Evaluation of the Antiangiogenic Potential of AQ4N

• Published in: Clinical cancer research 2008-03, Vol.14 (5), p.1502-1509
• Main Authors: O'ROURKE, Martin, WARD, Claire, WORTHINGTON, Jenny, MCKENNA, Julie, VALENTINE, Andrea, ROBSON, Tracy, HIRST, David G, MCKEOWN, Stephanie R
• Format: Article
• Language: English
• Subjects: Angiogenesis; Angiogenesis Inhibitors - pharmacology; Animals; Anthraquinones; Anthraquinones - pharmacology; Antineoplastic agents; Antineoplastic Agents - pharmacology; Aorta - drug effects; AQ4N; Biological and medical sciences; Cell Hypoxia; Cell Proliferation; Cells, Cultured; Collagen - metabolism; Colonic Neoplasms - drug therapy; Cyclohexanes - pharmacology; Cytoskeleton - metabolism; Drug Combinations; Endothelium, Vascular - drug effects; Fatty Acids, Unsaturated - pharmacology; HMEC-1 cells; Humans; Laminin - metabolism; Male; Medical sciences; Mice; Mice, Inbred BALB C; Microcirculation; Neovascularization, Physiologic; Pancreatic Neoplasms - drug therapy; Pharmacology. Drug treatments; Prostatic Neoplasms - drug therapy; Proteoglycans - metabolism; Rats; Rats, Wistar; Sesquiterpenes - pharmacology; Skin - blood supply; Surgical Flaps; Wound Healing - drug effects
• ISSN: 1078-0432; 1557-3265
• DOI: 10.1158/1078-0432.CCR-07-1262

Purpose: A number of cytotoxic chemotherapy agents tested at low concentrations show antiangiogenic properties with limited cytotoxicity, e.g., cyclophosphamide, tirapazamine, and mitoxantrone. AQ4N is a bioreductive alkylaminoanthraquinone that is cytotoxic when reduced to AQ4; hence, it can be used to target hypoxic tumor cells. AQ4N is structurally similar to mitoxantrone and was evaluated for antiangiogenic properties without the need for bioreduction. Experimental Design: The effect of AQ4N and fumagillin on human microvascular endothelial cells (HMEC-1) was measured using a variety of in vitro assays, i.e., 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, wound scrape, tubule formation, rat aortic ring, and invasion assays. Low-dose AQ4N (20 mg/kg) was also given in vivo to mice bearing a tumor in a dorsal skin flap. Results: AQ4N (10 −11 to 10 −5 mol/L) had no effect on HMEC-1 viability. AQ4N (10 −9 to 10 −5 mol/L) caused a sigmoidal dose-dependent inhibition of endothelial cell migration in the wound scrape model. Fumagillin showed a similar response over a lower dose range (10 −13 to 10 −9 mol/L); however, the maximal inhibition was less (25% versus 43% for AQ4N). AQ4N inhibited HMEC-1 cell contacts on Matrigel (10 −8 to 10 −5 mol/L), HMEC-1 cell invasion, and sprouting in rat aorta explants. Immunofluorescence staining with tubulin, vimentim, dynein, and phalloidin revealed that AQ4N caused disruption to the cell cytoskeleton. When AQ4N (20 mg/kg) was given in vivo for 5 days, microvessels disappeared in LNCaP tumors grown in a dorsal skin flap. Conclusions: This combination of assays has shown that AQ4N possesses antiangiogenic effects in normoxic conditions, which could potentially contribute to antitumor activity.