Sandow Jarrod J, Infusini Giuseppe, Holik Aliaksei Z, Brumatti Gabriela, Averink Tessa V, Ekert Paul G, Webb Andrew I
The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville, Australia.
Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Australia.
Proteomics Clin Appl. 2017 Sep;11(9-10). doi: 10.1002/prca.201700013. Epub 2017 May 15.
Chromosomal translocation of the mixed lineage leukemia (MLL) locus generates fusion proteins that drive acute myeloid leukemia (AML) resulting in atypical histone methyltransferase activity and alterations in the epigenetic regulation of gene expression. Targeting histone regulators, such as Enhancer of Zeste Homologue 2 (EZH2), has shown promise in AML. Profiling differential protein expression following inhibition of epigenetic regulators in AML may help to identify novel targets for therapeutics.
Murine models of AML combined with quantitative SILAC analysis were used to identify differentially expressed proteins following inhibition of EZH2 activity using 3-Deazaneplanocin A (DZnep). Western blotting and flow cytometry were used to validate a subset of differentially expressed proteins. Gene set analysis was used to determine changes to reported EZH2 target genes.
Our quantitative proteomic analysis and subsequent validation of protein changes identified that epigenetic therapy leads to cell death preceded by the induction of differentiation with concurrent p53 up-regulation and cell cycle arrest. Gene set analysis revealed a specific subset of EZH2 target genes that were regulated by DZnep in AML.
These discoveries highlight how this new class of drugs affects AML cell biology and cell survival, and may help identify novel targets and strategies to increase treatment efficacy.
混合谱系白血病（MLL）基因座的染色体易位产生融合蛋白，驱动急性髓系白血病（AML），导致非典型组蛋白甲基转移酶活性以及基因表达表观遗传调控的改变。靶向组蛋白调节剂，如Zeste同源物2增强子（EZH2），已在AML治疗中显示出前景。分析AML中表观遗传调节剂抑制后的差异蛋白表达可能有助于识别新的治疗靶点。
利用AML小鼠模型结合定量SILAC分析，以鉴定使用3-去氮杂氮胞苷（DZnep）抑制EZH2活性后差异表达的蛋白质。采用蛋白质印迹法和流式细胞术验证差异表达蛋白质的一个子集。基因集分析用于确定已报道的EZH2靶基因的变化。
我们的定量蛋白质组学分析及随后对蛋白质变化的验证表明，表观遗传疗法导致细胞死亡，之前伴有分化诱导、p53上调和细胞周期停滞。基因集分析揭示了AML中受DZnep调控的EZH2靶基因的一个特定子集。
这些发现突出了这类新型药物如何影响AML细胞生物学和细胞存活，并可能有助于识别新的靶点和提高治疗疗效的策略。
