AKR1C3 inhibitor(Queen Elizabeth Hospital)

Aldo-keto reductase family 1 member C3 (AKR1C3) is a member of the AKR superfamily of enzymes that metabolize androgen, estrogen, and prostaglandin substrates that drive proliferation in hormone-dependent cancers. Interest in developing selective inhibitors has produced tool compounds for the inactivation or degradation of AKR1C3 with varying degrees of selectivity among the 14 known AKR proteins. Selectivity of AKR1C3 inhibitors across the AKR family is critical since a clinical candidate failed due to hepatotoxicity from off-target inhibition of AKR1D1. Here, we report development of a sulfonyl-triazole (SuTEx) covalent AKR1C3 inhibitor (RJG-2051) that selectively engages a noncatalytic tyrosine residue (Y24) on AKR1C3. Importantly, RJG-2051 exhibited negligible cross-reactivity with AKRs or other proteins across 1800+ tyrosine and lysine sites quantified by chemical proteomics. Our disclosure of a covalent inhibitor for potent AKR1C3 inactivation with proteome-wide selectivity in cells will expedite cell biological studies for testing the therapeutic potential of this metabolic target.

Aldo-keto reductase 1C3 (AKR1C3) plays a key role in tumor progression and chemotherapy resistance, particularly in sorafenib-resistant hepatocellular carcinoma (HCC). Targeting AKR1C3 represents a promising strategy to restore chemosensitivity in resistant HCC. Previous research identified the lead compound S07-2005 through a cascade virtual screening approach (AKR1C3 IC₅₀ = 130 ± 30 nM, SI (selective index) > 77). Using cocrystal-guided drug design, 30 was optimized to adopt an "L"-shaped conformation targeting AKR1C3's subpocket 1 (SP1) and oxyanion site (OS), enhancing inhibitory potency and selectivity (AKR1C3 IC₅₀ = 5 ± 1 nM, SI > 2000). It enhanced sorafenib-induced ROS generation, promoted apoptosis, and restored sorafenib sensitivity in HCC models. In combination with sorafenib, compound 30 restored sorafenib sensitivity in HCC both in vitro and in vivo. Additionally, compound 30 demonstrated a favorable safety profile and pharmacokinetic properties, suggesting its potential as an adjunct to overcome AKR1C3-mediated chemotherapy resistance in cancer treatment.