Objective To investigate the effect of forsythigenin on the malignant progression of lung cancer cells by regulating the cyclic adenosine monophosphate/exchange protein directly activated by cAMP1/Ras-associated protein 1(cAMP/EPAC1/RAP1)signaling pathway.Methods Lung cancer cell line A549 was cultured in vitro and grouped into the control group,the low dose forsythigenin group(25 mg/L),the medium dose forsythigenin group(50 mg/L),the high dose forsythigenin group(100 mg/L),the high dose forsythigenin+specific increase in intracellular cAMP content(pertussis toxin PTX)group(100 mg/L forsythigenin+5 μmol/L PTX)and high dose forsythigenin+EPAC1 antagonist(ESI-09)group(100 mg/L forsythigenin+1.5 μmol/L ESI-09).CCK-8 experiment was applied to detect cell proliferation.Scratch test was applied to detect cell migration.Flow cytometry was applied to detect cell apoptosis.Transwell was applied to detect cell invasion.ELISA method was applied to detect cAMP level in cell supernatant.Western blot assay was applied to detect expression levels of cAMP/EPAC1/RAP1 signaling pathway proteins and apoptotic proteins[B lymphoblastoma-2(Bcl-2)and Bcl-2 associated X protein(Bax)].Results Compared with the control group,the OD450 value of A549 cells,number of cell invasions,scratch healing rate,level of cAMP,expression levels of Bcl-2,EPAC1 and RAP1 proteins were significantly reduced in the low dose,medium dose and high dose forsythigenin groups,and the expression of Bax protein and the rate of cell apoptosis were significantly increased in a dose-dependent manner(P＜0.05).Compared with the high-dose forsythigenin group,the OD450 value of A549 cells,scratch healing rate,number of cell invasions,level of cAMP,expression levels of Bcl-2,EPAC1 and RAP1 proteins were obviously increased in the high-dose forsythigenin+PTX group,the expression of Bax protein and the apoptosis rate were obviously reduced(P＜0.05).Levels of all indexes in the high dose forsythigenin+ESI-09 group were opposite.Conclusion Forsythigenin inhibits proliferation,migration,and invasion of A549 cells and promotes apoptosis by down-regulating the cAMP/EPAC1/RAP1 signaling pathway.

Objective To investigate the effect of forsythigenin on the malignant progression of lung cancer cells by regulating the cyclic adenosine monophosphate/exchange protein directly activated by cAMP1/Ras-associated protein 1(cAMP/EPAC1/RAP1)signaling pathway.Methods Lung cancer cell line A549 was cultured in vitro and grouped into the control group,the low dose forsythigenin group(25 mg/L),the medium dose forsythigenin group(50 mg/L),the high dose forsythigenin group(100 mg/L),the high dose forsythigenin+specific increase in intracellular cAMP content(pertussis toxin PTX)group(100 mg/L forsythigenin+5 μmol/L PTX)and high dose forsythigenin+EPAC1 antagonist(ESI-09)group(100 mg/L forsythigenin+1.5 μmol/L ESI-09).CCK-8 experiment was applied to detect cell proliferation.Scratch test was applied to detect cell migration.Flow cytometry was applied to detect cell apoptosis.Transwell was applied to detect cell invasion.ELISA method was applied to detect cAMP level in cell supernatant.Western blot assay was applied to detect expression levels of cAMP/EPAC1/RAP1 signaling pathway proteins and apoptotic proteins[B lymphoblastoma-2(Bcl-2)and Bcl-2 associated X protein(Bax)].Results Compared with the control group,the OD450 value of A549 cells,number of cell invasions,scratch healing rate,level of cAMP,expression levels of Bcl-2,EPAC1 and RAP1 proteins were significantly reduced in the low dose,medium dose and high dose forsythigenin groups,and the expression of Bax protein and the rate of cell apoptosis were significantly increased in a dose-dependent manner(P＜0.05).Compared with the high-dose forsythigenin group,the OD450 value of A549 cells,scratch healing rate,number of cell invasions,level of cAMP,expression levels of Bcl-2,EPAC1 and RAP1 proteins were obviously increased in the high-dose forsythigenin+PTX group,the expression of Bax protein and the apoptosis rate were obviously reduced(P＜0.05).Levels of all indexes in the high dose forsythigenin+ESI-09 group were opposite.Conclusion Forsythigenin inhibits proliferation,migration,and invasion of A549 cells and promotes apoptosis by down-regulating the cAMP/EPAC1/RAP1 signaling pathway.