Fig. 1: Dual HSP90-HSF1 inhibition via p53 activation synergistically impairs colorectal cancer cell growth.

A Cell viability matrices of HCT116 (left) and RKO (right) cells treated with Ganetespib – RG-7388 combinations for 72 h at indicated concentrations. Color scheme represents changes in cell viability. Numbers within the matrix indicate the HSA synergy score. Synergy scores: <−10 antagonistic; −10 to 10 additive; >10 synergistic. ≥3 biological replicates. B Relative confluence after 72 h treatment of HCT116 (top) and RKO (bottom) cells. Cell confluence was analyzed by Celigo imaging cytometer. Confluence relative to DMSO control, set at value 1. C Induction of cell death. PI/Hoechst/Annexin V staining of HCT116 (left) and RKO (right) cells treated for 72 h with Ganetespib and RG-7388 at the indicated concentrations. Percent dead cells include PI+ only, annexin V+ only and PI+Annexin V+ cells and were analyzed by Celigo imaging cytometer. D PARP-1 immunoblots of HCT116 (left) and RKO (right) cells treated for 48 h. HCT116 were treated with 50 nM Ganet and 1 μM RG. RKO were treated with 25 nM Ganet and 1.5 μM RG. Representative immunoblots shown from 3 replicates with 2 independent experiments each. For HCT116 cells, actin corresponding to PARP-1 is in parallel shown in Fig. 2D for tAKT staining. PARP-1 and tAKT were processed in parallel on the same membrane, and consequently actin as loading control is shown twice. B, C Mean ± SEM from ≥3 biological replicates, Student’s t-test, *p ≤ 0.05, **p ≤ 0.01, ***p ≤ 0.001; ns not significant. Ganet: Ganetespib, RG: RG-7388.