Noninvasive monitoring of therapy-induced microvascular changes in a pancreatic cancer model using dynamic contrast-enhanced magnetic resonance imaging with P846, a new low-diffusible gadolinium-based contrast agent

Radiat Res. 2011 Jan;175(1):10-20. doi: 10.1667/RR2068.1. Epub 2010 Oct 7.

Abstract

A predictive technique in the management of patients with cancer could improve the therapeutic index by allowing better individualization of treatment. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is a noninvasive technique that can provide anatomical and physiological information on the tumor and its microenvironment. We studied the effect of chemotherapy (gemcitabine), anti-angiogenesis therapy (sunitinib) and radiotherapy on the kinetics of DCE-MRI parameters in a preclinical model of pancreatic cancer using P846, a new low-diffusible contrast agent. Mice underwent DCE-MRI before treatment (MRI1), after 1 week of treatment (MRI2), and after 1 additional week (MRI3). Combined treatment with radiotherapy and sunitinib had a synergistic effect on tumor growth. In radiotherapy/sunitinib-treated mice, a decrease in K(trans) at MRI2 predicted its superior antivascular and antitumor effect at an early time. An increased K(trans) at MRI2, as seen in gemcitabine- and gemcitabine/sunitinib-treated mice, reflects increased permeability for P846 and might predict a smaller therapeutic effect at this early time. This study shows that the kinetics of DCE-MRI parameters depends on the contrast agent used. P846 appears to be a promising low-diffusible agent to monitor therapeutic effects in this preclinical cancer model, but further studies are needed to compare its behavior with Gd-DTPA and macromolecular-weight contrast agents. Sunitinib as a radiosensitizer is promising for future clinical trials in human pancreatic cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Apoptosis
  • Cell Line, Tumor
  • Combined Modality Therapy
  • Contrast Media*
  • Image Enhancement / methods*
  • Magnetic Resonance Imaging / methods*
  • Male
  • Mice
  • Microvessels / drug effects
  • Microvessels / radiation effects
  • Organometallic Compounds*
  • Pancreatic Neoplasms / blood supply
  • Pancreatic Neoplasms / pathology
  • Pancreatic Neoplasms / therapy*
  • Placenta Growth Factor
  • Pregnancy Proteins / analysis
  • Pregnancy Proteins / physiology
  • Vascular Endothelial Growth Factor A / analysis

Substances

  • Contrast Media
  • Organometallic Compounds
  • P846 compound
  • PGF protein, human
  • Pgf protein, mouse
  • Pregnancy Proteins
  • Vascular Endothelial Growth Factor A
  • Placenta Growth Factor