Surveillance of urachal abscess in the Kyushu-Okinawa area of Japan.

OBJECTIVE: To report a multicenter experience with the management of urachal abscess treatment in Japan. METHODS: This was a retrospective study of 263 cases of urachal abscess managed at 12 university hospitals in the Kyushu-Okinawa region over a 10-year period. Age, sex, abscess size, clinical symptoms, type of urachal remnants, and treatment were collected and analyzed. RESULTS: The average age was 29.8 ± 18.1 years, with males accounting for approximately two-thirds of the study population. The average abscess size was 1.7 cm (range 0-11 cm). The most common presenting symptom was umbilical secretion (66%), followed by abdominal pain (46%). A total of 127 patients (48.3%) were treated with antibiotics alone, whereas 136 patients (51.7%) received surgical treatment. The surgical approach was laparotomy in 75 patients (61.0%) and laparoscopic surgery in 48 patients (39.0%). Regarding the type of urachal remnant, the urachus sinus (180 patients) accounted for 68.4% of the total. CONCLUSIONS: To our knowledge, this study represents the first report on urachal abscess treatment in Japan. Our data show that the clinical symptoms might vary depending on the type of urachus remnant. It should be noted that gross hematuria, a characteristic symptom of urachal cancer, is rare in patients with urachal abscess.

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.

Expression of the tumor suppressive miRNA-23b/27b cluster is a good prognostic marker in clear cell renal cell carcinoma.

PURPOSE: We observed abnormal expression of the microRNA-23b/27b (miR-23b/27b) cluster in our previous study of miRNA expression signatures. However, the relationship between aberrant miRNA expression and clear cell renal cell carcinoma is not well established. We investigated the functional significance of the miR-23b/27b cluster in clear cell renal cell carcinoma cells and evaluated these miRNAs as biomarkers to predict the risk of clear cell renal cell carcinoma. MATERIALS AND METHODS: Expression levels of miR-23b and miR-27b were determined by quantitative real-time reverse transcriptase-polymerase chain reaction. The association between miRNA expression and overall survival was estimated by the Kaplan-Meier method. Gain of function assays were performed using mature miR-23b and miR-27b in the 786-O and A498 renal cell carcinoma cell lines. Targets regulated by these miRNAs were predicted by in silico analysis. RESULTS: Expression of the miR-23b/27b cluster was significantly decreased in clear cell renal cell carcinoma tissue specimens and associated with pathological grade and stage. Significantly shorter overall survival was observed in patients with lower expression of the miR-23b/27b cluster. Restoration of miR-23b and miR-27b significantly inhibited cancer cell proliferation, migration and invasion. CONCLUSIONS: Expression of the miR-23b/27b cluster was frequently decreased in clear cell renal cell carcinoma tissue. Reduced expression of these miRNAs increased the risk of disease progression and predicted poor survival. Thus, miR-23b and miR-27b function as tumor suppressors, targeting several oncogenic genes in clear cell renal cell carcinoma cells.

The tumor-suppressive microRNA-143/145 cluster inhibits cell migration and invasion by targeting GOLM1 in prostate cancer.

Our recent study of microRNA (miRNA) expression signature of prostate cancer (PCa) has revealed that the microRNA-143/145 (miR-143/145) cluster is significantly downregulated in cancer tissues, suggesting that these cluster miRNAs are candidate tumor suppressors. The aim of this study was to investigate the functional significance of the miR-143/145 cluster in PCa cells and to identify novel targets regulated by these cluster miRNAs in PCa. Restoration of miR-143 or miR-145 in PCa cell lines (PC3 and DU145) revealed that these miRNAs significantly inhibited cancer cell migration and invasion. Gene expression data and in silico analysis demonstrated that Golgi membrane protein 1 (GOLM1) resembling a type II golgi transmembrane protein was a potential target of miR-143/145 cluster target gene. Gene expression studies and luciferase reporter assays showed that GOLM1 was directly regulated by the miR-143/145 cluster. Silencing of GOLM1 resulted in significant inhibition of cell migration and invasion in PCa cells. Furthermore, the expression of GOLM1 was upregulated in cancer tissues by immunohistochemistry. Loss of the tumor-suppressive miR-143/145 cluster enhanced cancer cell migration and invasion in PCa through directly regulating GOLM1. Our data on target genes regulated by the tumor-suppressive miR-143/145 cluster provide new insights into the potential mechanisms of PCa oncogenesis and metastasis.

Tumor-suppressive microRNA-135a inhibits cancer cell proliferation by targeting the c-MYC oncogene in renal cell carcinoma.

Recently, many studies have suggested that microRNAs (miRNAs) are involved in cancer cell development, invasion, and metastasis of various types of human cancers. In a previous study, miRNA expression signatures from renal cell carcinoma (RCC) revealed that expression of microRNA-135a (miR-135a) was significantly reduced in cancerous tissues. The aim of this study was to investigate the functional significance of miR-135a and to identify miR-135a-mediated molecular pathways in RCC cells. Restoration of mature miR-135a significantly inhibited cancer cell proliferation and induced G0 /G1 arrest in the RCC cell lines caki2 and A498, suggesting that miR-135a functioned as a potential tumor suppressor. We then examined miR-135a-mediated molecular pathways using genome-wide gene expression analysis and in silico analysis. A total of 570 downregulated genes were identified in miR-135a transfected RCC cell lines. To investigate the biological significance of potential miR-135a-mediated pathways, we classified putative miR-135a-regulated genes according to the Kyoto Encyclopedia of Genes and Genomics pathway database. From our in silico analysis, 25 pathways, including the cell cycle, pathways in cancer, DNA replication, and focal adhesion, were significantly regulated by miR-135a in RCC cells. Moreover, based on the results of this analysis, we investigated whether miR-135a targeted the c-MYC gene in RCC. Gain-of-function and luciferase reporter assays showed that c-MYC was directly regulated by miR-135a in RCC cells. Furthermore, c-MYC expression was significantly upregulated in RCC clinical specimens. Our data suggest that elucidation of tumor-suppressive miR-135a-mediated molecular pathways could reveal potential therapeutic targets in RCC.

Tumor-suppressive microRNA-143/145 cluster targets hexokinase-2 in renal cell carcinoma.

Our recent studies of microRNA (miRNA) expression signatures have indicated that the miR-143/145 cluster is significantly downregulated in several types of cancer and represents a putative tumor-suppressive miRNA in human cancers. The aim of this study was to investigate the functional significance of the miR-143/145 cluster in cancer cells and to identify novel molecular targets of the miR-143/145 cluster in renal cell carcinoma (RCC). The expression levels of miR-143 and miR-145 were significantly downregulated in RCC tissues compared with adjacent non-cancerous tissues. A significant positive correlation was recognized between miR-143 and miR-145 expression. Restoration of mature miR-143 or miR-145 in 786-O and A498 RCC cells revealed that both mature miRNAs significantly inhibited cancer cell proliferation and invasion, suggesting that the miR-143/145 cluster functioned as a tumor suppressor in RCC. Gene expression data and in silico database analysis showed that the hexokinase-2 (HK2) gene, which encodes a glycolytic enzyme crucial for the Warburg effect in cancer cells, was a candidate target of the miR-143/145 cluster. Luciferase reporter assays showed that both miR-143 and miR-145 directly regulated HK2. In RCC clinical specimens, the expression of HK2 was significantly higher in cancer tissues than in non-cancerous tissues. Silencing HK2 suppressed RCC cell proliferation and invasion, suggesting that HK2 has oncogenic functions in RCC. Thus, our data showed that loss of the tumor-suppressive miR-143/145 cluster enhanced RCC cell proliferation and invasion through targeting HK2.

Tumor-suppressive microRNA-1291 directly regulates glucose transporter 1 in renal cell carcinoma.

Our recent studies of microRNA (miRNA) expression signatures demonstrated that microRNA-1291 (miR-1291) was significantly downregulated in renal cell carcinoma (RCC) clinical specimens and was a putative tumor-suppressive miRNA in RCC. The aim of the present study was to investigate the functional significance of miR-1291 in cancer cells and to identify novel miR-1291-mediated cancer pathways and target genes in RCC. Expression of miR-1291 was significantly downregulated in RCC tissues compared with adjacent non-cancerous tissues. Restoration of mature miR-1291 in RCC cell lines (A498 and 786-O) revealed significant inhibition of cell proliferation, migration and invasion, suggesting that miR-1291 functioned as a tumor suppressor. To identify miR-1291-mediated molecular pathways and targets, we used gene expression analysis (expression of RCC clinical specimens and miR-1291-transfected A498 cells) and in silico database analysis. Our data demonstrated that 79 signaling pathways were significantly regulated by tumor-suppressive miR-1291 in RCC cells. Moreover, solute career family 2 member 1 (SLC2A1) was a candidate target of miR-1291 regulation. The SLC2A1 gene provides instructions for producing glucose transporter protein type 1 (GLUT1). Luciferase reporter assays showed that miR-1291 directly regulated SLC2A1/GLUT1. In RCC clinical specimens, the expression of SLC2A1/GLUT1 mRNA was significantly higher in cancer tissues than in non-cancerous tissues. A significant inverse correlation was recognized between SLC2A1/GLUT1 and miR-1291 expression (r = -0.55, P < 0.0001). Loss of tumor-suppressive miR-1291 enhanced RCC cell proliferation, migration and invasion through targeting SLC2A1/GLUT1. The identification of novel tumor-suppressive miR-1291-mediated molecular pathways and targets has provided new insights into RCC oncogenesis and metastasis.

MicroRNA-218 inhibits cell migration and invasion in renal cell carcinoma through targeting caveolin-2 involved in focal adhesion pathway.

PURPOSE: Our microRNA expression signature of renal cell carcinoma revealed that miR-218 expression was significantly decreased in cancer tissues, suggesting that miR-218 is a candidate tumor suppressor. We investigated the functional significance of miR-218 in cancer cells and identified what are to our knowledge novel miR-218 mediated cancer pathways in renal cell carcinoma. MATERIALS AND METHODS: Gain of function studies using mature miR-218 were performed to investigate cell proliferation, migration and invasion in the A498 and 786-O renal cell carcinoma cell lines. To identify miR-218 mediated molecular pathways and responsible genes in renal cell carcinoma, we used gene expression and in silico database analyses. Loss of function assays were performed to investigate the functional significance of miR-218 target genes. RESULTS: Restoration of mature miR-218 significantly inhibited RCC cell proliferation, migration and invasion. Gene expression studies and luciferase reporter assays showed that CAV2 involved in the focal adhesion pathway was directly regulated by miR-218. A silencing study of CAV2 revealed significant inhibition of cell proliferation, migration and invasion. CAV2 mRNA and protein expression was significantly up-regulated in renal cell carcinoma clinical specimens. CONCLUSIONS: Loss of tumor suppressive miR-218 enhances cancer cell migration and invasion through dysregulation of the focal adhesion pathway, especially CAV2 as an oncogenic function in renal cell carcinoma. Tumor suppressive microRNA mediated cancer pathways and responsible genes provide new insights into the potential mechanisms of renal cell carcinoma oncogenesis and metastasis.

Epithelial-mesenchymal transition-related microRNA-200s regulate molecular targets and pathways in renal cell carcinoma.

Our recent studies of microRNA (miRNA) expression signatures demonstrated that the epithelial-mesenchymal transition (EMT)-related microRNA-200 family (miR-200s: miR-200a/b/c, miR-141 and miR-429) were significantly downregulated in renal cell carcinoma (RCC) and putative tumor-suppressive miRNAs in RCC. In this study, our aim was to investigate the functional significance of the miR-200s in cancer cells and to identify novel miR-200s-regulated molecular targets and pathways in RCC. Expression levels of all the miR-200s members were significantly downregulated in human RCC tissues compared with normal renal tissues. Restoration of mature miR-200s in RCC cell line resulted in significant inhibition of cell proliferation and migration, suggesting that miR-200s function as tumor suppressors in RCC. Furthermore, we utilized gene expression analysis and in silico database analysis to identify miR-200s-regulated molecular targets and pathways in RCC. The miR-200s was categorized into two groups, according to their seed sequences, miR-200b/c/429 and miR-200a/141. Our data demonstrated that the 'Focal adhesion' and 'ErbB signaling' pathways were significantly regulated by miR-200b/c/429 and miR-200a/141, respectively. The identification of novel tumor-suppressive miR-200s-regulated molecular targets and pathways has provided new insights into RCC oncogenesis and metastasis.

Efficacy of vesicostomy for refractory metabolic acidosis in persistent cloaca.

Persistent cloaca involves fusion of the bladder, vagina, and rectum into a single duct called the common duct. Although its pathogenesis remains unclear, it has been associated with hyperchloremic metabolic acidosis. Herein, we present the case of a neonatal girl with high-confluence type variant of persistent cloaca treated with vesicostomy (Blocksom) for refractory metabolic acidosis. She was diagnosed with persistent cloaca before birth; colostomy was performed and a urinary catheter was placed in the bladder. Voiding cystourethrography on day 19 after birth showed that most of the contrast material leaked into the rectum; hence, the urinary catheter was removed. On day 27, hyperchloremic metabolic acidosis was detected and treatment with oral sodium bicarbonate was initiated; however, the infant showed no response. Because hyperchloremia occurred after removal of the urinary catheter, continuous urine retention in the colon through the common duct was believed to have caused the progression of hyperchloremic metabolic acidosis through transporters in the intestinal mucosa. As reinstallation of a urinary catheter was technically difficult, vesicostomy was performed on day 29, after which the metabolic acidosis improved. This report suggests vesicostomy as an effective treatment for refractory hyperchloremic metabolic acidosis associated with high-confluence type persistent cloaca.

Acquired undescended testes in boys with hypospadias.

PURPOSE: We determined the incidence of acquired undescended testes in boys with hypospadias. MATERIALS AND METHODS: We retrospectively reviewed the records of 566 boys with hypospadias who were referred to our outpatient clinic between January 2000 and September 2009. Acquired undescended testes were defined as testes that were documented at the bottom of the scrotum at least once after birth by the pediatric urologist at our institution but were subsequently documented to have moved from a satisfactory scrotal position by the same pediatric urologist or an equally experienced pediatric urologist. However, this definition did not include undescended testes after inguinoscrotal surgery. We excluded boys with gender development disorders with testicular dysgenesis, those who underwent bilateral inguinoscrotal surgery and those without congenital cryptorchidism who were followed less than 3 months. RESULTS: Of the 566 boys with hypospadias 100 met study exclusion criteria. Of the 466 boys included in analysis 29 (6.2%) had congenital cryptorchidism and 15 (3.2%) had acquired undescended testes. Urethroplasty was performed in 413 boys, including 91 with distal, 132 with mid and 181 with proximal hypospadias. The incidence of congenital cryptorchidism and acquired undescended testes in boys with proximal hypospadias was significantly higher than that in boys with other types of hypospadias (p = 0.03 and 0.001, respectively). CONCLUSIONS: Boys with proximal hypospadias are at a higher risk for acquired undescended testes than those with other mild types of hypospadias. Thus, testicular location should be monitored regularly until after puberty.

Positioning the instillation of contrast at the ureteral orifice cystography can be useful to predict postoperative contralateral reflux in children with unilateral vesicoureteral reflux.

The aim of the present study was to evaluate the usefulness of positioning the instillation of contrast at the ureteral orifice (PIC) cystography in prediction of postoperative contralateral reflux in patients with unilateral vesicoureteral reflux (VUR) undergoing ureteral reimplantation. Between January 2007 and March 2009, 34 children (20 boys and 14 girls) had antireflux surgery for unilateral primary VUR. This was diagnosed by conventional fluoroscopic voiding cystourethrography (VCUG) in all patients. After induction of general anesthesia, PIC cystography was carried out immediately before ureteral reimplantation by instilling contrast material at the ureteral orifice. Patients with positive PIC cystogram on the contralateral side underwent bilateral ureteral reimplantation via the Cohen technique. VCUG was repeated at 6-12 months postoperatively. Of the 34 patients, 16 (47%) showed VUR on the contralateral side on PIC cystography and underwent bilateral reimplantation. The remaining 18 patients (53%) with negative PIC cystogram underwent unilateral reimplantation, and no VUR was detected by postoperative VCUG in all ureters. None of the 34 patients had surgical complications or recurrent urinary tract infections. In conclusion, PIC cystography represents a useful tool to predict new onset contralateral VUR in patients with unilateral VUR on conventional VCUG.

Long-term outcome of ovotesticular disorder of sex development: a single center experience.

OBJECTIVES: To describe the clinical features of children with ovotesticular disorder of sex development (DSD) and to review cases of ovotesticular DSD in Japan. METHODS: Medical records of eight children diagnosed with ovotesticular DSD at our institute during the past 17 years were retrospectively evaluated. A review of 165 reported cases of ovotesticular DSD from Japanese institutions was carried out. RESULTS: Mean follow up was 8.2 years for six children, with two children lost to follow up. Mean age at first presentation was 2.4 months. All children were Japanese. The most common initial manifestation was ambiguous genitalia. The female:male ratio as the sex of rearing was 1:1. Gender reassignment, from male to female, was carried out in one child at 4-months-old. Genital surgery was always carried out in early childhood as per family desire. Appropriate gonadal tissue was preserved except for one child. No gonadal tumors were detected during follow up. Spontaneous pubertal development occurred in one boy. In reviewing Japanese data, the frequency of testes was higher than in other ethnicities and this was related to the higher incidence of 46,XY. CONCLUSIONS: According to our experience, most families in Japan desire early genital surgery in the case of ovotesticular DSD. Chromosomal and gonadal distributions in patients with ovotesticular DSD differ between Japanese and other ethnic groups. Treatment for these patients needs to be provided after considering the cultural and social backgrounds of DSD in Japan.

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.

CpG hypermethylation of the UCHL1 gene promoter is associated with pathogenesis and poor prognosis in renal cell carcinoma.

PURPOSE: Aberrant DNA hypermethylation has been reported in renal cell carcinoma. We performed microarray analysis in the renal cancer cell line ACHN treated with the demethylating agent 5-aza-2'-deoxycytidine and investigated the UCHL1 gene involved in the regulation of cellular ubiquitin levels. MATERIALS AND METHODS: We subjected 131 renal cell carcinoma and 61 corresponding normal kidney tissue samples to real-time reverse transcriptase-polymerase chain reaction, quantitative methylation specific polymerase chain reaction and immunohistochemistry. We also established a stable UCHL1 transfectant to evaluate cell growth. RESULTS: We identified 10 genes that were up-regulated more than 2.5-fold in 5-aza-2'-deoxycytidine treated vs untreated ACHN cells. UCHL1 expression was increased 3.41-fold by 5-aza-2'-deoxycytidine treatment. In clinical samples the UCHL1 methylation index was significantly higher in renal cell carcinoma than in normal kidney tissue (p = 0.011). Conversely UCHL1 mRNA expression was significantly lower in renal cell carcinoma than in normal kidney tissue (p <0.0001). There was a negative correlation between mRNA expression and the UCHL1 methylation index (p = 0.017). The immunostaining score for UCHL1 was significantly higher in normal kidney tissue than in renal cell carcinoma (p <0.0001). Kaplan-Meier analysis showed that a positive UCHL1 methylation index had a significant adverse effect on prognosis (p = 0.048). Significant growth inhibition in UCHL1 transfectant compared to that in WT ACHN (p <0.0001) suggests that UCHL1 functions as a potential tumor suppressor gene in human renal cell carcinoma. CONCLUSIONS: To our knowledge we report the first study demonstrating that the mechanism of UCHL1 down-regulation in renal cell carcinoma is through CpG hypermethylation of the promoter region and methylation of the UCHL1 gene is associated with a poor prognosis in patients with renal cell carcinoma.

Oral Propranolol in a Child With Infantile Hemangioma of the Urethra.

Infantile hemangiomas (IH) are the most common in the head and neck region.1 They can occur anywhere in the skin, however, urethral hemangiomas are very rare. We describe a case report of a 3-year-old boy with extensive lesions of IH in the anterior urethra. Urethral IH were disappeared during 1 year of oral administration of propranolol though it brought on urinary retention. This is the first report about oral propranolol treatment in a child with urethral IH. Oral administration of propranolol may be effective for urethral IH and beneficial especially for lesions requiring extensive surgical resection and reconstruction.

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.

Dual regulation of receptor tyrosine kinase genes EGFR and c-Met by the tumor-suppressive microRNA-23b/27b cluster in bladder cancer.

Recent clinical trials of chemotherapeutics for advanced bladder cancer (BC) have shown limited benefits. Therefore, new prognostic markers and more effective treatment strategies are required. One approach to achieve these goals is through the analysis of RNA networks. Our recent studies of microRNA (miRNA) expression signatures revealed that the microRNA-23b/27b (miR-23b/27b) cluster is frequently downregulated in various types of human cancers. However, the functional role of the miR-23b/27b cluster in BC cells is still unknown. Thus, the aim of the present study was to investigate the functional significance of the miR-23b/27b cluster and its regulated molecular targets, with an emphasis on its contributions to BC oncogenesis and metastasis. The expression levels of the miR-23b/27b cluster were significantly reduced in BC clinical specimens. Restoration of mature miR-23b or miR-27b miRNAs significantly inhibited cancer cell migration and invasion, suggesting that these clustered miRNAs function as tumor suppressors. Gene expression data and in silico analysis demonstrated that the genes coding for the epidermal growth factor receptor (EGFR) and hepatocyte growth factor receptor (c-Met) were potential targets of the miR-23b/27b cluster. Luciferase reporter assays and western blotting demonstrated that EGFR and c-Met receptor trypsine kinases were directly regulated by these clustered miRNAs. We conclude that the decreased expression of the tumor-suppressive miR-23b/27b cluster enhanced cancer cell proliferation, migration and invasion in BC through direct regulation of EGFR and c-Met signaling pathways. Our data on RNA networks regulated by tumor-suppressive miR-23b/27b provide new insights into the potential mechanisms of BC oncogenesis and metastasis.

The microRNA expression signature of bladder cancer by deep sequencing: the functional significance of the miR-195/497 cluster.

Current genome-wide microRNA (miRNA) expression signature analysis using deep sequencing technologies can drive the discovery of novel cancer pathways regulated by oncogenic and/or tumor suppressive miRNAs. We determined the genome-wide miRNA expression signature in bladder cancer (BC) by deep sequencing technology. A total of ten small RNA libraries were sequenced (five BCs and five samples of histologically normal bladder epithelia (NBE)), and 13,190,619 to 18,559,060 clean small RNA reads were obtained. A total of 933 known miRNAs and 17 new miRNA candidates were detected in this analysis. Among the known miRNAs, a total of 60 miRNAs were significantly downregulated in BC compared with NBE. We also found that several miRNAs, such as miR-1/133a, miR-206/133b, let-7c/miR-99a, miR-143/145 and miR-195/497, were located close together at five distinct loci and constituted clustered miRNAs. Among these clustered miRNAs, we focused on the miR-195/497 cluster because this clustered miRNA had not been analyzed in BC. Transfection of mature miR-195 or miR-497 in two BC cell lines (BOY and T24) significantly inhibited cancer cell proliferation, migration and invasion, suggesting that the miR-195/497 cluster functioned as tumor suppressors in BC. Regarding the genes targeted by the miR-195/497 cluster, the TargetScan algorithm showed that 6,730 genes were putative miR-195/497 targets, and 113 significantly enriched signaling pathways were identified in this analysis. The "Pathways in cancer" category was the most enriched, involving 104 candidate target genes. Gene expression data revealed that 27 of 104 candidate target genes were actually upregulated in BC clinical specimens. Luciferase reporter assays and Western blotting demonstrated that BIRC5 and WNT7A were directly targeted by miR-195/497. In conclusion, aberrant expression of clustered miRNAs was identified by deep sequencing, and downregulation of miR-195/497 contributed to BC progression and metastasis. Tumor suppressive miRNA-mediated cancer pathways provide new insights into the potential mechanisms of BC oncogenesis.