title: Diphtheria toxin fused to human interleukin-3 is toxic to blasts from patients with myeloid leukemias.
abstract: Leukemic blasts from patients with acute phase chronic myeloid leukemic and refractory acute myeloid leukemia are highly resistant to a number of cytotoxic drugs. To overcome multi-drug resistance, we engineered a diphtheria fusion protein by fusing human interleukin-3 (IL3) to a truncated form of diphtheria toxin (DT) with a (G4S)2 linker (L), expressed and purified the recombinant protein, and tested the cytotoxicity of the DTLIL3 molecule on human leukemias and normal progenitors. The DTLIL3 construct was more cytotoxic to interleukin-3 receptor (IL3R) bearing human myeloid leukemia cell lines than receptor-negative cell lines based on assays of cytotoxicity using thymidine incorporation, growth in semi-solid medium and induction of apoptosis. Exposure of mononuclear cells to 680 pM DTLIL3 for 48 h in culture reduced the number of cells capable of forming colonies in semi-solid medium (colony-forming units leukemia) > or =10-fold in 4/11 (36%) patients with myeloid acute phase chronic myeloid leukemia (CML) and 3/9 (33%) patients with acute myeloid leukemia (AML). Normal myeloid progenitors (colony-forming unit granulocyte-macrophage) from five different donors treated and assayed under identical conditions showed intermediate sensitivity with three- to five-fold reductions in colonies. The sensitivity to DTLIL3 of leukemic progenitors from a number of acute phase CML patients suggests that this agent could have therapeutic potential for some patients with this disease.
authors.affiliation: Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: A E
authors.initials: AE
authors.lastname: Frankel
authors.forename: J A
authors.initials: JA
authors.lastname: McCubrey
authors.forename: M S
authors.initials: MS
authors.lastname: Miller
authors.forename: S
authors.initials: S
authors.lastname: Delatte
authors.forename: J
authors.initials: J
authors.lastname: Ramage
authors.forename: M
authors.initials: M
authors.lastname: Kiser
authors.forename: G L
authors.initials: GL
authors.lastname: Kucera
authors.forename: R L
authors.initials: RL
authors.lastname: Alexander
authors.forename: M
authors.initials: M
authors.lastname: Beran
authors.forename: E P
authors.initials: EP
authors.lastname: Tagge
authors.forename: R J
authors.initials: RJ
authors.lastname: Kreitman
authors.forename: D E
authors.initials: DE
authors.lastname: Hogge
mesh_terms: D004261:DNA Replication / Q000187:drug effects; D004167:Diphtheria Toxin / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology*; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D007377:Interleukin-3 / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology*; D007951:Leukemia, Myeloid / Q000473:pathology*; D009363:Neoplasm Proteins / Q000187:drug effects; D014411:Neoplastic Stem Cells / Q000187:drug effects*; D016133:Polymerase Chain Reaction; D016185:Receptors, Interleukin-3 / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D014407:Tumor Cells, Cultured / Q000187:drug effects; D014410:Tumor Stem Cell Assay
chemical_list: D004167:Diphtheria Toxin; D007377:Interleukin-3; D009363:Neoplasm Proteins; D016185:Receptors, Interleukin-3; D011993:Recombinant Fusion Proteins; C407154:diphtheria toxin-interleukin-3 fusion protein, recombinant