Role of PTCH1 gene methylation in gastric carcinogenesis

The present study aimed to investigate the role of PTCH1 methylation in gastric carcinogenesis and the therapeutic effect of the methylation inhibitor, 5-aza-2′-deoxycytidine (5-aza-dC), in the treatment of gastric cancer. Total RNA was extracted from 20 gastric cancer tissues, their corresponding adjacent normal tissues and a gastric cancer AGS cell line. PTCH1 mRNA expression was detected by quantitative PCR, and the PTCH1 methylation of the promoter was examined by methylation-specific PCR. The AGS cells were treated with 5-Aza-dC; apoptosis and the cell cycle were examined by flow cytometry, and the PTCH1 methylation level was observed. PTCH1 expression was negatively correlated with promoter methylation in the gastric cancer tissues, their corresponding adjacent normal tissues and the gastric cancer AGS cell line (r=−0.591, P=0.006). 5-Aza-dC treatment caused apoptosis and the G(0)/G(1) phase arrest of the AGS cells, and also induced the demethylation and increased expression of PTCH1. In conclusion, the study found that the hypermethylation of the PTCH1 gene promoter region is one of the main causes of low PTCH1 expression in AGS cells. Demethylation agent 5-Aza-dC can reverse the methylation status of PTCH1 and regulate the expression of PTCH1, indicating its potential role in gastric cancer treatment.