タイトル；KDM6B modulates MAPK pathway mediating multiple myeloma cell growth and survival.
（熊本大学 生命資源研究・支援センター 疾患エピゲノム制御分野、大学院先導機構）
Recent studies have delineated cancer-type-specific roles of histone 3 lysine 27 (H3K27) demethylase KDM6B/JMJD3 depending on its H3K27 demethylase activity. Here we show that KDM6B is expressed in multiple myeloma (MM) cells; and that shRNA-mediated knockdown and CRISPR-mediated knockout of KDM6B abrogate MM cell growth and survival. Tumor necrosis factor-α or bone marrow stromal cell culture supernatants induce KDM6B, which is blocked by IKKβ inhibitor MLN120B, suggesting that KDM6B is regulated by NF-κB signaling in MM cells. The ectopic expression of KDM6B partially rescued MM cells from MLN120B-induced growth inhibition, suggesting KDM6B is at least one of the downstream effectors of NF-κB pathway in MM.RNA-seq and subsequent ChIP-qPCR analyses reveal that KDM6B is recruited to the loci of genes encoding components of MAPK signaling pathway including ELK1 and FOS, and upregulates expression of these genes without affecting H3K27 methylation level. Overexpression of catalytically inactive KDM6B activates expression of MAPK pathway related genes, confirming its function independent of demethylase activity. We further demonstrate that downstream targets of KDM6B, ELK1 and FOS, confer MM cell growth. Our study therefore delineates KDM6B function that links NF-κB and MAPK signaling pathway mediating MM cell growth and survival.