The Effection Of Arsenic Trioxide In Human Lung Adenocarcinoma A549 Cell Line Proliferation And C-Myc Gene Expression

Objective: Observe the arsenic trioxide (As₂O₃) on human lung adenocarcinoma cell lineA-549cell growth, proliferation, cell cycle arrest, apoptosis and other aspects, and to explore its mechanism.Methods: Choose man lung cancer A-549 cell lines as specimen. Select logarithmic growth phase cells and set the negative control group. After the cells being effected by different concentrations of As₂O₃ , staining them with Trypan Blue and counting them under light microscope to describe the cells'growth curve and calculate the doubling time of the cells. Investigate the inhibition rate of cell growth and proliferation with MTT colorimetric assay. Using flow cytometry (FCM) to determine the cell cycle (CC) and apoptosis index (AI). Dynamically observe the A-549 cells'morphological changes by using inverted phase contrast microscope. Using immunohistochemistry (SABC) method to analysis the influence of different concentrations of As₂O₃ on the c-Myc gene expression.Results: As₂O₃ has a significant inhibited effect on the growth and proliferation of in vitro growing human lung cancer A-549. And the effection depend on time and dosage (time-effect and dose-effect relationship).As₂O₃ has regulatory effect on A-549 cell cycle. A-549 cells appeared S period block when being treated by 0.5μmol/LAs₂O₃ for 72 hours.But if p>0.05, there is no statistical difference when compared with the control group.The target cells in the group which treated by 1.0μmol/L,2.0μmol/L and 4.0μmol/L As₂O₃ appeared G₂/M period block. That is to say in G₂/M period the ratio of cells increased. And there is a statistical significance when compared with the control group (p>0.05) whereas no obvious difference between the groups. The group which treated by 8.0μmol/LAs₂O₃ appeared S period block(p<0.05). As₂O₃ onproliferation of A-549 cell growth inhibition induced by different concentration groups showed induction of apoptosis or necrosis, 0.5μmol/L group had no obvious apoptosis and necrosis, compared with the control group, no significant difference; 1.0, 2.0, 4.0μmol/L As₂O₃ role of A-549 cells can induce apoptosis in the apoptosis rate within this concentration increases with the concentration; 8.0μmol/L mainly induced necrosis. As₂O₃ in various groups were on the A-549 cellsexpression of c-Myc gene downward effect, 0.5 4.0μmol/L in a dose depend entrelationship between the two groups, 4.0μmol/L decreased the most obvious, 8.0μmol/L compared with 4.0 does not find significant differences (p > 0.05).As₂O₃。Conclusion: Arsenic trioxide has a significant inhibited effect on the growth and proliferation of in vitro growing human lung cancer A-549. And can regulate the cell cycle. in the 1.0 4.0μmol/L, It's mainly inhibition mechanism is promoting apoptosis. Preliminary speculated, apoptosis induction suppresses the expression of c - Myc gene, which indicate As₂O₃ is a more valuable anti-lung cancer drug. We think 0.5 4.0 muon mol/L concentration is safe and effective range when doing in vivo experiments. Future research's focus and direction is that carry out toxic effect observation in safety range, change medicine way and dosage form, and combined As₂O₃ application with other classical chemotherapeutic drugs.