The group of prof. Gołąb is interested in pursuing the molecular mechanisms of antitumor effects of photodynamic therapy (PDT). PDT is a clinically approved therapeutic modality that makes use of specifically designed or natural chemical compounds that can be activated by a visible light in the red or infra-red range of electromagnetic spectrum. These non-toxic chemical compounds referred to as photosensitizing drugs or simply photosensitizers (PS) are administered either locally or systemically. In the next step, light is delivered to either surface of the body or to internal organs via fiber-optic systems and the tumors are il- luminated. Energy from light is transformed by PSs in a complex photochemical reaction leading to formation of singlet oxygen, an extremely reactive molecule that leads to the damage of biological macromolecules. Tumor cells with damaged organelles or enzymes cannot survive and die (necrotic cell death, when the damage is overwhelming) or commit suicide (apoptotic cell death, when the damage is less pronounced). However, light dis- tribution within a tumor is inhomogeneous due to its absorption, reflection or scattering by cells, natural dyes or components of extracellular matrix. Therefore, suboptimal PS activation in some tumor regions can be insuffcient to trigger lethal damage. In that case tumor cells can trigger protective mechanism to repair the damage.
The research interests of the PDT group are focused on iden- tification of the mechanisms participating in the repair of macromolecules damaged during PDT, i.e. how cells try to cope with the injury to avoid death. This knowledge can be translated into improved therapeutic approaches. By knocking-down cytoprotec- tive mechanisms operating in tumor cells it should be possible to increase the effcacy of PDT.
In addition to destroying tumor cells PDT produces an acute inflammation, and attracts leukocytes to treated areas. PDT can facilitate development of immune response by exposing or creating new molecules that can be recognized by lymphocytes. The PDT group is studying molecular mechanisms of immune response triggered by PDT. The aim of these studies is to further improve the ability of PDT to trigger systemic and highly effcient immune response against tumor cells.
Moreover, PDT is destroying tumor blood vessels that carry oxygen and nutrients to proliferating tumor cells. Little is known about the impact of PDT on lymphatic vessels that drain lymph, growth factors and cells from the tumor to the local lymph nodes. The PDT group is studying the impact of PDT on lymphatics and whether damage to lymphatic cells affects tumor response or development of antitumor immunity.