Objective:
To study the effect of PTCH1
methylation on gastric
carcinogenesis and the
therapeutic effect of
methylation inhibitor, 5-aza-2′-deoxyeytidine (5-aza-dC), for
treatment of
gastric cancer.
Methods:
The total RNAs were extracted from 10
gastric cancer tissues, their corresponding adjacent normal
tissues, and
gastric cancer cell line AGS. The PTCH1
mRNA expression was detected by
Quantitative real-time PCR (QRT-
PCR) and the
methylation of the promoter was examined by
methylation specific
PCR (MSP). AGS
cells were treated by 5-Aza-dC; the
cell cycle and
apoptosis were examined by
flow cytometry, and the
methylation level was also observed.
Results:
PTCH1 expression was negatively correlated with promoter
methylation in
gastric cancer tissues, their corresponding adjacent normal
tissues, and
gastric cancer cell line AGS (r = -0.591, P = 0.006). 5-Aza-dC
treatment caused
apoptosis and G 0/
G1 phase arrest of AGS
cells, and also induced
demethylation of PTCH1 and increased its expression.
Conclusion:
Hypermethylation of PTCH1
gene promoter region is one of the main causes of low PTCH1 expression in AGS
cells.
Demethylation agent 5-Aza-dC can reverse this
methylation status of PTCH1 and regulate the expression of PTCH1, suggesting a
role for it in
gastric cancer treatment.