Study Of Methylation Of Galectin-1 Gene In Patients With Acute Myeloid Leukemia

Objective: To study the methylation level of Galectin-1 gene in acute myeloid leukemia(AML)and to explore the relationship between Galectin-1gene expression and promoter methylation.Methods: All patients come from the Oncology Department of Xiangya hospital of Central South University during January 2014-December 2015,54 cases of patients bone marrow with AML before the treatment,8 cases of patients bone marrow with AML complete remission after treatment and 35 cases of normal bone marrow as control,the methylation status of Galectin-1 gene were detected by methylation specific PCR(MS-PCR).After the Leukemia cell lines [AML cell lines: HL-60,Kasumi-1,THP-1 and chronic myeloid leukemia(CML)cell line: K562] were all treated with 5-aza-2 ’-deoxycytidine(5-aza-2dC),MS-PCR were used to detect the methylation status of Galectin-1 gene,RT-PCR were used to detect expression of Galectin-1 mRNA,werstern blot were used to expression detect expression of Galectin-1.Results:(1)The expression level of Galectin-1 gene in the bone marrow of AML was significantly lower than the control group(0.35+0.09 VS 0.87+0.22)(t=11.124,P=0.000);The expression level of Galectin-1 gene in the bone marrow of complete remission of AML was significantly higher than that of before treatment(0.79+0.21 VS 0.33+0.11)(t=9.512,P,=0.000).(2)The positive rate of Galectin-1 gene methylation was 79.6%(43/54)inAML,positive control group was 17.1%(6/35),the positive rate of methylation was significantly higher than that of control group(χ2=33.510,P=0.000);the positive rate of Galectin-1 methylation in AML before treatment was 75%(6/8),and it was 12.5(1/8)in AML for complete remission,there was significant difference between them(2=6.349,P=0.012).(3)The methylation level of Galectin-1 gene in AML cell lines was higher than that of CML cell line(P < 0.01);Galectin-1 mRNA expression level in AML cell lines was significantly lower than that in that of CML cell line(P<0.01).After treated by 5-aza-2dC,the expression level of Galectin-1 mRNA was significantly higher in AML cell lines than that in CML cell lines(P<0.01)and there was no significant difference between the expression of Galectin-1 mRNA in CML cell line and AML cell lines.(4)Galectin-1 expression level in AML cell lines was significantly lower than that in that of CML cell line(P<0.01).After treated by 5-aza-2dC,the expression level of Galectin-1 was significantly higher in AML cell lines than that in CML cell lines(P<0.01).and there was no significant difference between the expression of Galectin-1 in CML cell line and AML cell lines.(5)After 5-aza-2dC treatment,the methylation level of Galectin-1 gene in AML cell lines was significantly downregulated(P<0.01),while the methylation level of Galectin-1 gene in CMLwas not significantly reduced.Conclusion:(1)The promoter hypermethylation was founded in AML and lead to downregulation of Galectin-1 gene.(2)5-aza-2dC can promote the expression of Galectin-1 gene and protein through demethylation.