Cadmium Promotes Proliferation Of Thyroid Cancer Cells Through GPER1-ERK/AKT-NF-κB Pathway

Objection: To investigate the mechanism of proliferative effect of cadmium(Cd) on thyroid cancer cells and the involvement of GPER1 in this process.Methods: Expression of GPER1 in MCF-7,WRO and FRO cell lines were detected by Western blot. WRO and FRO cells were divided into 7 groups, respectively: control, Cd(250, 500, 750 and 1000 n M), E2(10 n M) and G1(10 n M) groups, cells proliferation were measured by MTT method. WRO and FRO cell were divided into groups, respectively:(1) control, Cd(5, 10, 15 and 30 min), E2(15 min) and G1(15 min) groups;(2) control, Cd(1, 3, 6 and 12 h), E2(12 h) and G1(12 h) groups;(3) control, G15, Cd+G15, E2 and E2+G15 groups;(4) control, Cd, Cd+scramble si RNA and Cd+GPER1-si RNA groups; the levels of p-ERK, t-ERK, p-AKT and AKT were detected by Western blot in(1),(2),(3); the levels of NF-κB(p65), Cyclin A and Cyclin D1 were detected by Western blot in(2),(3),(4); WRO and FRO cell were divided into 7 groups: control, Cd, Cd+G15, Cd+PD98095, Cd+LY294002,Cd+PDTC and Cd+GPER1-si RNA groups, cell proliferation was measured by MTT method.Results: Thyroid cancer WRO and FRO cells expressed GPER1. Cd promoted cell proliferation in low concentrations(P<0.05), 500 n M Cd exhibited the most effective proliferative effect. Cd induced rapid phosphorylation of ERK and AKT in a time dependent manner(P<0.05), which peaked at 15 min. Cd induced nuclear translocation of NF-κB(p65), up-regulation of Cyclin A and Cyclin D1 in a time dependent manner(P<0.05), which peaked at 12 h. Cd-induced phosphorylation of ERK and AKT were inhibited(P<0.05) either by inhibitor for GPER1 or si RNA target GPER1. Cd-induced nuclear translocation of NF-κB(p65) and up-regulation of Cyclin A and Cyclin D1 were inhibited(P<0.05) either by inhibitor for GPER1 or si RNA target GPER1. Cd-induced cell proliferation was suppressed(P<0.05) by G15,LY294002,PD98059, PDTC and GPER1-si RNA.Conclusion: GPER1-ERK/AKT-NF-κB signaling pathway was involved in Cd-induced proliferation of GPER1-positive thyroid cancer WRO and FRO cells.