Effects of deguelin on proliferation and apoptosis of MCF-7 breast cancer cells by phosphatidylinositol 3-kinase/Akt signaling pathway / 中西医结合学报

ABSTRACT

Objective: To study the effects of deguelin on proliferation and apoptosis of human breast cancer cell line MCF-7 and on phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway. Methods: After treatment with 0, 1, 5, 10, 15 and 20 μmol/L of deguelin for 6, 24, 48 and 72 hours, the proliferation inhibition rate of MCF-7 cells was measured by cell counting kit-8 assay. Apoptosis rate of MCF-7 cells was detected with Annexin V-fluorescein isothiocyanate/propidium iodide double staining by flow cytometry and the apoptotic morphology was observed under a transmission electron microscope. After treatment with 0, 1 and 5 μmol/L of deguelin for 6 hours, 5 proteins involved in the PI3K/Akt signaling pathway were examined by Western blot analysis. Results: Deguelin at doses of 5, 10, 15 and 20 μmol/L inhibited the proliferation of MCF-7 cells at 6, 24, 48 and 72 hours. There was a significant difference in each group compared with the control group (P0.05). Deguelin at doses of 5, 10, 15 and 20 μmol/L induced apoptosis of MCF-7 cells at 6 hours. There were significant differences (P<0.01) in the early and late apoptosis rate between the treated groups and the control group. The typical apoptotic MCF-7 cells were observed under the transmission electron microscopy. However, 1 μmol/L of deguelin had no apparent effect in inducing apoptosis of MCF-7 cells at 6 hours. After treatment with 5 μmol/L of deguelin for 6 hours the expression of phosphorylated phosphatase and tensin homologue deleted on chromosome 10 (PTEN) (Ser380), phosphorylated 3-phosphoinositide-dependent protein kinase 1 (PDK1) (Ser241), phosphorylated Akt (Thr308) and phosphorylated glycogen synthase kinase-3β (GSK-3β) (Ser9) proteins were significantly reduced in MCF-7 cells, while there was no significant change in the expression of total Akt protein. However, after treatment with 1 μmol/L of deguelin for 6 hours, there was no apparent change in the expression of these 5 proteins. Conclusion: Deguelin can inhibit the phosphorylation of GSK-3β (Ser9) via inhibition of the phosphorylation of PTEN (Ser380) and PDK1 (Ser241) pathway, thus inducing apoptosis and inhibiting proliferation of MCF-7 cells.