Background
Despite its inconsistent response rate, decitabine, a demethylating agent, is often used as a non-intensive alternative therapeutic agent for acute myeloid leukemia (AML). It has been reported that relapsed/refractory AML patients with t(8;21) translocation achieved better clinical outcomes with a decitabine-based combination regimen than other AML subtypes; however, the mechanisms underlying this phenomenon remain unknown. Herein, the DNA methylation landscape of de novo patients with the t(8;21) translocation was compared with that of patients without the translocation. Moreover, the methylation changes induced by decitabine-based combination regimens in de novo/complete remission paired samples were investigated to elucidate the mechanisms underlying the better responses observed in t(8;21) AML patients treated with decitabine.
Conclusion
The findings of this study suggest that LIN7A is a decitabine-sensitive gene in t(8;21) AML patients that may serve as a prognostic biomarker for decitabine-based therapy.
Methods
Thirty-three bone marrow samples from 28 non-M3 AML patients were subjected to DNA methylation sequencing to identify the differentially methylated regions and genes of interest. TCGA-AML Genome Atlas-AML transcriptome dataset was used to identify decitabine-sensitive genes that were downregulated following exposure to a decitabine-based regimen. In addition, the effect of decitabine-sensitive gene on cell apoptosis was examined in vitro using Kasumi-1 and SKNO-1 cells.
Results
A total of 1377 differentially methylated regions that specifically responsive to decitabine in t(8;21) AML were identified, of which 210 showed hypomethylation patterns following decitabine treatment aligned with the promoter regions of 72 genes. And the methylation-silencing genes, LIN7A, CEBPA, BASP1, and EMB were identified as critical decitabine-sensitive genes in t(8;21) AML. Moreover, AML patients with hypermethylated LIN7A and reduced LIN7A expression had poor clinical outcomes. Meanwhile, the downregulation of LIN7A inhibited decitabine/cytarabine combination treatment-induced apoptosis in t(8;21) AML cells in vitro.