Investigation of chlorin photosensitizers distribution in monolayer and spheroid cell cultures

Abstract

The aim of this study was to analyze the distribution of chlorin type photosensitizers (PS): chlorin e6 (Ce6) and dimethyl ester of chlorin e6 (DME), in human adenocarcinoma HT29 monolayer and multicellular spheroid cell cultures. There is an assumption, that the chemical modification of Ce6 molecules causes a change of intracellular location and the enhanced photosensitizing activity. Indeed, photodynamic therapy on monolayer cell culture with DME showed two times higher photokilling ability comparing with that of non-modified analogue. Ce6 and DME biodistribution processes in tumor tissue were studied on multicellular tumor spheroids model. Total amount of DME in multicellular tumor spheroids exceeded 1,3 times accumulation of Ce6. According to fluorescence microscopy studies, Ce6 and DME distribution patterns in the spheroids bulk were similar. Application of 2D and 3D tumor models for the analysis of photosensitizer distribution may allow predicting the photosensitizer biodistribution features for photodynamic therapy in vivo.