小鼠中MOZ-TIF2癌蛋白的表达可抑制细胞衰老。
Expression of the MOZ-TIF2 oncoprotein in mice represses senescence.
作者信息
Largeot Anne, Perez-Campo Flor Maria, Marinopoulou Elli, Lie-a-Ling Michael, Kouskoff Valerie, Lacaud Georges
机构信息
Cancer Research UK Stem Cell Biology Group, CR-UK Manchester Institute, University of Manchester, Manchester, UK.
Cancer Research UK Stem Cell Biology Group, CR-UK Manchester Institute, University of Manchester, Manchester, UK.
出版信息
Exp Hematol. 2016 Apr;44(4):231-7.e4. doi: 10.1016/j.exphem.2015.12.006. Epub 2016 Feb 5.
The MOZ-TIF2 translocation, which fuses monocytic leukemia zinc finger protein (MOZ) histone acetyltransferase (HAT) with the nuclear co-activator TIF2, is associated with the development of acute myeloid leukemia. We recently found that in the absence of MOZ HAT activity, p16(INK4a) transcriptional levels are significantly increased, triggering an early entrance into replicative senescence. Because oncogenic fusion proteins must bypass cellular safeguard mechanisms, such as senescence and apoptosis, to induce leukemia, we hypothesized that this repressive activity of MOZ over p16(INK4a) transcription could be preserved, or even reinforced, in MOZ leukemogenic fusion proteins, such as MOZ-TIF2. We describe here that, indeed, MOZ-TIF2 silences expression of the CDKN2A locus (p16(INK4a) and p19(ARF)), inhibits the triggering of senescence and enhances proliferation, providing conditions favorable to the development of leukemia. Furthermore, we describe that abolishing the MOZ HAT activity of the fusion protein leads to a significant increase in expression of the CDKN2A locus and the number of hematopoietic progenitors undergoing senescence. Finally, we report that inhibition of senescence by MOZ-TIF2 is associated with increased apoptosis, suggesting a role for the fusion protein in p53 apoptosis-versus-senescence balance. Our results underscore the importance of the HAT activity of MOZ, preserved in the fusion protein, for repression of the CDKN2A locus transcription and the subsequent block of senescence, a necessary step for the survival of leukemic cells.
MOZ-TIF2易位将单核细胞白血病锌指蛋白(MOZ)组蛋白乙酰转移酶(HAT)与核共激活因子TIF2融合,与急性髓系白血病的发生有关。我们最近发现,在缺乏MOZ HAT活性的情况下,p16(INK4a)转录水平显著升高,引发细胞过早进入复制性衰老。由于致癌融合蛋白必须绕过细胞保护机制,如衰老和凋亡,才能诱发白血病,我们推测MOZ对p16(INK4a)转录的这种抑制活性在MOZ致白血病融合蛋白(如MOZ-TIF2)中可能得以保留,甚至增强。我们在此描述,事实上,MOZ-TIF2使CDKN2A基因座(p16(INK4a)和p19(ARF))的表达沉默,抑制衰老的触发并增强增殖,为白血病的发生提供了有利条件。此外,我们还描述了消除融合蛋白的MOZ HAT活性会导致CDKN2A基因座的表达显著增加以及经历衰老的造血祖细胞数量增加。最后,我们报告MOZ-TIF2对衰老的抑制与凋亡增加有关,提示该融合蛋白在p53凋亡与衰老平衡中起作用。我们的结果强调了融合蛋白中保留的MOZ HAT活性对于抑制CDKN2A基因座转录以及随后阻止衰老的重要性,这是白血病细胞存活的必要步骤。