Ping Wang1, Juan Mei, Ning Zhang, Jing Tao, Hua Tian, Guo-Hui Fu. 1. Department of Pathology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Institutes of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
Abstract
BACKGROUND/AIMS: Previous studies have suggested that p16(INK4) protein is over expressed in gastric cancer. However, whether H. pylori infection induces p16(INK4) in human gastric epithelial cells remains to be determined. The aim of this study was to analyze the molecular mechanism of H. pylori-induced p16(INK4) expression. METHODOLOGY: Expression of p16(INK4) mRNA and Sp1 mRNA were assessed by reverse transcription-PCR. Expression of p16(INK4) protein was assessed by Western blot and immunocytochemistry. A luciferase assay was used to monitor activation of the p16(INK4) gene promoter and to explore the binding of transcription factors to this promoter. RESULTS: H. pylori upregulates the expression of p16(INK4) in gastric cancer SGC7901 cells. p16 promoter is highly actived in SGC7901 cells by H. pylori. Sp1 activates the expression of p16(INK4)-Luc and promotes the protein level of p16(INK4). CONCLUSION: H. pylori upregulates the expression of p16(INK4) in gastric cancer SGC7901 cells via the p16(INK4) promoter, and Sp1 is involved in the activation of p16(INK4) promoter by H. pylori.
BACKGROUND/AIMS: Previous studies have suggested that p16(INK4) protein is over expressed in gastric cancer. However, whether H. pyloriinfection induces p16(INK4) in human gastric epithelial cells remains to be determined. The aim of this study was to analyze the molecular mechanism of H. pylori-induced p16(INK4) expression. METHODOLOGY: Expression of p16(INK4) mRNA and Sp1 mRNA were assessed by reverse transcription-PCR. Expression of p16(INK4) protein was assessed by Western blot and immunocytochemistry. A luciferase assay was used to monitor activation of the p16(INK4) gene promoter and to explore the binding of transcription factors to this promoter. RESULTS:H. pylori upregulates the expression of p16(INK4) in gastric cancer SGC7901 cells. p16 promoter is highly actived in SGC7901 cells by H. pylori. Sp1 activates the expression of p16(INK4)-Luc and promotes the protein level of p16(INK4). CONCLUSION:H. pylori upregulates the expression of p16(INK4) in gastric cancer SGC7901 cells via the p16(INK4) promoter, and Sp1 is involved in the activation of p16(INK4) promoter by H. pylori.