Objective      To determine the role of microRNA-451 (miR-451) in the proliferation in non-small cell lung cancer cells and investigate the underlying regulative mechanism.       Methods      The eukaryotic expression vector of miR-451 (pGenesil-miR-451) was tr

ansfected into A549 cells using Lipofectamine 2000

and then the cell proliferation was tested by MTT assay

and cell apoptosis and cell cycle were examined by flow cytometry. Bioinformatics analysis was used for miR-451 target prediction. The target gene functional analysis was carried on by GO and KEGG pathway analysis. Among the candidate genes

PSMB8 was chosen. The luciferase gene expression vectors containing PSMB8 3′ UTR widetype and PSMB8 3′ UTR mutant were constructed. And the luciferase activity was detected by dual-luciferase reporter assay. Moreover

the expression of PSMB8 and NOS2 was determined by Western blotting.       Results      MTT assay showed that the cell proliferation was inhibited by over-expression of miR-451 in A549 cells. Flow cytometry indicated that the cells were arrested at G

2

phase in the A549 cells after transfection of pGenesil-miR-451

however

no significant difference was seen in the apoptotic rates among the transfected cells

control cells and A549 cells (P0.05). By bioinformatics analysis

there were 17 potential target genes found for miR-451. Meanwhile

PSMB8 was found to contain a phylogenetically conserved binding site with miR-451. Evidence showed that miR-451 negatively regulated the expression of PSMB8 through PSMB8 3′ UTR. Moreover

the expression of PSMB8 was declined in miR-451 over-expressed A549 cells

while the expression of PSMB8 was enhanced in miR-451 down-expressed normal 16HEB cells by Western blotting. Additionally

the expression of NOS2 was also decreased in miR-451 A549 cells.       Conclusion      MiR-451 may regulate the cell proliferation of non-small cell lung cancer cells by targeting inflammatory factors PSMB8/NOS2

and participate in the regulation of the occurrence and development of lung cancer.