The vascular disrupting activity of OXi8006 in endothelial cells and its phosphate prodrug OXi8007 in breast tumor xenografts. Issue 1 (1st December 2015)

• Record Type: Journal Article
• Authors: Strecker, Tracy E.; Odutola, Samuel O.; Lopez, Ramona; Cooper, Morgan S.; Tidmore, Justin K.; Charlton-Sevcik, Amanda K.; Li, Li; MacDonough, Matthew T.; Hadimani, Mallinath B.; Ghatak, Anjan; Liu, Li; Chaplin, David J.; Mason, Ralph P.; Pinney, Kevin G.; Trawick, Mary Lynn
• Is Part Of: Cancer letters. Volume 369:Issue 1(2016)
• Page Start: 229
• Page End: 241
• Publication Date: 2015-12-01
• Subjects: ANOVA analysis of variance -- BLI bioluminescence imaging -- CA4 combretastatin A-4 -- CA4P combretastatin A-4 phosphate -- DAPI 4′, 6-diamidino-2-phenylindole -- DMSO dimethyl sulfoxide -- DTT dithiothreitol -- FAK focal adhesion kinase -- FDA Federal Drug Administration -- FITC fluorescein isothiocyanate -- GI50 median growth inhibitory concentration -- HRP horseradish peroxidase -- HUVEC human umbilical vein endothelial cells -- MLC myosin light chain -- NMII non-muscle myosin II -- OXi8006 2-(3′-hydroxy-4′-methoxyphenyl)-3-(3″, 4″, 5″-trimethoxybenzoyl)-6-methoxyindole -- OXi8007 2-(3′-disodium phosphate-4′-methoxyphenyl)-3-(3″, 4″, 5″-trimethoxybenzoyl)-6-methoxyindole -- PBS phosphate buffered saline -- PI propidium iodide -- PLSD protected least significant difference -- pMLC phosphorylated myosin light chain -- ROCK RhoA kinase -- SCID severe combined immunodeficiency -- SDS sodium dodecyl sulfate -- SRB sulforhodamine B -- VDA vascular disrupting agent -- Y-27632 (R)-(+)-trans-4-(1-aminoethyl)-N-(4-pyridyl)cyclohexanecarboxamide dihydrochloride; Vascular disrupting agent (VDA) -- Microtubules -- Focal adhesion kinase (FAK) -- Bioluminescence imaging (BLI) -- Breast cancer; Cancer -- Periodicals; Neoplasms -- Periodicals; Cancer -- Périodiques; Electronic journals; 616.994
• DOI: 10.1016/j.canlet.2015.08.021
• Languages: English
• ISSNs: 0304-3835

Abstract

Highlights: The indole-based OXi8006 and its phosphate prodrug OXi8007 are potent vascular disrupting agents. Bioluminescence imaging in a breast cancer xenograft mouse model demonstrated that OXi8007 is a potent VDA in vivo. VDA properties were confirmed by complementary studies in activated endothelial cells. OXi8006 treatment resulted in microtubule disruption, and activation of RhoA kinase. Phosphorylation of focal adhesion kinase is essential for the OXi8006 mechanism. Graphical abstract: Abstract: This study describes the vascular disrupting ability and the mechanism of action of the indole-based tubulin-binding compound, OXi8006, and its water-soluble phosphate prodrug OXi8007. Treatment of rapidly proliferating human umbilical vein endothelial cells (HUVECs), used as a model for the tumor vasculature, with OXi8006 or OXi8007, caused potent microtubule disruption followed by extensive reorganization of the cytoskeletal network. The mechanism of action involved an increase in focal adhesion formation associated with an increase in phosphorylation of both non-muscle myosin light chain and focal adhesion kinase. These effects were dramatically diminished by an inhibitor of RhoA kinase, a downstream effector of RhoA. Cell cycle blockade at G2/M and cytotoxicity toward rapidly proliferating HUVECs were also observed. Capillary-like networks of HUVECs were disrupted by the action of both OXi8006 and OXi8007. The prodrug OXi8007 exhibited potent and rapid dose-dependent antivascular activity assessed by dynamic bioluminescence imaging (BLI) in an MDA-MB-231-luc breast cancer xenograft mouse model. By 6 hours post treatment, over 93% of the BLI signal was abolished with only a slight recovery at 24 hours. These findings were confirmed by histology. The results from this study demonstrate that OXi8007 is a potent vascular disrupting agent acting through an anti-microtubule mechanism involving RhoA.