Active hexose-correlated compound down-regulates heat shock factor 1, a transcription factor for HSP27, in gemcitabine-resistant human pancreatic cancer cells

Abstract

Background: Active hexose-correlated compound (AHCC) is an extract of a basidiomycete mushroom that enhances the therapeutic effects and reduces the side- effects of chemotherapy. Our previous studies demonstrated that heat-shock protein 27 (HSP27) was involved in gemcitabineresistance of pancreatic cancer cells and it was downregulated by AHCC-treatment. However, how AHCC downregulated HSP27 is unknown. In the present study, we focused on two transcription factors reported to induce HSP27, heat shock factor 1 (HSF1) and high-mobility group box 1 (HMGB1) and investigated the effect of AHCC on their expression. Materials and Methods: KLM1-R cells were treated with AHCC and the protein expression of HSF1 and HMGB1 were analyzed by western blotting. Results: The protein expression of HSF1 in KLM1-R was down-regulated by AHCC treatment. On the other hand, the protein expression of HMGB1 was not reduced in KLM1-R cells after AHCC treatment. Conclusion: The possibility that AHCC down-regulated HSP27