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The use of chemiluminescent reaction of polyoxalate for elimination of tumor cellsтезисы доклада
- Авторы: Ezhov A.A., Romanyuk A.V., Grozdova I.D., Melik-Nubarov N.S.
- Сборник: Biocatalysis-2017: Abstracts of 11th International Conference “Biocatalysis: Fundamentals and Applications” / Editors V. Tishkov and V. Fedorchuk
- Тезисы
- Год издания: 2017
- Место издания: Innovations and High Technologies MSU Ltd, Moscow
- Первая страница: 148
- Последняя страница: 149
- Аннотация: The use of chemiluminescence as a source of light for photodynamic therapy of tumors allows overcoming the limitations caused by difficulties in delivering light through absorbing and diffusing tissues. One of possible endogenous source of light is peroxyoxalate chemiluminescent (PO-CL) reaction. This reaction proceeds between active derivatives of oxalic acid and hydrogen peroxide. It is known that increased production of hydrogen peroxide is characteristic for inflamed tissues and cells of some tumors. The present study was aimed at creating polyoxalatecontaining dispersions capable of eliminating tumor cells through the PO-CL reaction with endogenous hydrogen peroxide. Tetramethyl hematoporphyrin (TMHP) included into the dispersions acted as an activator in PO-CL reaction as well as an effective photosensitizer for singlet oxygen generation and illumination of cells, thus avoiding a superfluous step of energy transfer from activator to photosensitizer. Polyoxalate for PO-CL reaction in aqueous environment was synthesized through polycondensation of oxalyl chloride, bisphenol A and oligo(propylene glycol). Polyoxalate and TMHP were formed into dispersion droplets of dimethyl phthalate (DMP) stabilized with Pluronic L64 as a surfactant. It was shown by dynamic light scattering that the dispersions prepared from polyoxalate solutions in DMP revealed two types of particles with the average hydrodynamic radii about 105±25 nm and 400±100 nm, which remained practically unchanged during several hours. The light emitted by TMHP in the PO-CL reaction in the model system without cells was used to optimize the composition of the dispersion. The optimum L64/DMP/ polyoxalate /TMHP weight ratio was equal to 1:2.7:0.3:0.05. Experimental evidence for singlet oxygen generation in PO-CL reaction was obtained by the use of the commercially available probe singlet oxygen sensor green (SOSG). Chemiluminescent dispersion were tested on multidrug resistant human breast adenocarcinoma MCF-7/ADR cells. To increase the content of endogenous ROS, MCF-7/ADR cells were subjected to oxidative stress induced by hydrogen peroxide at a non-toxic concentration (about 200 μM). A significant photosensitizer -mediated cytotoxicity was observed in the cells under oxidative stress. Chemiluminescence in MCF-7/ADR cells under oxidative stress conditions was observed by modified chemiluminescent dispersion composition. It caused by the low fluorescent quantum yield of TMHP which was replaced for perylene that does not exhibit photosensitizing activity, but manifests extremely high fluorescence quantum yield. Benzimidazole as a nucleophilic catalyst was added for increasing the rate of light emission. This modification resulted in a detectable emission of light from cell culture. The integral of emitted light decreased with diminution in the amount of cells confirming that hydrogen peroxide in the sample was originated from the cells and not from the oxidative stress stimulation chemicals. The result confirmed that PO-CL reaction can be triggered by intracellular hydrogen peroxide. SOSG was used to obtain evidence for singlet oxygen generation in the cells due to PO-CL reaction. Obtained with confocal laser scanning microscope distributions of cells by the fluorescence intensity in the samples show that the mean fluorescence of the cells in the sample treated with chemiluminescent dispersion is twice of that treated with the dispersion without TMHP. Results confirmed the formation of singlet oxygen due to PO-CL reaction both in aqueous solution and in cells. Moreover in was found that the chemiluminescent dispersion composition optimized by means of chemiluminescence measurements in cell-free systems appeared to be optimum to cause photosensitizer-mediated cytotoxicity in vitro. The relative photosensitizer-mediated cytotoxicity of chemiluminescent dispersion increased in line with augmentation of hydrogen peroxide concentration in the cells. This proved that the level of ROS determines the photosensitizer-mediated cytotoxicity of chemiluminescent dispersion. This conclusion was supported in the experiments with such well-known inducers of oxidative stress as doxorubicin, menadione and paraquat instead of hydrogen peroxide. As s result it was shown that the cytotoxicity induced by the photosensitizer correlated with the level of intracellular ROS.Designed approach for the elimination of tumor cells by PO-CL reaction using endogenous ROS, complementary classical chemotherapy of tumors and may be applied to improve its efficiency.
- Добавил в систему: Ежов Александр Анатольевич