Poster Presentation 11th Australian Peptide Conference 2015

Ppa-iRGD-BK01 as a Depot Peptide for Effective Photodynamic Therapy (#157)

SungJun Park 1 , HongJun Cho 2 , SeHoon Kim 3 , Yoon-Sik Lee 1
  1. School of Chemical and Biological Engineering, Seoul National University, Seoul, South Korea
  2. National Institutes of Health, Bethesda, Maryland, United States of America
  3. Korea Institute of Science and Technology, Seoul, South Korea

A key issue in clinical photodynamic therapy (PDT) is the non-invasive, controlled release of singlet oxygen (1O2) for effective treatment with minimal side effects. In our work, we describe a photosensitizer (pyropheophorbide a, Ppa) conjugated to a tumor targeting cyclic iRGD peptide, together with a quencher (Ppa-iRGD-BK01). Ppa-iRGD-BK01 peptide was designed to target cancer cells by the RGD motif, and the Ppa could be internalized into cancer cells via protease cleavage. Peritumoral injection of Ppa-iRGD-BK01 resulted in the formation of a molecular depot, which remained stable at the tumor tissue environment acting as a storehouse of the Ppa. While the quencher protected Ppa from photodegradation, the depot was able to release Ppa in a controlled manner. The released Ppa was well internalized into the tumor allowing effective PDT by the generation of 1O2. We propose Ppa-iRGD-BK01 peptide as a suitable drug candidate for non-invasive, controllable PDT for effective cancer treatment.

  1. KN. Sugahara, T. Teesalu, PP. Karmali, VR. Kotamraju, L. Agemy, OM. Girard, D. Hanahan, RF. Mattrey, and E. Ruoslahti, “Tissue-penetrating delivery of compounds and nanoparticles into tumors”, Cancer Cell, Vol. 16, 6 (2009), pp 510-520.
  2. AP. Castano, P. Mroz, MR. Hamblin, “Photodynamic therapy and anti-tumour immunity”, Nat. Rev. Vol. 6 (2006), pp 535-545.