Effect of thymol vapor phase on lung cancer cells exposed to radiation / Efeito da fase vapor do timol em células de câncer de pulmão expostas à radiação

Abstract

Radiotherapy is one of the therapeutic strategies for lung cancer treatment. However, it is important to improve the radiation effect in order to minimize the influence of radioresistance on lung cancer cells. Thymol is a volatile natural compound that could directly reach the lung tissue by inhalation and cause greater tumor cell death. We evaluated the cytotoxic activity of thymol vapor phase combined with radiation on A549 lung tumor cells to determine whether this compound would have a radiosensitizing potential. Lung tumor (A549) and non-tumor (MRC-5) cells were treated with thymol vapor phase (31.25-125 ?g/mL/well) for 6 hours before exposure to 9 Gray of radiation. After 48 hours, cell viability assays were performed to assess whether the treatment led to cell death. The pretreatment with thymol vapor phase enhanced death of A549 lung tumor cells exposed to radiation; the reduction on cell viability was greater than that caused only by radiation. For MRC-5 non-tumor cells the pretreatment was less cytotoxic compared to tumor cells. Therefore, thymol vapor phase acted in synergy with the radiation selectively on the tumor cells