ABSTRACT
@#[Abstract] Objective: To explore the effects of miR-21 targeting PDCD4 (programmed cell death factor 4) on proliferation and migration of non-small cell lung cancer (NSCLC) A549 cells and the possible mechanism. Methods: The miR-21 mimics, miR-21 inhibitors and miR-NC plasmids were transfected into A549 cells in logarithmic growth phase by liposome transfection technology. Forty-eight hours after transfection, the transfection efficiency was observed under a fluorescence microscope, and the mRNA expression levels of miR-21 and PDCD4 in A549 cells were detected by qPCR. Dual luciferase reporter gene experiment was used to detect the targeting relationship between miR-21 and PDCD4, MTT method was used to detect cell proliferation, Transwell chamber method was used to detect cell migration ability, and ELISA was used to detect the content of TNF-α in each group of cell culture fluids. WB was used to detect the protein expression levels of PDCD4, NF-κB p65 and p-NF-κB p65 in cells. Results: The A549 cell line with miR-21 over-expression or knockdown was successfully constructed. Dual luciferase reporter gene assay confirmed that miR-21 targetedly inhibited PDCD4 expression. Over-expression of miR-21 could significantly inhibit the mRNA expression of PDCD4 in A549 cells (P<0.01), promote cell proliferation and migration (P<0.05 or P<0.01), increase the secretion level of TNF-α (P<0.01), down-regulate the expression of PDCD4 protein (P<0.01), and up-regulate p-NF-κB p65 protein level (P<0.05). The effect of silencing miR-21 on cells was opposite to the effect of miR-21 over-expression. Conclusion: Over-expression of miR-21 can promote the proliferation and migration ability of A549 cells, which may be related to its targeted inhibition of PDCD4 and activating the NF-κB/TNF-α pathway.