Cancer Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA.
Cancer Biology and Genetics Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA; Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA.
Cancer Cell. 2018 Mar 12;33(3):527-541.e8. doi: 10.1016/j.ccell.2018.01.018. Epub 2018 Mar 1.
Synovial sarcoma is an aggressive cancer invariably associated with a chromosomal translocation involving genes encoding the SWI-SNF complex component SS18 and an SSX (SSX1 or SSX2) transcriptional repressor. Using functional genomics, we identify KDM2B, a histone demethylase and component of a non-canonical polycomb repressive complex 1 (PRC1.1), as selectively required for sustaining synovial sarcoma cell transformation. SS18-SSX1 physically interacts with PRC1.1 and co-associates with SWI/SNF and KDM2B complexes on unmethylated CpG islands. Via KDM2B, SS18-SSX1 binds and aberrantly activates expression of developmentally regulated genes otherwise targets of polycomb-mediated repression, which is restored upon KDM2B depletion, leading to irreversible mesenchymal differentiation. Thus, SS18-SSX1 deregulates developmental programs to drive transformation by hijacking a transcriptional repressive complex to aberrantly activate gene expression.
滑膜肉瘤是一种侵袭性癌症,总是与涉及编码 SWI-SNF 复合物成分 SS18 和 SSX(SSX1 或 SSX2)转录抑制剂的染色体易位相关。通过功能基因组学,我们确定了组蛋白去甲基酶 KDM2B,作为非典型多梳抑制复合物 1(PRC1.1)的组成部分,是维持滑膜肉瘤细胞转化所必需的。SS18-SSX1 与 PRC1.1 物理相互作用,并与 SWI/SNF 和 KDM2B 复合物在未甲基化的 CpG 岛上共定位。通过 KDM2B,SS18-SSX1 结合并异常激活发育调控基因的表达,否则这些基因是多梳介导的抑制的靶标,在 KDM2B 耗尽后恢复,导致不可逆的间充质分化。因此,SS18-SSX1 通过劫持转录抑制复合物异常激活基因表达来调节发育程序以驱动转化。