Hoonsung Cho
Chonnam National University, South Korea
Title: Protamine conjugated fluorochromes: A new photosensitizer for photodynamic tumor therapy
Biography
Biography: Hoonsung Cho
Abstract
The Photodynamic therapy (PDT) is a promising alternative therapy that could be used adjunct to chemotherapy and surgery for curing cancer causing tissue destruction by visible light in the presence of a photosensitizer (PS) and oxygen. The high arginine peptides like the cell-penetrating peptide have membrane translocating and nuclear localizing activities that have led to their use in a wide range of drug delivery applications. Protamine is a high arginine peptide with membrane translocating and nuclear localizing properties. The reaction of an NHS-ester of methylene Blue (MB) and clinical protamine (Pro), to yield MB-Pro, was described in this context and demonstration of phototoxicity which clinical protamine improved PDT effect was performed. The reaction between clinical protamine (Pro) an NHS ester of MB is a solution phase reaction with the complete modification of the protamine peptides which feature a single reactive amine at the N-terminal proline and single carboxyl group at the C-terminal arginine. The aim of this study was to find a new type of photosensitizer (PS) for PDT on in vitro and in vivo experiments and to assess the anti-tumor effect of PDT using the protamine conjugated-PS on the cancer cell line. Photodynamic cell death studies show that the MB-Pro produced has more efficient photodynamic activities than MB alone, causing rapid light induced cell death. The attachment of MB to clinical Pro, yielding MB-Pro, confers the membrane internalizing activity of its high arginine content on methylene blue and can induce a rapid photodynamic cell death, presumably due to cell membrane rupture induced by light. The PDT using MB-Pro for HT-29 cells was very effective and those findings suggest that MB-Pro is one of candidate for photosensitizer in solid tumors.
