Fig. 1.

Clonogenic survival and Bliss analysis for concurrent cisplatin radiotherapy (CCRT) and AUY922. Clonogenic survival assay showing cisplatin, radiation, or CCRT sensitizing effect of HSP90i by AUY922 on p53 mutant head and neck cell lines CAL27, FaDu and HN5. a Clonogenic drug scheduling. 5 nM AUY922 was added 16 h before addition of 5 μM cisplatin and/or immediate irradiation. Cisplatin and AUY922 were replaced with fresh media 3 h post-radiation. b Surviving fractions were calculated by normalization of treated wells to the plating efficiency of untreated controls. Values ± SEM of at least 3 independent experiments. Statistical analysis by 2-tailed t-test; *p < 0.05, **p < 0.01, ***p < 0.001. c Representative images of colonies for each cell line and each condition. Numbers indicate number of cells plated per well shown. d Analysis of synergy for the addition of AUY922 to cisplatin, radiation or CCRT as indicated by the Bliss Independence Model plotted as ΔE values ± 95% confidence intervals. ΔE = Observed reduction in clonogenicity – Expected reduction in clonogenicity, with survival expressed as a fraction of 1. Values with confidence intervals falling above zero represent synergy, negative values antagonism