James Inkster, Msc., SFU/TRIUMF Simplifying the Preparation of 18 F-based Biomolecular Imaging Agents Through ‘Click’ Chemistry CANADA’S NATIONAL LABORATORY FOR PARTICLE AND NUCLEAR PHYSICS Owned and operated as a joint venture by a consortium of Canadian universities via a contribution through the National Research Council Canada LABORATOIRE NATIONAL CANADIEN POUR LA RECHERCHE EN PHYSIQUE NUCLÉAIRE ET EN PHYSIQUE DES PARTICULES Propriété d’un consortium d’universités canadiennes, géré en co-entreprise à partir d’une contribution administrée par le Conseil national de recherches Canada

Biomolecules as molecular imaging agents  Why biomolecules? Established synthetic procedures Exquisite specificity

Biomolecules as molecular imaging agents  Why biomolecules? Established synthetic procedures Exquisite specificity  Why not? Often requires a complex radiosynthesis Certain species may have issues with in vivo stability, bioavailability Most biomolecules are incompatible with many radiolabelling protocols

‘Click’ is a concept Kolb, H.C. & Sharpless, K.B. Drug Discovery Today 2003, 8, ,2,3- triazoles epoxide ring openings oximes hydrazones

[ 18 F]FPy5yne: an optimized 18 F- based bifunctional molecule  Efficient incorporation of [ 18 F]fluoride via 2-substitued pyridinyl nucleophilic heteroaromatic substitution  Efficient bioconjugation via Huisgen [3+2] cycloaddition reaction Inkster, J. A. H. et al. Journal of Labelled Compounds and Radiopharmaceuticals 2008, 51,

A typical radioTLC Radiochemical Yield: 89.6%±2.0% (n=4) 18 F -

Peptide labelling with [ 18 F]FPy5yne

Co-injections: (A) [ 18 F]FPy5yne (B) 18 F-Peptide RCY = 89.6%±2.0% (n =4) (A)(B)

Proposed biological applications i.e. Where are we going with all this? 18 F-BBN [ 18 F-bombesin(7-14)]  GRP receptors expressed in ~65% breast cancers*  18 F analogs of bombesin have been prepared 18 F-BVD15  NPY1 receptors expressed in 58%-85% breast cancers*  Attractive target, not yet labelled with 18 F 18 F-Senktide (a NK-3 receptor agonist)  Neuropeptide analog of substance P *Reubi J.C. European Journal of Nuclear Medicine 2002, 29, 855.

Same Prosthetic Group, Different Biomolecule

Why make radioactive DNA? Robinson, R. PLoS Biology, 2004, 2,

“I’ve seen the future, brother: it is murder.” –L.Cohen The challenge: the in vivo delivery of nucleic-acid based radiotracers into target cells, followed by retention of the probe by an antisense mechanism Abes, R. et al., Journal of Peptide Science 2008, 14, Juliano, R. et al. Nucleic Acids Research 2008, 36, Debart, F. et al. Current Topics in Medicinal Chemistry 2007, 7, F CP Peptide Oligo CP Peptide Oligo 18 F

Conclusion & Acknowledgements  The goal: t o employ TRIUMF LS’s expertise in synthetic organic and radiochemistry to develop simple, efficient and high-impact protocols for the preparation of biological radiopharmaceuticals  The Team PET Group (TRIUMF) Tim Storr (SFU) Mike Adam (UBC/TRIUMF) David Perrin (UBC) Fr anç ois Bernard (BC Cancer) Brigitte Guérin (U. de Sherbrooke) Tom Ruth

“I’ve seen the future, baby: it is murder.” –L.Cohen The challenge: the in vivo delivery of nucleic-acid based radiotracers into target cells, followed by retention of the probe by an antisense mechanism Some options:  Mismatched support strands  Cell-penetrating peptide-ON conjugates Tat(48-60), Transportan  Guanidino ON 18 F-(R-Ahx-R) 4 -PNA or 18 F-(R-Ahx-R) 4 -PMO Abes, R. et al., Journal of Peptide Science 2008, 14, Juliano, R. et al. Nucleic Acids Research 2008, 36, Debart, F. et al. Current Topics in Medicinal Chemistry 2007, 7,

Peptide labeling with Tri[ 18 F]fluoroarylborates  an application of technology developed by the Perrin lab.

[ 18 F]Fluorination of Sulfonyl Chlorides

Scavenging [ 18 F]Fluoride from Aqueous Solutions with Cationic Boranes (19) (20)

A Maxim “Synthetic organic chemistry is hard work. Radiochemistry is just hard.” - J. Inkster

A Maxim “Synthetic organic chemistry is hard work. Radiochemistry is just hard.” - J. Inkster “And don’t even ask me about radiobioconjugate chemistry…”

18 F-labelled Bombensein(7-14)