DEC2 expression antagonizes cisplatin-induced apoptosis in human esophageal squamous cell carcinoma

Differentiated embryonic chondrocyte expressed gene 1 (DEC1) and differentiated embryonic chondrocyte expressed gene 2 (DEC2) belong to the Hairy/ Enhancer of Split subfamily of basic helix-loop-helix factors. Previous studies have demonstrated that DEC proteins are involved in the regulation of circadian rhythms, response to hypoxia, and tumorigenesis. However, the roles of DEC1 and DEC2 in apoptosis of esophageal carcinoma remain unclear. In the present study, alterations in expression of apoptosis-related markers in human esophageal squamous cell carcinoma TE-11 cells treated with cisplatin were examined by western blot, while overall cell viability and apoptosis were analyzed by MTS assay and hematoxylin and eosin staining, respectively. Following cisplatin treatment, expression of DEC2 was downregulated, whereas expression of DEC1 was upregulated. DEC2 overexpression during cisplatin treatment markedly inhibited expression of the pro-apoptotic factor Bim and slightly increased the anti-apoptotic factor Bcl-xL. However, overexpression of DEC1 during cisplatin treatment failed to affect expression of these markers. Additionally, overexpression of DEC2 improved cell viability and decreased cell apoptosis induced by cisplatin. These results suggested that DEC2 exhibits anti-apoptotic effects in TE-11 esophageal squamous cell carcinoma cells. Inhibiting DEC2 may therefore have therapeutic potential for the treatment of esophageal cancer, in combination with cisplatin.