Validation of the risk stratification newly defined in the Japanese Urological Association guidelines 2019 for non-muscle invasive bladder cancer: A multi-institutional collaborative study.

OBJECTIVES: To validate the risk stratification newly defined in the Japanese Urological Association guidelines 2019 for non-muscle invasive bladder cancer and provide a more accurate stratification model for a heterogeneous intermediate-risk group. METHODS: A total of 1610 patients, who underwent transurethral resection, diagnosed with non-muscle invasive bladder cancer in nine collaborating hospitals were retrospectively reviewed. They were classified into low-risk, intermediate-risk, high-risk, and highest-risk groups, and recurrence-free survival, progression-free survival, cancer-specific survival, and overall survival were compared among the groups. The intermediate-risk group was subdivided into two groups based on the multivariable Cox regression model of recurrence and progression risk factors, and a revised risk model was created. RESULTS: The progression-free survival, cancer-specific survival, and overall survival were well stratified, while the recurrence-free survival of the intermediate-risk group was the shortest among the four groups (p < 0.001). The independent risk factors for recurrence and progression-free survival in the intermediate-risk group were as follows: age ≥ 70 years, sex, multiple tumors, tumor size ≥3 cm, and recurrent cases. The intermediate-risk group was subdivided into two groups: favorable intermediate-risk group and unfavorable intermediate-risk group. The revised risk model showed significant differences. CONCLUSION: We validated the Japanese Urological Association guidelines 2019 stratification model. The revised risk model provided a more accurate treatment selection for this disease subset.

EHHADH contributes to cisplatin resistance through regulation by tumor-suppressive microRNAs in bladder cancer.

BACKGROUND: Cisplatin-based chemotherapy is recommended as the primary treatment for advanced bladder cancer (BC) with unresectable or metastatic disease. However, the benefits are limited due to the acquisition of drug resistance. The mechanisms of resistance remain unclear. Although there are some reports that some molecules are associated with cisplatin resistance in advanced BC, those reports have not been fully investigated. Therefore, we undertook a new search for cisplatin resistance-related genes targeted by tumor suppressive microRNAs as well as genes that were downregulated in cisplatin-resistant BC cells and clinical BC tissues. METHODS: First, we established cisplatin-resistant BOY and T24 BC cell lines (CDDP-R-BOY, CDDP-R-T24). Then, Next Generation Sequence analysis was performed with parental and cisplatin-resistant cell lines to search for the microRNAs responsible for cisplatin resistance. We conducted gain-of-function analysis of microRNAs and their effects on cisplatin resistance, and we searched target genes comprehensively using Next Generation mRNA sequences. RESULTS: A total of 28 microRNAs were significantly downregulated in both CDDP-R-BOY and CDDP-R-T24. Among them, miR-486-5p, a tumor suppressor miRNA, was negatively correlated with the TNM classification of clinical BC samples in The Cancer Genome Atlas (TCGA) database. Transfection of miRNA-486-5p significantly inhibited cancer cell proliferation, migration, and invasion, and also improved the cells' resistance to cisplatin. Among the genes targeted by miRNA-486-5p, we focused on enoyl-CoA, hydratase/3-hydroxyacyl CoA dehydrogenase (EHHADH), which is involved in the degradation of fatty acids. EHHADH was directly regulated by miRNA-486-5p as determined by a dual-luciferase reporter assay. Loss-of-function study using EHHADH si-RNA showed significant inhibitions of cell proliferation, migration, invasion and the recovery of cisplatin sensitivity. CONCLUSION: Identification of EHHADH as a target of miRNA-486-5p provides novel insights into the potential mechanisms of cisplatin resistance in BC.

Oncological outcome of neoadjuvant low-dose estramustine plus LHRH agonist/antagonist followed by extended radical prostatectomy for Japanese patients with high-risk localized prostate cancer: a prospective single-arm study.

BACKGROUND: Patients with advanced high-risk prostate cancer (PCa) are prone to have worse pathological diagnoses of positive surgical margins and/or lymph node invasion, resulting in early biochemical recurrence (BCR) despite having undergone radical prostatectomy (RP). Therefore, it is controversial whether patients with high-risk PCa should undergo RP. The purpose of this study was to evaluate the efficacy of neoadjuvant chemohormonal therapy (NAC) followed by "extended" RP. METHODS: A total of 87 patients with high-risk PCa prospectively underwent extended RP after NAC; most of the patients underwent 6 months of estramustine phosphate (EMP) 140 mg twice daily, along with a luteinizing hormone-releasing hormone agonist/antagonist. We developed our surgical technique to reduce the rate of positive surgical margins. We aimed to approach the muscle layer of the rectum by dissecting the mesorectal fascia and continuing the dissection through the mesorectum until the muscle layer of the rectum was exposed. RESULTS: More than 1 year had elapsed after surgery in all 86 patients, with a median follow-up period of 37.7 months. The 3-year BCR-free survival was 74.9%. Multivariate Cox-regression analysis revealed that a positive core ratio of 50% or greater and pathological stage of pT3 or greater were independent predictors for BCR. About 17 of 23 cases received salvage androgen deprivation therapy and concurrent external beam radiotherapy, and showed no progression after the salvage therapies. CONCLUSIONS: NAC concordant with extended RP is feasible and might provide good cancer control for patients with high-risk PCa.

Regulation of ITGA3 by the dual-stranded microRNA-199 family as a potential prognostic marker in bladder cancer.

This corrects the article DOI: 10.1038/bjc.2017.43.

Regulation of ITGA3 by the dual-stranded microRNA-199 family as a potential prognostic marker in bladder cancer.

BACKGROUND: Based on the microRNA (miRNA) signature of bladder cancer (BC) by deep sequencing, we recently found that several double-stranded mature miRNAs derived from the same pre-miRNAs were sufficiently expressed and acted as tumour suppressors by regulating common target genes in BC. Our deep-sequencing signature of BC showed that all miR-199 family members (miR-199a-3p/-5p and miR-199b-3p/-5p) were also downregulated. We hypothesised that these miRNAs may function as tumour suppressors by regulating common target genes. METHODS: Functional assays of BC cells were performed using transfection of mature miRNA. In silico analyses and luciferase reporter analyses were applied to identify target genes of these miRNAs. The overall survival of patients with BC in The Cancer Genome Atlas (TCGA) database was evaluated by the Kaplan-Meier method. RESULTS: Restoration of these miRNAs significantly inhibited cell migration and invasion in BC cells. Integrin α3 (ITGA3) was directly regulated by these miRNAs. The Cancer Genome Atlas database showed that patients with low pre-miR-199 family (miR-199a-1/-2 and miR-199b) expression exhibited significantly poorer overall survival compared with patients with high pre-miR-199 family expression. CONCLUSIONS: miR-199 family miRNAs functioned as tumour suppressors in BC cells by targeting ITGA3 and might be good prognostic markers for predicting survival in patients with BC.

Dual tumor-suppressors miR-139-5p and miR-139-3p targeting matrix metalloprotease 11 in bladder cancer.

Our recent study of the microRNA (miRNA) expression signature of bladder cancer (BC) by deep-sequencing revealed that two miRNA, microRNA-139-5p/microRNA-139-3p were significantly downregulated in BC tissues. The aim of this study was to investigate the functional roles of these miRNA and their modulation of cancer networks in BC cells. Functional assays of BC cells were performed using transfection of mature miRNA or small interfering RNA (siRNA). Genome-wide gene expression analysis, in silico analysis and dual-luciferase reporter assays were applied to identify miRNA targets. The associations between the expression of miRNA and its targets and overall survival were estimated by the Kaplan-Meier method. Gain-of-function studies showed that miR-139-5p and miR-139-3p significantly inhibited cell migration and invasion by BC cells. The matrix metalloprotease 11 gene (MMP11) was identified as a direct target of miR-139-5p and miR-139-3p. Kaplan-Meier survival curves showed that higher expression of MMP11 predicted shorter survival of BC patients (P = 0.029). Downregulated miR-139-5p or miR-139-3p enhanced BC cell migration and invasion in BC cells. MMP11 was directly regulated by these miRNA and might be a good prognostic marker for survival of BC patients.

Validation of non-muscle-invasive bladder cancer risk stratification updated in the 2021 European Association of Urology guidelines.

Objective: The objective of this study is to validate the predictive ability of the 2021 European Association of Urology (EAU) risk model compared to that of existing risk models, including the 2019 EAU model and risk scoring tables of the European Organization for Research and Treatment of Cancer, Club Urologico Espanol de Tratamiento Oncologico, and Japanese Nishinihon Uro-oncology Extensive Collaboration Group. Patients and methods: This retrospective multi-institutional database study included two cohorts-3024 patients receiving intravesical bacillus Calmette-Guerin (BCG) treatment (BCG cohort) and 789 patients not receiving BCG treatment (non-BCG cohort). The Kaplan-Meier estimate and log-rank test were used to visualize and compare oncological survival outcomes after transurethral surgery among the risk groups. Harrell's concordance index (C-index) was used to evaluate the predictive ability of the models. Results: We observed a risk shift from the 2019 EAU risk grouping to the 2021 EAU risk grouping in a substantial number of patients. For progression, the C-index of the 2021 EAU model was significantly higher than that of the 2019 EAU model in both the BCG (0.617 vs. 0.572; P = 0.011) and non-BCG (0.718 vs. 0.560; P < 0.001) cohorts. According to the 2021 EAU model, 731 (24%) and 130 (16%) patients in the BCG and non-BCG cohorts, respectively, were considered to have a very high risk. Survival analysis showed no significant differences among the five very high-risk subgroups in both cohorts. A major limitation was potential selection bias owing to the retrospective nature of this study. Conclusions: The updated 2021 EAU model showed better stratification than the three existing risk models, especially for progression, in both cohorts, determining the most appropriate postoperative treatment and identifying patients requiring intensified surveillance or early cystectomy.

microRNA-99a-5p induces cellular senescence in gemcitabine-resistant bladder cancer by targeting SMARCD1.

Patients with advanced bladder cancer are generally treated with a combination of chemotherapeutics, including gemcitabine, but the effect is limited due to acquisition of drug resistance. Thus, in this study, we investigated the mechanism of gemcitabine resistance. First, gemcitabine-resistant cells were established and resistance confirmed in vitro and in vivo. Small RNA sequencing analyses were performed to search for miRNAs involved in gemcitabine resistance. miR-99a-5p, selected as a candidate miRNA, was downregulated compared to its parental cells. In gain-of-function studies, miR-99a-5p inhibited cell viabilities and restored sensitivity to gemcitabine. RNA sequencing analysis was performed to find the target gene of miR-99a-5p. SMARCD1 was selected as a candidate gene. Dual-luciferase reporter assays showed that miR-99a-5p directly regulated SMARCD1. Loss-of-function studies conducted with si-RNAs revealed suppression of cell functions and restoration of gemcitabine sensitivity. miR-99a-5p overexpression and SMARCD1 knockdown also suppressed gemcitabine-resistant cells in vivo. Furthermore, ß-galactosidase staining showed that miR-99a-5p induction and SMARCD1 suppression contributed to cellular senescence. In summary, tumor-suppressive miR-99a-5p induced cellular senescence in gemcitabine-resistant bladder cancer cells by targeting SMARCD1.

Site-specific Risk Stratification Models for Postoperative Recurrence and Survival Prediction in Patients with Upper Tract Urothelial Carcinoma Undergoing Radical Nephroureterectomy: Better Stratification for Adjuvant Therapy.

Background: Site-specific postoperative risk models for localized upper tract urothelial carcinoma (UTUC) are unavailable. Objective: To create specific risk models for renal pelvic urothelial carcinoma (RPUC) and ureteral urothelial carcinoma (UUC), and to compare the predictive accuracy with the overall UTUC risk model. Design setting and participants: A multi-institutional database retrospective study of 1917 UTUC patients who underwent radical nephroureterectomy (RNU) between 2000 and 2018 was conducted. Outcome measurements and statistical analysis: A multivariate hazard model was used to identify the prognostic factors for extraurinary tract recurrence (EUTR), cancer-specific death (CSD), and intravesical recurrence (IVR) after RNU. Patients were stratified into low-, intermediate-, high-, and highest-risk groups. External validation was performed to estimate a concordance index of the created risk models. We investigated whether our risk models could aid decision-making regarding adjuvant chemotherapy (AC) after RNU. Results and limitations: The UTUC risk models could stratify the risk of cumulative incidence of three endpoints. The RPUC- and UUC-specific risk models showed better stratification than the overall UTUC risk model for all the three endpoints, EUTR, CSD, and IVR (RPUC: concordance index, 0.719 vs 0.770, 0.714 vs 0.794, and 0.538 vs 0.569, respectively; UUC: 0.716 vs 0.767, 0.766 vs 0.809, and 0.553 vs 0.594, respectively). The UUC-specific risk model can identify the high- and highest-risk patients likely to benefit from AC after RNU. A major limitation was the potential selection bias owing to the retrospective nature of this study. Conclusions: We recommend using site-specific risk models instead of the overall UTUC risk model for better risk stratification and decision-making for AC after RNU. Patient summary: Upper tract urothelial carcinoma comprises renal pelvic and ureteral carcinomas. We recommend using site-specific risk models instead of the overall upper tract urothelial carcinoma risk model in risk prediction and decision-making for adjuvant therapy after radical surgery.

Significance of preoperative screening of deep vein thrombosis and its indications for patients undergoing urological surgery.

PURPOSE: Preoperative deep vein thrombosis (pre-DVT) is a risk of symptomatic venous thromboembolism (VTE) and a serious postoperative surgical complication. However, little is known about pre-DVT in patients undergoing surgery. This study aimed to investigate the incidence and screening criteria of pre-DVT in patients undergoing urological surgery. MATERIALS AND METHODS: Between 2015 and 2017, 320 patients admitted to our hospital for urological surgery were included in this retrospective study. All patients underwent preoperative D-dimer testing. Patients with elevated D-dimer (≥1.0 µg/mL) levels underwent lower-limb compression ultrasonography (CUS). Clinical parameters were analyzed as predictors of pre-DVT, and modest cutoff value of D-dimer to predict pre-DVT were evaluated. RESULTS: Of 320 patients, preoperative elevated D-dimer levels and DVT were found in 81 (25.3%) and 20 (6.3%) patients, respectively. The positive predictive value (PPV) was 24.7% (20/81). ROC curve analysis revealed a cutoff D-dimer level of 1.8 µg/mL, yielding a PPV of 40.7% for pre-DVT among patients with elevated D-dimer levels. Preoperative DVT was detected in 16 (7.6%, n=210) patients with malignancy, 3 (5.7%, n=53) with adrenal tumors, and in 1 (1.8%, n=57) kidney donor. An age of >70 years was significantly associated with risk for pre-DVT (odds ratio, 2.81; 95% confidence interval, 1.12-7.19; p=0.0270). During a postoperative follow-up period of 90 days, no patient developed symptomatic VTE. CONCLUSIONS: The incidence of pre-DVT was 6.3% in patients undergoing urological surgery. Elderly patients and/or a cutoff D-dimer level of 1.8 µg/mL might be good indications for pre-DVT screening by CUS.

Characterization of PHGDH expression in bladder cancer: potential targeting therapy with gemcitabine/cisplatin and the contribution of promoter DNA hypomethylation.

d-3-Phosphoglycerate dehydrogenase (PHGDH) conducts an important step in the synthesis of serine. Importantly, the PHGDH gene is often amplified in certain cancers. Our previous studies revealed that PHGDH gene amplification was associated with poor overall survival in clear cell renal cell carcinoma (ccRCC) and that metabolic reprogramming of serine synthesis through PHGDH recruitment allowed ccRCC cells to survive in unfavorable environments. There have been no investigations of the role of PHGDH expression in bladder cancer (BC). In this investigation, we examined the clinical importance of PHDGH in BC. Furthermore, we asked whether PHGDH expression could be exploited for BC therapy. Finally, we investigated the regulatory mechanisms that modulated the expression of PHGDH. Using data from The Cancer Genome Atlas, we found that patients with high-grade BC had significantly higher PHGDH expression levels than did those with low-grade BC. In addition, patients with high PHGDH expression did not survive as long as those with low expression. PHGDH downregulation by si-RNAs or an inhibitor in BC cell lines significantly inhibited proliferative ability and induced apoptosis. Furthermore, combined treatment using a PHGDH inhibitor and gemcitabine/cisplatin achieved synergistic tumor suppression compared to use of a single agent both in vitro as well as in vivo. Mechanistic analyses of PHGDH regulation showed that PHGDH expression might be associated with DNA copy number and hypomethylation in BC. These findings suggest novel therapeutic strategies could be used in BC. Finally, our data enhance our understanding of the role of PHGDH in BC.

Potential tumor­suppressive role of microRNA­99a­3p in sunitinib­resistant renal cell carcinoma cells through the regulation of RRM2.

Sunitinib is the most common primary molecular­targeted agent for metastatic clear cell renal cell carcinoma (ccRCC); however, intrinsic or acquired sunitinib resistance has become a significant problem in medical practice. The present study focused on microRNA (miR)­99a­3p, which was significantly downregulated in clinical sunitinib­resistant ccRCC tissues in previous screening analyses, and investigated the molecular network associated with it. The expression levels of miR­99a­3p and its candidate target genes were evaluated in RCC cells, including previously established sunitinib­resistant 786­o (SU­R­786­o) cells, and clinical ccRCC tissues, using reverse transcription­quantitative polymerase chain reaction. Gain­of­function studies demonstrated that miR­99a­3p significantly suppressed cell proliferation and colony formation in RCC cells, including the SU­R­786­o cells, by inducing apoptosis. Based on in silico analyses and RNA sequencing data, followed by luciferase reporter assays, ribonucleotide reductase regulatory subunit­M2 (RRM2) was identified as a direct target of miR­99a­3p in the SU­R­786­o cells. Loss­of­function studies using small interfering RNA against RRM2 revealed that cell proliferation and colony growth were significantly inhibited via induction of apoptosis, particularly in the SU­R­786­o cells. Furthermore, the RRM2 inhibitor Didox (3,4­dihydroxybenzohydroxamic acid) exhibited anticancer effects in the SU­R­786­o cells and other RCC cells. To the best of our knowledge, this is the first report demonstrating that miR­99a­3p directly regulates RRM2. Identifying novel genes targeted by tumor­suppressive miR­99a­3p in sunitinib­resistant RCC cells may improve our understanding of intrinsic or acquired resistance and facilitate the development of novel therapeutic strategies.

Tumor­suppressive microRNA­223 targets WDR62 directly in bladder cancer.

miRNA­223 (miR­223) has been reported to function not only as a tumor suppressor, but also as an oncogenic microRNA (miRNA or miR) in various cancer cells. Therefore, the functional role of miR­223 has not been elucidated to date, at least to the best of our knowledge. We previously performed the deep sequencing analysis of clinical bladder cancer (BC) specimens. It was revealed that miR­223 expression was significantly downregulated in BC, suggesting that miR­223 functions as a tumor suppressor miRNA in BC. The aim of this study was to investigate the functional roles of miR­223 and to identify its targets in BC. The expression levels of miR­223 were significantly decreased in our clinical BC specimens. The Cancer Genome Atlas (TCGA) database indicated that miR­223 expression was related to lymphovascular invasion and distant metastasis. The restoration of miR­223 expression significantly inhibited tumor aggressiveness and induced apoptosis via caspase­3/7 activation in BC cells. WD repeat domain 62 (WDR62), a candidate target of miR­223 according to in silico analyses, has been previously proposed to play a role in neurodevelopment. Direct binding between WDR62 and miR­223 was confirmed by luciferase assay. The TCGA database revealed positive associations between WDR62 mRNA expression and a higher tumor grade and stage in BC. The knockdown of WDR62 significantly inhibited tumor aggressiveness and induced the apoptosis of BC cells. On the whole, the findings of this study reveal a novel miR­223 target, oncogenic WDR62, and provided insight into the oncogenesis of BC.

Anatomical Variations of the Left Renal Vein During Laparoscopic Donor Nephrectomy.

OBJECTIVES: The aim of this study is to investigate the outcome of laparoscopic donor nephrectomy with vascular anomalies of the left renal vein. PATIENTS AND METHODS: Between August 2010 and September 2018, a total of 120 laparoscopic donor nephrectomies were performed at Kagoshima University. Among them, we experienced 7 cases of donors with anomalous left renal vein (circumaortic left renal vein n = 5, retroaortic left renal vein n = 1, left renal vein drainage into hemiazygos vein n = 1). We analyzed the following clinical outcomes: pneumoperitoneum time, estimated blood loss, warm ischemia time, length of hospital stay, and serum creatinine level of 1 month after surgery for evaluating the safety of laparoscopic donor nephrectomy. RESULTS: Among the 7 cases, 3 cases underwent transperitoneal approach, and 4 cases underwent retroperitoneal approach. The median pneumoperitoneum time was 168 (108-191) minutes. The median estimated blood loss was 90 (23-170) mL, and no donor required a blood transfusion. Median warm ischemia time was 4 (3-7) minutes. Length of hospital stay was 7 (6-9) days, and no readmission occurred. Median serum creatinine level of 1 month after surgery was 1.19 (0.84-1.74) mg/dL. Kidneys were transplanted successfully, and none of recipients required dialysis. CONCLUSIONS: Laparoscopic donor nephrectomy was safe for donors with an anomalous left renal vein. Preoperative recognition of anomalous left renal vein in computed tomography is important for avoiding hemorrhagic complication.

HRAS as a potential therapeutic target of salirasib RAS inhibitor in bladder cancer.

The active form of the small GTPase RAS binds to downstream effectors to promote cell growth and proliferation. RAS signal enhancement contributes to tumorigenesis, invasion, and metastasis in various different cancers. HRAS proto-oncogene GTPase (HRAS), one of the RAS isoforms, was the first human oncogene for which mutations were reported in T24 bladder cancer (BC) cells in 1982, and HRAS mutation or upregulation has been reported in several cancers. According to data from The Cancer Genome Atlas, HRAS expression was significantly upregulated in clinical BC samples compared to healthy samples (P=0.0024). HRAS expression was also significantly upregulated in BC with HRAS mutation compared to patients without HRAS mutation (P<0.0001). The tumor suppressive effect of salirasib, a RAS inhibitor, has been reported in several cancer types, but only at relatively high concentrations. As such, RAS inhibitors have not been used for clinical applications. The aim of the current study was to investigate the therapeutic potential of targeting HRAS using salirasib and small interfering RNA (siRNA) and to characterize the mechanism by which HRAS functions using recently developed quantitative in vitro proteome-assisted multiple reaction monitoring for protein absolute quantification (iMPAQT), in BC cells. iMPAQT allows measurement of the absolute abundance of any human protein with the high quantitative accuracy. Salirasib and siRNA targeting of HRAS inhibited cell proliferation, migration and invasion in HRAS wild type and HRAS-mutated cell lines. Proteomic analyses revealed that several metabolic pathways, including the oxidative phosphorylation pathway and glycolysis, were significantly downregulated in salirasib-treated BC cells. However, the expression levels of hexokinase 2, phosphoglycerate kinase 1, pyruvate kinase, muscle (PKM)1, PKM2 and lactate dehydrogenase A, which are downstream of RAS and target genes of hypoxia inducible factor-1α, were not notably downregulated, which may explain the high concentration of salirasib required to inhibit cell viability. These findings provide insight into the mechanisms of salirasib, and suggest the need for novel therapeutic strategies to treat cancers such as BC.

Downregulation of microRNA-1274a induces cell apoptosis through regulation of BMPR1B in clear cell renal cell carcinoma.

Our previous studies of the microRNA (miRNA) expression signature in clear cell renal cell carcinoma (ccRCC) indicated that miRNA-1274a (miR-1274a) was significantly upregulated in clinical specimens, suggesting that miR-1274a may act as an oncogenic miRNA in ccRCC. The aim of this study was to investigate the functional roles of miR-1274a and identify downstream tumor-suppressive targets regulated by miR­1274a in ccRCC cells. Functional studies of miR-1274a were carried out by anti-miRNA to investigate cell proliferation and apoptosis using the A498, ACHN and Caki1 ccRCC cell lines. Suppression of miR-1274a significantly inhibited cancer cell proliferation and induced apoptosis in the ccRCC cells. Gene expression data combined with in silico analysis and luciferase reporter assays demonstrated that bone morphogenetic protein receptor type 1B (BMPR1B) was directly regulated by miR-1274a. Moreover, TCGA database as well as immunohistochemistry demonstrated low expression of BMPR1B in ccRCC clinical specimens compared to that in normal kidney tissues. We conclude that loss of oncogenic miR-1274a reduced cancer cell proliferation and induced apoptosis in ccRCC through targeting BMPR1B. Our data revealing molecular pathways and a target gene regulated by oncogenic miR-1274a provide new insight into the potential mechanisms of ccRCC oncogenesis.

Bromodomain protein BRD4 inhibitor JQ1 regulates potential prognostic molecules in advanced renal cell carcinoma.

Sunitinib is a standard molecular-targeted drug used as a first-line treatment for metastatic clear cell renal cell carcinoma (ccRCC); however, resistance to sunitinib has become a major problem in medical practice. Recently, bromodomain containing 4 (BRD4), a member of the bromodomain family proteins, was identified as a promising therapeutic target, and its inhibitor JQ1 has been shown to have inhibitory effects in various human cancers. However, the anti-cancer effects of JQ1 in ccRCC, particularly sunitinib-resistant ccRCC, are still unclear. Here, we aimed to elucidate the anti-cancer effects of JQ1 and the mechanisms underlying BRD4 inhibition in sunitinib-sensitive and -resistant ccRCCs. Analysis of The Cancer Genome Atlas (TCGA) ccRCC cohort showed that patients with high BRD4 expression had shorter overall survival than those with low expression. JQ1 treatment significantly inhibited tumor growth of sunitinib-sensitive and -resistant ccRCC cells in part through MYC regulation. Based on RNA sequencing analyses of ccRCC cells treated with JQ1 to elucidate the mechanisms other than MYC regulation, we identified several oncogenes that may be potential therapeutic targets or prognostic markers; patients with high expression of SCG5, SPOCD1, RGS19, and ARHGAP22 had poorer overall survival than those with low expression in TCGA ccRCC cohort. Chromatin immunoprecipitation assays revealed that these oncogenes may be promising BRD4 targets, particularly in sunitinib-resistant ccRCC cells. These results identified SCG5, SPOCD1, RGS19, and ARHGAP22 as potential prognostic markers and showed that BRD4 inhibition may have applications as a potential therapeutic approach in sunitinib-sensitive and -resistant ccRCC.

microRNA-210-3p depletion by CRISPR/Cas9 promoted tumorigenesis through revival of TWIST1 in renal cell carcinoma.

Previous studies showed that five miRNAs (miR-885-5p, miR-1274, miR-210-3p, miR-224 and miR-1290) were upregulated the most in clear cell renal cell carcinoma (ccRCC). Our focus was to understand from a clinical standpoint the functional consequences of upregulating miR-210-3p. Towards this, we utilized the CRISPR/Cas9 gene editing system to deplete miR-210-3p in RCC cell lines (786-o, A498 and Caki2) and characterized the outcomes. We observed that miR-210-3p depletion dramatically increased tumorigenesis, including altering the morphology of A498 and Caki2 cells in a manner characteristic of epithelial-mesenchymal transition (EMT). These results were corroborated by in vivo xenograft studies, which showed enhanced growth of tumors from miR-210-3p-depleted A498 cells. We identified Twist-related protein 1 (TWIST1) as a key target of miR-210-3p. Analysis of the ccRCC patient data in The Cancer Genome Atlas database showed a negative correlation between miR-210-3p and TWIST1 expression. High TWIST1 and low miR-210-3p expression associated with poorer overall and disease-free survival as compared to low TWIST1 and high miR-210-3p expression. These findings suggest that renal cell carcinoma progression is promoted by TWIST1 suppression mediated by miR-210-3p.

PHGDH as a Key Enzyme for Serine Biosynthesis in HIF2α-Targeting Therapy for Renal Cell Carcinoma.

Continuous activation of hypoxia-inducible factor (HIF) is important for progression of renal cell carcinoma (RCC) and acquired resistance to antiangiogenic multikinase and mTOR inhibitors. Recently, HIF2α antagonists PT2385 and PT2399 were developed and are being evaluated in a phase I clinical trial for advanced or metastatic clear cell RCC (ccRCC). However, resistance to HIF2α antagonists would be expected to develop. In this study, we identified signals activated by HIF2α deficiency as candidate mediators of resistance to the HIF2α antagonists. We established sunitinib-resistant tumor cells in vivo and created HIF2α-deficient variants of these cells using CRISPR/Cas9 technology. Mechanistic investigations revealed that a regulator of the serine biosynthesis pathway, phosphoglycerate dehydrogenase (PHGDH), was upregulated commonly in HIF2α-deficient tumor cells along with the serine biosynthesis pathway itself. Accordingly, treatment with a PHGDH inhibitor reduced the growth of HIF2α-deficient tumor cells in vivo and in vitro by inducing apoptosis. Our findings identify the serine biosynthesis pathway as a source of candidate therapeutic targets to eradicate advanced or metastatic ccRCC resistant to HIF2α antagonists. Cancer Res; 77(22); 6321-9. ©2017 AACR.