Cytosolic delivery of peptidic STAT3 SH2 domain inhibitors.

Cytosolic delivery of peptidic STAT3 SH2 domain inhibitors. Bioorg Med Chem. 2020 Jun 15;28(12):115542 Authors: Cerulli RA, Shehaj L, Tosic I, Jiang K, Wang J, Frank DA, Kritzer JA Abstract The signal transducer and activator of transcription 3 (STAT3) protein is constitutively activated in several cancers. STAT3 activity can be blocked by inhibiting its Src Homology 2 (SH2) domain, but phosphotyrosine and its isosteres have poor bioavailability. In this work, we develop peptide-based inhibitors of STAT3-SH2 by combining chemical strategies that have proven effective for targeting other SH2 domains. These strategies include a STAT3-specific selectivity sequence, non-hydrolyzable phosphotyrosine isosteres, and a high-efficiency cell-penetrating peptide. Peptides that combined these three strategies had substantial biological stability and cytosolic delivery, as measured using highly quantitative cell-based assays. However, these peptides did not inhibit STAT3 activity in cells. By comparing in vitro binding affinity, cell penetration, and proteolytic stability, this work explores the delicate balance of factors that contribute to biological activity for peptidic inhibitors of STAT3. PMID: 32503696 [PubMed - as supplied by publisher]
Source: Bioorganic and Medicinal Chemistry - Category: Chemistry Authors: Tags: Bioorg Med Chem Source Type: research