Photonanomedicine against EpCAM and Ki-67 positive head and neck tumors

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Head and neck tumor is a malignancy with rising incidence and to date, surgical resection is the primary treatment option, which is associated with facial disfigurement and a high risk for recurrence. Therefore, the development of new therapies for this tumor type is of high clinical value. We plan to use photonanomedicine as a basis to develop such an approach and to evaluate it in animal experiments. In a previous project, we successfully developed the toolbox for a targeting concept against Ki-67 positive cells, which is based on nano-constructs and light irradiation. Antibody conjugates of TuBB-9 (an anti-Ki-67 antibody) with different photosensitizers suitable for in vivo applications were prepared and tested. Coupling to different cell and nucleus penetrating peptides or encapsulation into liposomes ensures cellular und nuclear delivery. Intracellular release of the antibodies from endososomes by photochemical internalization (PCI) drastically increased efficiency. We were able to demonstrate the following points, which provide strong evidence for the effectiveness of the new method:1. Reliable distribution of the antibody-dye conjugates in tissues and uptake in cells by liposomes and photochemical internalization (PCI).2. A pronounced tumor selectivity by targeting of the tumor specific membrane protein EpCAM and by local light application.3. An effective mechanism that leads to cell death. This is ensured by the light inactivation of Ki-67, which is feasible with antibody concentration in the nanomolar range.In the proposed project, the antibody-assisted photomedical therapy shall be simplified and tested in a mouse model for head and neck squamous cell carcinoma. To increase the tumor selectivity, liposomes directed against the EpCAM protein will be used. EpCAM is not only used as a target structure for the transport of liposomes, but it will also be investigated as a direct target for light inactivation. For the tumor mouse model, GFP transfected cells will be used, which enable fluorescence assisted identification of tumor cells and mechanistic studies in living mice by intra-vital multiphoton microscopy. For photochemical internalization, the photosensitizer Amphinex, which is already used in clinical studies, will be applied. With the help of cell-penetrating immunoconjugates, proliferating cells will be effectively damaged after irradiation. Short-term and long-term treatment successes in the animal model will be evaluated and cellular effects of Ki-67 inactivation will be investigated with the help of multiphoton microscopy.A successful elimination of the tumor in the animal model would be an important first step towards the application of photonanotherapy for the treatment of head and neck tumors in humans, providing new treatment options for this crippling disease.