Quantum dots biodistribution: ultrastructural analysis of tissues

Primary brain tumours, including gliomas, often represent the most devastating and difficult to treat tumours. In the current project, we aim to exploit different imaging modalities to validate the use of bioluminescence imaging to monitor tumour progression in live animals. In vivo bioluminescence imaging has become a cornerstone technology for preclinical molecular imaging. This imaging method is based on light-emitting enzymes, Luciferase, with specific substrates (luciferine). When linked to a specific biological process/pathway in an animal model of human disease, the enzyme-substrate interactions become biological indicators that can be studied noninvasively in living animals. For the current study stably expressing TCF-Luciferase glioblastoma cells have been generated. That cell line was implanted orthotopically and used to monitor tumour growth in vivo. To validate the bioluminescence technology, MRI, routinely used in clinic to diagnose and quantify tumor volumes, was applied on the same animals.Nude females mice: 2 groups (n=7); 1x10^6 cells GBM cells stably transfected with TCF-Luciferase and 1x10^6 cells GBM cells untransfected were implanted in the brain of animals.MR Images were acquired (Biospec Tomograph, Bruker, Germany) weekly for 6 weeks starting 1 week after implantation. Optical Imaging (IVIS®200 Series, Xenogen Corporation, USA), acquisitions were carried out weekly for 6 weeks starting immediately after implantation. There is a great inter-subjects variability of data: visualization technique of Optical Imaging has been optimum validation because in the first week after inoculation of tumor cells it is already a method for looking up GMB. GMB is not a tumour that grows like a mass but it’s classified as an infiltrative one. Classical imaging technique such as MRI has great problem for early visualization of that tumor type while optical imaging technique represents a precocious diagnosis, as a fundamental parameter in oncology.