Methylation-Associated Gene Silencing ofRARBin Areca Carcinogens Induced Mouse Oral Squamous Cell Carcinoma

Abstract

Regarding oral squamous cell carcinoma (OSCC) development, chewing areca is known to be a strong risk factor in many Asian cultures. Therefore, we established an OSCC induced mouse model by 4-nitroquinoline-1-oxide (4-NQO), or arecoline, or both treatments, respectively. These are the main two components of the areca nut that could increase the occurrence of OSCC. We examined the effects with the noncommercial MCGI (mouse CpG islands) microarray for genome-wide screening the DNA methylation aberrant in induced OSCC mice. The microarray results showed 34 hypermethylated genes in 4-NQO plus arecoline induced OSCC mice tongue tissues. The examinations also used methylation-specific polymerase chain reaction (MS-PCR) and bisulfite sequencing to realize the methylation pattern in collected mouse tongue tissues and human OSCC cell lines of different grades, respectively. These results showed that retinoic acid receptor β (RARB) was indicated in hypermethylation at the promoter region and the loss of expression during cancer development. According to the results of real-time PCR, it was shown that de novo DNA methyltransferases were involved in gene epigenetic alternations of OSCC. Collectively, our results showed that RARB hypermethylation was involved in the areca-associated oral carcinogenesis.

Longer Duration and Earlier Age of Onset of Paternal Betel Chewing and Smoking Increase Metabolic Syndrome Risk in Human Offspring, Independently, in a Community-Based Screening Program in Taiwan

“…INK4a , one of the epigenetic silencing markers responsible for betel-associated oral carcinogenesis, has been shown to be associated with body mass index, total cholesterol, low-density lipoprotein cholesterol, and HbA1c in patients who have renal disease with type 2 diabetes mellitus, 35 and with retinoid acid receptor β hypermethylation in the chromosomal region containing a major oral carcinogenesis gene, Nitrilase homolog I (Nit1), 36 whereas retinoid acid receptor β also regulates transcription of the hepatic fibroblast growth factor 21 gene, which has well-known metabolic effects on lipid oxidation, ketogenesis, and whole-body energy expenditure. 23 Although the evidence we present is compatible with epigenetic effects of chewing A catechu (and of smoking), they could be related to underlying genetic variants, such as the DRD2 Taq1A, DRD4 48 bp VNTR and OPRM1 genotypes reported to play a role in the development of nicotine craving in young novice smokers, 37 or those found to be associated with dopamine binding potential, such as the OPRM1 A118G genotype.…”

Sexually Dimorphic Expression of eGFP Transgene in the Akr1A1 Locus of Mouse Liver Regulated by Sex Hormone-Related Epigenetic Remodeling

“…Finally, the sections were stained with 3,3′ diaminobenzidine (DAB) and counterstained with hematoxylin. All slide images were observed and captured with a Zeiss Axio microscope (Zeiss, Germany) 45 .…”

Overview of biological mechanisms of human carcinogens

“…Arecoline produced alterations in expression of several genes catalyzing histone methylation, acetylation, and demethylation in human K-562 myelogenous leukemia cells (Lin et al 2011). Silencing of the Rarb (retinoic acid receptor β) gene, by hyper-methylation, was reported in areca nut-induced oral squamous cell carcinoma in mice (Lai et al 2014).…”