title: Biotinidase Resistant68Gallium-Radioligand Based on Biotin/Avidin Interaction for Pretargeting: Synthesis and Preclinical Evaluation.
abstract: A new macrocyclic system 2,2'-(12-amino-11,13-dioxo-1,4,7,10-tetraazacyclotridecane-4,7-diyl)diacetic acid (ATRIDAT) was designed for coordinating metals in +2 and +3 oxidation states particularly68Ga(III), for PET imaging. ATRIDAT was conjugated to d-biotin for pretargeting via biotin-avidin interaction. This model provides high tumor targeting efficiency and stability to biotinidase activity leading to modest signal amplification at the tumor site. Cyclization of triethylenetetramine with protected diethylamino malonate resulted in the formation of 13 membered diamide ring. d-Biotin was then anchored on the pendant amine rendering α-methyne carbon to the biotinamide bond which blocks the biotinidase enzyme activity. Biotinidase stability assay showed remarkable stability toward the action of biotinidase with ∼95% remaining intact after treatment following 4 h. Binding affinity experiments such as HABA assay, competitive displacement studies with d-biotin and CD showed high binding affinity of the molecule with avidin in nanomolar range. Biotin conjugate was successfully radiolabeled with68Ga(III) with radiolabeling efficiency of ∼70% and then purified to get 99.9% radiochemical yield. IC50of the compound was found to be 2.36 mM in HEK cell line and 0.82 mM in A549 as assessed in MTT assay. In biodistribution studies, the major route of excretion was found to be renal. Significant uptake of 4.15 ± 0.35% was observed in tumor in the avidin pretreated mouse at 1 h. μPET images also showed a high tumor to muscle ratio of 26.8 and tumor to kidney ratio of 1.74 at 1 h post-injection after avidin treatment.
authors.affiliation: Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences , Brig SK Mazumdar Road, Delhi-110054, India.|Department of Chemistry, University of Delhi , Delhi-110007, India.
authors.forename: Surbhi
authors.initials: S
authors.lastname: Prakash
authors.affiliation: Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences , Brig SK Mazumdar Road, Delhi-110054, India.
authors.forename: Puja Panwar
authors.initials: PP
authors.lastname: Hazari
authors.affiliation: Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences , Brig SK Mazumdar Road, Delhi-110054, India.
authors.forename: Virendra Kumar
authors.initials: VK
authors.lastname: Meena
authors.affiliation: Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences , Brig SK Mazumdar Road, Delhi-110054, India.
authors.forename: Ambika
authors.initials: A
authors.lastname: Jaswal
authors.affiliation: Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences , Brig SK Mazumdar Road, Delhi-110054, India.
authors.forename: Harleen
authors.initials: H
authors.lastname: Khurana
authors.affiliation: Department of Chemistry, University of Delhi , Delhi-110007, India.
authors.forename: Shrikant
authors.initials: S
authors.lastname: Kukreti
authors.affiliation: Division of Cyclotron and Radiopharmaceutical Sciences, Institute of Nuclear Medicine and Allied Sciences , Brig SK Mazumdar Road, Delhi-110054, India.
authors.forename: Anil Kumar
authors.initials: AK
authors.lastname: Mishra
mesh_terms: D000818:Animals; D001360:Avidin / Q000378:metabolism*; D001710:Biotin / Q000378:metabolism*; D043523:Biotinidase / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects; D060326:Chemistry Techniques, Synthetic; D005710:Gallium Radioisotopes; D057809:HEK293 Cells; D006801:Humans; D007700:Kinetics; D008024:Ligands; D047028:Macrocyclic Compounds / Q000737:chemistry* / Q000378:metabolism* / Q000493:pharmacokinetics / Q000494:pharmacology; D051379:Mice; D049268:Positron-Emission Tomography; D011485:Protein Binding; D011522:Protons; D011854:Radiochemistry; D051381:Rats; D014018:Tissue Distribution
chemical_list: D005710:Gallium Radioisotopes; D008024:Ligands; D047028:Macrocyclic Compounds; D011522:Protons; D001360:Avidin; D001710:Biotin; D043523:Biotinidase