406986

MIR203A

epithelial-mesenchymal transition (EMT) is a developmental program that is associated with esophageal squamous cell carcinoma (ESCC) progression and metastasis. Recently, C/EBPbeta has been reported to be an EMT inducer in cancer. However, the detailed molecular mechanisms remain unclear. Here, we report for the first time, that the truncated CCAAT-enhancer-binding protein beta (C/EBPbeta) LIP isoform is abnormally overexpressed and correlated with cancer metastasis in clinical specimens of human ESCC. Furthermore, we demonstrate that C/EBPbeta LIP mediates epithelial growth factor (EGF)-induced EMT and increases migration and invasion of esophageal cancer cells in a manner that is dependent on miR-203 inactivation. Finally, we identified miR-203 as a direct target of C/EBPbeta LIP. Disruption of C/EBPbeta LIP attenuated the EGF-mediated decrease in miR-203, whereas overexpression of C/EBPbeta LIP alone markedly suppressed miR-203. In addition, we demonstrated that C/EBPbeta LIP inhibited miR-203 transcription by directly interacting with a conserved distal regulatory element upstream of the miR-203 locus, and in doing so, orchestrated chromatin remodeling. In conclusion, our results have revealed a new regulatory mechanism that involves C/EBPbeta-LIP-mediated downregulation of miR-203, which plays a key role in EMT and metastasis.CI - (c) 2014. Published by The Company of Biologists Ltd.

epithelial-mesenchymal transition (EMT) has been recognized as a key element of cell migration, invasion, and drug resistance in several types of cancer. In this study, our aim was to clarify microRNAs (miRNAs)-related mechanisms underlying EMT followed by acquired resistance to chemotherapy in glioblastoma (GBM). We used multiple methods to achieve our goal including microarray analysis, qRT-PCR, western blotting analysis, loss/gain-of-function analysis, luciferase assays, drug sensitivity assays, wound-healing assay and invasion assay. We found that miR-203 expression was significantly lower in imatinib-resistant GBM cells (U251AR, U87AR) that underwent EMT than in their parental cells (U251, U87). Ectopic expression of miR-203 with miRNA mimics effectively reversed EMT in U251AR and U87AR cells, and sensitized them to chemotherapy, whereas inhibition of miR-203 in the sensitive lines with antisense oligonucleotides induced EMT and conferred chemoresistance. SNAI2 was identified as a direct target gene of miR-203. The knockdown of SNAI2 by short hairpin RNA (shRNA) inhibited EMT and drug resistance. In GBM patients, miR-203 expression was inversely related to SNAI2 expression, and those tumors with low expression of miR-203 experienced poorer clinical outcomes. Our findings indicate that re-expression of miR-203 or targeting SNAI2 might serve as potential therapeutic approaches to overcome chemotherapy resistance in GBM.

Head and neck squamous cell carcinoma (HNSCC) has a high capacity for invasion. To identify microRNAs (miRNAs) that regulate HNSCC invasion, we compared miRNA expression profiles between a parent HNSCC cell line and a highly invasive clone. The miR-200 family and miR-203 were downregulated in the clone. Here we focused on the role of miR-203 in invasion and epithelial-mesenchymal transition (EMT) induction in HNSCC. miR-203 was downregulated during EMT induction. Moreover, ectopic overexpression of miR-203 suppressed the invasion and induced mesenchymal-epithelial transition (MET) in HNSCC cells. Interestingly, we identified NUAK family SNF1-like kinase 1 (NUAK1) as a novel target gene of miR-203 by cyclopedic analysis using anti-Ago2 antibody. Increased expression of NUAK1 was observed during EMT induction, and ectopic expression of miR-203 delayed EMT induction by suppressing NUAK1 expression. Moreover, NUAK1 overexpression promoted the invasion of HNSCC cells. Importantly, NUAK1 expression was well correlated with poor differentiation, invasiveness, and lymph node metastasis in HNSCC cases. Overall, miR-203 has a tumor-suppressing role in invasion and EMT induction by targeting NUAK1 in HNSCC, suggesting miR-203 as a potential new diagnostic and therapeutic target for the treatment of HNSCC.

PURPOSE: Long non-coding RNA (LncRNA) urothelial carcinoma-associated 1 (UCA1) is reported to be dysregulated in hepatocellular carcinoma (HCC) progression. However, the functions of UCA1 in HCC still need further study. The aim is to detect the role of UCA1 involving in HCC cells proliferation and invasion, and epithelial-mesenchymal transition (EMT). METHODS: The quantitative real-time PCR was used to detect the UCA1 and miR-203 expression levels in 60 cases' HCC tissues and adjacent normal tissues. Western blotting analysis was performed to detect the EMT markers E-cadherin, Vimentin and transcription factor Snail1, Snail2 expression. Luciferase reporter assay, RNA immunoprecipitation (RIP) and pull-down assays were used to evaluate whether miR-203 was a target of UCA1. RESULTS: Our results showed that UCA1 was markedly upregulated in HCC tissues and higher UCA1 expression in HCC was positively associated with tumor size, vascular invasion and American Joint Committee on cancer (AJCC) stage (P < 0.05). Furthermore, gain-of-function and loss-of-function analysis showed that UCA1 knockdown inhibited HCC cells proliferation and invasion in vitro and xenograft tumour growth in vivo. Moreover, UCA1 overexpression promoted cell epithelial-mesenchymal transition (EMT) in HCC via effectively sponging to miR-203 and thereby activating the expression of transcription factor Snail2. CONCLUSIONS: Our results identified that UCA1/miR-203/Snail2 pathway might involve in HCC progression. Inhibition of UCA1 acted as a promising therapeutic target for HCC patients.

miR-203 is an epigenetically silenced tumor-suppressive microRNA in tumors. This study was designed to investigate the effects of miR-203 on the proliferation, migration, invasion, and apoptosis of bladder cancer (BCa) cells. The expression levels of miR-203 in BCa tissues, normal adjacent tissues, and BCa cell lines were detected. BCa cells were transfected with miR-203 mimic and inhibitor to investigate the effect of miR-203 on cell functions and the epithelial-mesenchymal transition (EMT). Cotransfection with miR-203 inhibitor and shRNA of the predicted target gene Twist1 (si-Twist1) was performed to investigate the target relationship of miR-203 and Twist1. The effects of knockdown of Twist1 on cell functions were also investigated. The expression of miR-203 was significantly reduced in BCa tissues and cells, in comparison with the control. miR-203 mimic significantly reduced cell viability, invasion, migration, and EMT, and enhanced cell apoptosis. On the contrary, miR-203 inhibitor showed the opposite results. However, the administration of si-Twist1 cancelled the effect of miR-203 inhibitor on cell proliferation, apoptosis, invasion, and migration. These demonstrated that miR-203 may function as a tumor-suppressive microRNA in BCa by negatively targeting Twist1. Both Twist1 and miR-203 might be explored as potential targets for studying the mechanism related to BCa pathogenesis and therapy.

Liver resection is still the most commonly used therapeutic treatment for hepatocellular carcinoma (HCC), and liver regeneration promotes HCC growth in the regenerating liver. The high recurrence/metastasis of HCC is the main cause of death for HCC patients after liver resection. However, how the augmented growth and metastasis of residual HCC induced by the promoted liver regeneration following liver resection can be abolished remains unclear. In this study, a rat model with liver cirrhosis and diffused HCC was established by administration of diethylnitrosamine. Recombinant miR-203 adenovirus was administered to induce hepatic miR-203 overexpression and 30% partial hepatectomy (PH) followed. The effect of miR-203 on the proliferation, invasion and metastasis of the residual HCC in the remnant cirrhotic liver with promoted regeneration was investigated. We found that the basic spontaneous regeneration of the non-tumorous liver by 30% PH promoted proliferation, invasion and lung metastasis of the hepatic residual HCC. miR-203 overexpression further promoted the regeneration of the non-tumorous liver by upregulating Ki67 expression and enhancing IL-6/SOCS3/STAT3 pro-proliferative signals. Importantly, miR-203 overexpression markedly inhibited the proliferation, invasion and metastasis of hepatic residual HCC through suppressing expression of Ki67, CAPNS1 and lung metastasis. Moreover, it was found that miR-203 overexpression reversed the epithelial-mesenchymal transition induced by hepatectomy through targeting IL-1beta, Snail1 and Twist1. In conclusion, our results suggested that miR-203 overexpression inhibited the augmented proliferation and lung metastasis of the residual HCC induced by the promoted liver regeneration following PH partly by regulating epithelial-mesenchymal transition.CI - (c) 2017 The Authors. cancer Science published by John Wiley & Sons Australia, Ltd on behalf of Japanese cancer Association.