Inhibition of normal and experimental angiotumor endothelial cell proliferation and cell cycle progression by 2-methoxyestradiol.
With rapid growth and metabolism, aggressive cancers require an extensive vascular network, termed tumor angiogenesis. The body produces a variety of natural angiogenic inhibitors, among which is the mammalian estrogen metabolite, 2-methoxyestradiol (2-MeOE2). In this study, we compared the effects of 2-MeOE2 on a human umbilical vein cell line (HUVEC-C) and on an immortal, angiotumor-producing rat sinusoidal endothelial cell line (RSE-1). In vitro, the effects of varying concentrations of 2-MeOE2 from 0.01-100.0 microM were measured with cell counts and compared to control cells. HUVEC-C had an ED50 approximately 3.5 microM with approximately 27% inhibition of cell growth whereas RSE-1 had an ED50 approximately 2.2 microM with approximately 50% inhibition of cell growth compared with controls. The lowest concentration with maximal effect was 10.0 microM 2-MeOE2 for both cell lines. Using this concentration, flow cytometric analysis of cell cycles was performed with propidium iodide stained DNA of HUVEC-C and RSE-1 at 24 and 48 hr. Both demonstrated a significant (P < 0.0001) block at G2M of the cell cycle. At 48 hr, HUVEC-C had 32% of cells in G2M (control = 9% G2M), and RSE-1 had 36% of cells in G2M (control = 18% G2M). These findings demonstrate a strong in vitro antiproliferative effect of 2-MeOE2 on normal dividing endothelial as well as angiotumor cells mediated through a cell cycle-specific block at G2M. The antiendothelial, antiangiotumor effect of 2-MeOE2 supports its potential as a therapeutic agent against solid organ cancers, benign or malignant vascular growths, and other pathologic states dependent on angiogenesis.
Reiser
F
F
Department of Surgery, The University of Arizona, Tucson, Arizona 85724, USA. reiser@azstarnet.com
Way
D
D
Bernas
M
M
Witte
M
M
Witte
C
C
D000077584:2-Methoxyestradiol; D000818:Animals; D002452:Cell Count / Q000187:drug effects; D002453:Cell Cycle / Q000187:drug effects*; D002455:Cell Division / Q000187:drug effects; D002461:Cell Line, Transformed; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects* / Q000473:pathology; D004958:Estradiol / Q000031:analogs & derivatives* / Q000494:pharmacology; D005434:Flow Cytometry; D006131:Growth Inhibitors / Q000494:pharmacology*; D006801:Humans; D051381:Rats; D014407:Tumor Cells, Cultured
D006131:Growth Inhibitors; D004958:Estradiol; D000077584:2-Methoxyestradiol