Title:Cellular Changes, Molecular Pathways and the Immune System Following Photodynamic Treatment
Volume: 21
Issue: 35
Author(s): P. Skupin-Mrugalska, L. Sobotta, M. Kucinska, M. Murias, J. Mielcarek and N. Duzgunes
Affiliation:
Keywords:
Angiogenesis, apoptosis, cell death, cellular mechanism, immunology, PDT mechanism, photodynamic therapy,
photosensitizer.
Abstract: Photodynamic therapy (PDT) is a novel medical technique involving three key components: light, a photosensitizer
molecule and molecular oxygen, which are essential to achieve the therapeutic effect. There has been great interest in
the use of PDT in the treatment of many cancers and skin disorders. Upon irradiation with light of a specific wavelength,
the photosensitizer undergoes several reactions resulting in the production of reactive oxygen species (ROS). ROS may
react with different biomolecules, causing defects in many cellular structures and biochemical pathways. PDT-mediated
tumor destruction in vivo involves cellular mechanisms with photodamage of mitochondria, lysosomes, nuclei, and cell
membranes that activate apoptotic, necrotic and autophagic signals, leading to cell death. PDT is capable of changing the
tumor microenvironment, thereby diminishing the supply of oxygen, which explains the antiangiogenic effect of PDT. Finally,
inflammatory and immune responses play a crucial role in the long-lasting consequences of PDT treatment. This review
is focused on the biochemical effects exerted by photodynamic treatment on cell death signaling pathways, destruction
of the vasculature, and the activation of the immune system.
