Effects Of EZH2 Inhibitor On Proliferation And Apoptosis Of Tongue Squamous Cell Carcinoma And Its Related Mechanism

ObjectiveThis study aims to study the effect of the enhancer of zeste homolog 2（EZH2）inhibitors GSK126 and EPZ005687 on the proliferation and apoptosis of human tongue squamous cell carcinoma cells CAL-27 in vitro and explore its related mechanisms in order to obtain insights into the clinical treatment of tongue squamous cell carcinoma.MethodsDifferent concentrations of EZH2 inhibitors GSK126 and EPZ005687 were applied to CAL-27 cells of tongue squamous cell carcinoma,and the effects of drugs on cell proliferation were detected through MTT assay,colony formation assay,and Ed U fluorescence staining.Hoechst33342 fluorescence staining and the JC-1 method were used in observing apoptosis.The expression levels of ERK,p-ERK,Bax,Bcl-2,and Cleaved caspase-9 in CAL-27 cells were detected through Western blot.ResultsMTT assay results showed that the cell survival rate continued to decrease with the increase of drug concentration.Compared with DMSO group,GSK126had a more significant inhibitory effect on the proliferation of CAL-27 cells in a concentration-dependent manner.The results of colony formation assay showed that with the increased concentration of EZH2 inhibitors,the number of clones gradually decreased and cell proliferation was inhibited.The results of Ed U fluorescence staining showed that the positive proportion of CAL-27 cells treated with 5 and 10μmol·L^-1 EZH2 inhibitor was significantly lower than that of DMSO group in a concentration-dependent manner.After staining with Hoechst33342,DMSO group showed normal cell morphology,while EZH2inhibitor treatment group showed apoptosis.The results of JC-1 fluorescence probe also suggested that the mitochondrial membrane potential was lower after drug treatment and early apoptosis might be occurring.Western blot results showed that EZH2 inhibitor could down-regulate the expression levels of p-ERK and Bcl-2,and meanwhile increase the expression of Bax and Cleaved caspase-9.ConclusionEZH2 inhibitor can inhibit the proliferation and promote the apoptosis of tongue squamous cell carcinoma CAL-27 cells,and the mechanism may be related to the inhibition of MEK/ERK signaling pathway and the activation of Bax/Bcl-2 signaling pathway.