Significance of second transurethral resection on patient outcomes in muscle-invasive bladder cancer patients treated with bladder-preserving multimodal therapy

Selective multimodal bladder-sparing therapy for muscle-invasive bladder cancer: the present and the future

INTRODUCTION

Despite the lack of level 1 evidence, selective bladder-sparing therapy using trimodal therapy is currently recommended by guidelines as a standard of care in patients with non-metastatic, muscle-invasive bladder cancer who are eligible for the treatment.

AREAS COVERED

This article reviews major studies of selective, bladder-sparing therapy utilizing multiple modalities for muscle-invasive bladder cancer and those comparing the oncological outcomes between bladder-sparing therapy and radical cystectomy. Also discussed are predictive biomarkers potentially capable of guiding treatment decisions by patients with muscle-invasive bladder cancer and a novel strategy for boosting the antitumor immune response in bladder-sparing therapy. PubMed databases were searched for records of 30 June 2023 or earlier.

EXPERT OPINION

Selective, bladder-sparing therapy appears to be underutilized at present. To promote its use, measures should be taken to facilitate the referral of eligible patients to specialist centers and broaden the number of facilities providing the therapy. Recent studies have suggested a prognostic benefit of radiotherapy for the primary lesion in patients with metastatic bladder cancer. Given that irradiation can induce the abscopal effect, particularly in combination with immune checkpoint inhibitors, demand for bladder-sparing therapies may increase in the context of treatments for metastases.

Combined Modality Bladder-Sparing Therapy for Muscle-Invasive Bladder Cancer: How (Should) We Do It? A Narrative Review

Organ-sparing combined-modality treatment for muscle-invasive bladder cancer remains underutilized despite high-quality evidence regarding its efficacy, safety, and preservation of quality of life. It may be offered to patients unwilling to undergo radical cystectomy, as well as those unfit for neoadjuvant chemotherapy and surgery. The treatment plan should be tailored to each patient's characteristics, with more intensive protocols offered to patients who are fit for surgery but opt for organ-sparing. After a thorough, debulking transurethral resection of the tumor and neoadjuvant chemotherapy, the response evaluation should trigger further management with either chemoradiation or early cystectomy in non-responders. A hypofractionated, continuous radiotherapy regimen of 55 Gy in 20 fractions with concurrent radiosensitizing chemotherapy with gemcitabine, cisplatin, or 5-fluorouracil and mitomycin C is currently preferred based on clinical trials. The response should be evaluated with repeated transurethral resections of the tumor bed and abdominopelvic-computed tomography after chemoradiation, with quarterly assessments during the first year. Salvage cystectomy should be offered to patients fit for surgery who failed to respond to treatment or developed a muscle-invasive recurrence. Non-muscle-invasive bladder recurrences and upper tract tumors should be treated in line with guidelines for respective primary tumors. Multiparametric magnetic resonance can be used for tumor staging and response monitoring, as it may distinguish disease recurrence from treatment-induced inflammation and fibrosis.

Health-related quality of life after curative treatment for muscle-invasive bladder cancer

Muscle-invasive bladder cancer (MIBC) is an aggressive disease for which the gold-standard treatment is radical cystectomy (RC) in combination with cisplatin-based neoadjuvant chemotherapy. Bladder-sparing strategies such as trimodal therapy (TMT) have also emerged to improve health-related quality of life (HRQoL) of patients. However, an improved understanding of the effect of all these treatment modalities on HRQoL is essential to provide personalized patient care. Different combinations of generic, cancer-specific and bladder cancer-specific questionnaires can be used as instruments for HRQoL evaluation in patients with MIBC before and after curative treatments, which can largely affect multiple domains of HRQoL including general health as well as physical, functional, social and emotional well-being. However, diagnosis of MIBC per se is also likely to affect HRQoL, and the perspective of cure after RC or TMT could induce a return to baseline HRQoL values for most of these domains. A considerable amount of data on HRQoL after RC is available, but conflicting results have been reported regarding the effect of urinary diversion (ileal conduit or orthotopic neobladder) and surgical approach (open or robotic surgery) on patient quality of life. Data on HRQoL after TMT are scarce, and additional comparative studies including patients receiving RC (especially using ileal orthotopic neobladder) are needed.

Fine particulate matter induces METTL3-mediated m6A modification of BIRC5 mRNA in bladder cancer

Long-term exposure to fine particulate matter (PM_2.5) is reportedly related to a variety of cancers including bladder cancer. However, little is known about the biological mechanism underlying this association. In the present study, PM_2.5 exposure was significantly associated with increased levels of m⁶A modification in bladder cancer patients and bladder cells. METTL3 expression was aberrantly upregulated after PM_2.5 exposure, and METTL3 was involved in PM_2.5-induced m⁶A methylation. Higher METTL3 expression was observed in bladder cancer tissues and METTL3 knockdown dramatically inhibited bladder cancer cell proliferation, colony formation, migration and invasion, inducing apoptosis and disrupting the cell cycle. Mechanistically, PM_2.5 enhanced the expression of METTL3 by inducing the promoter hypomethylation of its promoter and increasing the binding affinity of the transcription factor HIF1A. BIRC5 was identified as the target of METTL3 through m⁶A sequencing (m⁶A-Seq) and KEGG analysis. The methylated BIRC5 transcript was subsequently recognized by IGF2BP3, which increased its mRNA stability. In particular, PM_2.5 exposure promoted the m⁶A modification of BIRC5 and its recognition by IGF2BP3. In addition, BIRC5 was involved in bladder cancer proliferation and metastasis, as well as VEGFA-regulated angiogenesis_. This comprehensive study revealed that PM_2.5 exposure exerts epigenetic regulatory effects on bladder cancer via the HIF1A/METTL3/IGF2BP3/BIRC5/VEGFA network.

Bladder preservation versus radical cystectomy in transitional cell carcinoma and squamous cell carcinoma muscle invasive bladder cancer

Background

Randomizing patients to bladder preservation or radical cystectomy (RC) for the treatment of bladder cancer has not been practical, due to patient and physician preferences. Therefore, continually comparing the 2 treatment modalities is needed, in order to make the proper choice for each patient.

Patients and methods

The records of T1-4N0M0 bladder cancer patients, who presented to the South Egypt Cancer Institute between 2007 and 2017 and were treated by either bladder preservation or RC were reviewed.

Results

Out of the 166 included patients, 81 (48.8%) patients were treated by bladder preservation and 85 (51.2%) patients had RC. For the patients treated by bladder preservation and the patients treated by RC, the 5-year overall survival (OS) was 56% and 60% (p = 0.67), the 5-year local recurrence-free survival was 69% and 73% (p = 0.69), and the 5-year disease-free survival was 45% and 53% (p = 0.16), respectively. After propensity matching analysis, the mean 5-year OS was 58% for the bladder preservation patients and 61% for the RC patients (p = 0.51). It is notable that among the bladder preservation group, 8 patients (10%) had squamous cell carcinoma (SCC) pathology and refused RC. Their OS was 56% compared to 53% for the SCC patients treated by RC (p = 0.6).

Conclusion

Bladder preservation is a safe alternative to cystectomy in transitional cell carcinoma stages T1-4aN0M0, and its use in SCC bladder cancer should be further studied, as it could be feasible to spare them from initial cystectomy.

Identification of low-frequency variants of UGT1A3 associated with bladder cancer risk by next-generation sequencing

Although genome-wide association studies (GWASs) have successfully revealed many common risk variants for bladder cancer, the heritability is still largely unexplained. We hypothesized that low-frequency variants involved in bladder cancer risk could reveal the unexplained heritability. Next-generation sequencing of 113 patients and 118 controls was conducted on 81 genes/regions of known bladder cancer GWAS loci. A two-stage validation comprising 3,350 cases and 4,005 controls was performed to evaluate the effects of low-frequency variants on bladder cancer risk. Biological experiments and techniques, including electrophoretic mobility shift assays, CRISPR/Cas9, RNA-Seq, and bioinformatics approaches, were performed to assess the potential functions of low-frequency variants. The low-frequency variant rs28898617 was located in the first exon of UGT1A3 and was significantly associated with increased bladder cancer risk (odds ratio = 1.50, P = 3.10 × 10^-6). Intriguingly, rs28898617 was only observed in the Asian population, but monomorphism was observed in the European population. The risk-associated G allele of rs28898617 increased UGT1A3 expression, facilitated UGT1A3 transcriptional activity, and enhanced the binding activity. In addition, UGT1A3 deletion significantly inhibited the proliferation, invasion, and migration of bladder cancer cells and xenograft tumor growth. Mechanistically, UGT1A3 induced LAMC2 expression by binding CBP and promoting histone acetylation, which remarkably promoted the progression of bladder cancer. This is the first targeted sequencing study to reveal that the novel low-frequency variant rs28898617 and its associated gene UGT1A3 are involved in bladder cancer development, providing new insights into the genetic architecture of bladder cancer.

miR-140-3p inhibits bladder cancer cell proliferation and invasion by targeting FOXQ1

Upregulation of the forkhead box protein Q1 (FOXQ1) promotes bladder cancer (BCa) cell growth and metastasis. Factors affecting FOXQ1 expression at the post-transcriptional level have not yet been identified. We performed cell proliferation, cell invasion, and tumorigenesis experiments to characterize the relationship between FOXQ1 and miR-140-3p. We found that FOXQ1 was significantly upregulated and miR-140-3p was significantly downregulated in BCa tissues. We also identified an inverse correlation between miR-140-3p and FOXQ1 expression in BCa tissues. Overexpression of miR-140-3p reduced FOXQ1 expression, suppressing BCa cell proliferation and invasion. A luciferase assay confirmed that miR-140-3p bound to the 3’-UTR of FOXQ1 mRNA and decreased its expression. In addition, we used a mouse xenograft model to demonstrate that miR-140-3p suppressed tumor cell growth in vivo. Our findings suggest that miR-140-3p suppresses BCa cell proliferation and invasion by directly decreasing FOXQ1 expression.

LncRNA NRON promotes the proliferation, metastasis and EMT process in bladder cancer

Background: Bladder cancer (BC) is one of the most common malignancies world-wide with high morbidity and mortality. Long noncoding RNAs (lncRNAs) are thought to play a critical role in cancer development. LncRNA NRON, a repressor of activated T-cell nuclear factor (NFAT), has been shown to be dysregulated in many cancer types. However, the clinical significance and molecular mechanism of NRON in bladder cancer is still unknown.

Methods: The expression levels of NRON in BC tissues and cell lines were tested by RT-qPCR. Survival analysis was performed to detect the correlation between NRON expression and clinical outcomes in patients with BC. The biological role of NRON in BC cells proliferation and metastasis was examined in vitro and in vivo.

Results: The expression of NRON was significantly upregulated in BC specimens and cell lines compared with paired adjacent normal tissues and normal cell lines. The upregulation of NRON in bladder cancer patients was significantly associated with the depth of bladder tumor invasion and poor prognosis. Knockdown of NRON inhibited BC cells proliferation, migration, invasion and tumorigenicity. Furthermore, NRON promoted epithelial-mesenchymal transition (EMT) progression, and NRON-induced EZH2 expression contributed to this process.

Conclusion: In conclusion, our results suggested that NRON acted as an oncogene and tumor biomarker for BC.

Long non-coding RNA NEAT1 promotes bladder progression through regulating miR-410 mediated HMGB1

LncRNA NEAT1 is reported as a crucial oncogene in multiple cancers. But, its biological role in bladder cancer is barely understood. Therefore, we concentrated on the function and role of NEAT1 in bladder cancer. Firstly, NEAT1 expression in bladder cancer cells was determined and it was displayed NEAT1 was significant elevated. NEAT1 was knockdown and overexpressed in T24 and J82 cells. Then it was indicated that NEAT1 silence greatly inhibited bladder cancer cell proliferation with an increased ratio of apoptotic cells and severe cell cycle arrest. Overexpression of NEAT1 exhibited a reversed process in bladder cancer cells. Additionally, in vivo experiments were employed using establishment of nude mice models. NEAT1 knockdown inhibited bladder cancer growth while increase of NEAT1 promoted bladder cancer development in vivo. By employing the bioinformatics analysis, we speculated that miR-410 was as a downstream target of NEAT1. Then, the targeting association between them was proved in our research and we implicated miR-410 was dramatically restrained in bladder cancer cells. Meanwhile, it was exhibited that miR-410 was negatively regulated by NEAT1. Apart from these, HMGB1 was speculated as a downstream target of miR-410. Dual-luciferase reporter assay was used to prove the correlation between miR-410 and HMGB1. Up-regulation of miR-410 restrained HMGB1 levels and NEAT1 can regulate HMGB1 level via sponging miR-410. To sum up, we implied NEAT1/miR-410/HMGB1 axis participated in bladder cancer.

miR-7-5p acts as a tumor suppressor in bladder cancer by regulating the hedgehog pathway factor Gli3

Although important progresses have been made in the diagnosis and treatment of bladder cancer (BCa), the overall survival for patients with advanced BCa remains poor. It is necessary to uncover the molecular mechanism underlying the initiation and progression of bladder cancer. According to previous reports, mircoRNAs (miRNAs) can regulate tumorigenesis by targeting their downstream mRNAs. This study aims to explore and analyze a novel miRNA-mRNA axis which can regulate the progression of bladder cancer. Based on the microarray analysis, 182 mRNAs were found to be upregulated in BCa tissues. Gene oncology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that these upregulated mRNAs are related with hedgehog pathway. Gli3, an important factor of hedgehog pathway, belongs to these 182 upregulated mRNAs. Therefore, Gli3 was chosen to do further study. Kaplan-Meier analysis revealed that highly expressed Gli3 predicted unfavorable prognosis for patients with BCa. Results of functional experiments indicated the inhibitory effects of silenced Gli3 on cell proliferation, migration and EMT progress. Mechanically, Gli3 was the target mRNA of miR-7-5p in BCa cells. Finally, rescue assays were performed to validate the specific function of miR-7-5p/Gli3 axis in BCa progression. According to all data, we concluded that miR-7-5p acts as a tumor suppressor in BCa by downregulating Gli3.

High expression of TMEM40 is associated with the malignant behavior and tumorigenesis in bladder cancer

BACKGROUND

Bladder cancer (BCa) is one of the most common cancers in the urinary system among the world. Previous studies suggested that TMEM40 expression level was significantly associated with clinicopathological parameters including histological grade, clinical stage and pT status of bladder cancer. However, the molecular mechanism of TMEM40 in BCa remains poorly understood.

METHODS

Real-time quantitative RT-PCR (qRT-PCR) and western blot (WB) were used to examine the expression levels of TMEM40 in BCa tissues, paired non-cancer tissues and cell lines. A series of experiments, including CCK-8, wound healing, flow cytometry, transwell and EdU assays were performed to assess the effects of TMEM40 on cell proliferation, cell cycle and apoptosis, migration and invasion. In addition, tumor growth was evaluated in vivo using a xenogenous subcutaneously implant model. All statistical analyses were executed by using the SPSS 20.0 software. All experimental data from three independent experiments were analyzed by Student's t test and results were expressed as mean ± standard deviation.

RESULTS

In this study, we identified the role of TMEM40 in the tumorigenesis of bladder cancer and found that it was upregulated in bladder cancer tissues and cell lines, compared with their normal counterparts. The results demonstrated that effective silence of TMEM40 expression suppressed cell proliferation, blocked G1-to-S cell cycle transition, and inhibited cell migration and invasion in human bladder 5637 and EJ cell lines. Consistently, in vivo data showed that TMEM40 silencing could dramatically decreased tumor growth. Further study revealed that TMEM40 knockdown resulted in accumulation of p53 and p21 protein and decrease of c-MYC and cyclin D1 protein.

CONCLUSION

These data suggest that TMEM40 represents a potential oncogene, which exert a crucial role in the proliferation and apoptosis via the p53 signaling pathway in BCa, thus probably serve as a novel candidate biomarker and a potential therapeutic target for patients with BCa.

Long non-coding RNA XIST promotes cell growth and metastasis through regulating miR-139-5p mediated Wnt/β-catenin signaling pathway in bladder cancer

Bladder cancer is one of the most common urological malignancy all over the world. Recently, long non-coding RNA (lncRNA) XIST has been identified as an oncogenic gene in several type of cancers. However, the expression level and functional role of XIST in bladder cancer remain largely unknown. In the present study, we found that XIST was significantly up-regulated in bladder cancer tissues and cell lines, and was correlated with poor prognosis of bladder cancer patients. Furthermore, XIST knockdown significantly inhibited bladder cancer cell growth and metastasis in vitro and tumor growth in vivo. We also demonstrated that XIST acted as a competing endogenous RNA for miR-139-5p and repression of miR-139-5p could restore the inhibitory effects on bladder cancer cells induced by XIST shRNA. In addition, we identified that Wnt1 was a direct target of miR-139-5p, and XIST played the oncogenic role in bladder cancer by activating the Wnt/β-catenin signaling pathway. Taken together, our study suggested that lncRNA XIST may serve as a prognostic biomarker and a potential therapeutic target for bladder cancer.

LncRNA SPRY4-IT1 sponges miR-101-3p to promote proliferation and metastasis of bladder cancer cells through up-regulating EZH2

Emerging evidences have indicated that long non-coding RNAs (LncRNAs) play vital roles in cancer development and progression. Previous studies have suggested that overexpression of SPRY4-IT1 predicates poor prognosis and promotes tumor progress in several cancers. However, the underlying mechanism of SPRY4-IT1 in bladder cancer remains unknown. In this study, we found that SPRY4-IT1 knockdown induced inhibition of cell proliferation, cell migration and invasion ability, and caused promotion of apoptosis in bladder cancer both in vitro and in vivo. Mechanistically, knockdown of SPRY4-IT1 increased the expression of miR-101-3p and subsequently inhibited the expression of EZH2 at posttranscriptional level. Importantly, SPRY4-IT1 could directly interact with miR-101-3p and down-regulation of miR-101-3p efficiently reversed the suppression of EZH2 induced by SPRY4-IT1 shRNA. Thus, SPRY4-IT1 positively regulated the expression of EZH2 through sponging miR-101-3p, and played an oncogenic role in bladder cancer progression. Together, our study elucidates the role of LncRNA SPRY4-IT1 as a miRNA sponge in bladder cancer, and sheds new light on LncRNA-directed diagnostics and therapeutics in bladder cancer.