Objective: To investigate the effects of formononetin on proliferation and apoptosis of human non-small cell lung cancer cells and its relevant mechanism. Method: The human non-small cell lung cancer (NSCLC) cell line A549 was cultured

and added with formononetin with the concentrations of 10

20

40

80 and 160 μmol·L-1. The blank group was only added PBS. After cultured for 48 h

the cell proliferations were detected by using methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay

the cell apoptosis were tested by using Annexin V-FITC/propidium iodide (PI) double staining

the cell cycles were detected by using flow cytometry

the expressions of cyclin E1

Bcl-2 and Bax mRNA and proteins were detected by using Real-time PCR and Western blot method. Result: The cell growth inhibition rates and the cell apoptosis rates at the concentrations of 40

80 and 160 μmol·L-1 of formononetin were higher than the blank group (P<0.05). Compared with the blank group

the proportions of G0/G1 phase at the concentrations of 40

80 and 160 μmol·L-1 of formononetin were increased

while the proportions of S phase were decreased

especially the concentrations of 80 and 160 μmol·L-1 of formononetin (P<0.05). The gene and protein expressions of cyclin E1 and Bcl-2 at the concentrations of 40

80 and 160 μmol·L-1 were lower than the blank group

while the mRNA and protein expressions of Bax were increased; compared with 40 μmol·L-1 of formononetin

the expression levels of cyclin E1 and Bcl-2 mRNA and protein expressions were decreased at the concentrations of 80

160 μmol·L-1 of formononetin

but with increase in Bax mRNA and protein expressions (P<0.05). Conclusion: Formononetin could inhibit the proliferation of NSCLC cells

and accelerate cell apoptosis. It might affect the cell cycle by down-regulating cyclin E1 expression

and promote cell apoptosis by regulating the expressions of Bcl-2 and Bax.