Inhibition Of Thioredoxin Reductase By Auranofin Induced Antiangiogenesis And Radiosensitation Of NSCLC

PartⅠAuranofin Enhances Radiation sensitivity of NSCLC cellsObjective:Our goals in this study were to determine the role of Auranofin on radiation sensitivity of human non-small cell lung cancer cells in vitro.Methods:MTT assays were performed to study the effect of Auranofin on cell viability of human adenocarcinoma cells A549and human large cell lung cancer cells H460. We further analyzed cell survival of a combined treatment which A549cells underwent0,0.25,0.5or1.0μM Auranofin pretreatment firstly and irradiated with different doses of X-ray radiation afterwards, and calculated the parameters of radiation sensitivity.Result:Auranofin inhibited the cell viability of A549and H460cells on dose-dependent and time-dependent manner. The SF2of cell survival culve of0,0.25,0.5and1.0μM Auranofin pretreatment radiation group is0.827、0.7、0.653and0.393, respectively. The SER of1.0μM Auranofin pretreatment A549cells is3.0.Conclusion:Auranofin could enhance the radiation sensitivity of NSCLC cells. Part IIThe mechanism of Auranofin on radiation sensitivity in non small cell lung cancerObjective:Our goals in this study were to research the mechanism Auranofin enhance the radiation sensitivity of non small cell lung cancerMethods:Modified DTNB reduction assay was performed to determine TrxR activity of A549cells treated with Auranofin. HO-1protein was analysis by Western bloting after Auranofin treatment. phospho-JNK/P38, protein expression of anti-apoptosis family IAP, BCL2, and TRAF, mitochondrial potential, translocation of Bax to mitochondrial and cleaved PARP was determined when A549cells were treated by Auranofin pretreatment followed by radiotherapy.Results:By using the specific inhibitors Auranofin, activity of TrxR1and expression of HO-1protein were reduced. In Auranofin-radiotherapy treatment A549and H460cells, increasing of phospho-JNK/P38, protein expression inhibition of antiapoptosis family IAP, Bcl-2, and TRAF, mitochondrial potential decreasing, translocation of Bax to mitochondrial and cleaved PARP after X-ray radiation were developed to a much higher extent than X-ray radiation or Auranofin treatment only. By blocking Bax translocation using Bax inhibiting peptide, the Auranofin-enhanced radiosensitivity of A549was reduced.Conclusion:Our data suggest that Auranofin reduced the activity of TrxR and expression of HO-1protein, induced translocation to mitochondrial of bax, triggerd the apoptosis of cells exposes to radiation, and finally enhanced the radiation sensitivity of NSCLC cells. Part ⅢThe effect of Auranofin on angiogensis of lung cancerObjective:The present studies were designed to test the hypothesis that Auranofin negatively regulates VEGF through effects on transcriptional factor HIF1α, HIF2a or Sp1expression.Methods:To test this hypothesis, we first examined the levels of HIF1α, HIF2a or Sp1in A549and H460cells treatment with Auranofin. Then, we studied the effects of Auranofin on VEGF by Western. To overview the total effect of data above on angiogensis. Tranwells assay was perform to value the analysis of HUVECs when co-culture with A549cells treated with AuranofinResults:In Auranofin-treated A549and H460cells, decreasing of HIF2α, Spl, VEGF and increasing VEGF165b was observed. But Auranofin did not alter HIF1α expression in A549cells and increasing in H460cells. Auranofin enhanced the invasion of HUVECs when co-culture with A549cells.Conclusion:Auranofin could alter Transcriptional factor HIF1α, HIF2α and Sp1and VEGF expression in NSCLC cells and contribute to the inhibition of invasion of HUVECs.