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 (IC50≤30pM) 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.
|Original language||English (US)|
|Number of pages||6|
|State||Published - Jan 1 2003|
Bibliographical noteFunding Information:
This work was supported by the Leukemia and Lymphoma Society (LSA6114 to A. Frankel) and the National Institutes of Health (R01CA76,178, R21CA90,550, and R01CA090,263 to A. Frankel).
- Acute myeloid leukemia
- Diphtheria fusion protein
- Urokinase receptor