Editorial
Copyright ©2011 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Radiol. Jan 28, 2011; 3(1): 1-16
Published online Jan 28, 2011. doi: 10.4329/wjr.v3.i1.1
Multiparametric MRI biomarkers for measuring vascular disrupting effect on cancer
Huaijun Wang, Guy Marchal, Yicheng Ni
Huaijun Wang, Guy Marchal, Yicheng Ni, Department of Radiology, University Hospitals, University of Leuven, Herestraat 49, B-3000 Leuven, Belgium
Author contributions: All authors made a substantial contribution to the conception and design of the manuscript, drafting the article or revising it.
Supported by (partially) The grants awarded by Fonds voor Wetenschappelijk Onderzoek-Vlaanderen (FWO Vlaanderen) Impulsfinanciering project (ZWAP/05/018); Geconcerteerde Onderzoeksactie of the Flemish Government, OT project (OT/06/70); the K.U. Leuven Molecular Small Animal Imaging Center MoSAIC (KUL EF/05/08); the center of excellence In vivo Molecular Imaging Research of K.U. Leuven; and a EU project Asia-Link CfP 2006-EuropeAid/123738/C/ACT/Multi-Proposal No. 128-498/111
Correspondence to: Dr. Yicheng Ni, Professor, Department of Radiology, University Hospitals, University of Leuven, Herestraat 49, B-3000 Leuven, Belgium. yicheng.ni@med.kuleuven.be
Telephone: +32-16-330165 Fax: +32-16-343765
Received: December 7, 2010
Revised: January 13, 2011
Accepted: January 20, 2011
Published online: January 28, 2011
Abstract

Solid malignancies have to develop their own blood supply for their aggressive growth and metastasis; a process known as tumor angiogenesis. Angiogenesis is largely involved in tumor survival, progression and spread, which are known to be significantly attributed to treatment failures. Over the past decades, efforts have been made to understand the difference between normal and tumor vessels. It has been demonstrated that tumor vasculature is structurally immature with chaotic and leaky phenotypes, which provides opportunities for developing novel anticancer strategies. Targeting tumor vasculature is not only a unique therapeutic intervention to starve neoplastic cells, but also enhances the efficacy of conventional cancer treatments. Vascular disrupting agents (VDAs) have been developed to disrupt the already existing neovasculature in actively growing tumors, cause catastrophic vascular shutdown within short time, and induce secondary tumor necrosis. VDAs are cytostatic; they can only inhibit tumor growth, but not eradicate the tumor. This novel drug mechanism has urged us to develop multiparametric imaging biomarkers to monitor early hemodynamic alterations, cellular dysfunctions and metabolic impairments before tumor dimensional changes can be detected. In this article, we review the characteristics of tumor vessels, tubulin-destabilizing mechanisms of VDAs, and in vivo effects of the VDAs that have been mostly studied in preclinical studies and clinical trials. We also compare the different tumor models adopted in the preclinical studies on VDAs. Multiparametric imaging biomarkers, mainly diffusion-weighted imaging and dynamic contrast-enhanced imaging from magnetic resonance imaging, are evaluated for their potential as morphological and functional imaging biomarkers for monitoring therapeutic effects of VDAs.

Keywords: Vascular disrupting agents; Tumor vessels; Imaging biomarkers; Magnetic resonance imaging; Diffusion-weighted imaging; Dynamic contrast-enhanced magnetic resonance imaging