Antiangiogenic properties of 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin: an orally bioavailable heat shock protein 90 modulator.
OBJECTIVE
The purpose of this study was to investigate the antiangiogenic properties of 17-(dimethylaminoethylamino)-17-demethoxygeldanamycin (17-DMAG; NSC707545), a water-soluble benzoquinone ansamycin.


METHODS
The activity of 17-DMAG, in vivo, was evaluated for inhibition of fibroblast growth factor (FGF)-2-induced angiogenesis in s.c. implanted Matrigel in mice. In vitro, the activity of 17-DMAG on endothelial cells (human umbilical vein endothelial cells; HUVEC) was tested in FGF-2; and vascular endothelial growth factor (VEGF)-induced proliferation and apoptosis, motility, and extracellular matrix invasion; and on the alignment of capillary like structures in Matrigel. The protein level of heat shock protein (Hsp)90 and client proteins was examined by Western blot in FGF-2 and VEGF-stimulated HUVEC.


RESULTS
Daily oral administration of 17-DMAG affected the angiogenic response in Matrigel in a dose-dependent manner. The hemoglobin content in the Matrigel implants was significantly inhibited, and the histological analysis confirmed a decrease of CD31(+) endothelial cells and of structures organized in cord and erythrocyte-containing vessels. In vitro, the compound inhibited dose-dependently the migration and the extracellular matrix-invasiveness of HUVEC and their capacity to form capillary like structures in Matrigel. 17-DMAG treatment also inhibited FGF-2 and VEGF-induced HUVEC proliferation and resulted in apoptosis. Accordingly, the expression of Hsp90 direct client proteins (pAkt and c-Raf-1) or their downstream substrates including pERK was also affected. 17-DMAG consistently increased the expression of Hsp70. Throughout the study similar results were obtained with 17-allylamino-17-demethoxygeldanamycin (17-AAG; NSC330507), the analog compound currently undergoing clinical trials.


CONCLUSIONS
We show that the Hsp90 targeting agents 17-DMAG and 17-AAG inhibit angiogenesis. The strong effects on endothelial cell functions, in vitro, indicate that the antiangiogenic activity of 17-DMAG/17-AAG could also be due to a direct effect on endothelial cells. The oral bioavailability of 17-DMAG might be of advantage in investigating the potential of this compound in clinical trials with antiangiogenic as well as antiproliferative endpoints.
Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, Maryland, USA.
Gurmeet
G
Kaur
Dorina
D
Belotti
Angelika M
AM
Burger
Kirsten
K
Fisher-Nielson
Patrizia
P
Borsotti
Elena
E
Riccardi
Jagada
J
Thillainathan
Melinda
M
Hollingshead
Edward A
EA
Sausville
Raffaella
R
Giavazzi
D000284:Administration, Oral; D020533:Angiogenesis Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D016227:Benzoquinones; D001682:Biological Availability; D001808:Blood Vessels / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D003094:Collagen / Q000008:administration & dosage; D004338:Drug Combinations; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005260:Female; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D047029:Lactams, Macrocyclic; D007797:Laminin / Q000008:administration & dosage; D051379:Mice; D008810:Mice, Inbred C57BL; D019408:Platelet Endothelial Cell Adhesion Molecule-1 / Q000032:analysis; D011509:Proteoglycans / Q000008:administration & dosage; D011809:Quinones / Q000493:pharmacokinetics / Q000494:pharmacology*; D017828:Rifabutin / Q000031:analogs & derivatives* / Q000494:pharmacology; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A / Q000494:pharmacology
D020533:Angiogenesis Inhibitors; D016227:Benzoquinones; D004338:Drug Combinations; D018841:HSP90 Heat-Shock Proteins; D047029:Lactams, Macrocyclic; D007797:Laminin; D019408:Platelet Endothelial Cell Adhesion Molecule-1; D011509:Proteoglycans; D011809:Quinones; D042461:Vascular Endothelial Growth Factor A; C448659:17-(dimethylaminoethylamino)-17-demethoxygeldanamycin; D016222:Fibroblast Growth Factor 2; C059485:matrigel; D017828:Rifabutin; C112765:tanespimycin; D003094:Collagen