Effects of sodium arsenite on Cyclin D1 and Cyclin dependent kinase 4 of human normal liver cells

Abstract

Objective To investigate the effects of sodium arsenite (NaAsO2) on the expressions of Cyclin D1 and Cyclin dependent kinase 4 (CDK4) in human normal liver cells (L-02). Methods L-02 cells were exposed to different doses of NaAsO2 (0, 50, 100, 150 μmol/L) for 24 h, flow cytometry was used to detect the cell cycle, real time quantitative PCR and Western blotting were used to detect the Cyclin D1, CDK4 mRNA and protein expression. Results Cell cycle detection: compared with the control group G0-G1 phase [(60.33 ± 0.40)%], except 50 μmol/L NaAsO2 group [(54.58 ± 0.40)%], the numbers of cells in 100 and 150 μmol/L NaAsO2 groups [(64.60 ± 0.62)%, (83.13 ± 0.25)%] were increased, the differences were statistically significant (all P < 0.05); cell proportion of S phase in the control group, 50, 100 and 150 μmol/L NaAsO2 groups [(34.35 ± 0.30)%, (29.89 ± 0.32)%, (29.50 ± 0.44)%, (11.93 ± 0.12)%] were decreased, the differences were statistically significant (all P < 0.05); cell proportion of G2-M phase was compared between the control group, 50, 100 and 150 μmol/L NaAsO2 groups [(5.32 ± 0.11)%, (15.54 ± 0.14)%, (5.90 ± 0.20)%, (4.93 ± 0.15)%], the difference was statistically significant (F= 908.359, P < 0.05). Cyclin D1 and CDK4 detection: the expressions of Cyclin D1 mRNA (0.48 ± 0.17, 1.00 ± 0.31, 1.00 ± 0.21, 2.06 ± 0.53) and protein (0.65 ± 0.02, 0.64 ± 0.05, 0.71 ± 0.10, 0.84 ± 0.05) were compared betwee the control group, 50, 100 and 150 μmol/L NaAsO2 groups, the differences were statistically significant (F= 167.886, 46.575, all P < 0.05); the expressions of CDK4 mRNA (1.04 ± 0.19, 1.00 ± 0.21, 1.29 ± 0.22, 2.31 ± 0.31) and protein (0.67 ± 0.04, 0.74 ± 0.03, 0.83 ± 0.07, 0.94 ± 0.04) were compared betwee the control group, 50, 100 and 150 μmol/L NaAsO2 groups, the differences were statistically significant (F= 95.171, 145.848, all P < 0.05). Conclusions Treatment of L-02 cells with NaAsO2 has changed the expressions of Cyclin D1, CDK4 mRNA and protein, which leads to L-02 cell cycle arrested at G0-G1 phase, ultimately leads to cell damage. Key words: Arsenites; L-02 cells; Cell cycle; Cyclin D1; Cyclin dependent kinase 4