Photoinduced cytotoxic effect of fullerenes C60 on transformed T-lymphocytes

Aim: To estimate the viability of normal and transformed T-lymphocytes after UV/Vis irradiation in the presence of pristine fullerenes C60. Methods: Thymocytes were isolated from Wistar rats’ thymus. Murine leukemia L1210 and human lymphoma Jurkat cells were used in this study. Mercury-vapor lamp was used for fullerenes C60 photoexcitation. Cytotoxicity was etermined by MTT assay. Changes in cell morphology were monitored by phase-contrast light microscopy. Results: fullerenes C60 exhibit cytotoxic effect against transformed T-lymphocytes when combined with UV/Vis irradiation (320–600 nm). Photoinduced effect was enhanced with the increasing of irradiation time period and C60 concentration, cell death was registered after 24 hours incubation. Fullerenes C60 photocytotoxicity against normal T-lymphocytes (thymocytes) was not observed. Conclusion: The present study suggests that pristine fullerenes C60 have the potential to be an effective photosensitizer and exhibit cytotoxic effect on transformed T-cells in vitro

Enhanced cytotoxicity of рhotoexcited fullerene C60 and cisplatin combination against drug-resistant leukemic cells

Aim: To evaluate the viability of leukemic cells sensitive (L1210S) and resistant (L1210R) to cisplatin, ROS production and free cytosolic Ca²⁺ concentration under treatment with cisplatin or its combination with photoexcited fullerene C₆₀. Methods: Cell viability was assessed by the MTT reduction assay. Light-emitting diode lamp (2.45 J/сm2) was used for photoexcitation of intracellular accumulated fullerene C₆₀. Free cytosolic calcium concentration ([Ca²⁺]i) and ROS production in cells were estimated with the use of fluorescent probes Indo-1 and 2′,7′-dichlorodihydrofluorescein diacetate (DCF-DA), respectively. Results: It is shown that viability of L1210R cells wasn’t changed under treatment with cisplatin in concentration range 0.1–10 μg/ml. 50% and 30% decrease of L1210S cells were observed after 24 h of incubation with cisplatin at concentrations 5 and 1 μg/ml, respectively. Intensification of extranuclear cytotoxic effects (ROS production and [Ca²⁺]iincrease) after treatment with 1 μg/ml was detected in L1210S, but not in L1210R cells. The most strongly pronounced increase of ROS production and [Ca²⁺]i in both L1210 cell lines was revealed in dynamics after combined treatment with cisplatin (1 μg/ml) and photoexcited fullerene C₆₀ (10⁻⁵ M) and was followed by decreased viability of not only L1210S, but of L1210R cells as well.. Conclusion: Combined treatment with photoexcited C₆₀ and cisplatin allowed to decrease effective concentration of cisplatin against parental L1210 cells and to increase sensibility of resistant cells to the drug. Key Words: cisplatin, L1210 cells, photoexcited fullerene C₆₀, ROS, cytosolic Ca²⁺, cell viability

Effect of the visible light irradiation of fullerene containing composites on the ros generation and the viability of tumor cells

Aim: To study the effect of fullerene-containing composites, irradiated by visible light, on the radical oxygen species (ROS) generation in thymocytes, ascitic cells from Erlich’s tumor and leukemia cells L1210; to investigate viability of these cells in the presence of fullerene-containing composites under irradiation conditions. Materials and Methods: The viability of cells was evaluated by staining with 0.4% solution of the trypan blue; ROS were detected with the use of electron paramagnetic resonance (EPR) spectroscopy and spin traps; solutions of fullerene-containing composites were irradiated with mercury-vapor lamp. Results: We demonstrated that under irradiation conditions fullerene-containing composites increase the rate of ROS generation and decrease the number of viable tumor cells. Conclusions: The obtained data allow to consider the fullerene-containing composites as potential agents for photodynamic therapy.Цель: изучить влияние фуллеренсодержащих композитов, облученных видимым светом, на генерирование радикальных форм кислорода (РФК) в клетках тимоцитов, асцитного рака Эрлиха и лейкоза L1210. Исследовать жизнеспособность этих клеток в присутствии облученных фуллеренсодержащих композитов. Методы: жизнеспособность клеток определяли с использованием 0,4 % раствора трипанового синего; РФК регистрировали методом ЭПР- спектроскопии и спиновых ловушек; облучение водных раcтворов фуллеренсодержащих композитов в видимом диапазоне осуществляли с помощью ртутной лампы. Результаты: показано, что фуллеренсодержащие композиты при облучении повышают скорость генерирования РФК и уменьшают количество жизнеспособных опухолевых клеток. Выводы: полученные результаты позволяют рассматривать фуллеренсодержащие композиты как потенциальные препараты для фотодинамической терапии

Photocytotoxic effect of C₆₀ fullerene against L1210 leukemic cells is accomPanied by enhanced nitric oxide Production and p38 maPk activation

Aim: To estimate the combined action of C₆₀ fullerene and light irradiation on viability of L1210 leukemic cells, nitric oxide (NO) generation, p38 mitogen-activated protein kinase (MAPK) activity and cell cycle distribution. Methods: Cell viability was assessed by MTT test. Light-emitting diode lamp (λ = 410–700 nm, 2.45 J/cm²) was used for C₆₀ fullerene photoexcitation. Nitrite level and NO-synthase activity were measured by Griess reaction and by conversion of L-arginine to L-citrulline, respectively. p38 MAPK activity was assessed by Western blot analysis. Cell cycle distribution was determined by flow cytometry. Results: It was shown that light irradiation of C₆₀ fullerene-treated L1210 cells was accompanied by 55% decrease of their viability at 48 h of culture. Nitrite level measured as an index of reactive NO generation was increased at the early period after C₆₀ fullerene photoexcitation due to activation of both constitutive and inducible NO-synthase isoforms. The simultaneous activation of p38 MAPK was detected. Accumulation of L1210 cells in sub-G₁ phase of cell cycle was observed after C₆₀ fullerene photoexcitation. Conclusion: Photoexcited C₆₀ fullerene exerts cytotoxic effect, at least in part, through triggering production of reactive NO species and activation of p38 kinase apoptotic pathways in L1210 leukemic cells

ENHANCED CYTOTOXICITY OF РHOTOEXCITED FULLERENE C60 AND CISPLATIN COMBINATION AGAINST D RUGRESISTANT LEUKEMIC CELLS

Aim: To evaluate the viability of leukemic cells sensitive (L1210S) and resistant (L1210R) to cisplatin, ROS production and free cytosolic Ca²⁺ concentration under treatment with cisplatin or its combination with photoexcited fullerene C₆₀. Methods: Cell viability was assessed by the MTT reduction assay. Light-emitting diode lamp (2.45 J/сm2) was used for photoexcitation of intracellular accumulated fullerene C₆₀. Free cytosolic calcium concentration ([Ca²⁺]i) and ROS production in cells were estimated with the use of fluorescent probes Indo-1 and 2′,7′-dichlorodihydrofluorescein diacetate (DCF-DA), respectively. Results: It is shown that viability of L1210R cells wasn’t changed under treatment with cisplatin in concentration range 0.1–10 μg/ml. 50% and 30% decrease of L1210S cells were observed after 24 h of incubation with cisplatin at concentrations 5 and 1 μg/ml, respectively. Intensification of extranuclear cytotoxic effects (ROS production and [Ca²⁺]iincrease) after treatment with 1 μg/ml was detected in L1210S, but not in L1210R cells. The most strongly pronounced increase of ROS production and [Ca²⁺]i in both L1210 cell lines was revealed in dynamics after combined treatment with cisplatin (1 μg/ml) and photoexcited fullerene C₆₀ (10⁻⁵ M) and was followed by decreased viability of not only L1210S, but of L1210R cells as well.. Conclusion: Combined treatment with photoexcited C₆₀ and cisplatin allowed to decrease effective concentration of cisplatin against parental L1210 cells and to increase sensibility of resistant cells to the drug. Key Words: cisplatin, L1210 cells, photoexcited fullerene C₆₀, ROS, cytosolic Ca²⁺, cell viability