Rajan Neil, Elliott Richard J R, Smith Alice, Sinclair Naomi, Swift Sally, Lord Christopher J, Ashworth Alan
The CRUK Gene Function Laboratory and Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, SW3 6JB, UK. Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, NE1 3BZ, UK.
The CRUK Gene Function Laboratory and Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London, SW3 6JB, UK.
Oncotarget. 2014 Dec 15;5(23):12126-40. doi: 10.18632/oncotarget.2573.
CYLD, an ubiquitin hydrolase, has an expanding repertoire of regulatory roles in cell signalling and is dysregulated in a number of cancers. To dissect CYLD function we used a proteomics approach to identify CYLD interacting proteins and identified MIB2, an ubiquitin ligase enzyme involved in Notch signalling, as a protein which interacts with CYLD. Coexpression of CYLD and MIB2 resulted in stabilisation of MIB2 protein levels and was associated with reduced levels of JAG2, a ligand implicated in Notch signalling. Conversely, gene silencing of CYLD using siRNA, resulted in increased JAG2 expression and upregulation of Notch signalling. We investigated Notch pathway activity in skin tumours from patients with germline mutations in CYLD and found that JAG2 protein levels and Notch target genes were upregulated. In particular, RUNX1 was overexpressed in CYLD defective tumour cells. Finally, primary cell cultures of CYLD defective tumours demonstrated reduced viability when exposed to γ-secretase inhibitors that pharmacologically target Notch signalling. Taken together these data indicate an oncogenic dependency on Notch signalling and suggest potential novel therapeutic approaches for patients with CYLD defective tumours.
CYLD是一种泛素水解酶，在细胞信号传导中的调控作用不断扩展，且在多种癌症中失调。为了剖析CYLD的功能，我们采用蛋白质组学方法来鉴定与CYLD相互作用的蛋白质，并确定MIB2（一种参与Notch信号传导的泛素连接酶）为与CYLD相互作用的蛋白质。CYLD和MIB2的共表达导致MIB2蛋白水平稳定，并与Notch信号传导相关配体JAG2水平降低有关。相反，使用小干扰RNA（siRNA）对CYLD进行基因沉默，导致JAG2表达增加和Notch信号传导上调。我们研究了CYLD发生种系突变患者皮肤肿瘤中的Notch信号通路活性，发现JAG2蛋白水平和Notch靶基因上调。特别是，RUNX1在CYLD缺陷的肿瘤细胞中过表达。最后，CYLD缺陷肿瘤的原代细胞培养物在暴露于药理学上靶向Notch信号传导的γ-分泌酶抑制剂时，显示出活力降低。综上所述，这些数据表明对Notch信号传导存在致癌依赖性，并为CYLD缺陷肿瘤患者提出了潜在的新型治疗方法。
