Fig (2) HSE-bla HeLa cells respond to HSR inducers and heat shock. (A) HSE-bla HeLa cells were left untreated (unstim), or treated with 17-AAG (0.45 µM), Celastrol (1 µM) and Bortezomib (10 µM) for 5 hour, or incubated at 42°C for 1 hour and then recovered for 5 hours in a 37°C/5% CO2 incubator before the betalactamase assay was performed as described in Methods. Response Ratios were plotted for each condition (n=4 for each data point). (B) Dividing or cryopreserved HSE-bla HeLa cells were resuspended in Assay Medium and plated out in 384-well format as described in Methods. Following an overnight incubation at 37°C, the cells were treated with the indicated concentrations of 17-AAG for 5 hours before the beta-lactamase assay was performed as described in Methods. The calculated EC₅₀ value for 17-AAG was 49 nM for dividing cells, and 36 nM for cryopreserved cells (n=4 for each data point).