Synthesis and evaluation of a 18F-labeled 4-ipomeanol as an imaging agent for CYP4B1 gene prodrug activation therapy

Cancer Biother Radiopharm. 2013 Oct;28(8):588-97. doi: 10.1089/cbr.2012.1408. Epub 2013 May 19.

Abstract

We report the development of a (18)F-labeled 4-ipomeanol (4-IM), which is metabolized by the CYP4B1 enzyme, to image tumors and monitor enzyme-activating anticancer prodrugs. The fluorine-substituted derivative, 1-(3-furyl)-4-hydroxy-5-fluoro-1-pentanone (F-4-IM, 1), was synthesized from 3-furaldehyde. [(18)F]F-4-IM ([(18)F]1) was prepared in 20%-35% radiochemical yield by a fluorine-18 displacement reaction, followed by reduction and deprotection of the ketal group, and was shown to be stable (>96% at 2 hours) in human serum at 37°C. The biodistribution of [(18)F]F-4-IM in normal rats was high in the lung, where CYP4B1 gene is preferentially expressed. We transduced C6-glioma cells with a retrovirus-expressing CYP4B1 (C6-CYP4B1). Evaluation of CYP4B1 expression was confirmed by reverse transcription polymerase chain reaction and MTT assay. Cell assays were carried out using C6 and C6-CYP4B, and the uptake of [(18)F]F-4-IM in these cells was compared with that in parental controls. The uptake ratio of [(18)F]F-4-IM was 2.8-fold higher in C6-CYP4B1 compared with that in parental cells at 1 hour, whereas [(3)H]4-IM was taken up at similar rates in both cell lines after 6 hours. These results suggest that [(18)F]F-4-IM could be a promising PET imaging agent with potential to be used for imaging of CYP4B1-transfected tumor cells, as well as for monitoring CYP4B1 enzyme/prodrug interactions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aryl Hydrocarbon Hydroxylases / biosynthesis
  • Aryl Hydrocarbon Hydroxylases / chemistry*
  • Aryl Hydrocarbon Hydroxylases / genetics
  • Aryl Hydrocarbon Hydroxylases / metabolism
  • Drug Stability
  • Fluorine Radioisotopes / chemistry*
  • Glioma / enzymology
  • Glioma / genetics
  • Glioma / metabolism
  • Humans
  • Isotope Labeling / methods
  • Prodrugs / pharmacokinetics*
  • Radiopharmaceuticals / chemical synthesis*
  • Radiopharmaceuticals / chemistry
  • Radiopharmaceuticals / pharmacokinetics
  • Rats
  • Rats, Inbred F344
  • Terpenes / chemical synthesis*
  • Terpenes / pharmacokinetics
  • Transfection
  • Tumor Cells, Cultured

Substances

  • Fluorine Radioisotopes
  • Prodrugs
  • Radiopharmaceuticals
  • Terpenes
  • Aryl Hydrocarbon Hydroxylases
  • cytochrome P-450 CYP4B1
  • 4-ipomeanol