The function and mechanisms of action of circular RNAs in Urologic Cancer.

Kidney, bladder, and prostate cancer are the three major tumor types of the urologic system that seriously threaten human health. Circular RNAs (CircRNAs), special non-coding RNAs with a stabile structure and a unique back-splicing loop-forming ability, have received recent scientific attention. CircRNAs are widely distributed within the body, with important biologic functions such as sponges for microRNAs, as RNA binding proteins, and as templates for regulation of transcription and protein translation. The abnormal expression of circRNAs in vivo is significantly associated with the development of urologic tumors. CircRNAs have now emerged as potential biomarkers for the diagnosis and prognosis of urologic tumors, as well as targets for the development of new therapies. Although we have gained a better understanding of circRNA, there are still many questions to be answered. In this review, we summarize the properties of circRNAs and detail their function, focusing on the effects of circRNA on proliferation, metastasis, apoptosis, metabolism, and drug resistance in kidney, bladder, and prostate cancers.

Decreased SPTLC1 expression predicts worse outcomes in ccRCC patients.

OBJECTIVE: Serine palmitoyltransferase, long chain base subunit 1 (SPTLC1) catalyzes the first step in sphingolipid synthesis and has been implicated in the progression of various cancers. However, its role in clear cell renal cell carcinoma (ccRCC) remains unclear. Here, we investigated the expression and prognostic value of SPTLC1 in ccRCC. METHODS: Three ccRCC patient cohorts were studied. ccRCC and adjacent normal kidney tissue samples were obtained from 183 patients at the Fudan University Shanghai Cancer Center (FUSCC) and subjected to immunohistochemical staining and quantitative reverse-transcription polymerase chain reaction to evaluate SPTLC1 protein and messenger RNA (mRNA) expression. Two validation cohorts consisting of mRNA and clinicopathological data sets from patients with ccRCC were obtained from the Cancer Genome Atlas (TCGA, n = 429) and Oncomine (n = 178) databases. Associations between low and high SPTLC1 mRNA and protein expression and survival were evaluated using the Kaplan-Meier method and log-rank test. Independent prognostic factors were identified using univariate and multivariate Cox regression analysis. RESULTS: SPTLC1 mRNA or protein were expressed at significantly lower levels in ccRCC tissues compared with normal kidney tissues in all three patient cohorts (P < .001). Low SPTLC1 expression was significantly associated with shorter overall survival in the FUSCC (P = .041) and Oncomine (P < .001) cohorts, and was significantly associated with shorter overall survival (P < .0001) and progression-free survival (P < .001) in the TCGA cohort. Bioinformatics analysis identified 10 genes significantly coregulated with SPTLC1 in ccRCC, most of which contributed to sphingomyelin metabolism (SPTLC2, SPTLC3, SPTSSA, SPTSSB, ORMDL1, ORMDL2, ORMDL3, ZDHHC9, GOLGA7B, and KDSR). Functional enrichment analysis predicted that SPTLC1 and its network play significant roles in inflammatory, hypoxia, and interferon gamma responses, and in allograft rejection pathways. CONCLUSION: Low SPTLC1 expression is significantly associated with disease progression and poor survival in patients with ccRCC, suggesting that SPTLC1 may function as a tumor suppressor. Thus, SPTLC1 could be a potential new biomarker and/or therapeutic target for ccRCC.

Targeting CPT1B as a potential therapeutic strategy in castration-resistant and enzalutamide-resistant prostate cancer.

BACKGROUND: Prostate cancer is characterized by aberrant lipid metabolism, including elevated fatty acid oxidation. Carnitine palmitoyltransferase 1B (CPT1B) catalyzes the rate-limiting step of fatty acid oxidation. This study aimed to determine if CPT1B has a critical role in prostate cancer progression and to identify its regulatory mechanism. METHODS: CPT1B expression data from The Cancer Genome Atlas and Gene Expression Omnibus databases was compared with patient survival data. A tissue microarray was constructed with 60 samples of prostate cancer and immunohistochemically stained for CPT1B. Castration-resistant prostate cancer (CRPC) cell lines 22RV1 and C4-2 in which CPT1B expression had been stably knocked down were established; and cell proliferation, cell cycle distribution, and invasion were investigated by Cell Counting Kit-8 (CCK-8) and colony formation assays, flow cytometry, and Transwell assays, respectively. To examine the impact of androgen receptor (AR) inhibition on CPT1B expression, JASPAR CORE was searched to identify AR-binding sites in CPT1B. Dual luciferase and ChIP assays were performed to confirm CPT1B activity and AR binding, respectively. Differentially expressed genes (DEGs) in prostate cancer underwent gene set enrichment analysis (GSEA). Enzalutamide-resistant C4-2 cells were generated and the mechanism of enzalutamide resistance and downstream signaling pathway changes of CPT1B to C4-2 was explored through CCK-8 test. RESULTS: CPT1B expression was upregulated in human prostate cancer compared with normal prostate tissue and was associated with poor disease-free survival and overall survival. Silencing of CPT1B resulted in downregulated cell proliferation, reduced S-phase distribution, and lower invasive ability, whereas the opposite was observed in CRPC cells overexpressing CPTB1. DEGS in prostate cancer were correlated with G-protein-coupled receptor signaling, molecular transducer activity, and calcium ion binding. AR may regulate CPT1B expression and activity via specific binding sites, as confirmed by dual luciferase and ChIP assays. The CCK-8 experiment demonstrated that CPT1B overexpression in C4-2 cells did not significantly increase the ability of enzalutamide resistance. However, overexpression of CPT1B in C4-2R cells significantly increased the enzalutamide resistance. Upregulation of CPT1B expression increased AKT expression and phosphorylation. CONCLUSIONS: CPT1B is upregulated in prostate cancer and is correlated with poor prognosis, indicating its potential as a biomarker. AR inhibits the transcription of CPT1B. In the CRPC cell line, overexpression of CPT1B alone cannot promote enzalutamide resistance, but in the drug-resistant line C4-2R, overexpression of CPT1B can promote the resistance of C4-2R to enzalutamide.

Integration Analysis of Single-Cell Multi-Omics Reveals Prostate Cancer Heterogeneity.

Prostate cancer (PCa) is an extensive heterogeneous disease with a complex cellular ecosystem in the tumor microenvironment (TME). However, the manner in which heterogeneity is shaped by tumors and stromal cells, or vice versa, remains poorly understood. In this study, single-cell RNA sequencing, spatial transcriptomics, and bulk ATAC-sequence are integrated from a series of patients with PCa and healthy controls. A stemness subset of club cells marked with SOX9highARlow expression is identified, which is markedly enriched after neoadjuvant androgen-deprivation therapy (ADT). Furthermore, a subset of CD8+CXCR6+ T cells that function as effector T cells is markedly reduced in patients with malignant PCa. For spatial transcriptome analysis, machine learning and computational intelligence are comprehensively utilized to identify the cellular diversity of prostate cancer cells and cell-cell communication in situ. Macrophage and neutrophil state transitions along the trajectory of cancer progression are also examined. Finally, the immunosuppressive microenvironment in advanced PCa is found to be associated with the infiltration of regulatory T cells (Tregs), potentially induced by an FAP+ fibroblast subset. In summary, the cellular heterogeneity is delineated in the stage-specific PCa microenvironment at single-cell resolution, uncovering their reciprocal crosstalk with disease progression, which can be helpful in promoting PCa diagnosis and therapy.

Clinical Outcomes and Prognosis Analysis of Younger Bladder Cancer Patients.

BACKGROUND: Generally, little is known about prognostic factors in bladder cancer patients under 40 years of age. We therefore performed a retrospective study to identify prognostic factors in these younger bladder cancer patients. METHODS: We collected clinicopathological data on bladder cancer patients ≤40 years old diagnosed between 1975 and 2018 from the Surveillance, Epidemiology, and End Results (SEER) database. Survival curves were generated using the Kaplan-Meier method, and the differences between groups were analyzed using the log-rank test. Univariate and multivariate Cox hazards regression analyses were performed to define hazard ratios (HRs) for cancer-specific survival (CSS). RESULTS: There were statistical differences in race, histological type, cancer stage, tumor size, and surgery treatment groups between overall survival and CSS. Only tumor size and cancer stage were significant independent prognostic risk factors in younger bladder cancer patients for the prediction of CSS. CONCLUSION: Tumors greater than 30 mm in size and a more advanced stage of bladder cancer were indicative of a poor prognosis in bladder cancer patients ≤40 years old, and long-term follow-up is suggested.

Locoregional surgical treatment improves the prognosis in patients with primary metastatic testicular cancer with a single bone or brain metastasis.

The present study investigated the clinical significance afforded by locoregional surgery in improving the prognosis of primary metastatic testicular cancer (pMTC). The population-based Surveillance, Epidemiology and End Results database was used as the primary source of data in the present study. Stratification analysis was employed to identify the effects of testicular surgery on testicular cancer-specific survival and overall survival. Propensity score matching and Cox regression models were then employed to find and evaluate the extent of improvements to the survival of patients with pMTC by testicular surgery. The median testicular cancer-specific survival and overall survival in the surgery group were 10% higher than those in the group without surgery. Testicular surgery was demonstrated to have provided a survival advantage for patients with a single metastasis in the bone or brain, but not in the liver or lung. When combined with radiotherapy and chemotherapy, surgery significantly improved the survival of patients. However, according to the surgical outcome based on molecular subtypes, when deciding on the surgery for patients with metastatic testicular cancer, only human chorionic gonadotropin and lactate dehydrogenase, and not α-fetoprotein should be considered. Surgery serves a significant role in the management of non-seminoma, whereas its role in the management of seminoma is far more limited. The effects of locoregional surgery have been neglected when treating patients with pMTC. Surgical procedures should be considered more seriously when planning combination treatments for patients with pMTC with a single bone or brain metastasis.

The U Shape of Prostate-specific Antigen and Prostate Cancer-specific Mortality in High-grade Metastatic Prostate Adenocarcinoma.

BACKGROUND: Accumulated evidence suggests that metastatic prostate cancer (mPCa) with a low prostate-specific antigen (PSA) level may be a unique entity. However, its clinical features and prognosis have not been fully evaluated. OBJECTIVE: To investigate the clinical features of low-PSA mPCa and the impact of low PSA level on overall survival (OS) and PCa-specific mortality (PCSM) of mPCa. DESIGN, SETTING, AND PARTICIPANTS: A total of 8479 mPCa patients were retrieved from the Surveillance, Epidemiology, and End Results program (2010-2015). The median follow-up was 18 mo. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Cox regression and Fine-Gray competing risk were used to calculate the hazard ratio (HR) and subdistribution hazard ratio (sHR) for OS and PCSM, respectively. RESULTS AND LIMITATIONS: A higher rate of T4 stage disease (19.8%) and visceral metastasis (18.2%) and the shortest median OS (34 mo) were observed in mPCa patients with Gleason 8-10 and PSA ≤4ng/ml. In the Cox regression model, PSA ≤4ng/ml was a significant predictor of OS for Gleason 8-10 disease. The distribution of PCSM by PSA was U-shaped for Gleason score 8-10 (PSA 4.1-10ng/ml as the referent), with an adjusted sHR of 1.52 for PSA ≤4.0ng/ml (95% confidence interval: 1.17-1.96) versus 0.99 for PSA 10.1-20ng/ml and 1.35 for PSA >20ng/ml. In contrast, the distribution of PCSM by PSA was linear for Gleason 5-7. Sensitivity analyses showed similar results in Gleason 9-10 and Gleason 10 subgroup. The study is limited by its retrospective design. CONCLUSIONS: Low PSA, high-grade mPCa has a higher proportion of T4 stage disease, visceral metastasis, and PCSM. PATIENT SUMMARY: We found that 2.8% of high-grade metastatic prostate cancer has a prostate-specific antigen level ≤4ng/ml at diagnosis. This population has aggressive clinical features and a poor cancer-specific outcome. Our results highlighted this under-reported population, and the management of these patients warrants further research.

GLUT1 is an AR target contributing to tumor growth and glycolysis in castration-resistant and enzalutamide-resistant prostate cancers.

Castration-resistant prostate cancer (CRPC) displays a higher 18F-FDG PET SUVmax than hormone-sensitive prostate cancer, which suggests a greater need for glucose metabolism in CRPC. Targeting glucose metabolism in cancer cells remains attractive for cancer treatment. Glucose transporters (GLUTs) meditate the first and rate-limiting step of glucose metabolism. Here, we investigated the key mediator of glucose transporters and evaluated its therapeutic value in a preclinical model of CRPC. 18F-FDG PET showed a higher SUVmax in CRPC than in hormone-sensitive prostate cancer, and GLUT1 expression positively correlated with SUVmax and was associated with a worse CRPC outcome. GLUT1 inhibition significantly suppressed cell growth, glycolysis and tumor volume in a xenograft model both in CRPC and enzalutamide-resistant prostate cancer. Chromatin immunoprecipitation and dual luciferase reporter assay showed that androgen receptor (AR) directly bound to the GLUT1 gene promoter to promote GLUT1 transcription. Combining GLUT1 inhibition and enzalutamide remarkably suppressed proliferation and glycolysis and induced apoptosis in CRPC cells. Our results suggest that GLUT1 is an AR target and displays synergistic effects with enzalutamide. GLUT1 may act as a promising therapeutic target in CRPC and enzalutamide-resistant prostate cancer.

Prognosis of Patients With Testicular Carcinoma Is Dependent on Metastatic Site.

Background: Existing data on the association of metastatic sites and prognosis of patients with metastatic testicular malignancy are limited. In this study, the association of survival outcome and the prognostic value of different metastatic sites in patients with metastatic testicular cancer was investigated. Methods: A dataset from the Surveillance, Epidemiology and End Results (SEER) survey was selected for a retrospective metastatic testicular cancer cohort study. Patients with different metastatic sites were divided into corresponding groups for further analysis. Kaplan-Meier analysis with log-rank test was implemented for comparison of the survival distribution of cases. Multivariate Cox regression models were then applied to analyze the association of distant metastases with survival for all selected patients and subgroup based on different histological type with a single metastatic site. Results: A total of 1,661 patients treated for metastatic testicular malignant tumors between 2010 to 2016 were enrolled in this cohort study. Upon initial diagnosis, 61.9, 15.2, 6.7, 6.4, and 36.2% of patients were found to have lung, liver, bone, brain, and distant lymph nodes metastatic sites, respectively. Patients with lung, liver, or bone metastases showed more undesirable prognosis for overall survival (OS) and cancer-specific survival (CSS), in contrast with those with distant lymph node metastases (all P < 0.05). In comparison with patients with more than one metastatic site, those with a single metastasis had extended OS and CSS (both P < 0.001). In patients with a single metastatic site, Kaplan-Meier analysis and multivariate Cox regression demonstrated the association of bone and liver with the worst two groups of OS and CSS. Multivariate Cox models based on histological type showed different prognostic values of metastases in patients with seminoma or non-seminomatous germ cell tumors. Conclusion: There is much heterogeneity in the oncological outcome of site-specific metastatic patients. Metastatic profiles and the prognostic value of metastases are dependent on the histological type in TC patients. Distant lymph nodes and lung metastases indicate favorable prognostic factors, while bone and liver metastases indicate negative survival outcomes in TC.

Causes of Death and Conditional Survival of Renal Cell Carcinoma.

Background: As conditional survival could provide more relevant prognostic information at each follow-up time, the present study aimed to assess conditional overall survival (COS) based on two cohorts and assess the risks of death due to renal cell carcinoma (RCC) vs. other causes. Methods: The Fudan University Shanghai Cancer Center (FUSCC) and Surveillance, Epidemiology, and End Results (SEER) database were used as the source of data for our analysis. COS and cancer-specific survival were evaluated using the Kaplan-Meier method. Results: A total of 90,927 patients (SEER cohort = 88,807, FUSCC cohort = 2,120) were enrolled. Our results suggest that hazards of other causes-related death were always higher than that of cancer-specific death in low-risk RCC patients, but lower in metastatic RCC patients. It exceeded that of cancer-specific death by 8 years in high-risk RCC patients. Only in metastatic RCC patients, the COS improved markedly with survivorship increasing. After surviving 1, 2, 3, 4, and 5 years, the 5 years COS increased by +10, +18, +23, +29, and 35% (the observed 5 years OS: 12%), respectively. Conclusions: COS can better help patients with metastatic RCC rather than other RCC patients. Additionally, COS brings optimism for metastatic RCC patients with expected poorer prognosis psychologically.

Development and External Validation of a Novel 12-Gene Signature for Prediction of Overall Survival in Muscle-Invasive Bladder Cancer.

Purpose: We aimed to develop and validate a novel gene signature from published data and improve the prediction of survival in muscle-invasive bladder cancer (MIBC). Methods: We searched the published gene signatures associated with the overall survival (OS) of MIBC and compiled all 274 genes to develop a novel gene signature. RNAseq data of TCGA (the Cancer Genome Atlas) bladder cohort were downloaded. All genes were included in a univariate Cox hazard ratio model. We then used a reduced multivariate Cox regression model, which included only genes achieving P < 0.05 in the univariate model. A total of 172 patients at Fudan University Shanghai Cancer Center (FUSCC) and 61 patients from GEO datasets were used as an external validation set. Results: A total of 327 patients in the TCGA cohort were enrolled. We identified 274 genes from eight published papers on the OS of MIBC. Using the TCGA database, we identified 12 genes that correlated with OS (P < 0.05 in both univariate and multivariate analyses). By integrating these genes with the RT-qPCR data in our validation dataset and GEO datasets, we confirmed that the power for predicting OS of the 12-gene panel (AUC of 0.741 and 0.727, respectively) was higher than just clinical data (including gender, age, T stage, grade, and N stage) alone in the TCGA and FUSCC cohort (AUC of 0.667 and 0.631, respectively). Additionally, upon combining the clinical data and 12-gene panel together, the AUC increased to 0.768, 0.757, and 0.88 in the TCGA, FUSCC and GSE13507 cohorts, respectively. Conclusions: Applying published gene signatures and TCGA data, we successfully built and externally validated a novel 12-gene signature for the survival of MIBC. BRIEF EXPLANATION: We systemically reviewed all published prognostic gene signatures of muscle-invasive bladder cancer (MIBC) and integrated the genes in the TCGA MIBC cohort. This new gene panel was validated in a newly established MIBC cohort in GEO and FUSCC. This method can help update the previous established panels in a new way.

Prognosis of rare pathological primary urethral carcinoma.

PURPOSE: Urethral carcinoma (UC), as a rare tumor, is not widely studied. There have been no systematic studies of rare pathological types of UC. We conducted this study to further investigate rare pathological types of primary urethral carcinoma (PUC). MATERIALS AND METHODS: We used the population-based Surveillance, Epidemiology, and End Results (SEER) database to evaluate prognostic factors in rare pathological types of PUC. From 1978 to 2015, 2,651 and 257 cases were identified in the SEER database as common and rare pathological types of PUC, respectively. Overall and cancer-specific survival (CSS) times were computed using the Kaplan-Meier method, and the Cox proportional hazards analysis was used to evaluate patient age at diagnosis, gender, race, and TNM stage. RESULTS: The median overall survival (OS) rates were 36 and 59 months for rare and common pathological groups, respectively, and their respective 10-year OS rates were 31.9% and 42.4%, respectively. The median CSS rate was 61 months for the rare pathological group. Through multivariate analysis, it was found that age, race, T stage, and M stage were independent prognostic risk factors for rare pathological type of urethral cancer. In the age group, the HR ratio of patients aged older than 60 years and younger or equal to 60 years was 2.778 (P<0.001). The HR ratio of other races to Whites was 1.444 (P=0.040). In TNM staging, the HR ratio between T3-T4 and Ta-T2 was 2.386 (P=0.046), and the HR value of M1 and M0 was 5.847 (P<0.001). CONCLUSION: Age, race, T stage, and M stage were predictive of OS and CSS in rare pathological PUC.

Conventional versus laparoscopic surgery for hepatic hydatidosis: a 6-year single-center experience.

BACKGROUND: The aim of this study is to evaluate the clinical results of laparoscopic surgery compared with conventional surgery. METHODS: Records of patients who underwent surgery for liver hydatid disease between 2005 and 2011 were reviewed. Operative time, blood loss, conversion to open, postoperative morbidity, mortality, hospital stay, and recurrence rate were measured. RESULTS: Among 353 eligible patients, 60 were considered for laparoscopic and 293 for conventional surgery. Operative time was slightly increased in laparoscopic group. No major blood loss and blood transfusion were needed. Postoperative hospital stay was significantly short in laparoscopic group (3.8 ± 1.2 days) than that in conventional group (7.4 ± 1.4 days). The overall morbidity was 13.3 % (8/60) in laparoscopic and 19.8 % (58/293) in conventional group without significance. Both conversion rate and mortality was 0 %. One recurrence in laparoscopic (1.7 %, 1/60) and five in conventional group (1.7 %, 5/293) occurred within 48 months of follow-up. CONCLUSIONS: Laparoscopic treatment of liver hydatid disease is safe and effective in selected patients with all its advantages.