Objective: To investigate the molecular mechanism of autophagy of breast cancer MCF-7 cells induced by total saponins of Astragalus membranaceus through liver kinase B1/AMP-activated protein kinase(LKB1/AMPK) signaling pathway. Methods: 10 mL breast cancer MCF-7 cells were cultured in DMEM medium containing 10% fetal bovine serum in CO2incubator as breast cancer MCF-7 cells group, 10 mL breast cancer MCF-7 cells were cultured in DMEM medium containing 10% fetal bovine serum plus 5 mL Astragaloside (80 mg/UL) in CO2 incubator as low dose of total saponins of Astragaloside group, and 5 mL astragaloside (160 mg/UL) was added in high dose of total saponins of Astragaloside group. After culture, MTT assay was used to detect the cell viability, fluorescence microscopy was used to determine the level of autophagosomes, inverted microscopy was used to observe the number of clones, flow cytometry was used to determine the apoptotic rate and G1 phase, real-time fluorescence reverse transcription was used to determine the levels of LKB1 and AMPK mRNA, and enzyme-linked immunosorbent assay was employed to detect the expression levels of LKB1 and AMPK protein.Results: The OD value, survival rate and number of cell clones in low and high dose groups were lower than those in breast cancer MCF-7 cell group (P<0.05). The OD value, survival rate and number of cell clones in high dose group were lower than those in low dose group (P<0.05). The levels of autophagosome, G1 phase, apoptotic rate, LKB1, AMPK mRNA and protein expression in low and high dose groups were higher than those in breast cancer MCF-7 cell group (P<0.05). The levels of autophagosome, G1 phase, apoptotic rate, LKB1, AMPK mRNA and protein expression in high dose group were higher than those in low dose group (P<0.05).Conclusion: The total saponins of Astragalus induce autophagy of MCF-7 cells by promoting high expression of LKB1, AMPK mRNA and protein to activate LKB1/AMPK signaling pathway.
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