Objective To test the effects of arsenic exposure on DNA methylation of promoter of p53 and p16 genes in human biological samples.
Method Arsenic-exposed residents from a burning-coal-type endemic arsenic poisoning area in Guizhou Province (n=42) and another control residents who lived 12 km away from the endemic area (n=40) were recruited in the study. Blood, urine, and hair samples were collected from all the subjects giving informed consent. The levels of urinary and hair arsenic were measured by inductively coupled plasma mass spectrometry, and DNA methylation at CpG site of p53 and p16 were determined by bisulfite sequencing.
Results Compared with the control group, the arsenic-exposed residents exhibited higher levels of urinary(40.59±27.12) μg/g and hair arsenic(0.32±0.36) μg/g, p53 methylation(8.32±1.51)%, and the methylation at CpG sites of -71(11.44±3.64)%, +42(2.58±1.29)%, and +109(4.98±1.33)% (all Ps＜0.05). There was no difference in p16 methylation between the exposed and non-exposed residents (all Ps>0.05).
Conclusion Arsenic exposure is associated with CpG site methylation in p53 promoter and may induce CpG site-specific DNA methylation.
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