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Sensitivity of human acute myeloid leukaemia to diphtheria toxin‐GM‐CSF fusion protein
Author(s) -
Rozemuller Henk,
Rombouts Elwin J. C.,
Touw Ivo P.,
FitzGerald David J. P.,
Kreitman Robert J.,
Pastan Ira,
Hagenbeek Anton,
Martens Anton C. M.
Publication year - 1997
Publication title -
british journal of haematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.907
H-Index - 186
eISSN - 1365-2141
pISSN - 0007-1048
DOI - 10.1046/j.1365-2141.1997.2893106.x
Subject(s) - diphtheria toxin , in vitro , flow cytometry , fusion protein , microbiology and biotechnology , growth inhibition , biology , cell growth , immunology , toxin , recombinant dna , biochemistry , gene
The potential to selectively eliminate acute myeloid leukaemia (AML) cells with the GM‐CSF‐diphtheria toxin fusion protein (DT‐GM‐CSF) was studied under conditions of autonomous proliferation in vitro with no growth factors (GFs) added and after growth stimulation with a mixture of human (hu)G‐CSF, huIL‐3 and huSCF. DNA synthesis was maximally inhibited after 48 h exposure to DT‐GM‐CSF. Cell viability and AML colony forming ability in vitro were reduced. 18/22 samples were found to be sensitive to DT‐GM‐CSF, with 50% inhibition of DNA synthesis (ID 50 ) at concentrations ranging from 0.1 to 16 ng/ml, and four samples were minimally or not sensitive to DT‐GM‐CSF (ID 50 99 ng/ml). From the 15 samples which showed autonomous proliferation, 13 were sensitive to inhibition of proliferation by DT‐GM‐CSF. The level of GM‐CSF receptor (GM‐CSFR) expression was determined by flow cytometry after labelling with specific antibodies for the alpha and beta subunits. Although the toxicity to DT‐GM‐CSF was specifically mediated by the GM‐CSFR, no correlation was found between the level of expression of the GM‐CSFR alpha or beta subunit and the sensitivity for DT‐GM‐CSF. These in vitro studies show that the DT‐GM‐CSF fusion protein can be used for specifically targeting and eliminating leukaemic cells in the majority of AML cases.