PH-Binding Motif in PAR4 Oncogene: From Molecular Mechanism to Drug Design

Jeetendra Kumar Nag, Hodaya Malka, Shoshana Sedley, Priyanga Appasamy, Tatyana Rudina, Tgst Levi, Amnon Hoffman, Chaim Gilon, Beatrice Uziely, Rachel Bar-Shavit*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

1 Scopus citations


While the role of G-protein-coupled receptors (GPCR) in cancer is acknowledged, their underlying signaling pathways are understudied. Protease-activated receptors (PAR), a subgroup of GPCRs, form a family of four members (PAR1-4) centrally involved in epithelial malignancies. PAR4 emerges as a potent oncogene, capable of inducing tumor generation. Here, we demonstrate identification of a pleckstrin-homology (PH)-binding motif within PAR4, critical for colon cancer growth. In addition to PH-Akt/PKB association, other PH-containing signal proteins such as Gab1 and Sos1 also associate with PAR4. Point mutations are in the C-tail of PAR4 PH-binding domain; F347 L and D349A, but not E346A, abrogate these associations. Pc(4-4), a lead backbone cyclic peptide, was selected out of a mini-library, directed toward PAR2&4 PHbinding motifs. It effectively attenuates PAR2&4-Akt/PKB associations; PAR4 instigated Matrigel invasion and migration in vitro and tumor development in vivo. EGFR/erbB is among the most prominent cancer targets. AYPGKF peptide ligand activation of PAR4 induces EGF receptor (EGFR) Tyr-phosphorylation, effectively inhibited by Pc(4-4). The presence of PAR2 and PAR4 in biopsies of aggressive breast and colon cancer tissue specimens is demonstrated. We propose that Pc(4-4) may serve as a powerful drug not only toward PAR-expressing tumors but also for treating EGFR/ erbB-expressing tumors in cases of resistance to traditional therapies. Overall, our studies are expected to allocate new targets for cancer therapy. Pc(4-4) may become a promising candidate for future therapeutic cancer treatment.

Original languageAmerican English
Pages (from-to)1415-1429
Number of pages15
JournalMolecular Cancer Therapeutics
Issue number9
StatePublished - 6 Sep 2022

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© 2022 American Association for Cancer Research.


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