Amphinex-(TPCS2a)-based photodynamic therapy and photochemical internalization of bleomycin and temozolomide: - in vitro studies on the glioma cell line F98

Abstract

Presented in this master's thesis are studies on the response of glioma cells from rat (F98) to in vitro photodynamic therapy (PDT) and photochemical internalization (PCI), utilizing as photosensitizer the amphiphilic chlorin Amphinex (TPCS2a). Two different chemotherapeutic agents -- bleomycin (BLM) and temozolomide (TMZ) -- were examined in relation with the PCI ("light after") technology. The capacity of Amphinex-based PDT and PCI to impair viability of F98 cells was evaluated by means of the MTT assay, supplemented with analysis of clonal cell survival in the case of BLM-PCI. Additionally, a limited spectroscopic investigation on Amphinex solutions, prepared for HPLC, was accomplished.A laser light dose of 2.5 J/cm^2 (AT50) caused 50 % of PDT-exposed F98 cells to become unviable. Standard MTT experiments yielded no more than additive responses when PDT was combined with bleomycin or temozolomide incubation, i.e. when cells were exposed to PCI. In contrast, a synergetic increase in bleomycin activity was detected with clonogenic assessment, as well as with MTT analysis 48 hours after treatment. However, further confirmation of these results is required. Absorption and fluorescence emission measurements of Amphinex solutions suggested HPLC samples prepared within the same week, in tubes of different material, to be stable.