Proteins are targets for the majority of drugs and are involved in most cellular process. However, to study proteins and their interactions in live cells and tissues has been very challenging. Recently our group introduced a new method to meet this challenge: the Cellular Thermal Shift Assay (CETSA) (Science 341(6141):84-87). CETSA is a biophysical assay based on the principle of ligand-induced thermal stabilization of target proteins, meaning that a proteins melting temperature will change upon ligand interaction. Thus, by heating samples (lysate, cells or tissue pieces) to different temperatures, and quantifying proteins in the soluble fraction we can detect altered protein interactions after for example drug treatment. This can either be done for selected proteins of interest by using anti-body based assays or proteome wide by using mass spec. CETSA allows direct monitoring of ligand binding to a specific target (target engagement) in lysate, live cells or even tissue pieces. It can also be used to study downstream effects on protein interaction, providing a novel perspective on protein function in situ.
Using CETSA to study cancer
The current focus in our lab is to explore how CETSA can be used in order to improve cancer treatment. We study key processes in cancer cells as well as the effect of drug treatment on protein interactions. Today, a main drawback of many cytostatics is innate or acquired drug resistance. Thus, we also work on gaining knowledge about the cellular mechanisms during resistance development. These approaches will hopefully lead to the discovery of new biomarkers that in the future can be used to predict treatment outcome and help guiding personalized medicine.
Some of our projects also include studies on tumour associated immune cells and the interaction between the immune system and tumour cells. Novel findings in the immune-oncology field have raised hope that many previously untreatable cancers might be possible to target. For some patient groups such treatment may represent actual cures. However, a large proportion of patients does not respond to treatment or develop resistance. Thus, there is a large interest to gain a better understanding of the intricate interplay between the immune system and the tumour cells. Improved immunotherapies could be a game changer in cancer research and we believe that CETSA has the potential to contribute to this goal.
Taken together, we use CETSA to:
- Provide detailed mechanistic understanding of cellular proteomics in basic cancer processes
- Gain a better understanding of protein interactions in cancer-related immune processes
- Provide in-depth mechanistic understanding of resistance to cytostatics and immunotherapies
- Identify novel candidate drug targets
- Find new protein-based biomarkers that report on therapeutic efficacy and resistance that can help guide personalized therapy
In summary, we use CETSA to study protein interactions in order to acquire data that in has the potential to improve future cancer treatment.
- Knut och Alice Wallenbergs stiftelse
- Vetenskapsrådet Medicin och Hälsa