Dataset Information

MicroRNA-139-5p exerts tumor suppressor function by targeting NOTCH1 in colorectal cancer.

ABSTRACT:

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.

SUBMITTER: Zhang L

PROVIDER: S-EPMC4065091 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Similar Datasets

Project description:BackgroundGlioma metastasis, invasion, epithelial-mesenchymal transition (EMT) and chemoresistance indicate poor prognosis. Accumulating evidence reveals that Notch1 is an important factor in tumour progression. However, the role of Notch1 in glioma EMT and associated microRNAs (miRNAs) with the Notch pathway remain controversial.MethodsUtilizing cBioPortal database to examine the gene signature of NOTCH1 (encoding Notch1), CDH2 (encoding N-cadherin) and SNAI1 (encoding Snail-1) in disease-free survival (DFS) and overall survival (OS). We analyzed the Notch1 expression from Oncomine. We used Western blot (WB), immunohistochemistry (IHC) and immunofluorescence to determine protein levels. Transcription was evaluated by quantitative real-time (qRT)-PCR. siRNA and lentivirus were used to knock down Notch1 and overexpress miR-139-5p, respectively. The migration and invasion of glioma cells were assessed by wound healing and transwell assays. Luciferase reporter assays were utilized to verify the relationship between Notch1 and miR-139-5p. A U87-implanted intracranial model was used to study the effect of miR-139-5p on tumour growth and Notch1 suppression efficacy or EMT reversion.ResultsIt revealed the association of NOTCH1, CDH2, SNAI1 genomic alterations with decreases in DFS and OS. Notch1 was upregulated in classical and proneural subtypes of GBM, and associated with tumour grade. Notch1 inhibition suppressed the biological behaviours of metastasis, invasion and EMT. Notch1 was identified as a novel direct target of miR-139-5p. MiR-139-5p overexpression partially phenocopied Notch1 siRNA, whereas the forced expression of Notch1 reversed the effects of miR-139-5p on the invasion of glioma. Moreover, intracranial tumourigenicity and EMT behaviours were reduced by the introduction of miR-139-5p and partially mediated by the decreased Notch1 expression.ConclusionsmiR-139-5p was identified as a tumour suppressor by negatively targeting Notch1, and this work suggests a possible molecular mechanism of the miR-139/Notch1/EMT axis for glioma treatment.