Investigation of stereoisomeric bisarylethenesulfonic acid esters for discovering potent and selective PTP1B inhibitors

Protein tyrosine phosphatase 1B (PTP1B) has been considered as a promising therapeutic target for type 2 diabetes mellitus (T2DM) and obesity due to its key regulating effects in insulin signaling and leptin receptor pathways. In this work, a series of cis- and trans-pyrrolidine bisarylethenesulfonic acid esters were prepared and their PTP1B inhibitory potency, selectivity and membrane permeability were evaluated. These novel stereoisomeric molecules especially trans-isomers exhibited remarkable inhibitory activity, significant selectivity as well as good membrane permeability (e.g. compound 28a, IC₅₀ = 120, 1940 and 2670 nM against PTP1B, TCPTP and SHP2 respectively, and P_app = 1.74 × 10⁻⁶ cm/s). Molecular simulations indicated that trans-pyrrolidine bisarylethenesulfonic acid esters yielded the stronger binding affinity than their cis-isomers by constructing more interactions with non-catalytic sites of PTP1B. Further biological activity studies revealed that compound 28a could enhance insulin-stimulated glucose uptake and insulin-mediated insulin receptor β (IRβ) phosphorylation with no significant cytotoxicity.