Abstract #2696

Molecular NMR and EPR in Vivo Detection of Cell Death Using Specific Phosphatidylserine-Targeted Iron Oxide Particles.

Kim Anne Radermacher¹, Sbastien Boutry², Isabelle Mahieu², Sophie Laurent², Luce Vander Elst², Caroline Bouzin³, Julie Magat¹, Vincent Grgoire⁴, Olivier Feron³, Robert N. Muller², Bndicte F. Jordan¹, Bernard Gallez¹

¹Biomedical Magnetic Resonance Unit, Catholic University of Louvain, Bruxelles, Belgium; ²NMR and Molecular Imaging Laboratory, University of Mons, Mons, Belgium; ³Unit of Pharmacology and Therapeutics, Catholic University of Louvain, Bruxelles, Belgium; ⁴Center for Molecular Imaging and Experimental Radiotherapy, Catholic University of Louvain, Bruxelles, Belgium

The aim was to develop a molecular marker for non invasive monitoring of tumor cell death as a response to treatment. The phosphatidylserine-targeted peptide E3 was coupled to ultrasmall particles of iron oxide (USPIO). The USPIO concentration was evaluated in irradiated and untreated tumors by EPR and MRI in vivo. We also compared USPIO-E3 accumulation in three different tumor models presenting different degrees of radiosensitivity (fibrosarcoma is less radiosensitive than hepatocarcinoma which is less radiosensitive than lymphoma). The major finding of the present investigation is that USPIO-E3 allows the sensitive detection of tumor cell death after cytotoxic treatment.