Platinated porphyrin as a new organelle and nucleus dual-targeted photosensitizer for photodynamic therapy

Organelle and nucleus dual-targeted anticancer drugs are being increasingly used for efficient cancer therapy as they can attack the double vital sites of tumor cells. In this work, we synthesized and characterized two new porphyrin compounds Pt-Por-RB and Me-Por-RB. The spectral titration results suggest that both Pt-Por-RB and Me-Por-RB bind to DNA efficiently in an intercalation binding mode. Upon irradiation, Pt-Por-RB with low dark-cytotoxicity can rapidly generate singlet oxygen to damage the tumor cells through the process of photodynamic therapy. Compared with Me-Por-RB, Pt-Por-RB was not only internalized in the organelles, but also in the nuclei of HeLa cells, probably due to the presence of platinum complexes, as analyzed using the confocal laser scanning microscope. Thus, with the combination of organelle and nucleus dual-targeting property and high efficiency of singlet oxygen generation, Pt-Por-RB showed a significant therapeutic activity against tumor cells.