title: Evaluation of a (99m) Tc-labelled meso-bisphenylporphyrin as a tumour image agent.
abstract: Porphyrins are excellent agents for photodynamic treatment of various types of cancer and also good metal chelators that form highly stable metallo-complexes with different radionuclides. Therefore, radiolabelled porphyrins could also be potentially used as tumour imaging agents. In this context, the aim of this work was the radiolabelling of meso-bis[3,4-bis(carboxymethyleneoxy)phenyl]porphyrin, 2CPP, with Technetium-99 m ((99m) Tc) and the evaluation of its radiochemical and biological properties in vitro and in vivo. The labelling procedure was optimized resulting in an efficiency of 92.52 ± 0.48%. The complex (99m) TC-2CPP remained stable for more than 4 h. The biodistribution showed that (99m) Tc-2CPP is eliminated by gastrointestinal and urinary pathways. The tumour/muscle ratio increases over time, being 3.33 ± 1.22 and 3.55 ± 1.29 in WiDr-bearing tumours mice and in H1299-bearing tumours mice, respectively, 6 h post-injection, showing the tumour specificity of the (99m) Tc-2CPP complex. The favourable tumour/muscle ratio of (99m) Tc-2CPP shows that this complex could potentially be used as tumour imaging agent. Moreover, it could be used to follow the progression or regression of tumours before, during and after the radiotherapy, chemotherapy and photodynamic therapy.
authors.affiliation: Biophysics Unit, Faculty of Medicine, University of Coimbra, Azinhaga de Santa Comba, Celas, 3000-548, Coimbra, Portugal; University of Beira Interior, 6200-001, Covilhã, Portugal.
authors.forename: Pedro M
authors.initials: PM
authors.lastname: Santos
authors.forename: Mafalda
authors.initials: M
authors.lastname: Laranjo
authors.forename: Arménio C
authors.initials: AC
authors.lastname: Serra
authors.forename: Ana Margarida
authors.initials: AM
authors.lastname: Abrantes
authors.forename: Marta
authors.initials: M
authors.lastname: Piñeiro
authors.forename: João
authors.initials: J
authors.lastname: Casalta-Lopes
authors.forename: Diná
authors.initials: D
authors.lastname: Trindade
authors.forename: Jorge
authors.initials: J
authors.lastname: Maia
authors.forename: António
authors.initials: A
authors.lastname: Rocha-Gonsalves
authors.forename: Maria Filomena
authors.initials: MF
authors.lastname: Botelho
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D004355:Drug Stability; D006801:Humans; D007553:Isotope Labeling; D008297:Male; D051379:Mice; D015609:Organotechnetium Compounds / Q000737:chemistry / Q000493:pharmacokinetics; D011166:Porphyrins / Q000737:chemistry / Q000493:pharmacokinetics; D011854:Radiochemistry; D013667:Technetium
chemical_list: D015609:Organotechnetium Compounds; D011166:Porphyrins; C000593187:technetium 99m meso-bis(3,4-bis(carboxymethyleneoxy)phenyl)porphyrin; D013667:Technetium
keywords: Technetium-99 m (99mTc); colon adenocarcinoma; imaging; lung cancer; photodynamic therapy; photosensitizer