“Effects\nof Redox Status on Immediate Hypericin-Mediated\nPhotodynamic Therapy in Human Glioblastoma T98G Cell Line”

Glioblastoma Multiforme (GBM) is one of the most aggressive\ntypes\nof brain tumor. GBM can modulate glutathione (GSH) levels and regulate\ncellular redox state, which can explain its high resistance to chemotherapeutic\nagents. Photodynamic therapy (PDT) is a selective, nontoxic, and minimally\ninvasive treatment approved for many types of cancer. PDT leads to\ncell death mainly by promoting the generation of reactive oxygen species\n(ROS). Thus, in the current study, PDT with the photosensitizer hypericin\n(Hyp), formulated in mixed 1,2-dipalmitoyl-<i>sn</i>-glycero-3-phosphocholine\n(DPPC)/biotinylated-pluronic F127 (F127–B) liposomes, in combination\nwith the GSH synthesis inhibitor buthionine sulfoximine (BSO) were\ntested against T98G cell line of human glioblastoma. The mixed liposome\nwas effective in delivering Hyp to the cells, leading to a dose relationship\nbetween Hyp and ROS levels. BSO potentiated Hyp cell uptake, decreased\nGSH levels regardless of Hyp concentration, and intensified ROS generation\nfor 1.00 and 5.00 μmol L<sup>–1</sup> Hyp. Nonetheless,\ncell death was more pronounced in the groups not treated with BSO,\nindicating that reduced GSH levels are not a decisive factor in achieving\nthe PDT effects of Hyp. In conclusion, the mixed DPPC/F127–B\nliposomes were effective as a delivery system for Hyp. However, the\ncombination of BSO and Hyp was not capable of optimizing PDT against\nT98G cells.