[Show abstract][Hide abstract] ABSTRACT: 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.
[Show abstract][Hide abstract] ABSTRACT: Our recent studies of microRNA (miRNA) expression signatures demonstrated that microRNA-1291 (miR-1291) was significantly down-regulated in renal cell carcinoma (RCC) clinical specimens and was a putative tumor-suppressive miRNA in RCC. The aim of this 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. The expression of miR-1291 was significantly down-regulated 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. This article is protected by copyright. All rights reserved.
[Show abstract][Hide abstract] ABSTRACT: Genistein has been shown to inhibit cancers both in vitro and in vivo, by altering the expression of several microRNAs (miRNAs). In this study, we focused on tumor suppressor miRNAs regulated by genistein and investigated their function in prostate cancer (PCa) and target pathways. Using miRNA microarray analysis and real-time RT-PCR we observed that miR-574-3p was significantly up-regulated in PCa cells treated with genistein compared with vehicle control. The expression of miR-574-3p was significantly lower in PCa cell lines and clinical PCa tissues compared with normal prostate cells (RWPE-1) and adjacent normal tissues. Low expression level of miR-574-3p was correlated with advanced tumor stage and higher Gleason score in PCa specimens. Re-expression of miR-574-3p in PCa cells significantly inhibited cell proliferation, migration and invasion in vitro and in vivo. miR-574-3p restoration induced apoptosis through reducing Bcl-xL and activating caspase-9 and caspase-3. Using GeneCodis software analysis, several pathways affected by miR-574-3p were identified, such as 'Pathways in cancer', 'Jak-STAT signaling pathway', and 'Wnt signaling pathway'. Luciferase reporter assays demonstrated that miR-574-3p directly binds to the 3' UTR of several target genes (such as RAC1, EGFR and EP300) that are components of 'Pathways in cancer'. Quantitative real-time PCR and Western analysis showed that the mRNA and protein expression levels of the three target genes in PCa cells were markedly down-regulated with miR-574-3p. Loss-of-function studies demonstrated that the three target genes significantly affect cell proliferation, migration and invasion in PCa cell lines. Our results show that genistein up-regulates tumor suppressor miR-574-3p expression targeting several cell signaling pathways. These findings enhance understanding of how genistein regulates with miRNA in PCa.
[Show abstract][Hide abstract] ABSTRACT: 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.
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.
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.
No preview · Article · Feb 2013 · The Journal of urology
[Show abstract][Hide abstract] ABSTRACT: 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 G(0) /G(1) arrest in the RCC cell lines caki2 and A498, suggesting that miR-135a functioned as a potential tumor suppressor. Next, we 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 KEGG 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.
[Show abstract][Hide abstract] ABSTRACT: Recent our microRNA (miRNA) expression signature revealed that expression of microRNA-218 (miR-218) was reduced in cancer tissues, suggesting a candidate of tumor suppressor in head and neck squamous cell carcinoma (HNSCC). The aim of this study was to investigate the functional significance of miR-218 and its mediated moleculer pathways in HNSCC. Restoration of miR-218 in cancer cells led to significant inhibition of cell migration and invasion activities in HNSCC cell lines (FaDu and SAS). Genome-wide gene expression analysis of miR-218 transfectants and in silico database analysis showed that focal adhesion pathway was a promising candidate of miR-218 target pathways. The laminins are an important and biologically active part of the basal lamina, the function of that are various such as influencing cell differentiation, migration and adhesion as well as proliferation and cell survival. Interestingly, all components of laminin-332 (LAMA3, LAMB3 and LAMC2) are listed on the candidate genes in focal adhesion pathway. Furthermore, we focused on LAMB3 which has a miR-218 target site and gene expression studies and luciferase reporter assays showed that LAMB3 was directly regulated by miR-218. Silencing study of LAMB3 demonstrated significant inhibition of cell migration and invasion. In clinical specimens with HNSCC, the expression levels of laminin-332 were significantly upregulated in cancer tissues compared to adjacent non-cancerous tissues. Our analysis data showed that tumor suppressive miR-218 contributes to cancer cell migration and invasion through regulating focal adhesion pathway, especially laminin-332. Tumor suppressive miRNA-mediated novel cancer pathways provide new insights into the potential mechanisms of HNSCC oncogenesis.
[Show abstract][Hide abstract] ABSTRACT: Many studies have recently suggested that microRNAs (miRNAs) contribute to the development of various types of human cancers as well as to their invasive and metastatic capacities. Previously, our miRNA expression signature of renal cell carcinoma (RCC) revealed that microRNA‑138 (miR‑138) was significantly reduced in cancer cells. The aim of the present study was to investigate the functional significance of miR‑138 and to identify its target genes in RCC cells. Restoration of mature miR‑138 in two RCC cell lines (A498 and 786‑O) caused changes in the bleb-like cell morphology, characteristics of the epithelial-mesenchymal transition (EMT). Restoration also significantly inhibited migration and invasion in the two RCC cell lines, suggesting that miR‑138 functions as a tumor suppressor. Genome-wide gene expression analysis (miR‑138 transfectants and RCC clinical specimens) and TargetScan database studies showed that vimentin (VIM) is a promising candidate target gene of miR‑138. It is well known that VIM is one of the most widely expressed mammalian intermediate filament proteins. Recent studies showed that VIM functions in cell adhesion, migration, survival and cell signaling processes via dynamic assembly/disassembly in cancer cells. We focused on VIM and investigated whether VIM was regulated by tumor suppressive miR‑138 and contributed to cancer cell migration and invasion in RCC cells. Restoration of miR‑138 in RCC cell lines suppressed VIM expression at both the mRNA and protein levels. Silencing studies of VIM in RCC cell lines demonstrated significant inhibition of cell migration and invasion activities in si-VIM transfectants. In clinical specimens of RCC, the expression levels of VIM were significantly upregulated in cancer tissues compared to adjacent non-cancerous tissues. Furthermore, immunohistochemistry showed that VIM expression levels in RCC specimens were significantly higher than those in normal renal tissues. These data suggest that VIM may function as an oncogene and is regulated by tumor suppressive miR‑138. The existence of a tumor suppressive miR‑138-mediated oncogenic pathway provides new insights into the potential mechanisms of RCC oncogenesis and metastasis.
Full-text · Article · Jul 2012 · International Journal of Oncology