Celastrol Derivatives: Targeting RORα and RORγ for Enhanced Anti-Cancer and Neuroprotective Effects

Celastrol (CSL) is a pentacyclic triterpenoid terpene with potential anti-cancer and neuroprotective properties, but its toxicity limits its clinical use. To address this, we obtained a series of derivatives with reduced toxicity and increased efficacy through biotransformation. In this study, we used AlphaFold DB and the Schrödinger platform to perform reverse docking of CSL derivatives with 23391 human proteins to discover their pharmacological activity. We selected the Retinoic Acid Related-Orphan Receptors (RORs) family, specifically RORα and RORγ, as drug targets based on the drug target database. The compounds were filtered through QikProp, docked for dynamics simulation, and subjected to molecular mechanics-generalized born surface area (MMGBSA) binding energy calculations. We also conducted fluorescence polarization, luciferase reporter gene, and CCK8 assays. Our results identified RORα and RORγ as key targets for CSL derivatives and revealed GLN19, ARG97, ARG100 and GLN25, LEU26, ARG103, ARG106 as binding sites for RORα and RORγ, respectively. We also screened for the derivatives with the highest affinity and found that 2 μM 18-OH-CSL and 28-OH-CSL had the strongest agonistic effect on RORα-LBD, while 12-OH-CSL and a-ring aromatized 15-OH-CSL had the strongest inhibitory effect on RORγ-LBD. This was supported by the positive and negative coulomb energy in MMGBSA.