Role of YAP in the proliferation of lung cancer A549 cells induced by lipopolysaccharide / 医学研究生学报

ABSTRACT

Objective Chronicinflammation is closely related to the occurrence and development of tumor , but the specific mechanism is still unknown .The aim of this study was to investigate the effect of lipopolysaccharide ( LPS) on the proliferation of lung adenocarcinoma A 549 cells and the role YAP in the process . Methods CCK-8 was used to detect the proliferation of A 549 cells stimulated by different concentrations of LPS .Western-blot ( WB) and immunofluorescence were used to detect the expression and local-ization of YAP protein, respectively.Inhibition rate of target protein and mRNA was measured by WB and RT-PCR respectively after inhibiting the expression of YAP by siRNA .After inhibiting the expression of YAP , the cell proliferation of A 549 stimulated with LPS was detected by CCK-8 again. Results After treatment with LPS for 72 h, the A values increased significantly (P<0.05) after treat-ment with 0.01, 0.1, and 1μg/mL compared with those treated with 0μg/mL LPS.The cell proliferation ability remained the strongest af-ter treatment with 0.1 μg/mL LPS.Western blot analysis showed that compared with 0μg/mL, all the LPS treated A549 cells could up-reg-ulate the expression of YAP protein ( P<0.05) at 48 h.Andthe 0.1μg/mL LPS was the most obvious .The results of RT-PCR showed that the expression of YAP mRNA in YAP siRNA1 group, YAP siRNA2 group and YAP siRNA3 group was significantly lower than that in blank group (P<0.05).Compared with NC siRNA group, the ex-pression of YAP mRNA in YAP siRNA1 group,YAP siRNA2 group and YAP siRNA3 group was significantly decreased (P<0.05).The result of Western blot was consistent with that of RT-PCR.YAP siRNA could significantly inhibit the expression of YAP protein in A549 cells.And the inhibition rate of YAP siRNA1 was the highest (P<0.05).Compared with the control group, A549 cells were sig-nificantly proliferated in LPS group at 24, 48 and 72 h (1.17±0.08 vs 1.47±0.08, 1.95±0.16 vs 2.35±0.07, 2.46±0.07 vs 3.01±0.08, P<0.05).Compared with LPS group, the proliferation of A549 cells in YAP siRNA+LPS group at 48 and 72 h (1.92±0.15, 2.38± 0.07) was significantly decreased (P<0.05). Conclusion Our work suggested that low concentration of LPS promoted the prolifera-tion of A549 cells by enhancing the expression of YAP , and these results would provide a new theoretical basis for the mechanism of LPS-induced proliferation of lung cancer cell .