Synthesis and evaluation of a fluorine-18 labeled antisense oligonucleotide as a potential PET tracer for iNOS mRNA expression.

Inducible NO synthase (iNOS) is overexpressed in inflammatory bowel diseases. An antisense oligonucleotide with good hybridization properties for iNOS mRNA was selected using RT-PCR. The oligonucleotide was reliably labeled with fluorine-18 using N-(4-[(18)F]fluorobenzyl)-2-bromoacetamide.

Evaluation of fluorine-18-labeled alkylating agents as potential synthons for the labeling of oligonucleotides.

Six fluorine-18-labeled alkylating agents were selected as potentially suitable synthons for the labeling of antisense oligonucleotides. The selected synthons were evaluated in a model reaction with the monomer adenosine 5'-O-thiomonophosphate. Of these synthons, alpha-bromo-alpha'-[18F]fluoro-m-xylene and N-(4-[18F]fluorobenzyl)-2-bromoacetamide were found to be the most promising.