Affinity‐Driven Covalent Modulator of the Glyceraldehyde‐3‐Phosphate Dehydrogenase (GAPDH) Cascade

Abstract

Traditional medicines provide a fertile ground to explore potent lead compounds, yet their transformation into modern drugs is fraught with challenges in deciphering the target that is mechanistically valid for its biological activity. Herein we reveal that (Z)-(+)-isochaihulactone (1) exhibited significant inhibition against multiple-drug-resistant (MDR) cancer cell lines and mice xenografts. NMR spectroscopy showed that 1 resisted an off-target thiolate, thus indicating that 1 was a target covalent inhibitor (TCI). By identifying the pharmacophore of 1 (α,β-unsaturated moiety), a probe derived from 1 was designed and synthesized for TCI-oriented activity-based proteome profiling. By MS/MS and computer-guided molecular biology approaches, an affinity-driven Michael addition of the noncatalytic C247 residue of GAPDH was found to control the "ON/OFF" switch of apoptosis through non-canonically nuclear GAPDH translocation, which bypasses the common apoptosis-resistant route of MDR cancers.

Covalent inhibitors of GAPDH: From unspecific warheads to selective compounds

“…This novel mechanism of action highlights the importance of GAPDH as a target for tumor treatment, since this mechanism bypasses the standard apoptosis-resistant route of MDR cancers. 205 GAPDH covalent inhibition occurs via Michael addition on the α-methylene lactone group, which was already described as a thiol reacting feature. 206 This warhead presents a finely modulated reactivity due to the electron-donating properties of the conjugated trimethoxyphenyl moiety; therefore, unspecific reactions with thiols were only sluggishly observed.…”

“…203,204 In particular, the (S) enantiomer was found to be 7-10 times more active than its enantiomer, showing a 1 µM activity towards three different cancer cell lines. 205 In a very recent study using molecular probes, the non-catalytic Cys-247 of hGAPDH was identified as one of the main targets of (S)-13. The glycolytic activity of hGAPDH, which is mediated by the catalytic Cys-152, was not impaired.…”

“…206 This warhead presents a finely modulated reactivity due to the electron-donating properties of the conjugated trimethoxyphenyl moiety; therefore, unspecific reactions with thiols were only sluggishly observed. 205 Moreover, the selectivity of (S)-13 for Cys-247 over the much more nucleophilic catalytic Cys is due to the higher affinity of the recognition moiety for a site of the enzyme different from the catalytic pocket. Several SAR studies were carried out on the structure of this dibenzylbutyrolactone ligand and interesting findings emerged, which are resumed in Figure 13.…”

“…Several SAR studies were carried out on the structure of this dibenzylbutyrolactone ligand and interesting findings emerged, which are resumed in Figure 13. 204,205,207 Figure 13. Structure-Activity Relationship of compound (S)-13…”

Dirhodium(II)‐Catalyzed C(sp2)−H Azidation of Benzaldehydes

“…The key intermediate 2 a , for the synthesis of GPR109A analogs can be obtained in one step with good yield, which previously required five steps to prepare . Another key intermediate for the synthesis of a lignin derivative probe can be shortened from the previously reported four step synthesis to one step from commercially available 4‐methoxybenzaldehyde 1 d (Scheme ) . We envision that this efficient synthesis method may contribute to the preparation of nitrogen‐containing heterocyclic compounds, bioactive compounds, in the future.…”