Death Mechanism of Breast Adenocarcinoma Cells, Caused by BRET-Induced Cytotoxicity of miniSOG, Depends on Intracellular Localization of Hybrid Protein NanoLuc-miniSOG
Photodynamic therapy (PDT) is widely used in clinical practice to influence neoplasms in the presence of a photosensitizer, oxygen and light source. The main problem of PDT of deep tumors is the problem of delivering excitation light (without lost of its intensity) inside the body. An alternative to external light sources can be "internal" light sources based on bioluminescent systems of luciferase-substrate. In our work, as an internal light source, we used the NanoLuc-furimazine system. This system can be successfully used to excite the protein photosensitizer miniSOG and to induce the photo toxicity of this flavoprotein in cancer cells during bioluminescent resonance energy transfer (BRET). It was shown that the mechanism of cell death caused by BRET-induced phototoxicity of mimiSOG in the presence of furimazine depends on the intracellular localization of the NanoLuc-miniSOG fusion protein: BRET-mediated activation of miniSOG in mitochondrial localization causes apoptosis, while membrane localization of PS causes necrosis of cancer cells.