Isoform selective inhibition of STAT1 or STAT3 homo-dimerization via peptidomimetic probes: Structural recognition of STAT SH2 domains

The identification of constitutively activated STAT (Signal Transducers and Activators of Transcription) proteins in aberrant cell signaling pathways has led to investigations targeting the selective disruption of specific STAT isoforms directly associated with oncogenisis. We have identified, through the design of a library of peptidomimetic inhibitors, agents that selectively disrupt STAT1 or STAT3 homo-dimerization at low micromolar concentrations. ISS840 has 20-fold higher inhibition of STAT1 homo-dimerization (IC50 value of 31 μM) relative to STAT3 (IC50 value of 560 μM).