SOX2在食管鳞癌组织中的表达及意义

Progress in research of markers for cancer stem cells in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most common malignant tumors in China, with high morbidity or mortality. In recent years, there has been a growing amount of evidence supporting the existence of a rare proportion of tumor cells termed cancer stem cells (CSCs) in diverse solid malignancies including ESCC. CSCs are closely related to the poor biological behaviors and drug resistance of ESCC. Markers for CSCs play an important role in the separation of CSCs, and the research on CSC markers can help clarify the mechanisms behind tumor development and guide tumor treatment.

Construction of a reporter vector regulated by the Pdx1 promoter and evaluation of the effect of DNA methylation on Pdx1 promoter activity in gastric cancer cells

AIM: To construct a reporter vector regulated by the Pdx1 promoter to determine the effect of DNA methylation on the promoter activity of Pdx1 gene.

METHODS: PCR amplification was performed to obtain nine potential Pdx1 promoter fragments, which were then cloned into the pGL3-basic vector to obtain recombinant pGL3-Pdx1 constructs. Promoter activity of different Pdx1 fragments in gastric cancer cells was detected by luciferase assay to identify the potential promoter area. The activity of the Pdx1 promoter with or without SssI methylase treatment was also evaluated by luciferase assay.

RESULTS: Luciferase assay showed that three fragments (F383, F720 and F1039), all of which contained the F383 sequence, had stronger promoter activity than pGL3-basic control. The promoter activity of these three fragments decreased significantly after SssI methylase treatment (all P < 0.05).

CONCLUSION: A luciferase reporter gene system containing the Pdx1 promoter was successfully constructed. F383 is the potential core area of the Pdx1 promoter. These results provide a basis for studying the epigenetic mechanism of Pdx1 gene silencing in gastric cancer.