Evaluation of the Epigenetic Demethylation of NRF2, a Master Transcription Factor for Antioxidant Enzymes, in Colorectal Cancer

Colorectal Cancer
21/08/2020

Rep Biochem Mol Biol. 2020 Apr;9(1):33-39. doi: 10.29252/rbmb.9.1.33.

ABSTRACT

BACKGROUND: Epigenetic changes in CpG islands of the promoter regions of homeostasis-related genes, including nuclear factor erythroid 2-related factor 2 (NRF2), have been shown to hold a significant role in the development of colorectal cancer. Therefore, we aimed to examine the DNA demethylation pattern of the NRF2 promoter region in cancerous lesions from patients with colorectal cancer and the association of methylation status with clinicopathological features in the Iranian population.

METHODS: In this cross-sectional study, 114 colorectal tissue samples were collected. These samples included: 34 tumour tissue samples, 60 precancerous polyps, and 20 normal tissue samples. The promoter methylation status of the NRF2 gene was examined using methylation-specific PCR. Additionally, the relationship between the methylation status and the clinicopathological features was investigated.

RESULTS: The frequency of NRF2 demethylation in the tumour samples was significantly higher compared to the polyp tissues (p= 0.003) and normal tissue (p= 0.009), indicating that cancerous colorectal tissues exhibit increased demethylation of the NRF2 promoter. After examining the demethylation status of tissue samples, the clinicopathological features were compared to the demethylation results. No significant association was found between NRF2 promoter demethylation and the clinicopathological features of patient samples.

CONCLUSION: Our findings suggest that the epigenetic modifications leading to NRF2 demethylation found in colorectal tumour samples may contribute to cancer progression from precancerous polyps to cancerous lesions.