Non-invasive imaging to reduce and refine the use of animals and monitor their welfare during the course of experimentations in oncology

We have identified 7 probes for Near-infrared imaging (NIRI) (we are producing 1 of them) - 2-Deoxy-Glucose (2 sources) - MMPs sensitive probe - Cathepsins sensitive probe - Integrin alphov beta3 probe - Blood pool agent - Antibody directed against hCD33 (marker of AML) Very recent publications have reported that probes labelled with the radionuclide [18F], routinely exploited for positron emission tomography (PET) imaging, can be detected thanks to a technique called Cerenkov Luminescence imaging (CLI). We will evaluate the following PET probes: - 2-deoxy-2-[18F]fluoro-D-glucose - [18F]-3-fluorodeoxythymidine - [18] Fluorine We will be using a MouseOx system to measure various physiologic parameters like peripheral blood oxygen saturation, heart frequency or breathing frequency with a noninvasive sensor clip.

In the earliest stage of the project, we will use 1 or 2 luciferase-expressing leukaemic cell lines so that BLI can be used as a positive control and healthy mice will be used as negative controls. For each probe, 2-3 leukaemia bearing mice and 2 negative controls will receive the probe of interest and be imaged at different time points after administration of the probe. BLI will be co acquired with the NIRI / CLI signal. The operation will be repeated weekly until the apparition of clinical signs. The general status of the animals will be checked weekly using the MouseOx system. This information, together with BLI, NIRI and CLI quantification, will reinforce our daily observation for clinical signs.

To be selected, a probe will have to show in all leukaemia or tumour bearing mice at least a two-fold increase of the signal as compared to the negative controls. Successful candidates will then be tested on primary human AML and sporadic mouse lung tumours. Eventually we will optimise the procedures in order to allow simultaneous analysis of the successful probes on the same animal to maximise the reduction of animal use.