Exploring the immunogenic potential of photodynamic therapy

Abstract

Concentered efforts have been made in recent years to develop therapies that are able to treat various types of cancer more effectively. A promising alternative treatment is photodynamic therapy (PDT), consisting in tissue destruction by visible light in the presence of a photosensitizer substance and oxygen. Previous results from our group have shown that PDT using methylene blue as a photosensitizer (MB-PDT) is able to selectively eliminate human breast tumor cells using in models in vitro of cells cultured in monolayer or in spheroids. Interestingly, triple negative breast cancer cells, the most aggressive ones, display the highest sensitivity when submitted to MB-PDT. However, the effectiveness of this therapy in stimulate a favorable immune response to eradicate the tumor remains an aspect of great relevance. An ideal cancer treatment should merge the direct cytotoxic action on tumor cells with potent immunostimulatory effects based on the recognition of molecular immunogenic determinants on dying cells by immune cells. Therefore, in the present project, we set out to collaborate with Dr. Patrizia Agostinis, an expert in research on mechanisms of therapy-induced cancer cell death, including PDT, working at the School of Medicine of the University of Leuven, to study the induction of molecular markers of immunogenic cell death in cancer cells induced by different PDT-mediated stresses. We intent to contribute to indicate PDT as an effective therapy for tumors that present particular cell death resistance mechanisms, displaying minimal side effects if compared to conventional cancer treatments.