| Object: Lung cancer is one of the leading causes of cancer deaths worldwide.Lung cancer is divided into small cell lung cancer and nonsmall cell lung cancer(NSCLC).NSCLC is divided into lung squamous cell carcinoma(LUSC),large cell lung cancer and lung adenocarcinoma.Among them,LUSC patients are closely related to smoking,and the incidence is relatively high,accounting for about 30%of the total number of NSCLC.LUSC does not respond well to the currently widely used targeted drugs and conventional chemotherapeutic drugs,and is mostly in the late stage when discovered,and the prognosis is poor.Therefore,there is an urgent need to research and develop effective targeted drugs for LUSC.Studies have shown that fibroblast growth factor 1(FGFR1)expansion is a risk factor for poor prognosis in NSCLC patients.FGFR1 expansion is found in approximately 16% to 20% of LUSC cases.Therefore,targeted inhibition of FGFR1 may be a new and effective way to treat LUSC.BGJ398 is a selective FGFR inhibitor.Studies have shown that BGJ398 has a pro-apoptotic effect on ovarian cancer,metastatic urothelial cancer,cholangiocarcinoma and bladder cancer,but its role in the treatment of LUSC is still unclear.The purpose of this study was to explore the effect of BGJ398 on lung squamous cell carcinoma cell lines and its mechanism.Methods:(1)The MTT assay and Annexin V-FITC/PI double staining apoptosis kit combined with flow cytometry were used to detect the effect of BGJ398 on the proliferation and apoptosis of LUSC cell lines H520 and H226.(2)The DCFH-DA probe labeling method combined with flow cytometry was used to detect the effect of BGJ398 on the reactive oxygen species(ROS)in the LUSC cell lines H520 and H226.(3)The effect of BGJ398 on the mitochondrial ROS level in LUSC cell line was detected by the Mito SOX Red probe labeling method combined with fluorescence microscope.(4)In H520 and H226 cells,after administration of BGJ398 for 12 hours,the activities of mitochondrial complex I and complex III were detected using the mitochondrial complex Ⅰ and complex Ⅲ activity detection kit,respectively.(5)The JC-1 probe labeling method combined with flow cytometry was used to detect the effect of BGJ398 on the mitochondrial membrane potential(MMP)of LUSC cell lines H520 and H226.(6)Western blotting was used to detect the changes in the protein expression of JAK2,p-JAK2,Src,p-Src,STAT3,p-STAT3,Bcl-2,and Survivin 12 hours after the administration of BGJ398.In the LUSC cell line overexpressing STAT3 or adding Mito-TEMPO,after administration of BGJ398 for 12 hours,the protein expression changes of STAT3,p-STAT3,Bcl-2,and Survivin were observed.Result:(1)BGJ398 decreased the activity of LUSC cells in a dose-dependent and time-dependent manner,and its half inhibitory concentration(IC50)in H520 and H226 cells was 7.82±0.35 μM and11.82±0.55 μM,respectively.(2)BGJ398 induced apoptosis in LUSC cell lines H520 and H226 in a dose-dependent manner.(3)BGJ398dose-dependently increased the ROS levels of LUSC cell lines H520 and H226.(4)BGJ398 increased mitochondrial ROS levels in LUSC cell lines H520 and H226.(5)BGJ398 dose-dependently reduced the levels of MMP and the activities of mitochondrial complex I and III in LUSC cell lines H520 and H226.(6)BGJ398 dose-dependently inhibited the protein expression of p-Src,p-STAT3,Bcl-2 and Survivin in H520 and H226 cell lines.(7)In H520 and H226 cell lines,overexpression of STAT3 can reverse the inhibitory effect of BGJ398 on the expression of p-STAT3,Bcl-2,and Survivin,and can partially weaken the pro-apoptotic effect of BGJ398 on cells.(8)In H520 and H226 cell lines,using the specific mitochondrial ROS scavenger MitoTEMPO can reverse the inhibitory effect of BGJ398 on the expression of p-STAT3,Bcl-2,and Survivin,and can partially weaken the proapoptotic effect of BGJ398 on cells effect.Conclusion: The FGFR1 inhibitor BGJ398 inhibits the SrcSTAT3 signaling pathway by producing excessive mitochondrial ROS,thereby inducing LUSC cell apoptosis. |
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