Tumor necrosis factor (TNF)' has excellent anti-tumor capacities. Unfortunately its systemic use is accompanied by severe side effects due to the strong pro-inflammatory nature of TNF. To circumvent this toxicity. the anti-tumor effects of TNF can be mimicked in a non-toxic manner. It is believed that the anti-tumor effects are

mediated in part through the inactivation of the integrin aV133. This integrin is a useful target for multiple reasons: it is specifically expressed on a set of interesting celltypes, e.g. tumor neovasculature and certain tumor types

(melanomas, breast cancer and gliomas) where it is involved in angiogenesis. tumor progression and metastasis.

Multiple avb3 targeting molecules are in development or in clinical trials for either cancer treatment or imaging

purposes. These molecules are of great interest to determine the effectiveness of anti-angiogenic treatments.

Moreover, due to their specific expression pattem they may be useful for specific treatment delivery with reduced

chemotherapeutic induced side-effects.

For these reasons we decided to generate aVl33-targeting Nanobodies. We characterized six different Nanobodies

targeting aVB3, some with high affinity and blocking capacity. Preliminary experiments show interesting antitumoral

properties, alone or in combination with a non-toxic dose of TNF/IFNV. In this project we want to expand our cancer

studies with these Nanobodies and investigate possible applications such as tumor imaging and tumor targeting of

therapeutics.