Detection and analysis of the methylation status of PTCH1 gene involved in the hedgehog signaling pathway in a human gastric cancer cell line

The aim of this study was to investigate the correlation between patched 1 (PTCH1) expression and its methylation in a human gastric cancer cell line, in order to provide new information regarding carcinogenesis and the development of gastric cancer. Quantitative reverse transcription polymerase chain reaction (qPCR) and the immunocytochemical S-P method were used to identify the changes in PTCH1 mRNA and protein expression prior to and following the treatment of the AGS human gastric cancer cell line with 5-aza-2′-deoxycytidine (5-Aza-dc), a methylation inhibitor. The methylation status of the promoter region of the PTCH1 gene in the AGS gastric cancer cell line was examined using methylation-specific PCR (MSP), while CpG island methylation in the PTCH1 gene 5′ regulatory sequence was analyzed using DNA methylation analysis software. The expression of PTCH1 mRNA and protein was absent in the AGS gastric cancer cell line prior to 5-Aza-dc treatment. However, the expression of PTCH1 mRNA and protein appeared in the AGS cells treated with 5-Aza-dc. CpG island hypermethylation of the PTCH1 gene was observed in the AGS gastric cancer cell line using MSP combined with DNA sequencing. PTCH1 expression was negatively correlated with the level of promoter methylation in the AGS cells. In conclusion, the high level of methylation in the PTCH1 gene promoter region may be involved in carcinogenesis and the development of gastric cancer, and may provide a new biomarker for gastric cancer.