Design, synthesis, and evaluation of an 18F-labeled radiotracer based on celecoxib-NBD for positron emission tomography (PET) imaging of cyclooxygenase-2 (COX-2)

Jatinder Kaur, Ole Tietz, Atul Bhardwaj, Alison Marshall, Jenilee Way, Melinda Wuest, Frank Wuest*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Citations (Scopus)


A series of novel fluorine-containing cyclooxygenase-2 (COX-2) inhibitors was designed and synthesized based on the previously reported fluorescent COX-2 imaging agent celecoxib-NBD (3; NBD=7-nitrobenzofurazan). In vitro COX-1/COX-2 inhibitory data show that N-(4-fluorobenzyl)-4-(5-p-tolyl-3-trifluoromethylpyrazol-1-yl)benzenesulfonamide (5; IC50=0.36 μM, SI>277) and N-fluoromethyl-4-(5-p-tolyl-3-trifluoromethylpyrazol-1-yl)benzenesulfonamide (6; IC50=0.24 μM, SI>416) are potent and selective COX-2 inhibitors. Compound 5 was selected for radiolabeling with the short-lived positron emitter fluorine-18 (18F) and evaluated as a positron emission tomography (PET) imaging agent. Radiotracer [18F]5 was analyzed in vitro and in vivo using human colorectal cancer model HCA-7. Although radiotracer uptake into COX-2-expressing HCA-7 cells was high, no evidence for COX-2-specific binding was found. Radiotracer uptake into HCA-7 tumors in vivo was low and similar to that of muscle, used as reference tissue. From fluorescence to PET imaging: In line with the success of our fluorescent COX-2 imaging celecoxib-NBD probe, we extend our efforts to prepare an 18F-labeled PET imaging probe for in vivo detection of COX-2 expression in colorectal cancer. Herein we report the preparation of a series of COX-2 inhibitors, the radiosynthesis of an 18F-labeled radiotracer, results of in vitro cell uptake studies in colorectal cancer HCA-7 cells, radiometabolite analysis, and in vivo PET imaging studies in HCA-7 tumor-bearing NIH-III mice.

Original languageEnglish
Pages (from-to)1635-1640
Number of pages6
Issue number10
Publication statusPublished - 1 Oct 2015
Externally publishedYes


  • cancer
  • cyclooxygenases
  • drug design
  • positron emission tomography
  • radiochemistry


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