Dynamic magnetic resonance imaging assessment of vascular targeting agent effects in rat intracerebral tumor models

Leslie L. Muldoon, Seymur Gahramanov, Xin Li, Deborah J. Marshall, Dale F. Kraemer, Edward A. Neuwelt

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

We used dynamic MRI to evaluate the effects of monoclonal antibodies targeting brain tumor vasculature. Female athymic rats with intracerebral human tumor xenografts were untreated or treated with intetumumab, targeting aV-integrins, or bevacizumab, targeting vascular endothelial growth factor (n = 4-6 per group). Prior to treatment and at 1, 3, and 7 days after treatment, we performed standard MRI to assess tumor volume, dynamic susceptibility-contrast MRI with the blood-pool iron oxide nanoparticle ferumoxytol to evaluate relative cerebral blood volume (rCBV), and dynamic contrast-enhanced MRI to assess tumor vascular permeability. Tumor rCBV increased by 27 ± 13% over 7 days in untreated rats; intetumumab increased tumor rCBV by 65±10%, whereas bevacizumab reduced tumor rCBV by 31 ±10% at 7 days (P <.001 for group and day). Similarly, intetumumab increased brain tumor vascular permeability compared with controls at 3 and 7 days after treatment, whereas bevacizumab decreased tumor permeability within 24 hours (P =.0004 for group, P =.0081 for day). All tumors grew over the 7-day assessment period, but bevacizumab slowed the increase in tumor volume on MRI. We conclude that the vascular targeting agents intetumumab and bevacizumab had diametrically opposite effects on dynamic MRI of tumor vasculature in rat brain tumor models. Targeting αv-integrins increased tumor vascular permeability and blood volume, whereas bevacizumab decreased both measures. These findings have implications for chemotherapy delivery and antitumor efficacy.

Original languageEnglish (US)
Pages (from-to)51-60
Number of pages10
JournalNeuro-Oncology
Volume13
Issue number1
DOIs
StatePublished - Jan 2011

Keywords

  • Bevacizumab
  • Blood-brain barrier
  • Dynamic susceptibility-weighted contrast-enhanced magnetic resonance imaging
  • Intetumumab

ASJC Scopus subject areas

  • Oncology
  • Clinical Neurology
  • Cancer Research

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