Toxicological and efficacy assessment of post-transition metal (Indium) phthalocyanine for photodynamic therapy in neuroblastoma

Abstract

// Monica Neagu 1, 2 , Carolina Constantin 2 , Mircea Tampa 3 , Clara Matei 3 , Andreea Lupu 2 , Emilia Manole 2, 4 , Rodica-Mariana Ion 5, 6 , Concettina Fenga 7 , Aristidis M. Tsatsakis 8 1 Faculty of Biology, University of Bucharest, Romania 2 Immunobiology Laboratory and Alternative Testing Multi-Disciplinary Team, “Victor Babeş” National Institute of Pathology, Bucharest, Romania 3 Dermatology Department, “Carol Davila” University of Medicine and Pharmacy, Bucharest, Romania 4 Research Center, Colentina Clinical Hospital, Bucharest, Romania 5 Nanomedicine Research Group, National Institute of R&D for Chemistry and Petrochemistry – ICECHIM, Bucharest, Romania 6 Materials Engineering Department, Valahia University of Targovişte, Romania 7 Section of Occupational Medicine, University of Messina, Messina, Italy 8 Department of Toxicology and Forensic Sciences, Faculty of Medicine, University of Crete, Heraklion, Greece Correspondence to: Carolina Constantin, email: caroconstantin@gmail.com Keywords: photodynamic therapy, neuroblastoma, indium-phthalocyanine, toxicology, cellular impedance Received: March 25, 2016      Accepted: September 02, 2016      Published: September 10, 2016 ABSTRACT Metallo-phthalocyanines due to their photophysical characteristics as high yield of triplet state and long lifetimes, appear to be good candidates for photodynamic therapy (PDT). Complexes with diamagnetic metals such as Zn 2+ , Al 3+ Ga 3+ and In 3+ meet such requirements and are recognized as potential PDT agents. Clinically, Photofrin ® PDT in neuroblastoma therapy proved in pediatric subjects diagnosed with progressive/recurrent malignant brain tumors increased progression free survival and overall survival outcome. Our study focuses on the dark toxicity testing of a Chloro-Indium-phthalocyanine photosensitizer (In-Pc) upon SH-SY5Y neuroblastoma cell line and its experimental in vitro PDT. Upon testing, In-Pc has shown a relatively high singlet oxygen quantum yield within the cells subjected to PDT (0.553), and 50 μg/mL IC50. Classical toxicological and efficacy assessment were completed with dynamic cellular impedance measurement methodology. Using this technology we have shown that long time incubation of neuroblastoma cell lines in In-Pc (over 5 days) does not significantly hinder cell proliferation when concentration are ≤ 10 μg/mL. When irradiating neuroblastoma cells loaded with non-toxic concentration of In-Pc, 50% of cells entered apoptosis. Transmission electron microscopy has confirmed apoptotic characteristics of cells. Investigating the proliferative capacity of the in vitro treated cells we have shown that cells that “escape” the irradiation protocol, present a reduced proliferative capacity. In conclusion, In-Pc represents another photosensitizer that can display sound PDT properties enhancing neuroblastoma therapy armentarium.