Mitochondria-targeted Porphyrins: A New Class of Photosensitizers for Targeted Photodynamic Therapy

Targeted cancer therapies offer a promising strategy to overcome problems associated with conventional treatments [1]. Among several cancer treatment modalities, photodynamic therapy (PDT) is significant because of selective and minimally invasive treatment procedures [2]. However, traditional photosensitizers (PSs) used in PDT can accumulate in healthy tissues and cause adverse effects during treatment. Therefore, an enormous effort is being made to prepare an ideal PS that selectively targets tumor cells and specifically the subcellular organelles of the cancerous cells. Additionally, a specific targeting approach can greatly improve the therapeutic potential of PDT as well as overcome the problem of multidrug resistance caused by chemotherapeutic drugs. Mitochondria represent ideal targets as they are crucial regulators of apoptosis. Herein, we report on the design and development of new meso-substituted porphyrins bearing aromatic heterocyclic groups to target mitochondria and improve one- and two-photon phototoxicity. Studies on liposomal formulations exploited to increase the mitochondrial internalization of the new PSs will be also presented.