Synthesis and in Vitro Biological Effect of GNRH-Protoporphyrin IX Conjugates

Photodynamic therapy (PDT) combines non-toxic components, a photosensitizer (PS), light and oxygen.If the photosensitizer is activated to its excited states by irradiation with visible light in the presence of molecular oxygen, electron and energy transfers can produce reactive oxygen species (ROS) in the tissue.These ROS react rapidly with the biomolecules leading to cell death via apoptosis or necrosis.In most cases a singlet oxygen ( 1 O) is generated that has a short intracellular life time (3 µs) and a very small intracellular diffusion distance that makes PDT highly selective.Unfortunately, photosensitizers accumulate in healthy tissues too, causing severe side effects like prolonged skin and eye photosensitivity.Therefore, the conjugation of the PS to a carrier peptide that itself has anti-tumor effect can increase the efficacy and selectivity of the treatment.