406931

MIR139

microRNA 139;MIR139;microRNA 139

hsa-mir-139

11q13.4

ncRNA

MicroRNAs (miRNAs), which are noncoding RNAs that regulate gene expression, are involved in tumor metastasis. In this study, we describe the down-regulation and function of miR-139 in colorectal cancer (CRC) metastasis. MiR-139 was found underexpressed in 34 CRC tissues compared to their corresponding nontumor tissues. Decreased miR-139 in CRC tissue was associated with disease progression and metastasis. Re-expression of miR-139 did not inhibit CRC cell growth but suppresses CRC cell metastasis and invasion in vitro and in vivo. MiR-139 might suppress CRC cells invasion and metastasis by targeting type I insulin-like growth factor receptor (IGF-IR). We also found miR-139 directed migration inactivation of human CRC cells involves down-regulation of matrix metalloproteinase 2 (MMP-2). The IGF-IR/MEK/ERK signaling was inhibited by miR-139 overexpression and then resulted in MMP-2 promoter suppression. Taken together, our results provide evidence that miR-139 might function as a metastasis suppressor in CRC. Targeting miR-139 may provide a strategy for blocking CRC metastasis.

BACKGROUND: miR-139-5p was identified to be significantly down-regulated in colon tumor tissues by miRNA array. We aimed to clarify its biological function, molecular mechanisms and direct target gene in colorectal cancer (CRC). METHODS: The biological function of miR-139-5p was examined by cell growth, cell cycle and apoptosis analysis in vitro and in vivo. miR-139-5p target gene and signaling pathway was identified by luciferase activity assay and western blot. RESULTS: miR-139-5p was significantly down-regulated in primary tumor tissues (P < 0.0001). Ectopic expression of miR-139-5p in colon cancer cell lines significantly suppressed cell growth as evidenced by cell viability assay (P < 0.001) and colony formation assay (P < 0.01) and in xenograft tumor growth in nude mice (P < 0.01). miR-139-5p induced apoptosis (P < 0.01), concomitantly with up-regulation of key apoptosis genes including cleaved caspase-8, caspase-3, caspase-7 and PARP. miR-139-5p also caused cell cycle arrest in G0/G1 phase (P < 0.01), with upregulation of key G0/G1 phase regulators p21Cip1/Waf1 and p27Kip1. Moreover, miR-139-5p inhibited cellular migration (P < 0.001) and invasiveness (P < 0.001) through the inhibition of matrix metalloproteinases (MMP)7 and MMP9. Oncogene NOTCH1 was revealed to be a putative target of miR-139-5p, which was inversely correlated with miR-139-5p expression (r = -0.3862, P = 0.0002). CONCLUSIONS: miR-139-5p plays a pivotal role in colon cancer through inhibiting cell proliferation, metastasis, and promoting apoptosis and cell cycle arrest by targeting oncogenic NOTCH1.

Our previous studies have showed that chemokine receptor 4 (CXCR4) was over-expressed in laryngeal squamous cell carcinoma (LSCC). However, the mechanism underlying aberrant CXCR4 expression remains unclear. To investigate the roles played by miRNAs in CXCR4 over-expression in LSCC, putative miR-139 was predicted through computational algorithms, including TargetScan, PicTar and miRBase, and luciferase reporter assay was explored to confirm that whether CXCR4 was directly regulated by miR-139. Then, quantitative real-time PCR, immunohistochemistry and in situ hybridization methods were employed to detect the expression of miR-139 and CXCR4 in primary LSCC tissues, normal adjacent mucosal tissues and metastatic lesions derived from 40 LSCC patients in the Second Hospital, Xi'An JiaoTong University. Finally, gain- and loss-of-function assays were adopted to explore the effects of miR-139 and CXCR4 on proliferation, invasion and metastasis of the human LSCC cell line Hep-2 in vitro and in vivo. Our results showed that miR-139 dampened CXCR4 expression, and CXCR4 was directly targeted by miR-139. Additionally, the expression of miR-139 was reduced in alignment with the progression of primary to metastatic LSCC. Moreover, an inverse correlation was observed between miR-139 and CXCR4 protein levels in LSCC specimens. Functional analyses demonstrated that ectopic expression of miR-139 inhibited cell proliferation, migration and metastasis of Hep-2 cells in vitro and in vivo. Similar to the observations seen in restoring miR-139 expression, dampening of CXCR4 expression inhibited cell growth, migration and invasion, whereas miR-139 over-expression reversed the pro-metastatic effect of CXCR4. Taken together, we conclude that miR-139 targets CXCR4 and inhibits proliferation and metastasis of LSCC.

BACKGROUND & AIMS: We investigated mechanisms of hepatocellular carcinoma (HCC) metastasis and identified an antimetastatic microRNA (miRNA), miR-139, that is down-regulated in human HCC samples. METHODS: Effects of stable and transient expression of miRNA-139 and its inhibitors were studied in the human HCC cell lines SMMC-7721 and BEL7402; cells were analyzed for migration and invasion. Liver samples from patients with metastatic HCC were analyzed for levels of miRNA-139; data were compared with survival data using the Kaplan-Meier method and compared between groups by the log-rank test. tumor formation and metastasis from human HCC MHCC97L cells that did or did not express miR-139 were analyzed in mice. RESULTS: Down-regulation of miR-139 in HCC was associated significantly with poor prognosis of patients and features of metastatic tumors, including venous invasion, microsatellite formation, absence of tumor encapsulation, and reduced differentiation. miR-139 expression was reduced in metastatic HCC tumors compared with primary tumors. Overexpression of miR-139 in HCC cells significantly reduced cell migration and invasion in vitro and the incidence and severity of lung metastasis from orthotopic liver tumors in mice. miR-139 interacted with the 3' untranslated region of Rho-kinase 2 (ROCK2) and reduced its expression in HCC cells. Levels of miR-139 were correlated inversely with ROCK2 protein in human HCC samples. Overexpression of miR-139 did not inhibit HCC cell motility when ROCK2 was knocked down. CONCLUSIONS: The microRNA miR-139 interacts with ROCK2 and reduces its expression in HCC cells. Down-regulation of miR-139 increased the invasive abilities of HCC cells in vitro and HCC metastasis in vivo. expression of miR-139 is reduced in human metastatic HCC samples and correlates with prognosis.

This study investigates whether the anti-metastasis effect of microRNA-139 (miR-139) on hepatocellular carcinoma (HCC) is mediated through regulating c-fos expression. The expression levels of miR-139 and c-fos in human HCC cell sublines with high (MHCC97H) and low (MHCC97L) spontaneous metastatic potentials were quantified using QPCR or Western blot. miR-139 mimics was transfected into MHCC97H cells to overexpress miR-139, and miR-139 inhibitor was transfected into MHCC97L cells to down-express miR-139. The effect of overexpression or down-expression of miR-139 on c-fos expression of MHCC97H and MHCC97L cells was evaluated using QPCR and Western blot. The 3' untranslated region segments of FOS containing the miR-139 binding sites were amplified by PCR, and the luciferase activity in the transfected cells was assayed. In comparison with the expression level of miR-139 in MHCC97L cells, the expression level in MHCC97H cells was significantly decreased, whereas c-Fos was significantly up-regulated in MHCC97H. The overexpression of miR-139 significantly inhibited the expression of c-fos in MHCC97H cells, and the down-expression of miR-139 significantly promoted the expression of c-fos in MHCC97L cells. miR-139 suppressed the luciferase activity of the pGL-FOS by approximately 40% compared with the negative control. In vitro cell migration analysis demonstrated that depletion of c-fos or overexpression of miR-139 in MHCC97H cells reduced cell migration, whereas overexpression of c-fos or depletion of miR-139 in MHCC97L cells increased cell migration. Thus, we got the conclusion that miR-139 expression is down-regulated in human HCC cell sublines with high spontaneous metastatic potentials (MHCC97H). Derepression of c-Fos caused by miR-139 down-regulation contributes to the metastasis of HCC.