ABSTRACT
Objective To investigate the expression of Situin 1 ( SIRT1) in 5 strains of human lung adenocarcinoma cell lines, inclu-ding 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 concentra-tion ( IC50 ) was calculated. After the expressions of SIRT1 in A549, H1299, H1650 and H1975 cells were down-regulated by the siR-NA interference, the effects of NDP on the viability and apoptosis of these cells were determined by the CCK-8 method and flow cytom-etry, 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, re-spectively, 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.
ABSTRACT
Objective To investigate the expression of DNA methyltransferase 2 (DNMT2) and 3a (DNMT3a) in the epidermis of patients with psoriasis vulgaris.Methods Between March 2009 and December 2010,46 patients with psoriasis vulgaris were enrolled from the Department of Dermatology,Hospital for Skin Diseases,Chinese Academy of Medical Sciences and Peking Union Medical College,and the Department of Dermatology of Yixing People's Hospital,and 28 healthy controls were enrolled from the Department of Dermatologic Surgery,Hospital for Skin Diseases,Chinese Academy of Medical Sciences and Peking Union Medical College.Real-time quantitative PCR was performed to determine the mRNA expression of DNMT2 and DNMT3a in the epidermis of the lesional and nonlesional skin of patients with psoriasis vulgaris,as well as in the epidermis of normal skin of the healthy controls.Results The mRNA expression of DNMT2 (expressed as 2-△△Ct) in the lesional skin,non-lesional skin of the patients and normal skin of the healthy controls was 0.62 ± 0.02,0.36-± 0.05 and 0.15 ± 0.11,respectively.The mRNA expression of DNMT2 was significantly higher in the lesional skin than in the non-lesional skin of the patients (t =6.23,P ＜ 0.01),and higher in the non-lesional skin of the patients than in the normal skin of the healthy controls (t =7.33,P ＜ 0.01).Additionally,the mRNA expression of DNMT3a was significantly higher in the lesional skin (0.85 ± 0.03) than in the non-lesional skin (0.43 ± 0.04) of the patients (t =5.66,P ＜ 0.01),and higher in the non-lesiona] skin of the patients than in the normal skin of healthy controls (0.18 ± 0.09,t =8.62,P ＜ 0.01).Conclusion Both DNMT2 and DNMT3a mRNA were abnormally expressed in the epidermis of patients with psoriasis vulgaris.
ABSTRACT
Objective To investigate the effects of liver X receptor (LXR) agonist on the proliferation of mouse pancreatic β cell line MIN6 cells.Methods The viability,changes of cell cycle,mRNA levels of S phase kinase associated protein 2 (Skp2) and p27,and protein levels of Skp2 and p27 in MIN6 cells treated with LXR agonist T0901317 were determined by the CCK-8 method,flow cytometry,real-time RT-PCR and western blot,respectively.Results The viability of MIN6 cells treated with 1 μmol/L,5 μmol/L and 10 μnol/L of T0901317 were (98.54 ±0.94)％,(87.03 ±0.93)％ and (75.57 ± 1.85)％ of the controls,respectively,and there was significant difference among them (F =301.90,P ＜ 0.01).The percentages of G1 phase cells in the MIN6 cells treated with 0 μmol/L,1 μmol/L,5 μmol/L and 10 μmol/L of T0901317 were (35.93 ±2.25)％,(38.45 ±0.91)％,(45.46±1.34)％ and (53.28 ± 1.14) ％,respectively,and there was significant difference among them (F =80.83,P ＜ 0.01).Similarly,the percentages of S phase cells in the MIN6 cells treated with 0 μmol/L,1 μmol/L,5 μmol/L and 10 μmoi/L of T0901317 were (52.87 ± 1.19) ％,(48.65 ± 0.85) ％,(36.31 ± 1.37) ％ and (31.45 ± 1.22) ％,respectively,and there was also significant difference among them (F =221.30,P ＜ 0.01).The protein levels of p27 in the MIN6 cells treated with 10 μmol/L of T0901317 (2.84 ± 0.14) were significantly higher than that in the controls (2.28 ± 0.10) (t =4.54,P ＜ 0.05),while there was no significant difference in the mRNA levels of p27 between them (t =0.28,P ＞ 0.05).However,10 μmol/L of T0901317 significantly decreased mRNA (0.52 ± 0.02,t =29.22,P ＜ 0.01) and protein levels (0.98 ± 0.12 vs 1.89 ± 0.01,t =10.98,P ＜ 0.01) of Skp2 in MIN6 cells.Based on the control siRNA transfection group as a reference (100％),the cell survival rates of the p27 siRNA transfection group,10 μmol/L of T0901317 treatment group and the intervention group (p27 siRNA transfection + T0901317 treatment) were (100.97 ± 1.08) ％,(75.03 ± 1.83) ％ and (86.67 ± 2.45) ％,respectively.There was no significant difference between the control siRNA and p27 siR-NA transfection groups (t =1.542,P ＞ 0.05).Compared with the control siRNA transfection group,the cell survival rates of the T0901317 treatment group decreased (t =23.58,P ＜ 0.01).There was also significant difference in the cell survival rates between the T0901317 treatment group and the intervention group (t =7.77,P ＜ 0.01).Conclusion The activation of LXR may induce pancreatic β cell cycle arrest by up-regulating the expression of p27 and down-regulating the expression of Skp2.