Effective photodynamic therapy in drug-resistant prostate cancer cells utilizing a non-viral antitumor vector (a secondary publication).

Abstract

There is an urgent need to develop an efficient strategy for the treatment of drug-resistant prostate cancer. Photodynamic therapy (PDT), in which low incident levels of laser energy are used to activate a photosensitizer taken up by tumor cells, is expected as a novel therapy for the treatment of prostate cancer because of the minimal invasive nature of PDT. The present study was designed to assess the efficacy of a novel vector approach combined with a conventional porphyrin-based photosensitizer. Our group focused on a non-viral vector (hemagglutinating virus of Japan envelope; HVJ-E) combined with protoporphyrin IX (PpIX) lipid, termed the porphyrus envelope (PE). It has been previously confirmed that HVJ-E has drug-delivering properties and can induce cancer-specific cell death. The PE (HVJ-E contained in PpIX lipid) was developed as a novel photosensitizer. In this study, the antitumor and PDT efficacy of the PE against hormone-antagonistic human prostate cancer cells (PC-3) were evaluated. Our results demonstrated that, under specific circumstances, PDT using the PE was very effective against PC-3 cells. A novel therapy for drug-resistant prostate cancer based on this vector approach is eagerly anticipated.