Beclin 1 has a central role in the regulation of autophagy, differentiation, apoptosis resistance, tumorigenesis and cancer progression. The role of Beclin 1 in the development of esophageal squamous cell carcinoma (ESCC) and its subsequent progression is not fully characterized. In the present study, the role of Beclin 1 and autophagy in ESCC was evaluated. The expression of Beclin 1 mRNA and protein levels in human ESCC tumor and adjacent normal esophageal tissue was measured. Beclin 1 mRNA and protein were significantly lower in tumor tissue than in normal esophageal tissue (P<0.05). Cells of the less differentiated esophageal tumors expressed lower Beclin 1 mRNA and protein (P<0.05). Tumors from patients in early clinical stages (I/II) exhibited significantly higher Beclin 1 mRNA and protein expression levels than patients with tumors in mid-to-late stages (III/IV; P<0.05). Tumors from patients with lymph node metastasis exhibited significantly lower Beclin 1 mRNA and protein expression levels compared with tumors from patients without lymph node involvement (P<0.05). Beclin 1 downregulation was demonstrated to significantly upregulate invasion by ESCC EC9706 cells (P<0.01), and downregulate the number of acidic vesicular organelles, a process associated with autophagy. These results suggest that the expression of Beclin 1 is associated with the occurrence and development of ESCC. Measuring the Beclin 1 expression of tumors from patient may improve the understanding of the prognosis of patients with ESCC.
Keywords: Beclin 1; autophagy; esophageal squamous cell carcinoma.