In Vivo Labelling of Xenografted B16 Melanoma Cells with a Thiol-Responsive Gd(III) Based MRI Contrast Agent

Eliana Gianolio¹, Valeria Menchise², Giuseppe Digilio³, Evelina Cittadino⁴, Carla Carrera⁴, Valeria Catanzaro⁴, Silvio Aime⁴

Mammalian cells display a large number of reactive protein thiols on the extracellular side of the plasma membrane (Exofacial Protein Thiols, EPTs). These EPTs are quite reactive and can be chemically labeled by suitably designed MRI contrast agents. Compound Gd-DO3A-PDP can efficiently label B16 melanoma cells both ex vitro and in vivo (xenografted tumor) as a function of the levels of EPTs shown by cells.