Autophagy Induced by NGAL Protein in Esophageal Carcinoma Cells / 生物化学与生物物理进展

Previous studies suggest that NGAL (neutro phil gelatinase-associated lipocalin) is involved in the transformation and development of esophageal carcinoma. Alteration of NGAL expression can trigger the change of cellular morphology in esophageal carcinoma cells. However, the mechanisms remain unclear. To get a better understanding of NGAL function in esophageal carcinoma, NGAL protein was expressed in methylotrophic yeast, Pichia pastoris, and purified by chromatography. EC1.71 cells expressed high levels of NGALR (NGAL receptor) and EC109 cells expressed low levels of NGALR were used as cells model. The trafficking and the possible function of NGAL protein were then analyzed in the esophageal carcinoma cells. The results showed that 5-FAM-labeled recombinant NGAL protein could internalize into the EC1.71 and EC109 cells. Furthermore, the internalized NGAL protein could induce the alteration of cellular morphology, resulting in generation of autophagosome, transcriptional up-regulation of genes associated with autophagy and increase of phospho-ERK1/2 (p-ERK1/2). Interestingly, the treatment with the NGAL protein did not affect the intracellular iron level. These data indicate that induced autophagy by exogenous NGAL protein is a mechanism that internalized NGAL plays important roles in esophageal carcinoma cells, independent with NGAL-mediated iron transport process, while ERK1/2 signal pathway is involved in activation of autophagy by exogenous NGAL protein.

Role of transcription factors Sp1 and Sp3 in the expressional regulation of ezrin in esophageal carcinoma cells / 中国免疫学杂志

Objective:To identify the role of transcription factors Sp1 and Sp3 in the expressional regulation of ezrin in human esophageal carcinoma cells.Methods:Esophageal carcinoma EC109 cells were transfected with expressing vectors CMV-Sp1 or CMV-Sp3,and the effect of Sp1 and Sp3 over-expression on ezrin mRNA and protein expression was determined by real time RT-PCR and Western blot analysis.Furthermore,EC109 cells were cotransfected with the ezrin promoter-directed luciferase reporter vector and control vector pRL-TK along with transcription factor expression vector.The roles of Sp1 and Sp3 in ezrin promoter activation and whether this activation occurred through the Sp1 binding site,-75/-69,were analyzed by dual-luciferase reporter assay system.Results:Over-expression of transcription factors Sp1 and Sp3 significantly increased the expression of ezrin mRNA and protein and the ezrin promoter activity in EC109 cells.Sp1 and Sp3 enhanced the promoter activity through different binding sites and only Sp1 did that through the-75/-69 site.Conclusion:Sp1 and Sp3 can regulate ezrin expression in EC109 cells.