title: Histone deacetylase inhibitor SAHA mediates mast cell death and epigenetic silencing of constitutively active D816V KIT in systemic mastocytosis.
abstract: Systemic mastocytosis (SM) is a clonal bone marrow disorder, where therapeutical options are limited. Over 90% of the patients carry the D816V point mutation in the KIT receptor that renders this receptor constitutively active. We assessed the sensitivity of primary mast cells (MC) and mast cell lines HMC1.2 (D816V mutated), ROSA (KIT WT) and ROSA (KIT D816V) cells to histone deacetylase inhibitor (HDACi) treatment. We found that of four HDACi, suberoyl anilide hydroxamic acid (SAHA) was the most effective in killing mutated MC. SAHA downregulated KIT, followed by major MC apoptosis. Primary SM patient MC cultured ex vivo were even more sensitive to SAHA than HMC1.2 cells, whereas primary MC from healthy subjects were less affected. There was a correlation between cell death and SM disease severity, where cell death was more pronounced in the case of aggressive SM, with almost 100% cell death among MC from the mast cell leukemia patient. Additionally, ROSA (KIT D816V) was more affected by HDACi than ROSA (KIT WT) cells. Using ChIP qPCR, we found that the level of active chromatin mark H3K18ac/H3 decreased significantly in the KIT region. This epigenetic silencing was seen only in the KIT region and not in control genes upstream and downstream of KIT, indicating that the downregulation of KIT is exerted by specific epigenetic silencing. In conclusion, KIT D816V mutation sensitized MC to HDACi mediated killing, and SAHA may be of value as specific treatment for SM, although the specific mechanism of action requires further investigation.
authors.affiliation: Immunology and Allergy Unit, Department of Medicine Solna, Karolinska Institutet and clinical immunology and transfusion medicine, Karolinska University Hospital, Stockholm, Sweden.|Mastocytosis Center Karolinska, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden.
authors.forename: Katarina
authors.initials: K
authors.lastname: Lyberg
authors.affiliation: Department of Medicine Huddinge, Karolinska Institutet and Hematology Center, Karolinska University Hospital, Stockholm, Sweden.|Mastocytosis Center Karolinska, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden.
authors.forename: Hani Abdulkadir
authors.initials: HA
authors.lastname: Ali
authors.affiliation: Immunology and Allergy Unit, Department of Medicine Solna, Karolinska Institutet and clinical immunology and transfusion medicine, Karolinska University Hospital, Stockholm, Sweden.|Mastocytosis Center Karolinska, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden.
authors.forename: Jennine
authors.initials: J
authors.lastname: Grootens
authors.affiliation: Department of Medicine Huddinge, Karolinska Institutet and Hematology Center, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Matilda
authors.initials: M
authors.lastname: Kjellander
authors.affiliation: Immunology and Allergy Unit, Department of Medicine Solna, Karolinska Institutet and clinical immunology and transfusion medicine, Karolinska University Hospital, Stockholm, Sweden.
authors.forename: Malin
authors.initials: M
authors.lastname: Tirfing
authors.affiliation: Molecular and Cellular Oncology, LBPA CNRS UMR 8113, Ecole Normale Supérieure de Cachan, Cachan, France and Laboratoire Central d'Hématologie, Groupe Hospitalier Pitié-Salpêtrière, Paris, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Arock
authors.affiliation: Department of Medical Sciences, Uppsala University and Section of Hematology, Uppsala University Hospital, Uppsala, Sweden.
authors.forename: Hans
authors.initials: H
authors.lastname: Hägglund
authors.affiliation: Immunology and Allergy Unit, Department of Medicine Solna, Karolinska Institutet and clinical immunology and transfusion medicine, Karolinska University Hospital, Stockholm, Sweden.|Mastocytosis Center Karolinska, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Nilsson
authors.affiliation: Department of Medicine Huddinge, Karolinska Institutet and Hematology Center, Karolinska University Hospital, Stockholm, Sweden.|Mastocytosis Center Karolinska, Karolinska University Hospital and Karolinska Institutet, Stockholm, Sweden.
authors.forename: Johanna
authors.initials: J
authors.lastname: Ungerstedt
mesh_terms: D000107:Acetylation; D016022:Case-Control Studies; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D019175:DNA Methylation / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D005260:Female; D020868:Gene Silencing / Q000187:drug effects*; D056572:Histone Deacetylase Inhibitors / Q000494:pharmacology*; D006657:Histones / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology*; D008297:Male; D008407:Mast Cells / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology; D034721:Mastocytosis, Systemic / Q000188:drug therapy* / Q000201:enzymology / Q000235:genetics / Q000473:pathology; D009154:Mutation; D010766:Phosphorylation; D019009:Proto-Oncogene Proteins c-kit / Q000235:genetics* / Q000378:metabolism; D013997:Time Factors; D000077337:Vorinostat
chemical_list: D056572:Histone Deacetylase Inhibitors; D006657:Histones; D006877:Hydroxamic Acids; D000077337:Vorinostat; D019009:Proto-Oncogene Proteins c-kit
keywords: KIT; chromatin; epigenetics; mast cells; systemic mastocytosis