Specificity protein 1 regulates fascin expression in esophageal squamous cell carcinoma as the result of the epidermal growth factor/extracellular signal-regulated kinase signaling pathway activation

The overexpression of fascin in human carcinomas is associated with aggressive clinical phenotypes and poor prognosis. However, the molecular mechanism underlying the increased expression of fascin in cancer cells is largely unknown. Here, we identified a Sp1 binding element located at −70 to −60 nts of the FSCN1 promoter and validated that Sp1 specifically bound to this element in esophageal carcinoma cells. Fascin expression was enhanced by Sp1 overexpression and blocked by Sp1 RNAi knockdown. Specific inhibition of ERK1/2 decreased phosphorylation levels of Sp1, and thus suppressed the transcription of the FSCN1, resulting in the down-regulation of fascin. Stimulation with EGF could enhance fascin expression via activating the ERK1/2 pathway and increasing phosphorylation levels of Sp1. These data suggest that FSCN1 transcription may be subjected to the regulation of the EGF/EGFR signaling pathway and can be used as a viable biomarker to predict the efficacy of EGFR inhibitors in cancer therapies.