title: Diphtheria toxin-interleukin-3 fusion protein (DT(388)IL3) prolongs disease-free survival of leukemic immunocompromised mice.
abstract: The novel fusion protein DT(388)IL3, composed of the catalytic and translocation domains of diphtheria toxin (DT(388)) fused with a Met-His linker to human interleukin 3 (IL-3), was tested for anti-leukemia efficacy in an in vivo model of differentiated human acute myeloid leukemia (AML). Six-week-old female SCID mice were irradiated with 350 cGy, inoculated 24 h later with 20 million (i.v., i.p., or s.c.) TF1 cells transfected with the v-SRC oncogene, and treated i.p., starting 24 h later, with up to five daily injections of saline, DT(388)IL3 (2 microg), DT(388)GMCSF (2 microg), DAB(389)IL2 (2 microg), or cytarabine (80 microg) or two weekly injections of anti-CD33-calicheamicin conjugate (5 microg). Animals were monitored twice daily, and moribund animals killed and necropsied. Control animals had a median disease-free survival (DFS) of 37 days (i.v., n = 45), 35 days (i.p., n = 20), and 21 days (s.c., n = 20), respectively. Only 5/49 (10%) of the DT(388)IL3 treated i.v. inoculated animals died with leukemia. Median DFS with i.v., i.p. and s.c. tumor inoculated animals was prolonged by fusion protein treatment to >120 days, 66 days and 31 days (P < 0.001, = 0.0003, and = 0.0006), respectively. Median DFS with s.c. tumor inoculated animals was also prolonged by other active anti-leukemia agents (DT(388)GMCSF, cytarabine and anti-CD33-calicheamicin) relative to controls by 67%, 172% and 47% (P < 0.0001, <0.0001, and =0.0004), respectively. In contrast, median DFS with s.c. tumor inoculated animals treated with DAB(389)IL2 non-significantly reduced by 13% relative to controls (P = 0.21). Thus, DT(388)IL3 fusion protein demonstrates in vivo anti-leukemia efficacy and warrants further preclinical development for treatment of chemo-resistant, IL-3 receptor positive AML patients.
authors.affiliation: Department of Cancer Biology and Pathology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: J H
authors.initials: JH
authors.lastname: Black
authors.forename: J A
authors.initials: JA
authors.lastname: McCubrey
authors.forename: M C
authors.initials: MC
authors.lastname: Willingham
authors.forename: J
authors.initials: J
authors.lastname: Ramage
authors.forename: D E
authors.initials: DE
authors.lastname: Hogge
authors.forename: A E
authors.initials: AE
authors.lastname: Frankel
mesh_terms: D000208:Acute Disease; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D003561:Cytarabine / Q000008:administration & dosage; D004167:Diphtheria Toxin / Q000627:therapeutic use*; D018572:Disease-Free Survival; D019008:Drug Resistance, Neoplasm; D005260:Female; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000627:therapeutic use; D006801:Humans; D016867:Immunocompromised Host; D007274:Injections, Intraperitoneal; D007275:Injections, Intravenous; D007279:Injections, Subcutaneous; D007376:Interleukin-2 / Q000008:administration & dosage; D007377:Interleukin-3 / Q000627:therapeutic use*; D007951:Leukemia, Myeloid / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D016513:Mice, SCID; D014411:Neoplastic Stem Cells / Q000187:drug effects; D011993:Recombinant Fusion Proteins / Q000627:therapeutic use*
chemical_list: D000964:Antimetabolites, Antineoplastic; D000970:Antineoplastic Agents; D004167:Diphtheria Toxin; D007376:Interleukin-2; D007377:Interleukin-3; D011993:Recombinant Fusion Proteins; C407154:diphtheria toxin-interleukin-3 fusion protein, recombinant; D003561:Cytarabine; D016178:Granulocyte-Macrophage Colony-Stimulating Factor