Nutlin-3a is primarily used in research to study its role as an inhibitor of the MDM2-p53 interaction. By blocking this interaction, it activates the p53 pathway, which is crucial for tumor suppression. This makes it a valuable tool in cancer research, particularly in understanding how p53 can be reactivated in cancer cells that have lost its function. Additionally, Nutlin-3a is explored for its potential in chemotherapy, as it can induce apoptosis in cancer cells without harming normal cells. It is also used in studies related to cell cycle regulation and DNA damage response, providing insights into cellular mechanisms and potential therapeutic strategies.