Regulation of Breast Cancer-Induced Osteoclastogenesis by MacroH2A1.2 Involving EZH2-Mediated H3K27me3

• Main Authors: Jinman Kim, Yonghwan Shin, Sunyoung Lee, Miyeong Kim, Vasu Punj, Jason F. Lu, Hongin Shin, Kyunghwan Kim, Tobias S. Ulmer, Jungmin Koh, Daewon Jeong, Woojin An
• Format: Article
• Language: English
• Published: Elsevier 2018-07-01
• Series: Cell Reports
• Online Access: http://www.sciencedirect.com/science/article/pii/S221112471830915X

Summary: Breast cancer cells relocate to bone and activate osteoclast-induced bone resorption. Soluble factors secreted by breast cancer cells trigger a cascade of events that stimulate osteoclast differentiation in the bone microenvironment. MacroH2A is a unique histone variant with a C-terminal non-histone domain and plays a crucial role in modulating chromatin organization and gene transcription. Here, we show that macroH2A1.2, one of the macroH2A isoforms, has an intrinsic ability to inhibit breast cancer-derived osteoclastogenesis. This repressive effect requires macroH2A1.2-dependent attenuation of expression and secretion of lysyl oxidase (LOX) in breast cancer cells. Furthermore, our mechanistic studies reveal that macroH2A1.2 physically and functionally interacts with the histone methyltransferase EZH2 and elevates H3K27me3 levels to keep LOX gene in a repressed state. Collectively, this study unravels a role for macroH2A1.2 in regulating osteoclastogenic potential of breast cancer cells, suggesting possibilities for developing therapeutic tools to treat osteolytic bone destruction. : Kim et al. demonstrate that mH2A1.2 attenuates breast cancer-induced osteoclastogenesis by maintaining the LOX gene in an inactive state. Mechanistically, mH2A1.2 recruits EZH2 to induce H3K27me3 and create a repressive barrier to LOX transcription. Keywords: macroH2A, histone, bone, osteoclast, breast cancer, LOX, Src, EZH2