Discovery of novel STAT3 inhibitors with anti-breast cancer activity: structure-based virtual screening, molecular dynamics and biological evaluation.

Triple negative breast cancer (TNBC) is a fatal type of breast cancer due to its high recurrence and metastatic potential. Persistent activation of signal transducer and activator of transcription 3 (STAT3) is crucial for TNBC progression, making it an attractive drug target. In this study, two new STAT3 inhibitors with significant anti-TNBC activity, d2 and d10, were identified from 1.67 million candidates through a rapid and cost-effective strategy integrating high-throughput virtual screening (HTVS), molecular mechanics/generalized born surface area (MM/GBSA), and binding pose metadynamics (BPMD) methods. In-depth mechanistic studies revealed that d2 and d10 significantly inhibited cell proliferation and colony formation, induced G1 phase arrest, and reduced migration and invasion of TNBC cells. Moreover, both d2 and d10 were found to inhibit the nuclear translocation and phosphorylation of STAT3. Molecular dynamics simulations further indicated that both compounds can stably bind to STAT3 in the SH2 domain. Additionally, protein-ligand interaction fingerprints (IFPs) of the screened compounds from HTVS were generated to better guide the design and structural optimization of STAT3 inhibitors.