Inverse Correlation between Methylation and Expression of the Delta-like Ligand 1 Gene in Gastric Cancer.

ABSTRACT

Notch signaling is a candidate pathway that transmits environmental information into the cell and interferes with the epigenome of gastric cancer. This study aimed to explore if the Notch pathway was abnormally regulated during gastric tumorigenesis. To achieve the goal, Delta-like ligand 1 (DLL1) gene expression, Notch upstream signal, promoter methylation and its correlation with DLL1 expression were examined by methylation-specific polymerase chain reaction (PCR) and real-time PCR (RT-PCR) in cultured gastric cancer cell lines or gastric cancer patient samples. Immunostainings and tissue arrays (n = 40) were used to confirm the DLL1 expression was down-regulated in cancer cells. Transient or stable Notch1 active domain (NICD)-overexpression suppressed proliferation of the gastric cells but the in vivo tumor growth was enhanced. The results of abnormal DLL1 methylation and expression observed in early gastric lesions and in gastric cancers may be relevant to the pathogenesis of gastric cancer.