Effect Of Rrsenic Trioxide On Apoptosis And Expression Of Bcl-2 And CyclinD1 In Human Gastric Cancer SGC-7901 Cells And Gene

Background and ObjectivesArsenic trioxide (ATO) is a major compound of white arsenic in tradition Chinese medicine. In recent years, studies have shown that, in addition to the treatment of hematological disorders, arsenic trioxide has powerful anti-cancer effects on a variety of malignant solid tumors including gastric cancer Gastric cancer is a common malignant tumor in China, with low sensitivity to radiotherapy and chemotherapy, high mortality and lack of effective treatment for advanced cases. So finding new drugs and treatment for gastric cancer is a top priority.Aresnic trioxide can inhibit the growth of malignant tumor by inducing apoptosis. Many regulatory factors are involved in the molecular mechanism of inducing apoptosis, and uncontrolled apoptosis of turner cells is involved in multiple parts of development and progression of tumors. B-cell lymphoma/leukemia-2 gene(bcl-2)is a oncogene which was isolated from the follicular lymphoma. It is also a kind of apoptosis inhibitory factor which can inhibit apoptosis and prolong cell life. Currently considered, the relative expression level of pro-apoptotic factors and anti-apoptotic factors in bcl-2 family, at least partly, contributes to the responsiveness of cell apoptosis signal. Cyclin D1 gene is regard as an important proto-oncogene in recent years, Its protein products play an active role of cell cycle phase. The abnormal regulation of cyclin Dl will shorten the period between G1 phase and S phase. This can cause cells to be transformed malignant.In this study, gastric adenocarcinoma SGC7901 cells were treated with arsenic trioxide. The effects of arsenic trioxide on apoptosis and cycle were observed, and the expression of Bcl-2 and cyclin D1 were detected. The purpose of the present is to explore the mechanism of arsrnic trioxide-induced apoptosis in gastric adenocarcinoma SGC7901 cells.Materials and Methods1. After SGC7901 cell were treated with arsenic trioxide in different doses and with different time, MTT was used to detect the proliferation of SGC7901 cells. The Annexin VFITC/PI double staining analysis by flow cytometry was used to evaluate cell cycle and cell apoptosis rate. Bcl-2,cyclinDl gene expression were detected by RT-PCR and expression of Bcl-2, Cyclin D1 were detected by immunohistochemistry.2. Statistical analysis:The data were analyzed by solfware SPSS 13.0 Continuous variables were tested by t test, The mean varied was compared with single-factor analysis of variance, chi-square test was used to compare categorical variables, pearson correlation analysis was used for correlation analysis. Difference was considered as statistically significant when P<0.05.Results1.Arsenic trioxide could inhibit cell proliferation and induce cell apoptosis in SGC-7901 cells, the apoptotic rate was dose dependent and time dependent.2.Arsenic trioxide could induce early apoptosis of SGC7901 cells, with higher concentrations of arsenic trioxide, the number of apoptotic cells gradually increased, there was no significant difference of the number of apoptosis between 1μmol/L group and the control group (P>0.05), while the high concentration group and control group differences in the number of apoptosis was significantly (P＜0.05).3.Cell cycle has been a significant change after 48h of arsenic trioxide treatment, G1 phase cell percentage increased, S phase cell percentage decreased compared with the control group, the difference was statistically significant (P＜0.01).4.The transcription level of bcl-2, cyclin D1 gene was detected by RT-PCR, the study found that the bcl-2, cyclin D1 gene expression of arsenic trioxide group was significantly lower compared with the control group (P＜0.01).5.Compared with control, the expression of Bcl-2 and Cyclin D1 was downregulated. There was correlation between the expression of Bcl-2 and Cyclin D1(r=0.948,P<0.01).Conclusions1.Arsenic trioxide can effectively inhibit cell proliferation and induce apoptosis and inhibits the cell cycle in gastric adenocarcinoma SGC7901 cells, The role and function of dose and time-dependent, this may result from its action of reduce surviving and expression.2.Arsenic trioxide can inhibit the expression of Bcl-2 and Cyclin D1, and the expression of Bcl-2 and Cyclin D1 is relevance, which may be correlated with arsenic trioxide inhibiting tumor cell apoptosis mechanisms.