Abstract: Objective To explore the effect and mechanism of PIN1 inhibitor Juglone on cell proliferation of human lung cancer cells A549 in vitro. Methods A549 cells were treated by different concentrations of Juglone. Cell proliferation was measured by MTT assay respectively. The apoptosis rate and cell cycle of A549 cells were detected by Flow cytometry. Real-time PCR was carried to detect the mRNA expression of PIN1 and AKT. Western blot were used to observe the protein expression of PIN1 and AKT-pS473 in cells. Results With the increasing of Juglone’s concentration, the inhibition effect on proliferation and the apoptosis rate of A549 cells enhanced in a dose-depended manner, and A549 cells cycle were blocked in G2/M and S period. Real-time PCR result showed the mRNA level of PIN1 in A549 cells treated by Juglone significantly decreased compared with control group. Western blot showed that the protein expression of PIN1 in Juglone groups were 1.032±0.056, 0.892±0.024, 0.596±0.023, 0.396±0.021, significant lower than control group 1.280±0.046 (P＜0.05).the protein expression of AKT-pS473 in Juglone groups were 0.554±0.023, 0.464±0.018, 0.362±0.015, 0.228±0.020,significant lower than control group 0.626±0.015(P＜0.05). the protein expression of PIN1 and AKT-pS473 in cells treated by Juglone for 48h were 0.575±0.036 and 0.338±0.014, significant lower than 0.764±0.032 and 0.436±0.023 of 24h group(P＜0.05). Conclusion Inhibiting the expression of PIN1 with Juglone can significantly depress the proliferation activity of A549 through weakening the phosphorylation level of AKT.

Key words: Key words:peptidyl-prolyl cis/trans isomerase（Pinl）, Juglone, cell proliferation, lung cancer