High‐content screening of drug combinations of an mPGES‐1 inhibitor in multicellular tumor spheroids leads to mechanistic insights into neuroblastoma chemoresistance

High‐throughput drug screening enables the discovery of new anticancer drugs. Although monolayer cell cultures are commonly used for screening, their limited complexity and translational efficiency require alternative models. Three‐dimensional cell cultures, such as multicellular tumor spheroids (MCTS), mimic tumor architecture and offer promising opportunities for drug discovery. In this study, we developed a neuroblastoma MCTS model for high‐content drug screening. We also aimed to decipher the mechanisms underlying synergistic drug combinations in this disease model. Several agents from different therapeutic categories and with different mechanisms of action were tested alone or in combination with selective inhibition of prostaglandin E2 by pharmacological inhibition of microsomal prostaglandin E synthase‐1 (mPGES‐1). After a systematic investigation of the sensitivity of individual agents and the effects of pairwise combinations, GFP‐transfected MCTS were used in a confirmatory screen to validate the hits. Finally, inhibitory effects on multidrug resistance proteins were examined. In summary, we demonstrate how MCTS‐based high‐throughput drug screening has the potential to uncover effective drug combinations and provide insights into the mechanism of synergy between an mPGES‐1 inhibitor and chemotherapeutic agents. This study highlights the value of spheroids for screening drug combinations and selecting appropriate hits for preclinical testing. A low‐cost spheroid model was developed that combines viability testing and confocal imaging to increase the reliability of results. Further research is needed to fully investigate the mechanisms underlying the synergies between microsomal prostaglandin E synthase‐1 inhibitors and chemotherapeutic agents.