title: Givinostat and hydroxyurea synergize in vitro to induce apoptosis of cells from JAK2(V617F) myeloproliferative neoplasm patients.
abstract: We investigated whether clinically achievable concentrations of the histone deacetylase (HDAC) inhibitors givinostat and hydroxyurea induce synergistic cytotoxicity in Jak2(V617F) cells in vitro and through which possible mechanism. Givinostat and hydroxyurea at low doses potentiated the pro-apoptotic effects of each other in the Jak2(V617F) HEL and UKE1 cell lines. Givinostat induced 6.8%-20.8% and hydroxyurea (HU) 20.4%-42.4% cell death alone and 35.8%-75.3% in combination. The effect was statistically significant using the median effect Chou-Talalay method, resulting in a combination index less than 1, indicating synergy. Givinostat alone induced cell cycle arrest of the cell lines in G0/G1 and hydroxyurea in S phase, whereas both drugs together led to a G1 block. At the molecular level, hydroxyurea counteracted the induction of p21CDKN1A by Givinostat and potentiated caspase 3 activation, explaining at least in part the increased apoptosis observed in presence of both compounds. We also verified the effect of the same drugs in colony assays of freshly isolated Jak2(V617F) polycythemia vera cells. In this case, low doses of the compounds were additive to each other. These results suggest that combined treatment with givinostat and hydroxyurea is a potential strategy for the management of Jak2(V617F) myeloproliferative neoplasms.
authors.affiliation: Division of Hematology, Ospedali Riuniti, Bergamo, Italy.
authors.forename: Ariel
authors.initials: A
authors.lastname: Amaru Calzada
authors.forename: Olga
authors.initials: O
authors.lastname: Pedrini
authors.forename: Guido
authors.initials: G
authors.lastname: Finazzi
authors.forename: Flavio
authors.initials: F
authors.lastname: Leoni
authors.forename: Paolo
authors.initials: P
authors.lastname: Mascagni
authors.forename: Martino
authors.initials: M
authors.lastname: Introna
authors.forename: Alessandro
authors.initials: A
authors.lastname: Rambaldi
authors.forename: Josée
authors.initials: J
authors.lastname: Golay
mesh_terms: D019943:Amino Acid Substitution; D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002219:Carbamates / Q000494:pharmacology*; D053148:Caspase 3 / Q000378:metabolism; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D004357:Drug Synergism; D006801:Humans; D006918:Hydroxyurea / Q000494:pharmacology*; D053614:Janus Kinase 2 / Q000235:genetics / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009154:Mutation; D009196:Myeloproliferative Disorders / Q000097:blood / Q000235:genetics / Q000473:pathology; D011087:Polycythemia Vera / Q000097:blood / Q000378:metabolism / Q000473:pathology
chemical_list: D000970:Antineoplastic Agents; C493956:CDKN1A protein, human; D002219:Carbamates; D050759:Cyclin-Dependent Kinase Inhibitor p21; C575255:givinostat; D053614:Janus Kinase 2; D053148:Caspase 3; D006918:Hydroxyurea