General cellular components (Photodynamic Therapy) (PDT targets)

General cellular components (Photodynamic Therapy) refers to the broad array of molecular structures—including lipids, proteins, and nucleic acids—that are damaged during photodynamic therapy (PDT). In this therapeutic modality, a photosensitizing drug is administered and subsequently activated by a specific wavelength of light (National Cancer Institute, 2023). This activation triggers a photochemical reaction that generates reactive oxygen species (ROS), most notably singlet oxygen, which induce oxidative stress and irreversible damage to cellular membranes and organelles such as mitochondria and lysosomes (Agostinis et al., 2011, CA: A Cancer Journal for Clinicians). Because ROS have a very short half-life and limited diffusion distance, the damage is highly localized to the area of light exposure. This mechanism is widely utilized in the treatment of various cancers, where it induces tumor cell death via apoptosis or necrosis and can also damage the tumor vasculature (NIH, StatPearls). Beyond oncology, it is employed in treating age-related macular degeneration and certain dermatological and infectious diseases (PubMed, PMC3106199). Unlike traditional targeted therapies, the target here is the collective integrity of the cell's structural and functional molecules within the illuminated field rather than a specific protein or receptor.

Other names

Cellular membranesOrganellesProteins and DNA via ROSPhotodynamic therapy targetsPhotosensitizer targets

Light-induced activation of a photosensitizer leads to the production of singlet oxygen and other reactive oxygen species (ROS), which cause non-specific oxidative damage to cellular lipids, proteins, and nucleic acids, ultimately triggering cell death.