Influence To P53 And MGMT Gene Induced By Histone Acetylation In BEAS-2B Cells Exposed To Radon

Objective: The immortalized human bronchial epithelial cells(BEAS-2B cells) exposed to radon, observe the histone H3 acetylation changes and the effect on the P53 and MGMT gene. This research is designed to explore the molecular changes in the early stage of lung cancer induced by radon.Method: BEAS-2B cells are cultured in 37℃, 5% CO2 incubator with the LHC-8 serum-free medium, Cells are divided into control group(C) and radon group(Rn). Cells in exponential growth phase are planted onto Transwell membrane with 1.5×105 per well. After adherence, cells were directly exposed to radon. The concentration of radon is 20000bq/m3, the time exposed to radon is 30 min. Cells exposed to radon twice is regarded as one passgae(Rn1). After the exposure, cells are cultured to n passages(Rn1-n). The exposed cells are cultured to 40 passages. The control group is exposed to the same treatment without radon. Biological characteristics between control group and different passages of radon group are compared for cell cycle, apoptotic rate and mitochondrial membrane potential. The extend of malignant transformation is detected by soft agar colony formation. Chromatin immunoprecipitation assay(Ch IP) is used to detect the level of histone H3 acetylation of P53 and MGMT gene. The expression of m RNA of P53 and MGMT gene is detected by Ch IP-q PCR. The expression of protein of P53 and MGMT gene is detected by western blot test.Results:(1) A series of sequential steps emerged among cells which exposed to radon, showed similar characteristics of cancer cells. The percentage of G1 phase in the radon group cells is significantly lower and the percentage of S phase is significantly higher. The apoptosis rate is significantly lower in cells after generation. The mitochondrial membrane potential in radon exposure group is lower than control group. The capacity of colony formation rate is significantly higher in radon group compared to control group.(2) The level of histone H3 of P53 in radon group is lower than control group, level of histone H3 of MGMT in radon group is higher than control group.(3)After the histone H3 acetylation, the level of m RNA and protein of P53 are lower than control, the level of m RNA and protein of MGMT are higher than control group.Conclusion: 1.Cells have malignant transformation after exposed to radon.2. The acetylation level of histone H3 of P53 in radon group is lower than control group, the acetylation level of histone H3 of MGMT in radon group is higher than control group.3.After the histone H3 acetylation, the level of m RNA and protein of P53 are lower than control, the level of m RNA and protein of MGMT are higher than control group.