REST 依赖性下调 von Hippel-Lindau 肿瘤抑制因子促进 SHH 型髓母细胞瘤自噬。
REST-dependent downregulation of von Hippel-Lindau tumor suppressor promotes autophagy in SHH-medulloblastoma.
机构信息
Department of Pediatrics Research, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Unit 853, Houston, TX, 77030, USA.
Center for Cancer Epigenetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd, Houston, TX, 77030, USA.
出版信息
Sci Rep. 2024 Jun 12;14(1):13596. doi: 10.1038/s41598-024-63371-7.
The RE1 silencing transcription factor (REST) is a driver of sonic hedgehog (SHH) medulloblastoma genesis. Our previous studies showed that REST enhances cell proliferation, metastasis and vascular growth and blocks neuronal differentiation to drive progression of SHH medulloblastoma tumors. Here, we demonstrate that REST promotes autophagy, a pathway that is found to be significantly enriched in human medulloblastoma tumors relative to normal cerebella. In SHH medulloblastoma tumor xenografts, REST elevation is strongly correlated with increased expression of the hypoxia-inducible factor 1-alpha (HIF1α)-a positive regulator of autophagy, and with reduced expression of the von Hippel-Lindau (VHL) tumor suppressor protein - a component of an E3 ligase complex that ubiquitinates HIF1α. Human SHH-medulloblastoma tumors with higher REST expression exhibit nuclear localization of HIF1α, in contrast to its cytoplasmic localization in low-REST tumors. In vitro, REST knockdown promotes an increase in VHL levels and a decrease in cytoplasmic HIF1α protein levels, and autophagy flux. In contrast, REST elevation causes a decline in VHL levels, as well as its interaction with HIF1α, resulting in a reduction in HIF1α ubiquitination and an increase in autophagy flux. These data suggest that REST elevation promotes autophagy in SHH medulloblastoma cells by modulating HIF1α ubiquitination and stability in a VHL-dependent manner. Thus, our study is one of the first to connect VHL to REST-dependent control of autophagy in a subset of medulloblastomas.
RE1 沉默转录因子(REST)是 sonic hedgehog(SHH)髓母细胞瘤发生的驱动因素。我们之前的研究表明,REST 增强细胞增殖、转移和血管生长,并阻止神经元分化,从而推动 SHH 髓母细胞瘤肿瘤的进展。在这里,我们证明 REST 促进自噬,这一途径在人类髓母细胞瘤肿瘤中相对正常小脑明显富集。在 SHH 髓母细胞瘤肿瘤异种移植物中,REST 水平升高与缺氧诱导因子 1-α(HIF1α)的表达增加强烈相关,HIF1α 是自噬的正调节剂,与 von Hippel-Lindau(VHL)肿瘤抑制蛋白的表达减少相关,VHL 是一种 E3 连接酶复合物的组成部分,该复合物泛素化 HIF1α。具有更高 REST 表达的人类 SHH 髓母细胞瘤肿瘤表现出 HIF1α 的核定位,与低 REST 肿瘤中 HIF1α 的细胞质定位形成对比。在体外,REST 敲低促进 VHL 水平增加和细胞质 HIF1α 蛋白水平降低以及自噬流增加。相比之下,REST 升高导致 VHL 水平下降及其与 HIF1α 的相互作用减少,导致 HIF1α 泛素化减少和自噬流增加。这些数据表明,REST 升高通过调节 VHL 依赖性 HIF1α 泛素化和稳定性来促进 SHH 髓母细胞瘤细胞中的自噬。因此,我们的研究是第一个将 VHL 与 REST 依赖性控制自噬在髓母细胞瘤的一个亚群中联系起来的研究之一。