Objective:To study the effects of Hedgehog signal transduction pathway on the cell proliferation, apoptosis and connexin 32 (Cx32)and connexin 43 (Cx43)membranous distribution of breast cancer cells,and to explore its mechanism in the cell proliferation and metastasis of breast cancer.Methods:The breast cancer MCF-7 cells at logarithmic growth period were divided into cyclopamine groups and blank control groups. The MCF-7 in cyclopamine groups were treated with 5,10,20,30 and 40μmol·L-1 for 24,48 and 72 h;MTT assay was applied to detect the inhibitory rate of proliferation of MCF-7 cells. After the MCF-7 cells were treated with 0 (negative control group)and 25μmol·L-1 cyclopamine for 48 h,flow cytometry was employed to determine the apoptotic rate and to analyze membranous distribution of Cx32 and Cx43 in the MCF-7 cells.Results:Compared with blank control group,the inhibitory rates of proliferation in cyclopamine groups were increased (P<0.05), and the inhibitory effect of proliferation was increased with the increasing of cyclopamine doses and prolongation of treatment time.After treated with 25μmol·L-1 cyclopamine,the apoptotic rate of MCF-7 cells was higher than that in blank control group (P<0.05).The positive expression rates of Cx32 and Cx43 48 h after treatment were higher than those in negative control group (P<0.05).Conclusion:Hedgehog signal transduction pathway can inhibit the apoptosis and mediate membranous distribution of Cx32 and Cx43 in breast cancer cells.