|
|
 Previous Article | Table of Contents | Next Article 
Recombinant Toxins Containing Human Granulocyte-Macrophage Colony-Stimulating Factor and Either Pseudomonas Exotoxin or Diphtheria Toxin Kill Gastrointestinal Cancer and Leukemia Cells
Robert J. Kreitman and
Ira Pastan
From the Laboratory of Molecular Biology, Division of Cancer Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD.
The granulocyte-macrophage colony-stimulating factor receptor (GM-CSFR) is a potential target for toxin-directed therapy, because it is overexpressed on many leukemias and solid tumors and apparently not on stem cells. To investigate the potential therapeutic use of GM-CSF toxins, we fused human GM-CSF to truncated forms of either Pseudomonas exotoxin (PE) or diphtheria toxin (DT) and tested the cytotoxicity of the resulting GM-CSF-PE38KDEL and DT388-GM-CSF on human gastrointestinal (GI) carcinomas and leukemias. Toward gastric and colon cancer cell lines, GM-CSF-PE38KDEL was much more cytotoxic than DT388-GM-CSF, with IC50s (concentration resulting in 50% inhibition of protein synthesis) of 0.5 to 10 ng/mL compared with 4 to 400 ng/mL, respectively. In contrast, toward leukemia lines and fresh bone marrow cells DT388-GM-CSF was more cytotoxic than GM-CSF-PE38KDEL. The cytotoxicity of both GM-CSF-PE38KDEL and DT388-GM-CSF toward the human cells was specific, because it could be competed by an excess of GM-CSF. Binding studies indicated that human GM-CSF receptors were present on all of the human GI and leukemic cell lines tested, at levels of 540 to 3,700 sites per cell (kd = 0.2 to 2 nmol/L), and the number of sites per cell did not correlate with the cell type. A similar pattern of cytotoxicity was found with recombinant immunotoxins binding to the transferrin receptor, in that anti-TFR(Fv)-PE38KDEL was much more cytotoxic than DT388-anti-TFR(Fv) toward GI cells, but both were similar in their cytotoxic activity toward leukemia cells. The fact that PE is more effective than DT in killing GI but not leukemic tumor cells targeted by GM-CSF indicates a fundamental difference in the way PE or DT gains access to the cytosol in these cells. GM-CSF-PE38KDEL and DT388-GM-CSF deserve further evaluation as possible treatments for selected tumors.
Blood, Vol. 90 No. 1 (July 1), 1997:
pp. 252-259
© 1997 by The American Society of Hematology.
 CiteULike  Connotea  Del.icio.us  Digg  Reddit  Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
A. Antignani and R. J. Youle
The Cytokine, Granulocyte-Macrophage Colony-stimulating Factor (GM-CSF), Can Deliver Bcl-XL as an Extracellular Fusion Protein to Protect Cells from Apoptosis and Retain Differentiation Induction
J. Biol. Chem.,
April 13, 2007;
282(15):
11246 - 11254.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
R. J. Kreitman
Confirmation and prevention of targeted toxicity by a recombinant fusion toxin
Mol. Cancer Ther.,
December 1, 2004;
3(12):
1691 - 1692.
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. E. Frankel, B. L. Powell, P. D. Hall, L. D. Case, and R. J. Kreitman
Phase I Trial of a Novel Diphtheria Toxin/Granulocyte Macrophage Colony-stimulating Factor Fusion Protein (DT388GMCSF) for Refractory or Relapsed Acute Myeloid Leukemia
Clin. Cancer Res.,
May 1, 2002;
8(5):
1004 - 1013.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. Senchenkov, T.-Y. Han, H. Wang, A. E. Frankel, T. J. Kottke, S. H. Kaufmann, and M. C. Cabot
Enhanced ceramide generation and induction of apoptosis in human leukemia cells exposed to DT388-granulocyte-macrophage colony-stimulating factor (GM-CSF), a truncated diphtheria toxin fused to human GM-CSF
Blood,
September 15, 2001;
98(6):
1927 - 1934.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
A. E. Frankel, J. Ramage, M. Kiser, R. Alexander, G. Kucera, and M. S. Miller
Characterization of diphtheria fusion proteins targeted to the human interleukin-3 receptor
Protein Eng. Des. Sel.,
August 1, 2000;
13(8):
575 - 581.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
V. Rajagopal and R. J. Kreitman
Recombinant Toxins That Bind to the Urokinase Receptor Are Cytotoxic without Requiring Binding to the alpha 2-Macroglobulin Receptor
J. Biol. Chem.,
March 10, 2000;
275(11):
7566 - 7573.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
D. A. Vallera, S.-Y. Seo, A. Panoskaltsis-Mortari, J. D. Griffin, and B. R. Blazar
Targeting myeloid leukemia with a DT390-mIL-3 fusion immunotoxin: ex vivo and in vivo studies in mice
Protein Eng. Des. Sel.,
September 1, 1999;
12(9):
779 - 785.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
|
|
F. Vinante, A. Rigo, E. Papini, M. A. Cassatella, and G. Pizzolo
Heparin-Binding Epidermal Growth Factor-Like Growth Factor/Diphtheria Toxin Receptor Expression by Acute Myeloid Leukemia Cells
Blood,
March 1, 1999;
93(5):
1715 - 1723.
[Abstract]
[Full Text]
[PDF]
|
|
|
|
|
