Epithelial plasticity in urothelial carcinoma: Current advancements and future challenges

Therapeutic Potential of Regorafenib in Cisplatin-Resistant Bladder Cancer with High Epithelial-Mesenchymal Transition and Stemness Properties

Bladder cancer is becoming one of the most common malignancies across the world. Although treatment strategy has been continuously improved, which has led to cisplatin-based chemotherapy becoming the standard medication, cancer recurrence and metastasis still occur in a high proportion of patients because of drug resistance. The high efficacy of regorafenib, a broad-spectrum kinase inhibitor, has been evidenced in treating a variety of advanced cancers. Hence, this study investigated whether regorafenib could also effectively antagonize the survival of cisplatin-resistant bladder cancer and elucidate the underlying mechanism. Two types of cisplatin-resistant bladder cancer cells, T24R1 and T24R2, were isolated from T24 cisplatin-sensitive bladder cancer cells. These cells were characterized, and T24R1- and T24R2-xenografted tumor mice were created to examine the therapeutic efficacy of regorafenib. T24R1 and T24R2 cells exhibited higher expression levels of epithelial-mesenchymal transition (EMT) and stemness markers compared to the T24 cells, and regorafenib could simultaneously inhibit the viability and the expression of EMT/stemness markers of both T24R1 and T24R2 cells. Moreover, regorafenib could efficiently arrest the cell cycle, promote apoptosis, and block the transmigration/migration capabilities of both types of cells. Finally, regorafenib could significantly antagonize the growth of T24R1- and T24R2-xenografted tumors in mice. These results demonstrated the therapeutic efficacy of regorafenib in cisplatin-resistant bladder cancers. This study, thus, provides more insights into the mechanism of action of regorafenib and demonstrates its great potential in the future treatment of cisplatin-resistant advanced bladder cancer patients.

Robot-assisted partial nephrectomy for complex renal tumors: Analysis of a large multi-institutional database

INTRODUCTION

Highly complex renal masses pose a challenge to urologic surgeons' ability to perform robotic partial nephrectomy (RPN). Given the increased utilization of the robotic approach for small renal masses, we sought to characterize the outcomes and determine the safety and feasibility of RPN for complex renal masses from our large multi-institutional cohort.

METHODS

We performed a retrospective analysis of patients with R.E.N.A.L. Nephrometry Scores ≥10 who underwent RPN in our multi-institutional cohort (N = 372). Baseline demographic, clinical and tumor related characteristics were evaluated with the primary endpoint of trifecta achievement (defined as negative surgical margin, no major complications, and warm ischemia time ≤25 min). Relationships between variables were assessed using the chi-square test of independence, Fisher exact test, Mann-Whitney U test, and Kruskal Wallis test. Logistic regression was used to evaluate the relationship between baseline characteristics and trifecta achievement.

RESULTS

Of 372 patients in the study, mean age was 58 years, and median BMI was 30.49 kg/m². The median tumor size was 4.3 cm (3.0-5.9 cm). Most of the patients had R.E.N.A.L. scores of 10 (n = 253; 67.01%). Overall, trifecta was achieved in 72.04% of patients. Stratifying intraoperative and postoperative outcomes by R.E.N.A.L. scores, there was no significant difference in trifecta achievement, operative time, warm ischemia time (WIT), open conversion, major complication, or positive margin rates. Length of hospital stay was significantly longer for higher R.E.N.A.L. scores (median days 2 vs. 1, P = 0.012). Multivariate analyses for factors associated with trifecta achievement concluded that age and baseline eGFR were independently associated with trifecta achievement.

CONCLUSION

RPN is a safe and reproducible procedure for complex tumors with R.E.N.A.L. Nephrometry scores ≥10. Our results suggest excellent rates of trifecta achievement and short-term functional outcomes when performed by experienced surgeons. Long-term oncological and functional evaluation are needed to further support this conclusion.

Identification and validation of an immune signature associated with EMT and metabolic reprogramming for predicting prognosis and drug response in bladder cancer

Background

Epithelial-mesenchymal transition (EMT), one leading reason of the dismal prognosis of bladder cancer (BLCA), is closely associated with tumor invasion and metastasis. We aimed to develop a novel immune−related gene signature based on different EMT and metabolic status to predict the prognosis of BLCA.

Methods

Gene expression and clinical data were obtained from TCGA and GEO databases. Patients were clustered based on EMT and metabolism scores calculated by ssGSEA. The immune-related differentially expressed genes (DEGs) between the two clusters with the most obvious differences were used to construct the signature by LASSO and Cox analysis. Time-dependent receiver operating characteristic (ROC) curves and Kaplan–Meier curves were utilized to evaluate the gene signature in training and validation cohorts. Finally, the function of the signature genes AHNAK and NFATC1 in BLCA cell lines were explored by cytological experiments.

Results

Based on the results of ssGSEA, TCGA patients were divided into three clusters, among which cluster 1 and cluster 3 had completely opposite EMT and metabolic status. Patients in cluster 3 had a significantly worse clinical prognosis than cluster 1. Immune-related DEGs were selected between the two clusters to construct the predictive signature based on 14 genes. High-risk patients had poorer prognosis, lower proportions of CD8⁺ T cells, higher EMT and carbohydrate metabolism, and less sensitivity to chemotherapy and immunotherapy. Overexpression of AHNAK or NFATC1 promoted the proliferation, migration and invasion of T24 and UMUC3 cells. Silencing ANHAK or NFATC1 could effectively inhibit EMT and metabolism in T24 and UMUC3 cells.

Conclusion

The established immune signature may act as a promising model for generating accurate prognosis for patients and predicting their EMT and metabolic status, thus guiding the treatment of BLCA patients.

Single-Cell Analyses Reveal Mechanisms of Cancer Stem Cell Maintenance and Epithelial-Mesenchymal Transition in Recurrent Bladder Cancer

PURPOSE

Bladder cancer treatment remains a major clinical challenge due to therapy resistance and a high recurrence rate. Profiling intratumor heterogeneity can reveal the molecular mechanism of bladder cancer recurrence.

EXPERIMENTAL DESIGN

Here, we performed single-cell RNA sequencing and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) on tumors from 13 patients with low recurrence risk, high recurrence risk, and recurrent bladder cancer.

RESULTS

Our study generated a comprehensive cancer-cell atlas consisting of 54,971 single cells and identified distinct cell subpopulations. We found that the cancer stem-cell subpopulation is enriched during bladder cancer recurrence with elevated expression of EZH2. We further defined a subpopulation-specific molecular mechanism whereby EZH2 maintains H3K27me3-mediated repression of the NCAM1 gene, thereby inactivating the cell invasive and stemness transcriptional program. Furthermore, taking advantage of this large single-cell dataset, we elucidated the spectrum of epithelial-mesenchymal transition (EMT) in clinical samples and revealed distinct EMT features associated with bladder cancer subtypes. We identified that TCF7 promotes EMT in corroboration with single-cell ATAC with high-throughput sequencing (scATAC-seq) analysis. Additionally, we constructed regulatory networks specific to recurrent bladder cancer.

CONCLUSIONS

Our study and analytic approaches herein provide a rich resource for the further study of cancer stem cells and EMT in the bladder cancer research field.

Oct-4: a prognostic biomarker of urinary bladder cancer in North India

Background

The objective of this study was to evaluate Octamer-binding transcription factor 4 (Oct-4), neutrophil to lymphocyte ratio (NLR) and body mass index (BMI) as independent prognostic biomarkers for prediction of urinary bladder cancer (UBC) outcomes. With the advancement in prognostic biomarker discovery, tumor recurrence is difficult to accurately predict in UBC. UBC is costly to treat due to the requirement of frequent invasive follow-up sessions. Therefore, it is of utmost importance to evaluate good prognostic biomarkers for UBC surveillance.

Methods

We studied 39 UBC tissue samples. Oct-4 protein expression was evaluated semiquantitatively by immunohistochemistry (IHC). Complete blood count data and body weight as well as the height of the patients were retrieved and recorded before the date of the first transurethral resection of bladder tumor (TURBT). The follow-up period was 48 months for recurrence-free survival (RFS), progression-free survival (PFS), and overall survival (OS).

Results

Oct-4 expression profile was found to be significantly associated with gender (p = 0.028), tumor grade (p = 0.038), tumor stage (p = 0.003), lymph node status (p = 0.029), recurrence (p = 0.004), progression (p = 0.011), and treatment modality (p = 0.016). Tumor grade and progression were found significant with NLR values (tumor grade, p = 0.006; progression, p = 0.038) and BMI (tumor grade, p = 0.036; progression, p = 0.014). Moreover, BMI was also significantly associated with UBC recurrence (p = 0.014). Kaplan-Meier survival analysis showed poor prognosis with both high Oct-4 expression (RFS, p = 0.001; PFS, p = 0.004; OS, p = 0.014) and high NLR values (RFS, p = 0.049; PFS, p = 0.004; OS, p = 0.005). Patients with high BMI too had poor RFS (p = 0.025) and poor PFS (p = 0.032). Furthermore, multivariate Cox regression analysis, indicated Oct-4 as an independent prognostic biomarker for RFS (HR = 0.240, 95% CI, 0.072-0.804, p = 0.021).

Conclusions

We conclude that the expression profile of Oct-4 will be beneficial in prediction of UBC recurrence, and could have profound implications on the development of new therapeutic targets for UBC treatment.

WNT/β-catenin signaling in urothelial carcinoma of bladder

Urothelial carcinoma of bladder is the second most prevalent genitourinary disease. It is a highly heterogeneous disease as it represents a spectrum of neoplasms, including non-muscle invasive bladder cancer (NMIBC), muscle invasive bladder cancer (MIBC) and metastatic lesions. Genome-wide approaches and candidate gene analysis suggest that malignant transformation of the bladder is multifactorial and a multitude of genes are involved in the development of MIBC or NMIBC phenotypes. Wnt signaling is being examined to control and maintain balance between stemness and differentiation in adult stem cell niches. Owing to its participation in urothelial development and maintenance of adult urothelial tissue homeostasis, the components of Wnt signaling are reported as an important diagnostic and prognostic markers as well as novel therapeutic targets. Mutations/epigenetic alterations in the key molecules of Wnt/β-catenin canonical pathway have been linked with tumorigenesis, development of drug resistance and enhanced survival. Present review extends our understanding on the functions of key regulatory molecules of canonical Wnt/β-catenin pathway in urothelial tumorigenesis by inducing cancer stem cell phenotype (UCSCs). UCSCs may be responsible for tumor heterogeneity, high recurrence rates and complex biological behavior of bladder cancer. Therefore, understanding the role of UCSCs and the regulatory mechanisms that are responsible for high relapse rates and metastasis could help to develop pathway inhibitors and augment current therapies. Potential implications in the treatment of urothelial carcinoma of bladder by targeting this pathway primarily in UCSCs as well as in bulk tumor population that are responsible for high relapse rates and metastasis may facilitate potential therapeutic avenues and better prognosis.

Auxiliary diagnostic value of p16 amplification combined with the detection of heterozygous and homozygous loss for urothelial carcinoma

The present study aimed to investigate the significance of detecting cyclin dependent kinase inhibitor 2A (p16) gene aberrations in the diagnosis of urothelial carcinoma (UC) using fluorescence in situ hybridization (FISH). A total of 77 voided urine specimens from 65 patients with UC and 12 patients with benign urinary disease were recruited into the current study. Under a fluorescence microscope, cells with large and irregular nuclei were assessed for chromosomal aberrations. The positive rate of p16 amplification in UC samples was 32.3% (21/65), which was significantly higher than that in benign urinary disease samples (16.7%, 2/12; P<0.05). Heterozygous and homozygous loss of p16 was identified in 12 (18.5%) and 23 (35.4%) patients with UC, respectively; p16 expression in the remainder of patients was normal. In addition, as tumor stage or grade advanced, the positive rate of p16 aberrations also increased significantly (P<0.05). In conclusion, p16 gene aberrations may serve important roles in the auxiliary diagnosis of UC by FISH and could be utilized to monitor UC progression.

Cancer stem cells and epithelial-mesenchymal transition in urothelial carcinoma: Possible pathways and potential therapeutic approaches

There is growing evidence of the presence of cancer stem cells in urothelial carcinoma. Cancer stem cells have the ability to self-renew and to differentiate into all cell types of the original heterogeneous tumor. A panel of diverse cancer stem cell markers might be suitable for simulation studies of urothelial cancer stem cells and for the development of optimized treatment protocols. The present review focuses on the advances in recognizing the markers of urothelial cancer stem cells and possible therapeutic targets. The commonly reported markers and pathways that were evaluated include CD44, CD133, ALDH1, SOX2 & SOX4, BMI1, EZH1, PD-L1, MAGE-A3, COX2/PGE2/STAT3, AR, and autophagy. Studies on the epithelial-mesenchymal transition-related pathways (Shh, Wnt/β-catenin, Notch, PI3K/Akt, TGF-β, miRNA) are also reviewed. Most of these markers were recognized through the expression patterns of cancer stem cell-rich side populations. Their regulative role in the development and differentiation of urothelial cancer stem cells was confirmed in vitro by functional analyses (e.g. cell migration, colony formation, sphere formation), and in vivo in xenograft experiments. Although a small number of these pathways are targeted by currently available drugs or drugs that are the currently being tested in clinical trials, a clear treatment approach has not been developed for most pathways. A greater understanding of the mechanisms that control the proliferation and differentiation of cancer stem cells is expected to lead to improvements in targeted therapy.