Fig 1.
Analysis of cell viability after 72 h treatment with Hsp90 inhibitors NVP-AUY922, BIIB021 and AT-13387.
(A) Toxicity of NVP-AUY922 and BIIB021 in MCF7 cells did not reach 50% in 72 h. All experiments were repeated 4 times. (B) Comparison of IC20 of Hsp90 inhibitors in breast cancer cell lines. (C) The comparison of sensitivity based on p53 status, Her2 (ErbB2) status, and subtype of breast cancer.
Fig 2.
Analysis of HSF1 in response to NVP-AUY922.
(A) Western blot analysis of phosphorylated HSF1 (Ser326) and total HSF1 in breast cancer cell lines. A representative blot is shown of 3 biological replicates. (B) Graph shows increase in ratio of pSer326HSF1 to total HSF1 after 4 h treatment with 200 nM NVP-AUY922 correlated to IC20 (nM) values of NVP-AUY922 treated breast cancer cell lines (r = 0.718; p = 0.0161).
Fig 3.
Viability analysis of SK-BR-3 and T-47D cells.
SK-BR-3 and T-47D cells were cultivated in physiological conditions (37 °C) and elevated temperature (39 °C) after 72 h NVP-AUY922 treatment. Viability analysis was performed in 3 biological replicates. (* p = 0,0377; **p = 0,0023).
Fig 4.
Correlation of HSF1 basal activity characterised by HOP/CHIP ratio with sensitivity to Hsp90 inhibitors.
(A-C) HSF1 activity expressed as the ratio between the HSF1 regulated co-chaperone HOP and the HSF1 independent co-chaperone CHIP correlated with IC20 (nM) of the indicated Hsp90 inhibitors. (A) NVP-AUY922 (r = -0.707; p = 0.0178), (B) BIIB021 (r = -0.602; p = 0.0402) and (C) AT13387 (r = -0.530; p = 0.0637). (D) mRNA copy number of analysed genes per reaction. qPCR measurements were performed from 3 biological replicates.
Fig 5.
Correlation of HSF1 basal activity with sensitivity characterised by Hsp70/CHIP ratio to Hsp90 inhibitors.
(A-C) HSF1 activity expressed as the ratio between the HSF1 regulated co-chaperone Hsp70 and the HSF1 independent co-chaperone CHIP correlated with IC20 (nM) of the indicated Hsp90 inhibitors. (A) NVP-AUY922 (r = -0.711; p = 0.0171), (B) BIIB021 (r = -0.660; p = 0.0265) and (C) AT13387 (r = -0.591; p = 0.0435). (D) mRNA copy number of analysed genes per reaction. qPCR measurements were performed from 3 biological replicates.