MicroRNAs (miRNAs) are small noncoding RNAs that negatively regulate protein-coding genes. To identify miRNAs that have a tumor suppressive function in bladder cancer (BC), 156 miRNAs were screened in 14 BCs, 5 normal bladder epithelium (NBE) samples and 3 BC cell lines. We identified a subset of 7 miRNAs (miR-145, miR-30a-3p, miR-133a, miR-133b, miR-195, miR-125b and miR-199a*) that were significantly downregulated in BCs. To confirm these results, 104 BCs and 31 NBEs were subjected to real-time RT-PCR-based experiments, and the expression levels of each miRNA were significantly downregulated in BCs (p < 0.0001 in all). Receiver-operating characteristic curve analysis revealed that the expression levels of these miRNAs had good sensitivity (>70%) and specificity (>75%) to distinguish BC from NBE. Our target search algorithm and gene-expression profiling in BCs (Kawakami et al., Oncol Rep 2006;16:521-31) revealed that Keratin7 (KRT7) mRNA was a common target of the downregulated miRNAs, and the mRNA expression levels of KRT7 were significantly higher in BCs than in NBEs (p 5 0.0004). Spearman rank correlation analysis revealed significant inverse correlations between KRT7 mRNA expression and each downregulated miRNA (p < 0.0001 in all). Gain-of-function analysis revealed that KRT7 mRNA was significantly reduced by transfection of 3 miRNAs (miR-30-3p, miR-133a and miR-199a*) in the BC cell line (KK47). In addition, significant decreases in cell growth were observed after transfection of 3 miRNAs and si-KRT7 in KK47, suggesting that miR-30-3p, miR-133a and miR-199a* may have a tumor suppressive function through the mechanism underlying transcriptional repression of KRT7. ' 2009 UICC

Background:On the base of the microRNA (miRNA) expression signature of bladder cancer (BC), we found that miR-1 and miR-133a were significantly downregulated in BC. In this study, we focussed on the functional significance of miR-1 and miR-133a in BC cell lines and identified a molecular network of these miRNAs.Methods and results:We investigated the miRNA expression signature of BC clinical specimens and identified several downregulated miRNAs (miR-133a, miR-204, miR-1, miR-139-5p, and miR-370). MiR-1 and miR-133a showed potential role of tumour suppressors by functional analyses of BC cells such as cell proliferation, apoptosis, migration, and invasion assays. Molecular target searches of these miRNAs showed that transgelin 2 (TAGLN2) was directly regulated by both miR-1 and miR-133a. Silencing of TAGLN2 study demonstrated significant inhibitions of cell proliferation and increase of apoptosis in BC cell lines. The immunohistochemistry showed a positive correlation between TAGLN2 expression and tumour grade in clinical BC specimens.Conclusions:The downregulation of miR-1 and miR-133a was a frequent event in BC, and these miRNAs were recognised as tumour suppressive. TAGLN2 may be a target of both miRNAs and had a potential oncogenic function. Therefore, novel molecular networks provided by miRNAs may provide new insights into the underlying molecular mechanisms of BC.

BACKGROUND: We have recently identified down-regulated microRNAs including miR-145 and miR-133a in bladder cancer (BC). The aim of this study is to determine the genes targeted by miR-145, which is the most down-regulated microRNA in BC. METHODS: We focused on fascin homologue 1 (FSCN1) from the gene expression profile in miR-145 transfectant. The luciferase assay was used to confirm the actual binding sites of FSCN1 mRNA. Cell viability was evaluated by cell growth, wound-healing, and matrigel invasion assays. BC specimens were subjected to immunohistochemistry of FSCN1 and in situ hybridisation of miR-145. RESULTS: The miR-133a as well as miR-145 had the target sequence of FSCN1 mRNA by the database search, and both microRNAs repressed the mRNA and protein expression of FSCN1. The luciferase assay revealed that miR-145 and miR-133a were directly bound to FSCN1 mRNA. Cell viability was significantly inhibited in miR-145, miR-133a, and si-FSCN1 transfectants. In situ hybridisation revealed that miR-145 expression was markedly repressed in the tumour lesion in which FSCN1 was strongly stained. The immunohistochemical score of FSCN1 in invasive BC (n ¼ 46) was significantly higher than in non-invasive BC (n ¼ 20) (P ¼ 0.0055). CONCLUSION: Tumour suppressive miR-145 and miR-133a directly control oncogenic FSCN1 in BC.

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A new diagnostic marker for urothelial carcinoma (UC) is needed to avoid painful cystoscopy during the initial diagnosis and follow-up period. However, the current urine markers are useless because of the low sensitivities and specificities for UC detection. MiR-96 and miR-183 were differentially upregulated microRNA in our previous microRNA screening for UC. The expression levels of miR-96 and miR-183 in the urine samples were significantly higher in 100 UC than in healthy controls (miR-96, P = 0.0059; and miR-183, P = 0.0044). The receiver-operating characteristic curve analyses demonstrated that each microRNA had good sensitivity and specificity for distinguishing UC patients from non-UC patients (miR-96, 71.0% and 89.2%; and miR-183, 74.0% and 77.3%). Our cohort included 78 UC patients who had undergone urinary cytology. MiR-96 was positively detected in 27 of 44 patients who had had a ''negative'' urinary cytology diagnosis. We combined the miR-96 detection data with the urinary cytology data, and diagnosed 61 of 78 cases as UC; sensitivity rose from 43.6% to 78.2%. We found significant stepwise increases in miR-96 and miR-183 expression with advancing tumor grade (miR-96, P = 0.0057; and miR-183, P = 0.0036) and pathological stage (miR-96, P = 0.0332; and miR-183, P = 0.0117). The expression levels of the microRNA were significantly lower in urine collected after surgery (miR-96, P = 0.0241; and miR-183, P = 0.0045). In conclusion, miR-96 and miR-183 in urine are promising tumor markers for UC. In particular, miR-96 may be a good diagnostic marker in combination with urinary cytology. (Cancer Sci 2011; 102: 522-529) U rothelial carcinoma (UC) is among the five most common malignancies worldwide, and it is the second most common tumor of the genitourinary tract and the second most common cause of death in patients with genitourinary tract malignancies.(1) The current standard of diagnostic tool for UC depends on urethro-cystoscopy. This approach is costly, invasive and uncomfortable. The endoscopic approach using nephroureteroscope is also invasive for patients with upper urinary tract UC (renal pelvic and ureter UC). Urinary cytology is a reliable urine marker for UC diagnosis because of its high specificity (90-95%). In contrast, it has low sensitivity (30-40%) and patients are forced to undergo a painful cystoscopy to confirm diagnoses.(2) For these reasons, many new urine-based tests for UCC have been developed, and Bladder Tumor Antigen (BTA), Nuclear Matrix Protein 22 (NMP22), Urine fibrin fibrinogen Degradation Products (FDP), ImmunoCyt and FISH (UroVysion), etc., have been approved for clinical use.(3,4) However, the specificities of these new urine markers are rather low (60-80%) in comparison with urinary cytology, although they have higher sensitivities (50-70%). This implies that specificity may come at the cost of sensitivity, conventional urinary cytology being a good example of this.(3) Because of their insufficient sensitivity and specificity, none of the new urine markers can replace cys...