Effects of FBXW7α on Expression and Localization of Heat Shock Transcription Factor 1 in Colorectal Cancer Cells

Abstract

Objective To investigate the effect of FBXW7 on the expression and localization of HSF1 in colorectal cancer cells. Methods The expression levels of HSF1 and pHSF1Ser326 protein in FBXW7 deletion (KO) and wild-type (WT) FBXW7-expressing counterpart colorectal cancer cells were detected by Western blot. The nucleoprotein expression and localization of pHSF1Ser326 in heat-shocked or recovery stage cells were observed by Western blot and immunofluorescence method. Results The HSF1 expression level in DLD1 cells transfected with FBXW7α was decreased significantly (P < 0.01). The expression levels of HSF1 and pHSF1Ser326 protein in FBXW7 KO cells were higher than those in WT cells (all P < 0.05). HSF1 and pHSF1Ser326 in FBXW7 KO cells were mainly expressed in nucleus and weakly expressed in cytoplasm. After warm stimulation, the expression of HSF1 and pHSF1Ser326 in WT cells recovered to the unstimulated level, while the expression of HSF1 and pHSF1Ser326 in FBXW7 KO cells were higher in the nucleus (all P < 0.01). Conclusion Loss of FBXW7 could affect the nuclear HSF1 recovery after warm stimulation. It may be associated with FBXW7 deletion inhibiting the degradation of nuclear HSF1.

Keywords

• fbxw7
• hsf1
• crc cells
• heat shock reaction