Study Of Methylation Status In The Promoter Of SPRED1 Gene In Acute Myeloid Leukemia

Objective: Acute myeloid leukemia?AML?is a malignant clonal disease of hemopoietic stem cells characterized by the inhibition of differentiation and subsequent accumulation of cells at various stages of immaturity,and also by the decreased production of normal hemopoietic ingredients.Epigenetics refers to changes in gene expression but without changes in the DNA sequence itself.Currently,the most widely studied epigenetic modification in humans is DNA methylation,which occurs almost exclusively in the context of Cp G dinucleotides that control the transcriptional activity of genes and is observed in various diseases.Epigenetic silencing of tumor suppressor genes plays important role in acute myeloid leukemia?AML?.Human sprout-related EVH1 domain–containing 1?SPRED1?gene is located in 15q13.2 containing seven exons.Human SPRED1 protein consists of 444 amino acids and 3 domains.Recently,SPRED1,a negative regulator of the RAS MAPK pathway,is identified as a tumour suppressor downregulated in AML.In this study,we investigated methylation status of SPRED1 promoters and their association with m RNA levels and prognostic parameters in AML.Methods: Methylation level were measured in one regions of SPRED1?#1: 310 bp ⁷23 bp?in a total of 50 patients with acute myelocytic leukemia?AML?and 20 healthy controls using the Sequenom Mass ARRAY platform.Quantitative real-time polymerase chain reaction?q-RT PCR?was used to analyze SPRED1 m RNA levels.The Mann–Whitney test was performed to evaluate the significance of any differences between the patients with AML and controls.The Spearman correlation analysis was performed to evaluate the correlations between methylation statuses and m RNA levels of SPRED1 genes.All statistical analysis was two sided,and a P value significant.Results: AML patients had a significantly higher average methylation level than controls at regions of #1_Cp G₁?p< 0.01?,#1_Cp G₂?p=0.031?and #1_Cp G₁1 p=0.039).The methylation values for #1_Cp G₁1 were negatively correlated with m RNA levels?r=-0.427,p=0.004?but there was no significant association between #1_Cp G₁,#1_Cp G₂ methylation status and m RNA levels?r=-0.005,p=0.972;r=-0.033,p=0.822,respectly?in AML patients.There was no significant difference in the#1_Cp G₁1 methylation level when comparing with prognostic parameters?p>0.05?.The methylation level of 1_Cp G₁ in AML patients?including CR group and NR group?before induction therapy was higher than that after induction therapy?p=0.039?.The methylation level of 1_Cp G₁ in CR AML patients before induction therapy was higher than that after induction therapy?p=0.027?.Conclusions: Aberrant methylation statuses of the SPRED1 promoter regions are associated with the downregulation of gene transcription and treatment response in AML.