Abstract:Objective: To investigate the expression of Situin 1 (SIRT1) in 5 strains of human lung adenocarcinoma cell lines, including HCC827, H1650, H1975, A549 and H1299, and its relation to the susceptibility of nedaplatin (NDP). Methods: The SIRT1 mRNA and protein levels in 5 strains of human lung adenocarcinoma cells were detected by real-time quantitative PCR and Western blot, respectively. The viability of cells treated with NDP was detected by the CCK-8 method and the half growth inhibition concentration (IC₅₀) was calculated. After the expressions of SIRT1 in A549, H1299, H1650 and H1975 cells were down-regulated by the siRNA interference, the effects of NDP on the viability and apoptosis of these cells were determined by the CCK-8 method and flow cytometry, respectively. Results: The expression levels of SIRT1 mRNA (4.53 ± 0.74, 3.11 ± 0.64, 15.76 ± 2.28 and 18.09 ± 1.17) and protein (0.23 ± 0.03, 0.21 ± 0.02, 0.52 ± 0.11 and 0.56 ± 0.08) in H1650, H1975, A549 and H1299 cells were significantly higher than that in HCC827 cells (1.00 for SIRT1 mRNA and 0.11 ± 0.02 for SIRT1 protein, F=122.10 and 26.50, respectively, P＜0.01). The susceptibility of A549 and H1299 cells to NDP ［IC₅₀=(7.38 ± 1.59) and (8.14 ± 1.43) μmol/L, respectively］ was significantly higher than that of HCC827, H1650 and H1975 cells ［IC₅₀=(26.16±4.35),(22.29±3.26) and (24.41 ± 2.58), respectively, F=30.86, P＜0.01］.The survivals of A549 and H1299 cells transfected by siSIRT1 and treated with NDP were significantly higher than that in the NC group (F=235.10 and 39.20, respectively,P＜0.01), and the apoptotic rates were the reverse (t=7.29 and 6.68, respectively, P＜0.05). However, the survivals of H1650 and H1975 cells transfected by siSIRT1 and treated with NDP were significantly lower than that in the NC group (F=185.40 and 60.09, respectively,P＜0.01), and the apoptotic rates were the reverse (t=6.15 and 31.36, respectively,P＜0.01). Conclusion: The expression of SIRT1 in A549 and H1299 cells with high expression of SIRT1 increases their susceptibility to NDP, while that in H1650 and H1975 cells with moderate expression of SIRT1 decreases their susceptibility to NDP, indicating that SIRT1 may play dual roles in the resistance of human lung adenocarcinoma cells to platinum.