The Methylation Status And MRNA Expression Of Dkk-3 And Wif-1 Genes In Acute Myeloid Leukemia Patients

Background and objective:Acute myeloid leukemia(AML)was a source of hematopoietic stem cells malignant hyperplastic diseases,which development was a multiple factors and genes ralated complex process,many intracellular signal transduction pathways and regulation factors involved.Wnt/?-catenin signaling pathway was a deeply studied tumor related signal transduction pathway,and could been detected abnormal activation in a variety of malignant tumor cells.Dkk-3 and Wif-1were important inhibitory regulatory factor of Wnt/?-catenin signaling pathway,while gene promoter methylation could lead to Dkk-3 and Wif-1 gene expression in silence,then lose the inhibition effect in signaling pathway,its may be one of the mechanism in abnormal activation of Wnt signaling pathways.Thus,we conducted this study to analyze promoter methylation status and mRNA expression of Dkk-3 and Wif-1genes in AML cells,plan to explore possible pathogenesis of AL,and then provide some ideas for AL treatment.Methods:The Methylation specific polymerase chain reaction(Methylation specific PCR,MSP)mothod was carried out to detect Dkk-3 and Wif-1 gene promoter methylation status with bone marrow specimen from 56 cases acute myeloid leukemia patients(AML)and 20 patients with iron deficiency anaemia;Then use timely quantitative Reverse transcription polymerase chain reaction(Real time Reverse Transcriptase-PCR,rt-pcr)mothod to detect Dkk-3,Wif-1 gene and?-catenin mRNA expression in the sample told before.Result:1.The promoter methylation rate of Dkk-3 gene in AML patients and control group samples were 31/56 and 1/20 respectively;Similarly,the Wif-1 gene promoter methylation rate were 36/56 and 2/20 correspondently,the promoter methylation rate of Dkk-3 and Wif-1 gene in AML patients were significantly higher than control group(x~2=15.330,P<0.001;x~2=17.371,P<0.001).There is no relationship between Dkk-3 and Wif-1 gene promoter methylation rate and AML patients'gender,age,clinical classification.2.The relative expression of Dkk-3 and Wif-1 gene mRNA were 0.840�0.320 and0.792�0.313,lower than that of control group which were 1.134�0.392 and 1.047�0.334respectively,thedifferencewasstatisticallysignificant(t=3.415,P=0.000;t=3.070,P=0.003).The relative expression of Dkk-3 and Wif-1 gene mRNA have no relationship with AML patients'gender,age,clinical classification.3.The relative expression of?-catenin mRNA in AML bone marrow specimens was0.756�0.304,higher than that of 0.342�0.105 in control group,the difference was statistically significant(t=5.943,P=5.943);The expression of Dkk-3 and Wif-1 gene mRNA were negatively correlated with?-catenin mRNA(r=0.543,P=0.000;r=0.562,P=0.000).4.Kaplan Meier survival curve analysis showed that Dkk-3 gene positively methylation AML patients'overall survival time was shorter than the negatively methylation patients(x~2=3.957,P=3.957).Futhermore,wif-1 gene positively methylation AML patients'overall survival time was also shorter than the negatively methylation patients(x~2=4.520,P=4.520).Conclusion:1.The promoter methylation rate of Dkk-3 and Wif-1 gene in AML patients were high,leaded to the suppressed expression of Dkk-3 and Wif-1 gene,the mRNA value were also descended accordingly.There has no relationship between promoter methylation rate ofDkk-3 and Wif-1 gene with AML patients'age,gender,clinical classification.2.As an important regulatory factor in Wnt signaling transduction pathways,the?-catenin gene mRNA expression was increased relatively,suggested that Wnt/?-catenin signaling pathway was abnormally activated in AML patients.3.The expression of Dkk-3 and Wif-1 gene mRNA have negative correlation with?-catenin gene mRNA level.Promoter methylation leads to the inhibition of Dkk-3 and Wif-1 gene expression of in AML cells,which resulted in the high expression of?-catenin,Dkk-3 and Wif-1 gene promoter methylation may be involved in Wnt pathways activation and the pathogenesis of AML process.4.The overall survival time of Dkk-3 gene postive methylation and Wif-1 gene postive methylation AML patients were shorter than Dkk-3 and Wif-1 gene Methylation negative patients,AML patients with Dkk-3 or Wif-1 gene postive methylation may have poor prognosis.