Investigation of cellular response to the HSP90 inhibition in human cells through thermal proteome profiling

Heat shock proteins are responsible for protein folding in cells. HSP90 is one of the most important chaperones in human cells, and inhibiting HSP90 is a potential strategy for cancer therapy. Multiple HSP90 inhibitors have been in clinical trials. However, none of them has been approved for disease treatment due to unexpected cellular toxicity. Hence, a more comprehensive investigation of cellular responses to HSP90 inhibitors can aid in a better understanding of the molecular mechanisms of the cytotoxicity and side effects of these inhibitors. Protein thermal stability shift, which represents protein structure and interaction alterations, can provide another level of information complementary to commonly used abundance-based proteomics analysis. In this work, we systematically investigated cell responses to different HSP90 inhibitors through global quantification of protein thermal stability changes using thermal proteome profiling, together with quantification of protein abundance changes. Besides the targets and potential off-targets of the drugs, proteins with significant thermal stability changes under the HSP90 inhibition are found to be related to cell stress responses and the translation process. Moreover, proteins with thermal stability shifts under the inhibition are upstream of those with altered expressions. Importantly, the current results indicate that the inhibition of HSP90 results in a strong perturbance of cell transcription and translation processes. This study provides a different perspective to achieve a better understanding of cellular response to chaperone inhibition.