Structure-guided discovery of novel ERα-binding peptides with in vitro antiproliferative activity

Uterine leiomyoma (UL) is an oestrogen-dependent tumour, and ERα is closely associated with abnormal proliferation of UL cells. This study used structure-guided virtual screening of a 59,319-member peptide library, followed by molecular docking, MST, MD simulation, MM/PBSA analysis, MTT assays, ERα knockdown, and RT-qPCR, to identify ERα-binding peptides. Four peptides showed ERα binding, among which Peptide-4 exhibited the lowest K_d value (9.3 ± 0.5 nM). Docking, MD simulation, and MM/PBSA analyses suggested a relatively stable ERα-Peptide-4 binding mode supported by hydrogen-bonding, hydrophobic, and van der Waals interactions. Peptide-4 inhibited SK-UT-1 cell proliferation (IC₅₀ = 0.77 ± 0.04 μM) with limited activity in HUtSMC cells, and this effect was markedly attenuated after ERα knockdown. Peptide-4 reduced c-Myc and Cyclin D1 mRNA levels, while combined treatment with Anti-miR-149G further increased the antiproliferative effect in SK-UT-1 cells. These findings provide a basis for further evaluation of Peptide-4 in ERα-related UL models.