The Molecular Mechanism Of Metapristone On Lung Cancer By Inhibiting EGFR And Downstream Signaling Pathways

Objective:The aim of this study is to observe the effect of metapristone on proliferation and apoptosis ability of erlotinib resitance non-small lung cancer cell,to study its anti-tumor effect and molecular mechanism in vivo and in vivo.Methods:The cell proliferation and toxicity were determined using CCK8 colorimetric assay.After the non-small lung cancer cells A549,H1975,H1975,H520 and HCC827 were treated with the erlotinib,high-efficiency metapristone concentration and erlotinib-resistant or sensitive cells was selected.The light microscope and fluorescence microscope after DAPI staining,Propidium Iodide,mitochondrial membrane potential,Annexin V-FITC/PI double staining and caspase-3 activity assays in vitro were performed to evaluate the effects of metapristone on the apoptotic morphology,cell cycle and apoptosis of A549 and H975 cells.In nude mice A549 cells non-small lung cancer xenograft model was used to evaluate the anti-tumor activity of metapristone in vivo.Expression of genes and proteins were determined by quantitative real-time reverse transcription-PCR,western blotting and immunohistochemical staining,respectively.Results:Our results showed that A549,H1299,H1975 and H520 cells were erlotinib resitance cells,HCC827 was erlotinib sensitive cells.Metapristone significantly inhibited A549,H1299 and H1975 cells proliferation in dose-time dependent.Metapristone significantly inhibited A549 and H197 cells cycle and induced apoptosis in a dose-dependent manner in vitro.Metapristone was significantly inhibited the growth of tumor volume in vivo,80mg/kg of metapristone the inhibition rate was 79.47%.Further studies showed that metapristone significantly inhibited the expression of PARP and PCNA,activated caspase-3,down-regulated Bcl-2 and Bax protein,up-regulated P53 protein and gene regulation level.Further more,metapristone could also down-regulate inherent EGFR and EGF-included EGFR,its downstream pathway proteins including CyclinDl,p-AKT,P-ERK and PTEN.Conclusion:Metapristone was highly effective in suppressing cancer growth,including cell proliferation and apoptosis in vitro and in vivo.The mechanism probably attributed to P53 pathways that regulated PARP,caspase-3,Bcl-2 and Bax apoptotic protein and modulated expression of PI3K/PTEN/AKT and RAF/ERK/MAPK within EGFR signaling pathway in A549 and H1975 cells.Thus metapristone intervenes the.cell proliferation and apoptosis of non-small lung cancer cells and exerts significant anti-tumor activity.