Effects Of 5, 7-dimethoxyflavone On Inhibition Of Growth And Induction Of Apoptosis In Human Gastric Cancer Sgc7901 Cell Line

ObjectiveTo investigate whether 5, 7-dimethoxyflavone (DMF) induces the growth inhibition and apoptosis of human gastric cancer SGC7901 cell line through promoting the ratio of Bax protein to Bcl-2 protein.MethodsHuman gastric cancer SGC7901 cell line was cultured in vitro. MTS assay was used to determine the cell viability. Colony formation assay on plate were used to detect the colony formation capability. Flow cytometry (FCM) using Annexin V/PI staining was used to analyse the apoptotic rate of cells. Enzyme linked immunosorbent assay(ELISA) was used to detect the Histone/DNA fragments of cells. The indirect immunity fluorescence FCM technique was used to analyse the expression level of Bax and Bcl-2 proteins.ResultsMTS assay showed that DMF and its lead compound, 5, 7-dihydroxyflavone (chrysin, ChR) significantly inhibited the viability of SGC7901 cells(P<0.05), in a concentration-dependent manner. The results of colony formation assay on plate indicated that DMF obviously suppressed the anchorage-dependent growth of SGC7901 cells(P<0.05), in a concentration-dependent manner. By treatment with DMF(3.0,10.0,30.0μmol/L), the inhibitory rate of colony forming in SGC7901 cells was 27%±4%, 51%±8% and 79%±11% respectively. The inhibitory rate of colony forming with 10.0μmol/L DMF is similar to that with 30.0μmol/L ChR(43%±7%). Data of FCM analysis using Annexin V/PI staining demonstrated that DMF significantly induced apoptotic death of SGC7901 cells(P < 0.05), in a concentration-dependent manner. The apoptotic rate was 3.55%±0.39%, 25.30%±1.71% and 45.67%±2.90% after treatment with DMF(3.0,10.0,30.0μmol/L) for 24 h in SGC7901 cells. The apoptotic rate treated with 10.0μmol/L DMF was heighter than that with 30.0μmol/L ChR(7.50%±0.62%,P<0.05). The results of ELISA assay detected that DMF induced a increase of Histone/DNA fragment level in SGC7901 cells(P < 0.05), in a concentration-dependent manner. The level of Histone/DNA fragment in SGC7901 cells was 1.80, 5.23 and 8.19 fold of the vehicle group(0.1% DMSO, 1.00) after treatment with DMF(3.0,10.0,30.0μmol/L) for 24 h. The level of Histone/DNA fragments in SGC7901 cells was 3.46 fold of the vehicle group by treatment with 30.0 ChR. The indirect immunity fluorescence FCM analysis found that DMF significantly upregulated the expression level of Bax protein(P<0.05), in a concentration-dependent manner. The expression level of Bax protein was 1.56, 2.99 and 4.18 fold in comparison with the vehicle group(0.1% DMSO, 1.00) after treatment with DMF(3.0,10.0,30.0μmol/L) for 24 h. Simultaneously, DMF obviously down-regulated the expression level of Bcl-2 protein(P<0.05), in a concentration-dependent manner. The expression level of Bcl-2 protein was 0.55, 0.38 and 0.16 fold in comparison with the vehicle group after treatment with DMF(3.0,10.0,30.0μmol/L) for 24 h. Therefore, The ratio of Bax protein to Bcl-2 protein in SGC7901 cells is 2.83, 7.86 and 26.13 respectively after treatment with DMF(3.0,10.0,30.0μmol/L) for 24 h.Conclusion1. DMF possesses the inhibitory effects on the growth of human gastric cancer SGC7901 cells. 2. DMF can efficaciously induce apoptosis of human gastric cancer SGC7901 cells.3. The inhibitory effect of growth and induction of apoptosis in human gastric cancer SGC7901 cells is associated with that raise up the ratio of Bax protein to Bcl-2 protein.