Effect of acetyltransferase inhibitor Garcinol on estrogen-promoted proliferation of breast cancer cell line MCF-7 and the related mechanism

Abstract

Objective To investigate the effect of acetyltransferase inhibitor Garcinol on estrogen-induced proliferation,cell cycle promotion and apoptosis inhibition of human breast cancer MCF-7 cells and the related mechanism.Methods The effect of Garcinol on 17β-estradiol(17β-E2)-induced proliferation of MCF-7 cells was investigated using CCK-8 assay,and the optimal concentration of Garcinol was determine according to the inhibition rate.The cell cycle and apoptosis were analyzed by flow cytometry;the nuclear translocation of NF-κB/p65was examined by immune cell fluorescence.RT-PCR was used to determine the expressions of cyclin D1,Bcl-2 and Bcl-xLmRNA in MCF-7cells;and the expressions of acH3,ac-H4,NF-κB/ac-p65,cyclin D1,Bcl-2,and Bcl-xLprotein were determined by Western blotting analysis.Results Acetyltransferase inhibitor Garcinol inhibited 17β-E2-induced proliferation of MCF-7cells,arrested MCF-7cell cycle at G0/G1 phase,and increased the cell apoptosis(P0.01).17β-E2 increased the expressions of ac-H3,ac-H4 and NF-κB/ac-p65 protein in MCF-7cells(P0.01,P0.05,P0.01),while Garcinol significantly inhibited the increase of ac-H3and NF-κB/ac-p65(P0.01)but not ac-H4(P0.05).17β-E2-induced nuclear translocation of NF-κB/p65in MCF-7cells was also significantly inhibited by Garcinol(P0.01).Garcinol also significantly inhibited 17β-E2-induced transcription and protein expression of cyclin D1,Bcl-2and Bcl-xL mRNA in MCF-7 cells(P0.05).Conclusion 17β-E2-induced proliferation and apoptosisinhibition of MCF-7 cells are associated with elevated acetylation level of histone and nonhistone NF-κB/p65,and acetyltransferase inhibitor Garcinol may inhibit the effect of 17β-E2 by decreasing acetylation,probably through decreasing acp65 expression of NF-κB pathway,and subsequently down-regulating cyclin D1,Bcl-2,and Bcl-xL.