CETSA-MS unveils novel targets engaged by rigosertib to promote anti-tumor activity and inflammatory responses.

Rigosertib (RGS) is a small-molecule inhibitor known to interfere with multiple disease signaling pathways. Despite its promise as an anti-cancer drug, the exact mechanisms of its action and rational for its observed clinical efficacy remain subjects of ongoing research. Our study aimed to elucidate the mechanism of action of rigosertib and to identify its novel targets. We observed that rigosertib exerts its inhibitory effect on RAS-MAPK signaling through reactive oxygen species (ROS)-induced activation of c-Jun NH2-terminal kinase (JNK) signaling confirming previous studies. Using mass spectrometry-based cellular thermal shift assay (CETSA MS), we identified two potential novel targets, ERO1A and NQO2, which contribute to ROS-dependent JNK activation. Moreover, rigosertib induced caspase-1 activation and gasdermin cleavage leading to Nod-like receptor pyrin domain-containing 3 (NLRP3)-dependent inflammatory responses in human lung cancer organoids. Our results suggest that rigosertib may effectively inhibit RAS-MAPK signaling and reprogram the tumor immune environment, presenting the potential for a potent therapeutic strategy in cancer treatment.