β-Arrestin1Regulates Chronic Myeloid Leukemia Cell Proliferation：in An Epigenetic Genome-Wide Way

ObjectiveOur earlier studies demonstrated that β-arrestin1was significantlyelevated in CML cells,and it promotes CML K562cells proliferation.Here,we innovatived use MDIP-chip and CHIP-DSL in an epigeneticGenome-Wide way to define the epigenetic mechanism in β-arrestin1induced CML proliferation.Methods1. In K562and primary CML cells which were treated withβ-arrestin1-siRNA lentivirus particles respectively, we measured HOX-a9,PTEN, P15and P16expression levels,methylative change and geneacetylation alteration by real-time RT-PCR, Methylation specific PCR (MSP)and chromatin immunoprecipitation(CHIP) respectively.2. We used MDIP-Chip and CHIP-DSL to perform and analyze thealteration methylation profile and acetylation profile in K562cells regulatesby β-arrestin1in an Genome-Wide way.3. We analysis the fusion gene Bcr/Abl methylative and acetylative changes regulated by β-arrestin1.Results1. When β-arrestin1was knockdown,cancer suppressor gene(P15、P16and Pten)occurred hypomethylation,hyperacetylation,and mRNA expressionwas elevated compared with control.However, oncogene HOX-a9has aninverse change.2. The data from methylation MDIP-Chip indicated that themethylative level of whole genome in CML K562cells were decreased, andgenome hypermethylated was more obvious than hypomethylated whenβ-arrestin1knockdown. Despite the differences of CpG island numberbetween two groups located in the all promoter regions, methylativemodifications of influenced CpG island number easily occurred inchromosome1,4,13,14,19and X.3. The data from chromatin immunoprecipitation (ChIP)-DSL showedthat β-arrestin1mediated1316genes histone H4acetylation, with673common genes compared with control group. Clustering analysis showedthat β-arrestin1regulated genes were more likely involved in MAPKsignaling. Signaling analysis show that β-arrestin-1mainly mediated themethylation of genes related to cancers and immune system, the acetylationof genes related to folding sorting and degradation and lipid metabolism.Interestingly, the genes of cell part simultaneously affected with histone H4acetylation and methylation with GO analysis when K562cells depressed β-arrestin1.4. Further results showed that the expression of BCR/ABL was alteredwith the corresponding changes of acetylation and methylation,simultaneously regulated by β-arrestin1.Conclutionβ-arrestin1promotes CML proliferation through a genome-wideepigenetic mechanism,especially regulates the epigenetic modification ofthe marked fusion gene Bcr/Abl.These data demonstrated that β-arrestin1functions as a new regulator in mediating CML cells proliferation through awhole genome epigenetics modification.