The Relationship Between Caveolin-1 Gene And Energy Metabolism In Lung Adenocarcinoma And Its Mechanism

Objective:This study was designed to detect the relationship between synthesis of cytochrome c oxidase 2(SC02)and TP53-induced glycolysis and apoptosis regulator(TIGAR)expression level and tumor energy metabolism and its clinical significance in lung adenocarcinoma(AC),and to further investigate the effects of down-regulation of caveolin-1(Cav-1)combined with curcumin on the expression of SC02 and TIGAR,and cell activity and glucose metabolism in AC cells,finally which provide a new theoretical basis for targeted therapy and pathogenesis of lung AC.Methods:Part1:The expression of SCO2±TIGAR and p53 proteins were detected by quantum dots-based immunofluorescence histochemistry,and statistical analysis and survival assay were completed according to clinical prognosis data in lung AC tissues.Part 2:MTT assay was used to detect the effects of curcumin on the activity of lung adenocarcinoma A549 and SPC-A-1 cell lines.The SC02 and TIGAR localization was detected by immunofluorescence,in addition,the changes of cell morphology and number of cells were observed after curcumin treatment.The effects of curcumin on Cav-1,p53,SC02 and TIGAR mRNA were detected by qPCR technique and protein levels were detected by Western blot at different times on SPC-A-1.Simultaneously,the expression of Cav-1,p53,SC02,TIGAR proteins were detected by Western blot,after curcumin(0,5,10,20,30 and 40 ?M)treatment.Finally,knockdown of Cav-1 gene in A549 cells by siRNA technique,western blot was used to detect the knockdown efficiency of Cav-1 and the effect on the expression of SC02 and cyclinDl proteins.Results:Part 1:1.There was no significant association between the expression of SC02,p53 proteins and clinicopathological parameters of lung AC tissues(P>0.05),whereas,the positive rates of TIGAR in lung AC tissues was related to patients gender and smoking history(P<0.05);2.The survival curve presented that high SC02 expression and high TIGAR expression in lung AC predicted poorer survival and high mortality rate(P=0.024;P=0.030);3.High TIGAR expression was significantly correlated with high SC02 expression in cancer cells(P=0.019,rs=0.271);4.The multivariate analysis indicated that TIGAR expression in cancer cells(HR=2.819,95%CI=1.101-7.216,P=0.031)and tumor size(T)(HR=0.343,95%CI=0.149-0.792,P=0.012)were independent predictors for lung AC prognosis.Part 2:1.Curcumin inhibited the growth of A549 and SPC-A-1 cells in a time and dose-dependent manner,and decreased the expression of cyclinDl protein;2.SC02 and TIGAR proteins were located in the cytoplasm of cancer cells by immunofluorescence,in addition,the numbers of cancer cells was significantly decreased,cell morphology changed greatly,mainly for small,round after curcumin treatment;3.The results of qPCR showed that the mRNA level of SC02 and TIGAR decreased first and then increased with the prolongation of curcumin treatment time in SPC-A-1.Whereas,the change of Cav-1 mRNA was not significant,and p53 mRNA showed a downward trend.Howover,when curcumin was treated with the same concentration of SPC-A-1 cells for different time,found that Cav-1,TIGAR and cyclinD1 proteins were significantly decreased with the prolongation of curcumin treatment time;4.Western blot results showed that the expression of Cav-1 decreased with the curcumin concentration increasing in SPC-A-1 cells,and there was no significant alteration for other proteins;However,Cav-1 and SC02 proteins expression showed a downward trend with the increased drug concentration,but p53 protein expression had no significant difference in A549 cell;5.Curcumin significantly inhibited the expression of Cav-1 and SC02 in A549 cell.Furthermore,the expression of SC02 protein was significantly down regulated by Cav-1 siRNA.When curcumin combined with Cav-1 siRNA treated A549 cell simultaneously,the inhibitory effect of Cav-1 and SC02 was more obvious.Conclusion:1.The high expression of SC02 and TIGAR proteins is significantly associated with poor prognosis,suggesting a novel candidate prognostic marker and therapeutic target for lung adenocarcinoma patients;2.Curcumin can inhibit the proliferation of lung adenocarcinoma A549 and SPC-A-1 cells,because curcumin may down-regulate Cav-1 expression;3.Cav-1 may regulate the expression of SC02 in lung adenocarcinoma,which may affect the energy metabolism of tumor.