Non-monotonic changes in clonogenic cell survival induced by disulphonated aluminum phthalocyanine photodynamic treatment in a human glioma cell line | Gupta et al. Journal of Translational Medicine 2010 8 43 http content 8 1 43 RESEARCH JOURNAL OF TRANSLATIONAL MEDICINE Open Access Non-monotonic changes in clonogenic cell survival induced by disulphonated aluminum phthalocyanine photodynamic treatment in a human glioma cell line Seema Gupta 1 2 3 Bilikere S Dwarakanath 1 K Muralidhar4 Tulay Koru-Sengul3 5 and Viney Jain1 6 Abstract Background Photodynamic therapy PDT involves excitation of sensitizer molecules by visible light in the presence of molecular oxygen thereby generating reactive oxygen species ROS through electron energy transfer processes. The ROS thus produced can cause damage to both the structure and the function of the cellular constituents resulting in cell death. Our preliminary investigations of dose-response relationships in a human glioma cell line BMG-1 showed that disulphonated aluminum phthalocyanine AlPcS2 photodynamically induced loss of cell survival in a concentration dependent manner up to 1 pM further increases in AlPcS2concentration 1 pM were however observed to decrease the photodynamic toxicity. Considering the fact that for most photosensitizers only monotonic dose-response survival relationships have been reported this result was unexpected. The present studies were therefore undertaken to further investigate the concentration dependent photodynamic effects of AlPcS2. Methods Concentration-dependent cellular uptake sub-cellular localization proliferation and photodynamic effects of AlPcS2 were investigated in BMG-1 cells by absorbance and fluorescence measurements image analysis cell counting and colony forming assays flow cytometry and micronuclei formation respectively. Results The cellular uptake as a function of extra-cellular AlPcS2 concentrations was observed to be biphasic. AlPcS2 was distributed throughout the cytoplasm with intense fluorescence in the perinuclear regions at a concentration of 1 pM while a weak diffuse fluorescence was .
