Up-regulation of the HSP72 by Foxa1 in MCF-7 human breast cancer cell line.

Forkhead box protein A1 (Foxa1) is an evolutionarily conserved winged helix transcription factor. In this study, the effect of Foxa1 on the expression of HSP72 was examined by RT-PCR and Western blot in Foxa1 overexpression or deficient cells. The results showed overexpression of Foxa1 promoted the expression of HSP72, while Foxa1 depletion, induced by antisense oligonucleotides, decreased the expression of HSP72 in MCF-7 cells under normal and heat stress condition. Electrophoretic mobility shift assay and chromatin immunoprecipitation revealed that Foxa1 bound to HSP72 promoter, and heat stress promoted its DNA binding activity. Luciferase reporter showed that Foxa1 also increased the transcription activity of HSP72 promoter. These results indicate an important role for Foxa1 as a novel regulator of expression of HSP72.