ABSTRACT
OBJECTIVE： To study the effects of aspirin on the growth and autoghagy of human gastric cancer cells SGC-7901 and BGC-823. METHODS： SGC-7901 and BGC-823 cells were selected as research objects， with phosphate buffer （PBS） as negative control treated for 48 h， MTT assay was used to detect the effects of 1， 2， 4， 6， 8， 10 mmol/L aspirin， 5 mmol/L aspirin alone or combined with 2.5 μmol/L chloroquine， 2.5 μmol/L 3-methyladenine （3-MA） on survival rate of gastric cancer cells. Flow cytometry was used to detect the effects of 2 and 5 mmol/L aspirin， 5 mmol/L aspirin alone or combined with 2.5 μmol/L chloroquine and 2.5 μmol/L 3-MA on the apoptosis rate and cell cycle distribution of gastric cancer cells. Hoechst33258 staining was used to observe the effects of 5 mmol/L aspirin on morphology of gastric cancer cell nucleus； Transwell chamber test was adopted to detect the effects of 5 mmol/L aspirin on the migration of gastric cancer cell. Laser confocal scanning microscopy was used to observe the effects of 5 mmol/L aspirin on autophagy formation in gastric cancer cells. Western blot method was used to detect the effects of 2 and 5 mmol/L aspirin on the protein expression of autophagy markers LC3-Ⅱin gastric cancer cells. RESULTS： Compared with negative control group， aspirin could inhibit the survival rates of SGC-7901 and BGC-823 cells in dose-dependent manner， but had no significant effects on apoptosis rate of SGC-7901 and BGC-823 cells； SGC-7901 and BGC-823 cells were blocked in G1 phase. Compared with aspirin alone group， the survival rates of SGC-7901 and BGC-823 were increased significantly after treated with aspirin+chloroquine and aspirin+3-MA， while the distribution rate of SGC-7901 and BGC-823 cells at G1 phase were decreased significantly， with statistical significance （P＜0.05 or P＜0.01）. Compared with negative control group， there were no obvious DNA fragmentation fragments， apoptotic bodies and fragments of dense bright blue， while the number of migration cells were decreased significantly in SGC-7901 and BGC-823 cells after treated with aspirin （P＜0.001）； the number of autophagosome was increased significantly and the protein expression of LC3-Ⅱ was enhanced significantly （P＜0.05）. CONCLUSIONS： Aspirin can significantly inhibit the growth of SGC-7901 and BGC-823 cells， and arrest cell cycle in G1 phase， the mechanism of which may be associated with the activation of autophagy.
ABSTRACT
PURPOSE: The expression pattern of c-jun by ionizing radiation according to cell growth state (exponential growth phase vs. stationary phase) and its relationship with cell cycle redistribution were investigated. MATERIALS AND METHODS: The exponential growth phase (day 4) and stationary phase (day 9) cells were determined from cell growth curve according to the elapse of days in CaSki. The cells were irradiated using 6 MV X-ray with a dose of 2 Gy at a fixed dose rate of 3 Gy/min. Northern blot analysis was performed with total cellular RNA and cell cycle distribution was analyzed using flow cytometry according to time-course after irradiation. RESULTS: The maximum expression of c-jun occurred 1 hour after irradiation in both exponential growth and stationary phase cells. After then c-jun expression was elevated upto 6 hours in exponential growth phase cells, but the level decreased in stationary phase cells. Movements of cells from G0-G1 to S, G2-M phase after irradiation were higher in exponential growth phase than stationary phase. CONCLUSION: c-jun may be involved in the regulation of cellular proliferation according to the growth states after irradiation.