ABSTRACT
Objective@#To explore the trichloroethylene-induced alteration of methylation on the promoter region of SET and related mechanisms in hepatic L-02 cells.@*Methods@#L-02 cells were treated with different concentrations of TCE(0 mmol/L, 1 mmol/L, 2 mmol/L, 4 mmol/L, 8 mmol/L) for 24 h. The genomic DNA were then extracted and modified by bisulfite sodium. The DNA methylation was then analyzed using bisulfite sequencing PCR (BSP).@*Results@#The overall methylation on promoter region of SET was decreased along with the increased concentrations of TCE in hepatic L-02 cells. Moreover, 73 CpG islands were found abnormally altered, among which 9 were predicted in transcriptional factor binding regions.@*Conclusion@#The decreased levels of CpG islands in the transcriptional factor binding region may contribute to the elevation of SET in TCE-induced hepatotoxicity.
ABSTRACT
Objective@#To further explore TCE-induced hepatotoxicity and its mechanisms by identification of trichloroethylene (TCE) induced abnormal histone methylation in human liver cells.@*Methods@#L-02 cells were treated with 0 and 8 mmol/L TCE for 24 h. Histones were extracted by acid. Liquid chromatography electrospray ionization tandem mass spectrometry (ESI-LC-MS/MS) were used to identify and quantify TCE related histone methylations. TCE induced abnormal methylation of H3K79 me2 and H3K79 me3 were validated by Western blot analysis. The further analysis of the function of histone abnormal methylation modifications were done by single cell gel electrophoresis (SCGE) and Western blot analysis of p53 and ɤH2AX.@*Results@#After treatment with TCE for 24 h in L-02 cells, the 36 TCE related histone methylation sites in 28 peptide segments were identified by MS. After treatment with TCE in concentrations of 0 and 8.0 mmol/L in L-02 cells for 24 h, the relative expression level of histone H3K79 me3 were 1.00±0.06, 0.70±0.09 (t=15.01, P=0.015); the relative expression level of histone H3K79 me2 were 1.00±0.05, 0.74±0.07 (t=16.69, P=0.018); the Olive Tail Moment about DNA damage were 1.46±0.28, 3.12± 0.68 (t=15.22, P=0.018); the relative expression levels of p53 were 1.00±0.04, 1.24±0.04 (t=18.71, P= 0.012); and the relative expression levels of ɤH2AX were 1.00 ± 0.03, 1.56 ± 0.11 (t=8.32, P=0 045).@*Conclusion@#TCE can induce changes in the relative expression level of H3K79 me2 and H3K79 me3 in L-02 cell, and induce DNA damage, suggesting that TCE may induce changes in the relative expression level of H3K79 me2 and H3K79 me3 by DNA damage.