Effect of lentivirus-induced small interfering RNA targeted against toll-like receptor 3 on the proliferation and immune escape of human pulmonary adenocarcinoma cell line A549

Abstract

Objective Toll-like receptors (TLR) are very important innate immunity molecules.Recently the relationship between TLR and human tumors had been gradually focused on by more and more researchers.This study was to investigate the effect of TLR3 on the cell proliferation,anti-apoptosis and immune escape in human pulmonary adenocarcinoma cells.Methods A549 cells were transfected with TLR3-RNA interference (RNAi) lentiviral vector,blank vector or non-transfected,then incubated with TLR3 ligand Poly (I∶ C).The expression of B7-H1,prostaglandin E synthase-2 (PGE-2) and phosphorylated p38 were respectively evaluated by flow cytometry,real-time quantitative polymerase chain reaction (Real-time PCR) and Western blotting.Cells apoptosis was detected by flow cytometry with Annexin V fluoresceine isothiocyanate (FITC)/propidium iodide (PI) double staining.Results Under the same time and concentration stimulation with Poly (I∶ C),the percentage of B7-H1-positive cells,the expression of PGE-2 mRNA and the relative percentage of phosphoryated p38 in TLR3-RNAi lentiviral vector transfected A549 cells were significantly lower than those in the non-transfected and blank vector transfected A549 cells (P ＜ 0.01).The percentage of the apoptotic cells in TLR3-RNAi lentiviral vector transfected A549 cells [(44.40 ± 1.41) ％] was significantly higher than that in the non-transfected [(34.70 ± 0.89) ％] and blank vector transfected [(36.50 ± 1.12) ％] A549 cells (P ＜ 0.01).Conclusion Down-regulation of TLR3 could inhibit the expression of B7-H1,PGE-2 and phosphorylated p38 in A549 cells,and weaken the anti-apoptosis ability of A549 cells. Key words: Lung cancer; Toll-like receptor 3; Apoptosis