18F-CPFPX PET identifies changes in cerebral A1 adenosine receptor density caused by glioma invasion

J Nucl Med. 2005 Mar;46(3):450-4.

Abstract

Adenosine plays a critical role in both tumor proliferation and the cerebral response to tumor invasion. We used 8-cyclopentyl-3-(3-18F-fluoropropyl)-1-propylxanthine (18F-CPFPX) PET to investigate A1 adenosine receptor (A1AR) density as a potential indicator of the local cerebral response to glioma invasion.

Methods: A1AR density in F98 glioma-bearing rats was examined by 18F-CPFPX and 3H-CPFPX using PET, quantitative in vitro and ex vivo double-label receptor autoradiography, and immunohistochemical analyses.

Results: For all imaging modalities, A1AR signal intensity was increased in a zone surrounding experimental tumors (136%-146% that in control tissue) (P < 0.01). Immunostaining identified activated astrocytes as the main origin of peritumoral A1AR upregulation. The results of a pilot 18F-CPFPX PET study on a patient with recurrent glioblastoma multiforme confirmed increases in A1AR density in the immediate vicinity of the tumor.

Conclusion: 18F-CPFPX PET is suitable for the detection of peritumoral changes in A1AR density. Molecular imaging with 18F-CPFPX PET may open novel possibilities for gaining experimental and clinical insights into the cerebral response to tumor invasion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers, Tumor / metabolism*
  • Brain / diagnostic imaging
  • Brain / metabolism
  • Brain / pathology
  • Brain Neoplasms / diagnostic imaging
  • Brain Neoplasms / metabolism
  • Brain Neoplasms / pathology
  • Cell Line, Tumor
  • Glioma / diagnostic imaging*
  • Glioma / metabolism*
  • Glioma / pathology
  • Male
  • Neoplasm Invasiveness / diagnostic imaging*
  • Positron-Emission Tomography / methods
  • Radiopharmaceuticals / pharmacokinetics
  • Rats
  • Rats, Inbred F344
  • Receptor, Adenosine A1 / metabolism*
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Tissue Distribution
  • Xanthines / pharmacokinetics*

Substances

  • 8-cyclopenta-3-(3-fluoropropyl)-1-propylxanthine
  • Biomarkers, Tumor
  • Radiopharmaceuticals
  • Receptor, Adenosine A1
  • Xanthines