Cellular biomolecules (damaged by Protoporphyrin IX-generated reactive oxygen species)

Cellular biomolecules (damaged by Protoporphyrin IX-generated reactive oxygen species) refers to the collective group of intracellular constituents, including membrane lipids, structural proteins, and nucleic acids, that serve as the functional targets of photodynamic therapy (PDT). This therapeutic approach relies on the accumulation of the photosensitizer Protoporphyrin IX (PpIX) within target cells, often achieved by administering the precursor 5-aminolevulinic acid (ALA) (Wachowska et al., 2011). Upon exposure to specific wavelengths of light, PpIX enters an excited state and transfers energy to molecular oxygen, generating highly reactive oxygen species (ROS), predominantly singlet oxygen (Agostinis et al., 2011). These ROS cause immediate and localized oxidative damage to organelles where PpIX is concentrated, such as the mitochondria, lysosomes, and endoplasmic reticulum (Krammer, 2001). The resulting destruction of vital biomolecules disrupts cellular integrity and signaling, ultimately triggering cell death through apoptosis, necrosis, or autophagy. This mechanism is widely utilized in the clinical treatment of various malignancies and dermatological conditions like actinic keratosis. Because the damage is confined to the area of light illumination and photosensitizer accumulation, it offers a degree of selectivity for diseased tissue.

Other names

Cellular componentsLipids, proteins, and nucleic acidsPhotodynamic therapy substratesOxidative damage targetsPDT targets

Generation of reactive oxygen species (ROS), primarily singlet oxygen, upon light activation of Protoporphyrin IX, leading to oxidative damage of lipids, proteins, and DNA, ultimately causing cell death.