Radioiodinated indomethacin amide for molecular imaging of cyclooxygenase-2 expressing tumors

Agnieszka Morgenroth*, Andreas T. J. Vogg, Bernd Neumaier, Felix M. Mottaghy, Boris D. Zlatopolskiy

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

2 Citations (Web of Science)

Abstract

Cyclooxygenase-2 (COX-2) is an important biomarker in several tumors. Available imaging probes display relatively low tumor to background ratios (smaller than 2: 1). We evaluated newly developed indomethacin (Ind) derivatives for in vivo molecular imaging of COX-2 expressing carcinoma. Radioiodinated Ind derivatives Ind-NH( CH2)4-NH-3-[I-125]I-Bz ([I-125]5), Ind-NH-(CH2)4-NH-5-[I-124/125]I-Nic ([I-124/125]6) and Ind-NH-(CH2)4-NH-5-[I-125]I-Iphth ([I-125]7) were prepared from the respective SnBu3-precursors (45-80% radiochemical yield; > 95% radiochemical purity). The cellular uptake of [I-125]5 and [I-125]6 correlated with COX-2 expression determined by SDS page/Western blot analysis. [I-125]5 was predominantly localized in the cell membrane while [I-125]6 was internalized and displayed a diffuse and favorable cytoplasmic distribution. In contrast, [I-125]7 showed only low uptake in COX-2 positive cells. Co-incubation with the COX-2 inhibitor Celecoxib led to an almost complete suppression of cellular uptake of [I-125]5 and [I-125]6. In vivo molecular imaging using positron emission tomography (PET) in SCID mice xenografted with COX-2(+) (HT29) and COX-2-(HCT116) human colorectal carcinoma cells was performed for [I-124]6. HT29 xenografts displayed a significantly higher uptake than HCT-116 xenografts (5.6 +/- 1.5 vs. 0.5 +/- 0.1 kBq/g, P <0.05) with an extraordinary high tumor to muscle ratio (50.3 +/- 1.5). Immunohistological staining correlated with the imaging data. In conclusion, the novel radioiodinated indomethacin derivative ([I-124/125]6) could become a valuable tool for development of molecular imaging probes for visualization of COX-2 expressing tumors.

Original languageEnglish
Pages (from-to)18059-18069
Number of pages11
JournalOncotarget
Volume8
Issue number11
DOIs
Publication statusPublished - 14 Mar 2017

Keywords

  • cyclooxygenase-2
  • colorectal carcinoma
  • indomethacin
  • celecoxib
  • PET imaging
  • NONSTEROIDAL ANTIINFLAMMATORY DRUGS
  • SELECTIVE-INHIBITION
  • COX-2 INHIBITORS
  • IN-VIVO
  • AGENTS
  • DESIGN
  • CANCER
  • INFLAMMATION
  • SYSTEM
  • MOUSE

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