Final Report Summary - GLIO_IL-23 (EFFECT OF IL-23 ON IMMUNE CELL INFILTRATION AND TUMOR GROWTH IN A GLIOMA MODEL) Several hallmarks are involved in the development of cancer. As an example, induction of angiogenesis and evasion of the immune response are, amongst others, critical processes in the promotion of tumor cell survival and tumor growth. Thus, it has been described how glioblastoma cells display efficient mechanisms to avoid the host’s immune response. Malignant gliomas are considered one of the most aggressive cancers and the most common tumor affecting the central nervous system in humans. As a result, multiple current lines of research are focus on the development of new drugs with potential therapeutic effect. As with other experimental approaches testing new drugs, this work often requires in-vivo experimental studies. These studies involve the follow up of an experimental model and the discrimination of the effect induced by the tested drug. Considering that, the aim of the present project was to adapt a Fluorescence Molecular Tomography (FMT) system together with the acquisition and reconstruction method. This adapted system is aimed to allow the optical non-invasive in-vivo imaging of the mouse brain. Thus, the adapted system has been used for the in-vivo follow-up of tumor growth and tumor-associated protease activity in a glioma murine model. Moreover, experimental treatments have been tested and their potential anti-tumor effects have been evaluated.Two different aspects have been essential in the development of the present project: the adaptation of the optical system to fulfill the needs of our application and the experimental model to be used (in this case, a murine experimental model of glioma).In summary, the adaptations in the system have consisted on: a) designing and building a special holder which allowed us to perform the required optical measurements of the murine head; b) the adaptation of the system so as to obtain multispectral measurements (several pairs of excitation laser and emission filters); c) improvements in the acquisition procedures to allow measurements in an efficient manner; d) improvements in the reconstruction method.With these adaptations we are now able to acquire multispectral measurements and to obtain 3D reconstructed images of the different fluorescent signals.Regarding the model, the GL261 cell line was used. This is a widely used glioma cell line, which is orthotopically injected to establish an experimental in-vivo model of glioma. Stable transfectant expressing a near-infrared fluorescent protein (Turbo635 or iRFP) were obtained by transfection followed by clone selection. FACs analysis was used to select the clones with higher expression, based on the levels of intensity. The selected clones were then tested in-vivo and tumor growth was validated ex-vivo.On the other hand, commercially available fluorescent probes were also used for the determination of tumor protease activity in the glioma model. Analysis of the doses and kinetics of the fluorescent probes were performed in-vivo.Finally, FMT has also been used in combination with Magnetic Resonance Imaging (MRI). MRI has been used to validate 3D fluorescent images obtained by FMT. This system has successfully allowed us the in-vivo follow-up of tumor growth and tumor-associated protease activity in a glioma model. Moreover, potential beneficial effect of different treatments has been analyzed using this methodology. Results obtained in this regard are expected to be published soon in a high impact journal.