title: EZH2 or HDAC1 Inhibition Reverses Multiple Myeloma-Induced Epigenetic Suppression of Osteoblast Differentiation.
abstract: In multiple myeloma, osteolytic lesions rarely heal because of persistent suppressed osteoblast differentiation resulting in a high fracture risk. Herein, chromatin immunoprecipitation analyses reveal that multiple myeloma cells induce repressive epigenetic histone changes at theRunx2locus that prevent osteoblast differentiation. The most pronounced multiple myeloma-induced changes were at theRunx2-P1promoter, converting it from a poised bivalent state to a repressed state. Previously, it was observed that multiple myeloma induces the transcription repressor GFI1 in osteoblast precursors, which correlates with decreasedRunx2expression, thus prompting detailed characterization of the multiple myeloma and TNFα-dependent GFI1 response element within theRunx2-P1promoter. Further analyses reveal that multiple myeloma-induced GFI1 binding toRunx2in osteoblast precursors and recruitment of the histone modifiers HDAC1, LSD1, and EZH2 is required to establish and maintainRunx2repression in osteogenic conditions. These GFI1-mediated repressive chromatin changes persist even after removal of multiple myeloma. Ectopic GFI1 is sufficient to bind toRunx2, recruit HDAC1 and EZH2, increase H3K27me3 on the gene, and prevent osteogenic induction of endogenousRunx2expression.Gfi1knockdown in MC4 cells blocked multiple myeloma-induced recruitment of HDAC1 and EZH2 toRunx2, acquisition of repressive chromatin architecture, and suppression of osteoblast differentiation. Importantly, inhibition of EZH2 or HDAC1 activity in pre-osteoblasts after multiple myeloma exposurein vitroor in osteoblast precursors from patients with multiple myeloma reversed the repressive chromatin architecture atRunx2and rescued osteoblast differentiation.Implications:This study suggests that therapeutically targeting EZH2 or HDAC1 activity may reverse the profound multiple myeloma-induced osteoblast suppression and allow repair of the lytic lesions.Mol Cancer Res; 15(4); 405-17. ©2017 AACR.
authors.affiliation: Department of Medicine, Division of Hematology-Oncology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Juraj
authors.initials: J
authors.lastname: Adamik
authors.affiliation: Department of Medicine, Division of Hematology-Oncology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Shunqian
authors.initials: S
authors.lastname: Jin
authors.affiliation: Department of Medicine, Division of Hematology-Oncology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Quanhong
authors.initials: Q
authors.lastname: Sun
authors.affiliation: Department of Medicine, Division of Hematology-Oncology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Cancer Stem Cell Laboratory, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania.
authors.forename: Kurt R
authors.initials: KR
authors.lastname: Weiss
authors.affiliation: Department of Medicine, Division of Hematology-Oncology, Indiana University, Indianapolis, Indiana.
authors.forename: Judith L
authors.initials: JL
authors.lastname: Anderson
authors.affiliation: Department of Medicine, Division of Hematology-Oncology, Indiana University, Indianapolis, Indiana.
authors.forename: Rebecca
authors.initials: R
authors.lastname: Silbermann
authors.affiliation: Department of Medicine, Division of Hematology-Oncology, Indiana University, Indianapolis, Indiana. galson@pitt.edu groodman@iu.edu.|Richard L. Roudebush VA Medical Center, Indianapolis, Indiana.
authors.forename: G David
authors.initials: GD
authors.lastname: Roodman
authors.affiliation: Department of Medicine, Division of Hematology-Oncology, University of Pittsburgh Cancer Institute, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania. galson@pitt.edu groodman@iu.edu.|McGowan Institute for Regenerative Medicine, Pittsburgh, Pennsylvania.
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Galson
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D050659:Core Binding Factor Alpha 1 Subunit / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D000071221:Enhancer of Zeste Homolog 2 Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*; D044127:Epigenesis, Genetic; D056284:Histone Deacetylase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D056572:Histone Deacetylase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology; D006801:Humans; D007211:Indoles / Q000008:administration & dosage / Q000494:pharmacology; D051379:Mice; D009101:Multiple Myeloma / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects; D011401:Promoter Regions, Genetic; D011728:Pyridones / Q000008:administration & dosage / Q000494:pharmacology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D050659:Core Binding Factor Alpha 1 Subunit; D004268:DNA-Binding Proteins; C498275:GFI1 protein, human; C577920:GSK-2816126; D056572:Histone Deacetylase Inhibitors; D007211:Indoles; D011728:Pyridones; C493709:RUNX2 protein, human; D014157:Transcription Factors; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; C110550:HDAC1 protein, human; D056284:Histone Deacetylase 1