β-Arrestin1 promotes the progression of chronic myeloid leukaemia by regulating BCR/ABL H4 acetylation

BACKGROUND: β-Arrestins are scaffold proteins that interact with various cellular signals. Although β-arrestin2 mediates the initiation and progression of myeloid leukaemia, the critical role of β-arrestin1 in the chronic myeloid leukaemia (CML) is still unknown. The aim of this study is to investigate the essential function of β-arrestin1 in CML. METHODS: The expressions of β-arrestin1 and BCR/ABL in CML patients, animal models and K562 cells were measured by RT–PCR, immunofluorescence and western blotting. The effect of β-arrestin1 on CML animal models and K562 cells by colony formation, MTT and survival analysis were assessed. BCR/ABL H4 acetylation was analysed through the use of Chromatin-immunoprecipitation (ChIP) -on-chip and confirmed by ChIP respectively. Co-immunoprecipitation and confocal were examined for the binding of β-arrestin1 with enhancer of zeste homologue 2 (EZH2). RESULTS: The higher expression of β-arrestin1 is positively correlated with clinical phases of CML patients. Depletion of β-arrestin1 decelerates progression of K562 and primary cells, and increases survival of CML mice. Importantly, silenced β-arrestin1 results in the decrease of BCR/ABL H4 acetylation level in K562 cells. Further data illustrate that nuclear β-arrestin1 binds to EZH2 to mediate BCR/ABL acetylation and thus regulates cell progression in K562 cells and the survival of CML mice. CONCLUSIONS: Our findings reveal a novel function of β-arrestin1 binding to EZH2 to promote CML progression by regulating BCR/ABL H4 acetylation.