title: Responsive Mn(II) complexes for potential applications in diagnostic Magnetic Resonance Imaging.
abstract: The investigation of new Mn(II)-based MRI/Molecular Imaging probes responsive to the enzyme tyrosinase for potential diagnostic applications is herein described. The expression of the enzyme tyrosinase, an oxidoreductase, is up-regulated in melanoma cancer cells. Three novel ligands (L(1), L(2) and L(3)) were designed as modified acyclic polyaminocarboxylate chelates by introducing an l-tyrosine residue in place of an aminoacetate unit. The corresponding Mn(II) complexes were fully characterised by (1)H NMR relaxometric techniques in aqueous media. The responsive activity towards the expression of tyrosinase was then assessed by monitoring the (1)H 1/T(1) relaxivity changes during incubation experiments in buffered solutions containing tyrosinase at different concentrations and in B16F10 melanoma cell homogenate. New insight on the mechanism of action of these systems was gained by measuring the magnetic field dependence of the relaxivity and ESR spectra of the incubated solutions. The systems developed showed responsive activity to tyrosinase with a relaxation enhancement spanning from 50% (MnL(1)) to 350% (MnL(3)) which augurs well for the development of diagnostic probes to detect melanoma cancer.
authors.affiliation: Dipartimento di Scienze dell'Ambiente e della Vita, Università degli Studi del Piemonte Orientale Amedeo Avogadro, Viale T. Michel 11, 15121 Alessandria, Italy.
authors.forename: Gabriele A
authors.initials: GA
authors.lastname: Rolla
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Tei
authors.forename: Marianna
authors.initials: M
authors.lastname: Fekete
authors.forename: Francesca
authors.initials: F
authors.lastname: Arena
authors.forename: Eliana
authors.initials: E
authors.lastname: Gianolio
authors.forename: Mauro
authors.initials: M
authors.lastname: Botta
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D056831:Coordination Complexes / Q000138:chemical synthesis; D008024:Ligands; D008279:Magnetic Resonance Imaging; D008345:Manganese / Q000737:chemistry*; D051379:Mice; D015335:Molecular Probes; D014442:Monophenol Monooxygenase / Q000378:metabolism; D014407:Tumor Cells, Cultured; D014867:Water / Q000737:chemistry
chemical_list: D056831:Coordination Complexes; D008024:Ligands; D015335:Molecular Probes; D014867:Water; D008345:Manganese; D014442:Monophenol Monooxygenase