The Influence Of HL-7702Cell Cycle And The Expression Of G₁/S Checkpoint Related Gene MRNA Induced By Vinyl Chloride Monomer

ObjectiveAfter the human normal liver cells(HL-7702) was exposed to Vinyl chloride monomer(VCM),we detected the gene mRNA expression level of the G1/S checkpoint in order to explore the effect of G1/S checkpoints induced by VCM and the possible carcinogenic mechanisms.Method1. HL-7702cells were exposed to VCM (0.02mg/ml,0.05mg/ml,0.16mg/ml,0.32mg/ml,0.65mg/ml) and air control group for48h. We observed the morphological changes of the cells by optical microscope;2. The cell cycle and apoptosis of HL-7702were detected by flow cytometry;3. The levels of related gene mRNA expression were detected by real-time PCR.Results1. After exposed to VCM for48hours, the quantity of adherent cell reduced and the number of dead cells increased.2. After exposed to VCM for48hours, the number of cells in G1phase increased (P<0.05), while S phase (P<0.05) and G2phase cells didn’t change (P>0.05). All exposed groups early apoptosis rate increased along with the increases of the dose (P<0.01).3. The level of P53、P21、CDK2、cyclinE、cyclinA and cyclin D1activitives increased as the dose rises, and the different was statistically significant(P<0.05).The activities of CDK4didn’t change as the dose rises(P>0.05). The level of P16activitives decreased as the dose rises, and the different was statistically significant (P<0.05).4. There was an positive relationship between CDK4gene expression and the expression of cyclinD1(r=0.673, P<0.01) gene; The relationship of P16gene expression and cyclinD1gene expression showed negative correlation (r=-0.635, P<0.01).Conclusion1. VCM can lead to HL-7702cell cycle disorder and increase the number of dead cell.2. VCM can cause imbalance of the positive regulatory genes(CDK2,cyclinE,cyclinA, cyclinDl) and negative regulatory genes (P53, P21, P16), produce an effect on the function of G1/S checkpoint.