Expression Of CGAS And STING Genes In Non-M3 Acute Myeloid Leukemia And Its Effect On Prognosis

Research Purpose:Recent studies have reported that the cGAS-STING signaling pathway can produce anti-tumor effects through the immune mechanisms and play a critical role in tumor occurrence and development.Our preliminary bioinformatic data showed that cGAS and STING express significantly higher in AML cells when comparing with other tumor cells,but the clinical implication of cGAS and STING are stills unclear.Therefore,this study aims to further clarify the expression of cGAS and STING genes in AML(except M3 group)and explore their clinical significance,so as to provide a theoretical basis for individualized stratified therapy.Research method:We first analyzed the expression of cGAS and STING in AML using GEPIA and GEO databases.Then,bone marrow samples from 120 AML patients(except M3 group)diagnosed between 2018 and 2020 and 15 healthy donors were collected and processed for cGAS and STING gene expression levels detection by RT-q PCR.Thirdly,we divided cGAS and STING into low expression group and high expression group according to the median value.SPSS-20 software was used to compare the differences in laboratory indicators of patients with low expression group and analyze the effects on clinical prognosis.Finally,Speraman correlation analysis was performed on the expression levels of cGAS and STING in 120 AML patients.Research results:The GEPIA database showed that the expressions of cGAS and STING were significantly higher in AML comparing with the normal control group(P<0.05).The expressions of cGAS and STING genes in GEO GSE63270 and GEO GSE30029 database were higher than those in normal control group(Mann Whitney U=440,P<0.0001;Mann Whitney U=526,P<0.0001,Fig.2B)and(Mann Whitney U=376,P=0.0005;Mann Whitney U=123,P<0.0001,Fig.2C).Then,RT-q PCR results showed that the expressions of cGAS and STING were dramatically increased in non-M3 AML patients compared with the control group(Mann Whitney U=199,P<0.0001;Mann Whitney U=584.5,P=0.0274,Fig.2D).Furthermore,high and low expression patients through SPSS software in laboratory index,found in the cGAS low expression group and cGAS high expression in leukemia risk stratification exists obvious difference(X ~2=8.261,P=0.040,table3).Patients in the high-expression group had higher NRAS/KRAS mutation rate(X~2=4.235,P=0.040,table 3),and lower CR rate(X ~2=13.322,P<0.0001,table 3).There were no remarkable differences in age,WBC,HB,PLT,LDH,percentage of bone marrow blast counts,karyotype and other common genetic mutations between the two groups(P>0.05,table 3).Compared with the lower expression group of STING,the group with high expression of STING had higher NRAS/KRAS mutation rate(X ~2=9.366,P=0.002,Table 4).There was no statistical significance in age,WBC,HB,PLT,LDH,percentage of bone marrow blasts,karyotype,other common gene mutations and CR rate between the two groups(P>0.05,Table 4).Furthermore,Kaplan-Meier analysis indicated that the overall survival(OS)and disease free survival(DFS)of patients with high expression of cGAS(P=0.007,Fig.3A;P=0.012,Fig.3B)and STING(P=0.004,Fig.3C;P=0.034,Fig.3D)were observably shorter than those with low expression.Cox univariate and multivariate survival analysis further indicated that high expression of cGAS was an independent adverse prognostic factor affecting OS(HR=2.348,95%CI: 1.012-5.447;P=0.047,Table 5)and DFS(HR=2.420,95%CI:1.071-5.469;P=0.034,Table 6)in non-M3 AML patients.Finally,through Speraman correlation analysis,cGAS expression was positively correlated with STING expression(Speraman, R=0.77,P<0.0001;Figure 4).Conclusions:1.The expressions of cGAS and STING in AML(except M3 group)were significantly higher than those in the normal control group.2.The expression of cGAS gene is associated with risk stratification,NRAS/KRAS mutation,CR rate,OS and DFS;The expression of STING gene is associated with NRAS/KRAS mutation,OS and LFS.3.The high expression of cGAS gene was an independent prognostic factor in non-M3 AML patients.4.In non-M3 AML,cGAS gene expression was positively correlated with STING gene expression.