1] Center for Clinical Molecular Medicine, Children's Hospital, Chongqing Medical University, Chongqing 400014, China [2] Department of Laboratory Medicine, Children's Hospital, Chongqing Medical University, Chongqing 400014, China [3] Ministry of Education Key Laboratory of Child Development and Disorders, Children's Hospital, Chongqing Medical University, Chongqing 400014, China [4] Key Laboratory of Pediatrics in Chongqing, Children's Hospital, Chongqing Medical University, Chongqing 400014, China.
Chongqing Stem Cell Therapy Engineering Technique Center, Children's Hospital, Chongqing Medical University, Chongqing 400014, China.
Br J Cancer. 2014 Jul 29;111(3):568-76. doi: 10.1038/bjc.2014.335. Epub 2014 Jun 17.
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.
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).
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.
Our findings reveal a novel function of β-arrestin1 binding to EZH2 to promote CML progression by regulating BCR/ABL H4 acetylation.
β-arrestin 是一种与各种细胞信号相互作用的支架蛋白。虽然 β-arrestin2 介导髓性白血病的起始和进展，但β-arrestin1 在慢性髓性白血病（CML）中的关键作用尚不清楚。本研究旨在探讨β-arrestin1 在 CML 中的重要功能。
通过 RT-PCR、免疫荧光和 Western blot 检测 CML 患者、动物模型和 K562 细胞中β-arrestin1 和 BCR/ABL 的表达。通过集落形成、MTT 和生存分析评估β-arrestin1 对 CML 动物模型和 K562 细胞的影响。通过染色质免疫沉淀（ChIP）-on-chip 分析和 ChIP 分别分析 BCR/ABL H4 乙酰化。共免疫沉淀和共聚焦检测β-arrestin1 与增强子的结合EZH2 同源物 2（EZH2）。
β-arrestin1 的高表达与 CML 患者的临床分期呈正相关。β-arrestin1 的耗竭会减缓 K562 和原代细胞的进展，并增加 CML 小鼠的存活率。重要的是，沉默β-arrestin1 会导致 K562 细胞中 BCR/ABL H4 乙酰化水平降低。进一步的数据表明，核β-arrestin1 与 EZH2 结合，介导 BCR/ABL 乙酰化，从而调节 K562 细胞的细胞进展和 CML 小鼠的存活。
我们的研究结果揭示了β-arrestin1 与 EZH2 结合的新功能，通过调节 BCR/ABL H4 乙酰化来促进 CML 的进展。
