Figure 1

The effects of celastrol on HSPs expression in cancer cells accompanied by HSF1 activation. (A) Seven kinds of cancer cell lines were treated with 600 nM celastrol for 24 h. The culture medium with DMSO (vehicle) served as control for drugs. After treatment, cells were harvested and total protein was isolated. The levels of HSPs (HSP70, HSP90, and HSP40) were assayed by western blot (WB). (B) The cell lines were treated with 600 nM of celastrol, 17-AAG, or NB for 24 h. WB detected HSP70 expression. (C) Phosphorylation of HSF1 detected in PC3 cell. The cells were treated with 600 nM of celastrol, 17-AAG, or NB for 10 min. The total protein was subjected to SDS-PAGE. The activation of HSF1 was probed with anti-HSF1, and phosphorylated-HSF1 (s326 and s303) antibodies. (D) Distribution of HSF1 in cytoplasm and nuclei in PC3 cells. The cells were treated with 600 nM of celastrol for 10 min. The proteins in total cells, plasma, and nucleus were extracted and WB detected the levels of HSF1. (E) Nuclear accumulation of HSF1 in PC3 cells. The cells were grown on coverslips for at least 24 h in culture medium, then the medium was replaced by one of 600 nM of celastrol for 10 min. HSF1 was detected by immunofluorescence using an anti-HSF1 (green) antibody which mainly recognizes HSF1 in nuclei. DNA was stained with PI (red). The magnification was ×1000. Con: control; Cel: celastrol; 17-AAG: 17-allylamino-17- demethoxygeldanamycin; NB: novobiocin.