Objective To assess the effects of 2, 2', 4, 4', 5, 5'-hexachlorobiphenyl (PCB153) on long interspersed nuclear element-1 (LINE-1) gene expression and transposition in human renal tubular epithelial 293T cells.
Methods The 293T cells were transmitted every two days and exposed to PCB153 (5 μmol/L) in vitro after transmitting. The exposed cells were cultured in a 5% CO2 incubator at 37℃ and the exposure lasted for 10 days, with the 293T cells treated with dimethyl sulfoxide (DMSO) as control group. LINE-1 open read framework 1 (ORF-1) and open read framework 2 (ORF-2) gene mRNA expression levels and copy numbers (increasing copy number indicates transposition) were detected by real-time fluorescence quantitative PCR. LINE-1 ORF-1 and ORF-2 protein expression levels were measured by Western blot.
Results Compared with the control group, the mRNA expression level of LINE-1 ORF-1 in the PCB153 exposed group was increased from day 4 (P < 0.05), and the mRNA expression level of LINE-1 ORF-2 in the PCB153 exposed group was increased from day 6 (P < 0.05). On day 10, compared with the control group (LINE-1 ORF-1:2.74±0.51; LINE-1 ORF-2:0.57±0.10), the protein expression levels of LINE-1 ORF-1 (4.39±0.85) and LINE-1 ORF-2 (0.78±0.10) in the PCB153 exposed group were both increased (P < 0.05). In addition, on day 10, the copy numbers of LINE-1 ORF-1 were 1.43±0.64 and 0.83±0.37, and the copy numbers of LINE-1 ORF-2 were 1.11±0.52 and 0.81±0.12 in the PCB153 exposed group and the control group, respectively, with significant differences (P < 0.05).
Conclusion Exposure to PCB153 can increase the expression and copy number of LINE-1 and induce its transposition in 293T cells.
DownLoad: