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.
Kaur
Gurmeet
G
Division of Cancer Treatment and Diagnosis, National Cancer Institute, Bethesda, Maryland, USA.
Belotti
Dorina
D
Burger
Angelika M
AM
Fisher-Nielson
Kirsten
K
Borsotti
Patrizia
P
Riccardi
Elena
E
Thillainathan
Jagada
J
Hollingshead
Melinda
M
Sausville
Edward A
EA
Giavazzi
Raffaella
R
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