Study On The Effect Of Endoplasmic Reticulum Stress On Osteosarcoma Cell Apoptosis Induced By Stat3 Inhibitor Pimozide

Background Stat3 play an important role in cancer cell proliferation,its showed obvious activation in a wide variety of tumor,targeting the stat is a effective direction and control of cancer to develop targeted stat for this inhibitor pimozide.Endoplasmic reticulum stress is a common phenomenon in cells,often caused by the increase of unfoldable protein and misfolded protein.Research shows that antitumor drugs at the time of death caused by death or apoptosis tends to induce endoplasmic reticulum stress,and endoplasmic reticulum stress in the cell death induced by anti-tumor drugs play an important role,so the targeted endoplasmic reticulum stress as a novel strategy.Purpose Through this topic clear endoplasmic reticulum stress in apoptosis induced by pimozide,explore pimozide induced cell death mechanism,to better target the stat provides the new ideas to treatment of osteosarcomaMethods(1)MTT method was used to detect the effect of pimozide and the survival rate of U2 OS osteosarcoma cells.(2)Western blotting method was used to detect the expression of apoptosis-related proteins(caspase-3,PARP,bcl-2,Bax,Cytochrome C)and endoplasm signaling pathway proteins(GRP78,PERK,elf-2a,and ATF4).(3)Annexin v-fitc/PI dual-dye flow cytometry was used to detect apoptosis.(4)The changes of mitochondrial membrane potential of the cell were detected by JC-1 staining flow cytometry.(5)Using elf-2a si RNA cell transfection and endoplasmic reticulum stress inhibitor 4-PBA to observe the effect of inhibiting endoplasmic reticulum stress on the cell death and apoptosis induced by pimozide.Results(1)Pimozide can significantly inhibit the growth of U2 OS,in dose-dependent and time-dependent manner.(2)Pimozide induced apoptosis of cleaved caspase 3,cleaved PARP protein levels higher expression level,increase the rate of cell apoptosis,mitochondrial apoptosis related proteins expression of Cytochrome C levels rise,reduce the Bcl-2 /Bax ratio decreased,mitochondrial membrane potential decline at the same time.(3)Different concentrations of Pimozide can significantly increase the expression level of stress related protein GRP78,PERK,elf-2a,and ATF4 in U2 OS cells.(4)The combination of elf-2a si RNA and endoplasmic reticulum stress inhibitor4-pba can significantly enhance the cell survival rate induced by pimozide and the increase of apoptosis related protein expression.Conclusion Stat3 inhibitors pimozide decreased cell survival rate through apoptosis,endoplasmic reticulum stress can be induced to occur at the same time,inhibition of endoplasmic reticulum stress increased apoptosis induced by pimozide,as a result,the joint pimozide and endoplasmic reticulum stress inhibitors may be as a new strategy for clinical treatment of osteosarcoma.