title: Identification of STAT1 and STAT3 specific inhibitors using comparative virtual screening and docking validation.
abstract: Signal transducers and activators of transcription (STATs) facilitate action of cytokines, growth factors and pathogens. STAT activation is mediated by a highly conserved SH2 domain, which interacts with phosphotyrosine motifs for specific STAT-receptor contacts and STAT dimerization. The active dimers induce gene transcription in the nucleus by binding to a specific DNA-response element in the promoter of target genes. Abnormal activation of STAT signaling pathways is implicated in many human diseases, like cancer, inflammation and auto-immunity. Searches for STAT-targeting compounds, exploring the phosphotyrosine (pTyr)-SH2 interaction site, yielded many small molecules for STAT3 but sparsely for other STATs. However, many of these inhibitors seem not STAT3-specific, thereby questioning the present modeling and selection strategies of SH2 domain-based STAT inhibitors. We generated new 3D structure models for all human (h)STATs and developed a comparative in silico docking strategy to obtain further insight into STAT-SH2 cross-binding specificity of a selection of previously identified STAT3 inhibitors. Indeed, by primarily targeting the highly conserved pTyr-SH2 binding pocket the majority of these compounds exhibited similar binding affinity and tendency scores for all STATs. By comparative screening of a natural product library we provided initial proof for the possibility to identify STAT1 as well as STAT3-specific inhibitors, introducing the 'STAT-comparative binding affinity value' and 'ligand binding pose variation' as selection criteria. In silico screening of a multi-million clean leads (CL) compound library for binding of all STATs, likewise identified potential specific inhibitors for STAT1 and STAT3 after docking validation. Based on comparative virtual screening and docking validation, we developed a novel STAT inhibitor screening tool that allows identification of specific STAT1 and STAT3 inhibitory compounds. This could increase our understanding of the functional role of these STATs in different diseases and benefit the clinical need for more drugable STAT inhibitors with high specificity, potency and excellent bioavailability.
authors.affiliation: Department of Human Molecular Genetics, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University in Poznan, Umultowska 89, 61-614 Poznan, Poland.
authors.forename: Malgorzata
authors.initials: M
authors.lastname: Szelag
authors.affiliation: Bioinformatics Laboratory, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University in Poznan, Umultowska 89, 61-614 Poznan, Poland.
authors.forename: Anna
authors.initials: A
authors.lastname: Czerwoniec
authors.affiliation: Laboratory of High Throughput Technologies, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University in Poznan, Umultowska 89, 61-614 Poznan, Poland.
authors.forename: Joanna
authors.initials: J
authors.lastname: Wesoly
authors.affiliation: Department of Human Molecular Genetics, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University in Poznan, Umultowska 89, 61-614 Poznan, Poland.
authors.forename: Hans A R
authors.initials: HA
authors.lastname: Bluyssen
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D001688:Biological Products / Q000737:chemistry / Q000494:pharmacology; D057166:High-Throughput Screening Assays; D006801:Humans; D062105:Molecular Docking Simulation; D008969:Molecular Sequence Data; D011485:Protein Binding; D050794:STAT1 Transcription Factor / Q000037:antagonists & inhibitors* / Q000737:chemistry; D050796:STAT3 Transcription Factor / Q000037:antagonists & inhibitors* / Q000737:chemistry; D054852:Small Molecule Libraries / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D001688:Biological Products; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human; D054852:Small Molecule Libraries