Effect Of As₂O₃ On Apoptosis, Infecting Invasion And Adhesion Of Human Breast Cancer Cells And Its Mechanisms

Objective: To study expression of syk in human breast cancer cells, and effect of As₂O₃ on apoptosis, invasion and adhesion of human breast cancer cells associated with expression of syk.Methods: 1 The expression of Syk MMP-9 and ICAM-1 in MDA-MB-468 and MDA-MB-231 breast cancer cells were detected by using RT-PCR Western blot and flow cytometry (FCM).2 The suppressive effect of As₂O₃ on the proliferation of MDA-MB-468 and MDA-MB-231 cells were analyzed with MTT colorimetric method.3 After treatment with various concentration of As₂O₃, cell apoptosis was studied by Gimsa staining, flow cytometry (FCM). The expression changes of Syk MMP-9 and ICAM-1 were investigated by using semi-quantity RT-PCR technique and flow cytometry (FCM) respectively, and the possible mechanisms of apoptosis and influencing invasion and adhesion were analyzed.4 The suppressive effect of As₂O₃ on tumor was studied in vivo. Animal models were constructed on nude mice subcutaneously implanted MDA-MB-468 cells (syk+) and MDA-MB-231 cells (syk-). The mice were randomly divided into two groups: negative control (saline), experimental group (arsenic trioxide at the doses of 3.0mg/kg).Medicine were injected by vena caudalis for seven days consecutively.The tumor's formation and survival of mouse were observed.5 The tumors tissue from all nude mice was collected, and analyzed using immunohistochemistry and HE staining.6 The apoptosis of tumor cells and the expression changes of Syk MMP-9 and ICAM-1 were detected with flow cytometry (FCM).Results: 1 syk expression in MDA-MB-468 cells is positive, but in MDA-MB-231 cells is negative; MMP-9 and ICAM-1 were expressed in both two cells, but MMP-9 expression level is higher in MDA-MB-231 cells than in MDA-MB-468 cells. However, ICAM-1 expression level is lower in MDA-MB-231 cells than in MDA-MB-468 cells.2 As₂O₃ can inhibit the proliferation of MDA-MB-468 and MDA-MB-231 cells significantly, and in a time and dose-dependent manner (P<0.01). But the effect on MDA-MB-231 cells is stronger than on MDA-MB-468 cells.3 After treatment with As₂O₃, MDA-MB-468 and MDA-MB-231 cells shown some typical morphologic features of apoptosis, including cell shrinkage, cytoplasm concentration, nclius forming outwardly acute angle promineney, chromatin concentrating on karyotheca or forming meniscus, nuclear condensation, electric density increasing, nuclear fragmentation. The apoptosis rate of MDA-MB-468 cells was 5.80% after 4μg/ml As₂O₃ treating for 48h, untreated cells was 2.03%. The apoptosis rate of MDA-MB-231 cells was 9.32%, untreated cells was 1.41%. After treatment with As₂O₃, the cell cycles of MDA-MB-468 and MDA-MB-231 cells were changed, G2/M+S phase were increased and G0/G1 phase were induced, cell cycles were arrested in G2/M+S phase.4 After treated with various concentration of As₂O₃, the expression of MMP-9 was inhibited, ICAM-1 was increased, Syk was remaining negative in MDA-MB-231 cells, but in MDA-MB-468 cells, the expression of Syk was increased.5 As₂O₃ can inhibit the formation of tumor markebly in vivo. The cell apoptotic rate of MDA-MB-231 group was 49.04%, the control goup was 9.41%, the apoptotic rate of MDA-MB-468 group was 37.85%, the control group was 12.34%.6 In vivo studies, expression of ICAM-1 in experimental group is higher than in control group. The expression of MMP-9 in experimental group is lower than in control group. syk was negative expressed in tumor tissues.Conclusions: 1 As₂O₃ has very strong antitumor effect for breast cancer in vitro and in vivo.2 syk expressed in MDA-MB-468 cells but not expressed in MDA-MB-231 cells.3 As₂O₃ can decrease invasion, increase adhesion of MDA-MB-468 and MDA-MB-231 cells. Expression of syk is increased in MDA-MB-468 cells after treated with As₂O₃. These results suggested that the possible mechanisms of As₂O₃ inducing apoptosis, influencing invasion and adhesion of MDA-MB-468 and MDA-MB-231cells are associated with the expression of syk.