Analysis of p16 Gene Mutation, Deletion and Methylation in Patients with Arseniasis Produced by Indoor Unventilated-Stove Coal Usage in Guizhou, China

Abstract

The aim of this study was to determine p16 gene mutation, deletion, and promoter 5' CpG island hypermethylation in peripheral blood mononuclear leukocyte of patients with arseniasis as attributed to exposure to indoor unventilated coal stove. The role of the aberrant change of p16 gene in the induction and development of carcinogenesis in endemic arsenisiasis region in China was also examined. Polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP), multiplex PCR (mPCR), methylation-specific PCR (MSP), and sequencing techniques were performed to detect (1) mutation of the p16 gene exon 2, (2) homozygous deletion of the p16 gene exon 1 and exon 2, and (3) hypermethylation of the promoter CpG island in peripheral blood mononuclear leukocyte of patients with arseniasis. Results showed no mutation was found in exon 2 of p16 gene. The homozygous deletion frequency of p16 gene was 5 and 15% in control and arseniasis patients, respectively. The homozygous deletion occurred mainly in exon 2, with significant deletion frequencies of 9, 13, and 20% in mild, intermediate, and severe arseniasis groups. The significant homozygous deletion frequency was 9 and 39% in noncarcinoma and carcinoma individuals. The positive rate of p16 gene promoter CpG island hyermethylation was 42 and 2% in the exposed group and the control group, respectively. The positive rate was 26, 42, and 50% in mild, intermediate, and severe arseniasis. The marked different positive rate was 22 and 56% in noncarcinoma and carcinoma individuals, respectively. In conclusion, homozygous deletion and hypermethylation of p16 gene may play an important role in the initiation and development of manifestations seen in endemic arseniasis including carcinogenesis.

Air toxics and epigenetic effects: ozone altered microRNAs in the sputum of human subjects

“…Animal models have shown that chronic exposure to air pollutants can produce significant changes in gene expression patterns (8,15,18,28,44), and in humans changes in transcriptional profiles have been correlated with air pollutant exposure (7,9,10,11,30,34,40,45). Together, these data show that pollutant-induced changes in gene expression levels have biological importance.…”

CpG Site–Specific Hypermethylation of p16INK4α in Peripheral Blood Lymphocytes of PAH-Exposed Workers

“…When analyzing the difference at each CpG site between 2 groups using a Mann-Whitney U test, we found that 22 sites located at No. 1,2,8,9,11,12,17,18,[20][21][22][23][24], and 26-34 were significantly higher in PAH-exposed workers (Fig. 2B), indicating that these 22 CpG sites might be the regulatory "hot CpG sites" participating in gene transcriptional suppression.…”

“…INK4a gene promoter hypermethylation in peripheral blood leukocyte was much higher in the patients with arseniasis (22) and in the workers exposure to radon (23). However, it is still unclear that whether p16…”

DNA methylation in white blood cells

“…60 Hypermethylation of the p16 promoter was also observed in WBC DNA from 103 patients with arseniasis compared to 110 healthy subjects. 61 Air pollution. The effects of particulate matter (PM) exposure on Alu, LINE-1 and gene-specific methylation was examined in steel plant workers with well-characterized exposure to PM with aerodynamic diameters <10 μm (PM10).…”