their role as an adjunct to established histopathologic characteristics for clinical decision-making requires further validation along the biomarker phased approach.

Disease control with prior platinum-based chemotherapy is prognostic for survival in patients with metastatic urothelial cancer treated with atezolizumab in real-world practice

Background

Atezolizumab, a programmed-death ligand-1 (PD-L1) inhibitor, is a novel treatment option for patients with metastatic urothelial cancer (mUC). Clinical prognostic factors, survival outcomes, and the safety of patients with mUC treated with atezolizumab, in a real-world setting, were investigated.

Patients and methods

62 patients with mUC, treated at the Institute of Oncology Ljubljana between May 8th 2018 and Dec 31st 2019, were included. Response rates and immune-related adverse events (irAE) were collected. Progression-free survival and overall survival times were assessed using the Kaplan-Meier method. The Cox proportional hazards model was applied to identify the factors affecting survival.

Results

Of 62 patients, five (8.1%) have not yet been evaluated and 20 (32%) died prior to the first radiographic evaluation. We observed clinical benefit in 19 (33%), objective response in 12 (21%), and complete response in five (9%) patients. Median overall survival for the whole population was 6.8 (95% CI, 2.6–11.0), for platinum-naïve 8.7 (95% CI: 0.8–16.5), and for the platinum-treated group 6.8 (95% CI, 3.7–10) months. At the 5.8 (0.3–23.1) month median follow-up, the median duration of the response was not reached. IrAE occurred in 20 (32%) patients and seven (11%) of them discontinued the treatment. Multivariate analysis in platinum-treated patients showed that a treatment-free interval of more than six months was prognostic for overall survival (OS).

Conclusions

Responses to atezolizumab led to long disease remission in a subset of our patients. The median OS in our real-world population was compromised by a large percentage of patients with poor ECOG performance status (PS). A treatment-free interval from chemotherapy was associated with the longer survival of platinum-treated patients with mUC receiving further atezolizumab.

LACTB and LC3 could serve as potential biomarkers of gastric cancer to neoadjuvant chemotherapy with oxaliplatin plus S-1

The present study investigated and evaluated the correlation between the expression of LACTB and LC3 and the clinical outcomes of patients with advanced gastric cancer treated with oxaliplatin plus S-1 neoadjuvant chemotherapy (NACT). A total of 51 patients with advanced gastric cancer underwent NACT treatment between June 2015 and June 2017. Pathomorphological changes in gastric cancer were analyzed by H&E staining. The expression level and subcellular localization of LACTB and LC3 in paraffin-embedded biopsies were detected by immunohistochemistry and immunofluorescence. The mRNA and protein expression of LACTB were investigated by reverse transcription quantitative polymerase chain reaction and Western blotting, respectively. Statistical analysis was performed to determine the association between the expression of LACTB and LC3 and clinical chemotherapy efficacy of NACT for gastric cancer. Among the 51 patients, 3 (5.88%), 27 (52.94%), 13 (25.49%) and 8 (15.69%) displayed complete remission, partial remission, stable disease and progressive disease, respectively. The rate of decreased LACTB expression was 68.6%, while the rate of increased LC3 expression was 60.8%. Furthermore, there was a significant negative correlation between the expression of LACTB and that of LC3 following NACT (P<0.001). High expression of LC3 (P<0.01) and low expression of LACTB (P<0.01) were associated with a poor response of patients with advanced gastric cancer to NACT. In conclusion, the expression of LACTB and LC3 may serve as a promising novel biomarker for determining the prognosis of patients with advanced gastric cancer receiving NACT, while its potential clinical significance requires further elucidation.

KAT8/MOF-Mediated Anti-Cancer Mechanism of Gemcitabine in Human Bladder Cancer Cells

Histone acetylation is a well-characterized epigenetic modification controlled by histone acetyltransferases (HATs) and histone deacetylases (HDACs). Imbalanced histone acetylation has been observed in many primary cancers. Therefore, efforts have been made to find drugs or small molecules such as HDAC inhibitors that can revert acetylation levels to normal in cancer cells. We observed dose-dependent reduction in the endogenous and exogenous protein expression levels of KAT8 (also known as human MOF), a member of the MYST family of HATs, and its corresponding histone acetylation at H4K5, H4K8, and H4K16 in chemotherapy drug gemcitabine (GEM)-exposed T24 bladder cancer (BLCA) cells. Interestingly, the reduction in MOF and histone H4 acetylation was inversely proportional to GEM-induced γH2AX, an indicator of chemotherapy drug effectiveness. Furthermore, pGL4-MOF-Luc reporter activities were significantly inhibited by GEM, thereby suggesting that GEM utilizes an MOF-mediated anti-BLCA mechanism of action. In the CCK-8, wound healing assays and Transwell^® experiments, the additive effects on cell proliferation and migration were observed in the presence of exogenous MOF and GEM. In addition, the promoted cell sensitivity to GEM by exogenous MOF in BLCA cells was confirmed using an Annexin V-FITC/PI assay. Taken together, our results provide the theoretical basis for elucidating the anti-BLCA mechanism of GEM.

A Single-arm Phase II Trial of Neoadjuvant Cabazitaxel and Cisplatin Chemotherapy for Muscle-Invasive Transitional Cell Carcinoma of the Urinary Bladder

INTRODUCTION

Neoadjuvant cisplatin-based combination chemotherapy improves survival in muscle-invasive bladder cancer. However, response rates and survival remain suboptimal. We evaluated the efficacy, safety, and tolerability of cisplatin plus cabazitaxel.

METHODS

A phase II single-arm trial was designed to recruit at least 26 evaluable patients. This would give 80% power to detect the primary endpoint, an objective response rate defined as a pathologic complete response plus partial response (pathologic downstaging), measured by pathologic staging at cystectomy (p₀ = 0.35 and p₁ = 0.60, α = 0.05).

RESULTS

Objective response was seen in 15 of 26 evaluable patients (57.7%) and more than one- third of patients achieved a pathologic complete response (9/26; 34.6%). Seventy-eight percent of the patients (21/27) completed all cycles of treatment, with only 6.7% of the reported adverse events being graded 3 or 4. There were 6 treatment-related serious adverse event reported, but no suspected unexpected serious adverse reactions. In the patients who achieved an objective response, the median progression-free survival and overall survival were not reached (median follow-up of 41.5 months). In contrast, the median progression-free survival (7.2 months) and overall survival (16.9 months) were significantly worse (P = .001, log-rank) in patients who did not achieve an objective response.

CONCLUSION

Cabazitaxel plus cisplatin for neoadjuvant treatment of muscle-invasive bladder cancer can be considered a well-tolerated and effective regimen before definitive therapy with higher rates (57.7%) of objective response, comparing favorably to that with of cisplatin/gemcitabine (23%-26%). These results warrant further evaluation in a phase III study.

Current Management of Localized Muscle-Invasive Bladder Cancer: A Consensus Guideline from the Genitourinary Medical Oncologists of Canada

BACKGROUND: Despite recent advances in the management of muscle-invasive bladder cancer (MIBC), treatment outcomes remain suboptimal, and variability exists across current practice patterns. OBJECTIVE: To promote standardization of care for MIBC in Canada by developing a consensus guidelines using a multidisciplinary, evidence-based, patient-centered approach who specialize in bladder cancer. METHODS: A comprehensive literature search of PubMed, Medline, and Embase was performed; and most recent guidelines from national and international organizations were reviewed. Recommendations were made based on best available evidence, and strength of recommendations were graded based on quality of the evidence. RESULTS: Overall, 17 recommendations were made covering a broad range of topics including pathology review, staging investigations, systemic therapy, local definitive therapy and surveillance. Of these, 10 (59% ) were level 1 or 2, 7 (41% ) were level 3 or 4 recommendations. There were 2 recommendations which did not reach full consensus, and were based on majority opinion. This guideline also provides guidance for the management of cisplatin-ineligible patients, variant histologies, and bladder-sparing trimodality therapy. Potential biomarkers, ongoing clinical trials, and future directions are highlighted. CONCLUSIONS: This guideline embodies the collaborative expertise from all disciplines involved, and provides guidance to further optimize and standardize the management of MIBC.

Pathological downstaging following radical cystectomy for muscle-invasive bladder cancer: Survival outcomes in the setting of neoadjuvant chemotherapy versus transurethral resection only

INTRODUCTION

Neoadjuvant chemotherapy (NAC) improves survival for patients undergoing radical cystectomy for muscle-invasive bladder cancer (MIBC). The overall survival (OS) advantage with NAC is primarily seen in patients who achieve pathological downstaging. However, a substantial number of patients achieve pathological downstaging following transurethral resection (TUR) without NAC.

OBJECTIVES

To analyze the OS outcomes in patients who achieve pathological downstaging in the setting of NAC vs. TUR only.

MATERIALS AND METHODS

We reviewed the National Cancer Database (NCDB) for patients diagnosed with MIBC who underwent radical cystectomy between 2004 and 2014. Patients who achieved complete downstaging (CD) (pT0N0) or noninvasive downstaging (NID) (pT0/Tis/TaN0) were further analyzed. OS was evaluated by comparing those who underwent NAC to those who underwent TUR only.

RESULTS

A total of 24,763 patients with MIBC were identified. 1,781 (7.2%) patients had NID and 1,015 (4.1%) had CD. Of all patients, 3,838 (15.5%) underwent NAC. In patients with NID, 757 (42.5%) underwent NAC and 1024 (57.5%) had cystectomy after TUR only. In patients with CD, 465 (45.8%) had NAC, while 550 (54.2%) had TUR only. In both NID and CD, cT2 patients were more likely to have TUR only (P = 0.019, P < 0.001), cT3 patients were more likely to receive NAC (P = 0.008, P < 0.001). Compared to the TUR only group, NAC was associated with improved 5-year OS in those with NID, 77% compared to 68% (HR 0.68, 95% CI [0.52-0.90]), as well as those with CD, 80% vs. 70% (HR 0.59, 95% CI [0.39-0.89]).

CONCLUSIONS

NAC was associated with significant overall survival benefit in the subset of patients who achieved CD and NID at radical cystectomy. Overall, NAC was underutilized in patients with MIBC.

Identification of markers predictive for response to induction chemotherapy in patients with sinonasal undifferentiated carcinoma

OBJECTIVES

Sinonasal undifferentiated carcinoma (SNUC) is a rare, highly aggressive cancer. Despite aggressive multimodal therapy, its prognosis remains poor. Because of its locally advanced nature and high propensity for distant metastasis, we frequently use induction chemotherapy before definitive therapy in patients with SNUC. However, about 30% of patients do not respond to induction chemotherapy, and lack of response is associated with a poor survival rate. Therefore, in this study, we performed gene expression analysis of SNUC samples to identify prognostic markers for induction chemotherapy response.

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded SNUC tumor samples from previously untreated patients harvested before induction chemotherapy were used. Gene expression was performed using an oncology gene expression panel.

RESULTS

We identified 34 differentially expressed genes that distinguish the responders from the non-responders. Pathway analysis using these genes revealed alteration of multiple pathways between the two groups. Of these 34 genes, 24 distinguished between these two groups. Additionally, 16 gene pairs were associated with response to induction therapy.

CONCLUSION

We identified genes predictive of SNUC response to induction chemotherapy and pathways potentially associated with treatment outcome. This is the first report of identification of predictive biomarkers for response of SNUC to induction chemotherapy, and it may help us develop therapeutic strategies to improve the treatment outcomes of non-responders.

Long non-coding RNA GHET1 contributes to chemotherapeutic resistance to Gemcitabine in bladder cancer

PURPOSE

Bladder cancer (BC) ranks first in the incidence of urogenital tumors in China and second only to prostate cancer in the West. This study will clarify the roles and mechanism of lncRNA GHET1 in chemotherapeutic resistance of BC to Gemcitabine.

METHODS

The expression of GHET1 was examined using real-time quantitative PCR. Cell Counting Kit-8 assay was applied to analyze cell proliferation and Gemcitabine sensitivity. Cell apoptosis was detected using Annexin V-FITC/PI double-stained flow cytometry. The expression of ABCC1 protein was examined using Western blotting.

RESULTS

Firstly, the expression of GHET1 was up-regulated in BC, its high expression was relevant to high grade and muscle invasion of BC patients. Secondly, high expression of GHET1 was related to low Gemcitabine sensitivity of BC patients, and GHET1 was highly expressed in Gemcitabine-resistant BC cell lines. Thirdly, knockdown of GHET1 decreased the IC50 of Gemcitabine in Gemcitabine-resistant BC cell lines and advanced the Gemcitabine-induced cytotoxicity; GHET1 promoted Gemcitabine resistance in BC. Finally, knockdown of GHET1 also inhibited the expression of ABCC1 protein in Gemcitabine-resistant BC cells.

CONCLUSIONS

High expression of GHET1 was related with the low sensitivity to Gemcitabine of BC; GHET1 contributed to chemotherapeutic resistance to Gemcitabine in BC through up-regulating ABCC1 expression. Our findings are helpful to expound the molecular mechanism of chemotherapeutic resistance in BC.

Vitamin D3 enhances the response to cisplatin in bladder cancer through VDR and TAp73 signaling crosstalk

Background

Vitamin D₃ (VitD) deficiency is linked to increased incidence and worse survival in bladder cancer (BCa). In addition to cystectomy, patients are treated with cisplatin‐based chemotherapy, however 30%‐50% of patients do not benefit from this treatment. The effects of VitD deficiency on response to chemotherapy remain unknown.

Methods

To test effects of VitD supplementation on the response to cisplatin we analyzed patient serum VitD levels and correlated that with survival. In vivo, VitD deficient mice were treated with cisplatin, with or without pretreatment with the active VitD metabolite, 1,25 dihydroxyvitamin D₃ (1,25D₃). Lastly, using BCa cell lines, T24 and RT‐112, the mechanism of action of 1,25D₃ and cisplatin combination treatment was determined by apoptosis assays, as well as western blot and RT‐PCR.

Results

In this study, we determined that low serum 25 hydroxyvitamin D₃ (25D₃) levels was significantly associated with worse response to cisplatin. Pretreating deficient mice with 1,25D₃, reduced tumor volume compared to cisplatin monotherapy. In vitro, 1,25D₃ pretreatment increased the apoptotic response to cisplatin. 1,25D₃ pretreatment increased expression of TAp73 and its pro‐apoptotic targets, in a VDR dependent manner. VDR and its transcriptional targets were induced after 1,25D₃ treatment and further increased after the combination of 1,25D₃ and cisplatin in a TAp73 dependent manner.

Conclusions

Our data suggest that VitD deficiency could be a biomarker for poor response to cisplatin, and pretreating with VitD can increase the apoptotic response to cisplatin through VDR and TAp73 signaling crosstalk.

CIP2A depletion potentiates the chemosensitivity of cisplatin by inducing increased apoptosis in bladder cancer cells

Poor response and chemotherapy resistance to cisplatin (DDP)-based therapy frequently lead to treatment failure in advanced bladder cancer; however the underlying mechanism is extremely complex and unclear. Furthermore, cancerous inhibitor of protein phosphatase 2A (CIP2A), a recently identified human oncoprotein, has been shown to play important regulatory roles in cancer cell survival. The present study aimed to investigate the correlation of CIP2A with sensitivity to DDP in bladder cancer cells. In the present study, knockdown of CIP2A was performed using short hairpin-RNA. IC₅₀ determination was used to estimate the chemosensitivity of cells to DDP. Apoptosis and DNA damage indicators were tested in vitro and in vivo to clarify the role of CIP2A in enhancing DDP sensitivity. We observed that CIP2A knockdown enhanced DDP sensitivity. CIP2A depletion accelerated the process of DNA damage caused by DDP treatment. Furthermore, DDP triggered inhibition of CIP2A by preventing AKT Ser473 phosphorylation. In vivo, CIP2A suppression increased the cytotoxicity of DDP, which resulted in a decrease in the subcutaneous tumor growth in a xenograft mouse model. Our findings revealed that the mechanism underlying the involvement of CIP2A in DDP sensitivity enhancement is that CIP2A mediates DDP-induced cell apoptosis and DNA damage. CIP2A is a potential target to improve the response to DDP-based therapy in bladder cancer patients.

[Prognostic of older age for patients with invasive-muscle-bladder cancer and treated by radical cystectomy]

INTRODUCTION

Bladder tumor is a disease of older persons, but can also occur in young adults, because certainly an influence of environmental factors and a change of lifestyle. The aim of our retrospective analysis is to assess and evaluate the extent of the prognostic impact of age on the carcinological prognosis of invasive-muscle-bladder cancer treated by total cystotomy.

METHODS

To evaluate the association of patient age with pathological characteristics and recurrence-free and disease survival, we retrospectively reviewed 345 patients with invasive bladder cancer between January 2000 and January 2015.

RESULTS

We divided our patients into two groups: patients under 65 years of age=150 cases (group 1), patients aged 65 years and over=195 cases (group 2). The 3-year survival rates for patients according to the age groups were 88% and 64% respectively, end the recurrence-free survival 66% and 28%. When age was analysed as a categorical variable, was associated with hydronephrosis (P=0.001), advanced pathological stage (P=0.034), high grade (P=0.026), nodal involvement (P=0.011) and lymphovascular invasion (P=0.008). The multivariate Cox model analysis showed that hydronephrosis and pathological stage was prognostic factors of survival (P=0.012 and P=0.035, respectively). Higher age is significantly associated with the risk of pathologically advanced disease and poorer global survival.

CONCLUSION

This work allowed us to assert that advanced chronological age is significantly associated with an advanced pathological stage of the disease (volume, pT, grade, lymph nodes) and a low overall survival rate. This could be useful for selecting subjects who would require adjuvant therapy, as well as for planning early complementary therapies.

LEVEL OF EVIDENCE

3.

Various Mechanisms Involve the Nuclear Factor (Erythroid-Derived 2)-Like (NRF2) to Achieve Cytoprotection in Long-Term Cisplatin-Treated Urothelial Carcinoma Cell Lines

Therapeutic efficacy of cisplatin-based chemotherapy for advanced-stage urothelial carcinoma (UC) is limited by drug resistance. The nuclear factor (erythroid-derived 2)-like 2 (NRF2) pathway is a major regulator of cytoprotective responses. We investigated its involvement in cisplatin resistance in long-term cisplatin treated UC cell lines (LTTs). Expression of NRF2 pathway components and targets was evaluated by qRT-PCR and western blotting in LTT sublines from four different parental cells. NRF2 transcriptional activity was determined by reporter assays and total glutathione (GSH) was quantified enzymatically. Effects of siRNA-mediated NRF2 knockdown on chemosensitivity were analysed by viability assays, γH2AX immunofluorescence, and flow cytometry. Increased expression of NRF2, its positive regulator p62/SQSTM1, and elevated NRF2 activity was observed in 3/4 LTTs, which correlated with KEAP1 expression. Expression of cytoprotective enzymes and GSH concentration were upregulated in some LTTs. NRF2 knockdown resulted in downregulation of cytoprotective enzymes and resensitised 3/4 LTTs towards cisplatin as demonstrated by reduced IC₅₀ values, increased γH2AX foci formation, and elevated number of apoptotic cells. In conclusion, while LTT lines displayed diversity in NRF2 activation, NRF2 signalling contributed to cisplatin resistance in LTT lines, albeit in diverse ways. Accordingly, inhibition of NRF2 can be used to resensitise UC cells to cisplatin, but responses in patients may likewise be variable.

Diagnostic and prognostic value of long noncoding RNAs as biomarkers in urothelial carcinoma

Many long noncoding RNAs (lncRNAs) are deregulated in cancer and contribute to oncogenesis. In urothelial carcinoma (UC), several lncRNAs have been reported to be overexpressed and proposed as biomarkers. As most reports have not been confirmed independently in large tissue sets, we aimed to validate the diagnostic and prognostic value of lncRNA upregulation in independent cohorts of UC patients. Thus, expression of seven lncRNA candidates (GAS5, H19, linc-UBC1, MALAT1, ncRAN, TUG1, UCA1) was measured by RT-qPCR in cell lines and tissues and correlated to clinicopathological parameters including follow-up data (set 1: N n = 10; T n = 106). Additionally, publicly available TCGA data was investigated for differential expression in UC tissues (set 2: N n = 19; T n = 252,) and correlation to overall survival (OS). All proposed candidates tended to be upregulated in tumour tissues, with the exception of MALAT1, which was rather diminished in cancer tissues of both data sets. However, strong overexpression was generally limited to individual tumour tissues and statistically significant overexpression was only observed for UCA1, TUG1, ncRAN and linc-UBC1 in tissue set 2, but for no candidate in set 1. Altered expression of individual lncRNAs was associated with overall survival, but not consistently between both patient cohorts. Interestingly, lower expression of TUG1 in a subset of UC patients with muscle-invasive tumours was significantly correlated with worse OS in both cohorts. Further analysis revealed that tumours with low TUG1 expression are characterized by a basal-squamous-like subtype signature accounting for the association with poor outcome. In conclusion, our study demonstrates that overexpression of the candidate lncRNAs is found in many UC cases, but does not occur consistently and strongly enough to provide reliable diagnostic or prognostic value as an individual biomarker. Subtype-dependent expression patterns of lncRNAs like TUG1 could become useful to stratify patients by molecular subtype, thus aiding personalized treatments.