The role of 14-3-3σ and TPD52L1 in HaCaT cells treated with low dose ultraviolet B / 中国职业医学

ABSTRACT

OBJECTIVE: To explore the role of 14-3-3σ and TPD52L1 in apoptosis,proliferation and cell cycle in HaCaT cells treated with low dose ultraviolet B( UVB). METHODS: i) HaCaT cells in logarithmic growth phase were exposed to UVB irradiation( cumulative exposure dose was 2. 97 ×10~(-2)J /cm~2) and were harvested after culture for 6-48 hours.HaCaT cells with no UVB irradiation were set as the control( pseudo-irradiation). The apoptosis of cells was detected by flow cytometry. The cells were divided into the control group and the UVB group exposed to UVB irradiation. They were harvested after being cultured for 0-72 hours,and monotetrazolium assay was used to detect the proliferation ability of cells.ii) HaCaT cells were randomly divided into control group( given pseudo-irradiation) and UVB group. Cells were cultured for 0-24 hours and then harvested. Flow cytometry was used to detect the proportion of G2 / M phase of cells. iii) After HaCaT cells were exposed to low dose of UVB irradiation and cultured for 3-24 or 3-30 hours,they were harvested. In addition,the control was treated with pseudo-irradiation. Real-time fluorescence quantitative polymerase chain reaction was used to detect the mRNA relative expression levels of 14-3-3σ and TPD52L1. The Western blotting was used to detect the protein relative expression of 14-3-3σ and TPD52L1 in cells. RESULTS: i) With 24 hours after UVB irradiation as the cell cycle observation time,the apoptosis of HaCaT cells reached to the maximum value and the proliferation ability to the minimum value( P < 0. 05). ii) After irradiation,the proportion of G2 / M phase in the control group showed a periodic change that it maintained at the highest levels after 6-12 hours of exposure to pseudo-irradiation,and at the time point of 18 hours it was decreased to the lowest value,the proportion of G2 / M phase in the UVB group was higher than that in control group at time points of 6,12 and 18 hours after irradiation( P < 0. 05),and sustained at the highest value,which resulted in significant G2 / M phase block. iii) After UVB treatment,the relative expression of mRNA and protein of 14-3-3σ first increased and then decreased. The relative expression level of mRNA of 14-3-3σ reached the highest level in 3 hours after irradiation( P < 0. 05),and maintained at the peak level at time points of 3-12 hours( P < 0. 05),and then gradually decreased until it returned to normal level 24 hours after irradiation; the relative expression of 14-3-3σ protein began to rise at time point of 6 hours after irradiation( P < 0. 05),and reached the peak value at time point of 18 hours( P < 0. 05),and then gradually decreased,but it did not recover to normal level after irradiation for 30 hours. The relative expression of mRNA of TPD52L1 first decreased and then increased. It reached the lowest level in 12 hours after irradiation( P <0. 05),and then increased gradually and reached the peak value after 24 hours( P < 0. 05). The relative expression of TPD52L1 protein first increased and then decreased. It got to the peak 24 hours after irradiation( P < 0. 05),and 30 hours after irradiation it returned to normal level( P < 0. 05). CONCLUSION: 14-3-3σ and TPD52L1 might jointly play an important role in cell apoptosis,proliferation and G2 / M phase block in HaCaT cells induced by low dose UVB irradiation.