The diphtheria toxin/urokinase fusion protein (DTAT) is selectively toxic to CD87 expressing leukemic cells

• Published in: Leukemia research Vol. 27; no. 1; pp. 79 - 84
• Main Authors: Ramage, Jason G, Vallera, Daniel A, Black, Jennifer H, Aplan, Peter D, Kees, Ursula R, Frankel, Arthur E
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 2003; Elsevier Science
• Subjects: Acute Disease; Acute myeloid leukemia; Antineoplastic agents; Antineoplastic Agents - chemistry; Antineoplastic Agents - pharmacology; Biological and medical sciences; Blast Crisis - pathology; Burkitt Lymphoma - pathology; Diphtheria fusion protein; Flow Cytometry; General aspects; HL-60 Cells - drug effects; Humans; Jurkat Cells - drug effects; Leukemia, Myelogenous, Chronic, BCR-ABL Positive - pathology; Leukemia, Myeloid - pathology; Leukemia-Lymphoma, Adult T-Cell - pathology; Medical sciences; Multiple Myeloma - pathology; Neoplasm Proteins - drug effects; Neoplasm Proteins - physiology; Neoplastic Stem Cells - drug effects; Neoplastic Stem Cells - metabolism; Oncogene Proteins, Fusion - pharmacology; Pharmacology. Drug treatments; Protein Structure, Tertiary; Receptors, Cell Surface - drug effects; Receptors, Cell Surface - physiology; Receptors, Urokinase Plasminogen Activator; Recombinant Fusion Proteins - pharmacology; U937 Cells - drug effects; Urokinase receptor; uPA, urokinase-type plasminogen activator; Diphtheria fusion protein; GPI, glycosyl-phosphatidylinositol; IC 50, concentration of fusion protein which inhibits cell proliferation by 50; Urokinase receptor; DT, diphtheria toxin; DTAT, diphtheria toxin/urokinase fusion protein; AML, acute myelogenous leukemia; GM-CSF, granulocyte-macrophage colony-stimulating factor; uPAR, uPA receptor; Acute myeloid leukemia; IL-3, interleukin-3; Antineoplastic agent; Human; u-Plasminogen activator; Serine endopeptidases; Enzyme; Acute; Cytotoxicity; Malignant hemopathy; Diphtheria; In vitro; Biological activity; HL60 cell line; Infection; Peptidases; Toxin; Bacteriosis; Hydrolases; Fusion protein; Acute myelocytic leukemia; Biological receptor
• ISSN: 0145-2126; 1873-5835
• DOI: 10.1016/S0145-2126(02)00077-2

Diphtheria fusion proteins are a novel class of agents for the treatment of chemotherapy resistant acute myelogenous leukemia (AML). We prepared diphtheria toxin/urokinase fusion protein (DTAT) composed of the amino terminal fragment of the urokinase-type plasminogen activator (uPA) fused to the catalytic and translocation domains of diphtheria toxin (DT) and assessed its activity on leukemic cell lines. The number of uPA receptors (uPAR or CD87) was measured using a phycoerythrin conjugated monoclonal antibody to CD87 and flow cytometry. Seven of 23 cell lines (30%) showed CD87 expression (≥5000 receptors/cell). DTAT cytotoxicity (IC
50≤30
pM) was observed in all seven of these samples and none of the 16 samples with low or absent CD87 expression. There was a significant correlation between DTAT sensitivity and CD87 density (
P=0.0007). These results show that specific CD87 binding is one factor important in the sensitivity of patient’s leukemic blasts to DTAT and demonstrate for the first time that the CD87/uPAR can be used as a target for fusion protein therapy of AML.