Cellular and vascular membranes within illuminated tumor tissue

Cellular and vascular membranes within illuminated tumor tissue are the primary biological targets for photodynamic therapy (PDT) (Agostinis et al., 2011). This therapeutic modality relies on the accumulation of a photosensitizing drug within the tumor and its subsequent activation by a specific wavelength of light (NCI, 2023). Upon activation, the photosensitizer interacts with molecular oxygen to produce reactive oxygen species (ROS), such as singlet oxygen, which are highly cytotoxic (Castano et al., 2004). These ROS cause extensive oxidative damage to the lipids and proteins that constitute the cellular and vascular membranes (DrugBank, DB00435). Damage to cellular membranes leads to direct tumor cell death through necrosis or apoptosis, while damage to the vascular membranes results in microvascular collapse and tumor ischemia (Agostinis et al., 2011). This dual mechanism effectively destroys the tumor mass and its supporting nutrient network. Drugs like porfimer sodium and verteporfin are specifically designed to target these structures to treat various cancers and neovascular conditions (FDA, 2023). The specificity of the treatment is achieved by the localized application of light, minimizing damage to non-illuminated healthy tissues.

Other names

Tumor cell membranesVascular endothelial membranesNeovascular membranesPhotodynamic therapy target membranesTumor neovasculature

Photosensitizer-mediated generation of reactive oxygen species (ROS) upon light activation, leading to lipid peroxidation and protein oxidation of membranes (Agostinis et al., 2011; NCI, 2023).