SPEC-8

SPEC-8 is a novel, uncharged, low-molecular-weight small-molecule inhibitor of Signal Transducer and Activator of Transcription 3 (STAT3). It was identified through structure-based virtual ligand screening (SB-VLS) of the SPECS database, utilizing molecular dynamics simulations of the STAT3 SH2 domain to account for target flexibility. SPEC-8 binds directly to the SH2 domain of STAT3, specifically targeting the pY+0 binding pocket and forming hydrogen bonds with residues R609 and S613. This binding competitively blocks STAT3 from interacting with its phosphotyrosine peptide ligands, thereby preventing STAT3 phosphorylation, dimerization, and downstream transcriptional activation. In preclinical studies, SPEC-8 demonstrated potent inhibition of both cytokine-stimulated and constitutive STAT3 phosphorylation (pY-STAT3) with low micromolar IC50 values. It also significantly inhibited the growth of STAT3-dependent breast cancer cell lines, such as MDA-MB-468 and MDA-MB-231, in both anchorage-dependent and anchorage-independent assays. SPEC-8 is being investigated as a potential therapeutic candidate for cancer, chronic inflammation, and fibrosis.

Other names

Specs 8Specs8Specs-8