Mechanism Of Mitochondrial Complex Injury In Malignant Transformation Of BEAS-2B Exposed To Radon

Objective: The aim of the present study was to establish a model of malignant transformation of human bronchial epithelial(BEAS-2B)cells and explore the role and mechanisms of mitochondrial damage in the process of malignant transformation of human bronchial epithelial cells induced by radon.Methods:(1)To establish the malignant transformed BEAS-2B cell models induced by radon.The BEAS-2B cells were exposed to radon for 20 min at a concentration of 20000 Bq/m3.After that,the cells were collected and cultured for the next time.This process was repeated for 40 times.(2)Changes in the morphology and proliferation of cells were observed.Plate clone formation assay,wound healing assay were conducted during the process.(3)The ATP level was measured by luminometer;Flow cytometry was used to detect reactive oxygen species(ROS),mitochondrial membrane potential(MMP),cell cycle and cell apoptotic.Mitochondrial copy number was analyzed by real-time PCR.The expression of cytochrome-c was determined with western blot.Results:(1)Under microscope,the morphology of normal BEAS-2B cells was mainly fusiform,with uniform cell size,smooth and clear cell edge,clear cytoplasm and bright cytoplasm.The cells after exposure were irregular polygon or mesh,rough surface and unclear cell edge.(2)Compared with the Rn-0 generation cells,the number of colonies and cell migration of BEAS-2B cells increased significantly after radon exposure,and the cell doubling time decreased too.At the same time,the malignant transformation of BEAS-2B cells began to occur in 20 generations after radon exposure.(3)In the process of malignant transformation induced by radon exposure,the ATP synthesis increased gradually with the increase of the exposure algebra,and the mitochondrial membrane potential level increased with the increase of the infection algebra.The reactive oxygen level in the infected cells decreased with the increase of the infection algebra.(4)The number of mt DNA copies of radon infected BEAS-2B cells increased significantly from the tenth generation.In radon exposed cells,the expression level of cytochrome C increased in the fifth generation,but with the increase of exposure dose,the expression level of cytochrome c continued to decline.Conclusion:(1)A model of malignant transformation of human bronchial epithelial cells caused by radon exposure was successfully established.(2)We found that the malignant transformation induced by radon irradiation is the result of the combined action of mitochondrial damage and energy metabolism pathway.The change of mitochondrial function is an important factor in the process of malignant transformation of radon.