چکیده (انگلیسی):

Objective: To discuss the effect and molecular mechanism of miR-146a on the
proliferation of lung cancer cells by targeting and regulating the macrophage migration
inhibitory factor (MIF) gene.
Methods: RT-PCR was employed to detect expression of miR-146a; immunohistochemistry
was used to detect the expression of MIF. The luciferase reporter gene technique
was adopted to verify that MIF was the specific reverse target gene of miR-146a
and the liposome Lipofectamine™2000 was employed to transfer the modeled miR-146a
mimics, and miR-146a negative control (NC) in NSCLC cells to detect the expression of
MIF mRNA and protein. MTT assay was used to detect cell viability, cloning technique
to detect cell proliferation ability, AnnexinV-PI to detect cell apoptosis, UV spectrophotometry
to detect viability of cysteinyl aspartate specific proteinase 3 (Caspase 3), and
western blot to detect expression of nuclear factor-kB (NF-kB) in cells.
Results: The expression of miR-146a in NSCLC lung tissues was lower than that in the
normal lung tissues besides the lung cancer; while the expression of miR-146a in NSCLC
cells was lower than that in normal human embryonic lung tissues. It was chosen as the
subsequent cell line for its appropriate expression in A549. The expression of MIF protein
in NSCLC lung tissues was higher than that in the normal lung tissues besides the lung
cancer. The luciferase reporter gene proved that MIF was the reverse target gene of
miR-146a. The miR-146a mimics were transfected into A549 cells through the liposome.
Compared with NC group, the expression of MIF protein and mRNA was significantly
decreased (P < 0.01), with the decrease in the cell viability (P < 0.01), the decrease in the
number of clones (P < 0.01), cell apoptosis (P < 0.01), the increase in the activity of
Caspase 3 (P < 0.01), and decrease in the phosphorylation of NF-kB p65 (P < 0.01).
Conclusions: miR-146a has low expression in NSCLC tissues and cell lines, while MIF has
the over expression in NSCLC tissues. The increased expression of miR-146a can inhibit the
expression of MIF via the gene targeting and thus inhibit the proliferation of A549 cells and
induce the apoptosis of cancer cells, which may be realized through NF-kB signaling pathway.