406899

MIR106A

Carcinogenesis is a complex process during which cells undergo genetic and epigenetic alterations. MicroRNAs control gene expression by negatively regulating protein-coding mRNAs. Several reports demonstrated that miR-106a is up-regulated in gastric and colorectal cancers and promotes tumor progression. In contrast, in glioma miR-106a plays the role of a tumor suppressor gene rather than an oncogene. Here we demonstrate that a high level of miR-106a expression is present in pancreatic cancer. Furthermore, our investigation shows that miR-106a has an oncogenic role in pancreatic tumorigenesis by promoting cancer cell proliferation, epithelial-mesenchymal transition and invasion by targeting tissue inhibitors of metalloproteinase 2 (TIMP-2). MiR-106a could be a critical therapeutic target in pancreatic cancer.CI - Copyright (c) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Accumulated evidence suggests that miR-106b played a key role in the promotion of the metastases of cancer; however, little is known about miR-106b in esophageal squamous cell carcinoma (ESCC). To investigate expression level of miR-106b in ESCC tissues, quantitative real-time polymerase chain reaction (qRT-PCR) was used to detect miR-106b expression in 35 Kazakh's ESCC and paired normal adjacent tissues (NATs). To evaluate the role mediated by miR-106b in the proliferation, migration, and invasion, MTT, wound healing, and transwell assays were employed, respectively. Luciferase reporter assay was used to identify the downstream target through miR-106b. To understand the regulation between miR-106b and Smad 7, qRT-PCR and western blot were performed. The present study showed that miR-106b was pronouncedly upregulated in ESCC relative to paired NAT and that upregulated miR-106b was significantly associated with lymph node metastases. MiR-106b was found to be able to promote proliferation, migration, and invasion of ESCC cells in vitro. Smad 7 was confirmed as a downstream target of miR-106b in our experimental setting. Smad 7 was remarkably downregulated in ESCC compared with paired NAT. In addition, upregulation of miR-106b can promote epithelial mesenchymal transition (EMT) in ESCC cell in vitro. Our results indicated that miR-106b can promote migration and invasion of ESCC cells through enhancing EMT process via downregulation of Smad 7, suggesting that miR-106b can be a potential molecular phenotype in ESCC metastases.

BACKGROUND: Gastric cancer (GC) is a common malignancy and frequent cause of cancer-related death. Long non-coding RNAs (lncRNAs) have emerged as important regulators and tissue-specific biomarkers of multiple cancers, including GC. Recent evidence has indicated that the novel lncRNA LINC01133 plays an important role in cancer progression and metastasis. However, its function and molecular mechanism in GC remain largely unknown. METHODS: LINC01133 expression was detected in 200 GC and matched non-cancerous tissues by quantitative reverse transcription PCR. Gain- and loss-of-function experiments were conducted to investigate the biological functions of LINC01133 both in vitro and in vivo. Insights into the underlying mechanisms of competitive endogenous RNAs (ceRNAs) were determined by bioinformatics analysis, dual-luciferase reporter assays, quantitative PCR arrays, TOPFlash/FOPFlash reporter assay, luciferase assay, and rescue experiments. RESULTS: LINC01133 was downregulated in GC tissues and cell lines, and its low expression positively correlated with GC progression and metastasis. Functionally, LINC01133 depletion promoted cell proliferation, migration, and the epithelial-mesenchymal transition (EMT) in GC cells, whereas LINC01133 overexpression resulted in the opposite effects both in vitro and in vivo. Bioinformatics analysis and luciferase assays revealed that miR-106a-3p was a direct target of LINC01133, which functioned as a ceRNA in regulating GC metastasis. Mechanistic analysis demonstrated that miR-106a-3p specifically targeted the adenomatous polyposis coli (APC) gene, and LINC01133/miR-106a-3p suppressed the EMT and metastasis by inactivating the Wnt/beta-catenin pathway in an APC-dependent manner. CONCLUSIONS: Our findings suggest that reduced expression of LINC01133 is associated with aggressive tumor phenotypes and poor patient outcomes in GC. LINC01133 inhibits GC progression and metastasis by acting as a ceRNA for miR-106a-3p to regulate APC expression and the Wnt/beta-catenin pathway, suggesting that LINC01133 may serve as a potential prognostic biomarker and anti-metastatic therapeutic target for GC.

Background: LIM kinase 1 (LIMK1) expression levels are closely associated with microRNA (miRNA) processing. Higher levels of LIMK1 are reported during the progression of many cancers. Our study explored the interaction between LIMK1 and miR-106a in oral squamous cell carcinoma (OSCC). Methods: Quantitative RT-PCR was performed to detect the levels of LIMK1 and miR-106a in OSCC tissues and cell lines. The rates of cell proliferation and epithelial-mesenchymal transition (EMT) were assessed to determine the biological functions of miR-106a and LIMK1 in OSCC cells. The mRNA and protein levels of LIMK1 were measured using quantitative RT-PCR and western blotting. Luciferase assays were performed to validate LIMK1 as an miR-106a target in OSCC cells. Results: We found that the level of miR-106a significantly decreased and the expression of LIMK1 significantly increased in OSCC tissues and cell lines. There was a close association between these changes. Knockdown of LIMK1 significantly inhibited the proliferation and EMT of OSCC cells. The bioinformatics analysis predicted that LIMK1 is a potential target gene of miR-106a and the luciferase reporter assay confirmed that miR-106a could directly target LIMK1. Introduction of miR-106a to OSCC cells had similar effects to LIMK1 silencing. Overexpression of LIMK1 in OSCC cells partially reversed the inhibitory effects of the miR-106a mimic. Conclusion: MiR-106a inhibited the cell proliferation and EMT of OSCC cells by directly decreasing LIMK1 expression.