title: Radiolabeling and biological evaluation of DOTA-Ph-Al derivative conjugated to anti-EGFR antibody ior egf/r3 for targeted tumor imaging and therapy.
abstract: An appropriate bifunctional chelating agent namely DOTA-Ph-Al was developed for the conjugation with biological vectors (anti EGFr antibody). We hereby report the synthesis of p-bromoacetamidobenzyl derivative of DOTA and its conjugation to monoclonal antibody anti-EGFR ior egf/r3. Immunoconjugate was prepared by conjugation of p-bromoacetamidobenzyl derivative of DOTA with ior egf/r3. Modified antibody was purified by size exclusion chromatography. DOTA-Ph-Al-ior egf/r3 exhibited quantitative 99mTc-labeling (>96%) with specific activity 10-20 mCi/mg of protein and 90Y-labeling with specific activity 2-5 mCi/mg. Immunoreactivity was determined by flow cytometry. Receptor ligand assay on murine cell line EAT and human tumor cell line U-87MG showed Kd = 2.87 nM and 4.86 nM respectively. The stability in serum indicated that 99mTc remained bound to antibodies up to 24h and 98% 90Y was associated with the mAb for five days. Biodistribution characteristics of Ab-conjugate radiolabeled to 99mTc and 90Y radionuclide was examined in BALB/c mice grafted with EAT and athymic mice with U-87MG cell line demonstrated high tumor uptake with 5.5 +/- 1.3 and 7.85 +/- 1.2%ID/g at four and 24 h for 99mTc- DOTA-Ph-AI-ior egf/r3 in EAT tumors after post injection respectively. Maximal radiotracer uptake peaked 17.6 +/- 2.5%ID/g in EAT tumor and 12.89 +/- 0.66% ID/g in U-87MG tumor at 48h for 90Y. The drug excreted through renal routes as the activity in the kidneys was 13.42 +/- 0.33%ID/g at 1 h and 4.51 +/- 1.2%ID/g at 4 h for 99mTc- DOTA-Ph-Al-ior egf/r3.
authors.affiliation: Division of Radiopharmaceuticals and Radiation Biology, Institute of Nuclear Medicine and Allied Sciences, Delhi, India.
authors.forename: Puja
authors.initials: P
authors.lastname: Pnwar
authors.forename: Normando
authors.initials: N
authors.lastname: Iznaga-Escobar
authors.forename: Pushpa
authors.initials: P
authors.lastname: Mishra
authors.forename: Vibha
authors.initials: V
authors.lastname: Srivastava
authors.forename: Rakesh Kumar
authors.initials: RK
authors.lastname: Sharma
authors.forename: Ramesh
authors.initials: R
authors.lastname: Chandra
authors.forename: Anil K
authors.initials: AK
authors.lastname: Mishra
mesh_terms: D000081:Acetamides / Q000138:chemical synthesis / Q000737:chemistry; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000493:pharmacokinetics / Q000627:therapeutic use; D045744:Cell Line, Tumor; D003952:Diagnostic Imaging; D066246:ErbB Receptors / Q000276:immunology*; D006573:Heterocyclic Compounds, 1-Ring / Q000138:chemical synthesis / Q000737:chemistry; D006801:Humans; D018796:Immunoconjugates / Q000737:chemistry / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007553:Isotope Labeling; D051379:Mice; D008807:Mice, Inbred BALB C; D009369:Neoplasms / Q000175:diagnosis* / Q000188:drug therapy / Q000532:radiotherapy*; D016499:Radioimmunotherapy; D015021:Yttrium Radioisotopes / Q000737:chemistry / Q000627:therapeutic use
chemical_list: C511442:3-(4-bromoacetamidobenzyl)-2-(1,4,7,10-tetraazacyclodecane-1,4,7-triacetic acid-(10-acetamido))propanamide; D000081:Acetamides; D000911:Antibodies, Monoclonal; D006573:Heterocyclic Compounds, 1-Ring; D018796:Immunoconjugates; D015021:Yttrium Radioisotopes; D066246:ErbB Receptors