Inhibition of Ras signaling by blocking Ras-effector interactions with cyclic peptides.

Ras genes are frequently activated in human cancers, but the mutant Ras proteins remain largely "undruggable" through the conventional small-molecule approach owing to the absence of any obvious binding pockets on their surfaces. By screening a combinatorial peptide library, followed by structure-activity relationship (SAR) analysis, we discovered a family of cyclic peptides possessing both Ras-binding and cell-penetrating properties. These cell-permeable cyclic peptides inhibit Ras signaling by binding to Ras-GTP and blocking its interaction with downstream proteins and they induce apoptosis of cancer cells. Our results demonstrate the feasibility of developing cyclic peptides for the inhibition of intracellular protein-protein interactions and of direct Ras inhibitors as a novel class of anticancer agents.

[1]  M. Marshall,et al.  In vitro inhibition of Ras-Raf association by short peptides. , 1998, Biochemical and biophysical research communications.

[2]  B. Spencer‐Dene,et al.  Requirement for Interaction of PI3-Kinase p110α with RAS in Lung Tumor Maintenance , 2013, Cancer cell.

[3]  Philipp M. Cromm,et al.  Small-molecule modulation of Ras signaling. , 2014, Nature chemical biology.

[4]  L. Perkins,et al.  Ras oncoprotein inhibitors: the discovery of potent, ras nucleotide exchange inhibitors and the structural determination of a drug-protein complex. , 1997, Bioorganic & medicinal chemistry.

[5]  F. McCormick,et al.  Therapeutic strategies for targeting ras proteins. , 2011, Genes & cancer.

[6]  R. Briesewitz,et al.  Efficient delivery of cyclic peptides into mammalian cells with short sequence motifs. , 2013, ACS chemical biology.

[7]  Norbert Perrimon,et al.  Direct inhibition of oncogenic KRAS by hydrocarbon-stapled SOS1 helices , 2015, Proceedings of the National Academy of Sciences.

[8]  Kevan M. Shokat,et al.  K-Ras(G12C) inhibitors allosterically control GTP affinity and effector interactions , 2013, Nature.

[9]  S. Joo,et al.  High-throughput sequence determination of cyclic peptide library members by partial Edman degradation/mass spectrometry. , 2006, Journal of the American Chemical Society.

[10]  Qi Sun,et al.  Discovery of small molecules that bind to K-Ras and inhibit Sos-mediated activation. , 2012, Angewandte Chemie.

[11]  Paramjit S. Arora,et al.  An Orthosteric Inhibitor of the Ras-Sos Interaction , 2011, Nature chemical biology.

[12]  C. Der,et al.  Genetic and functional characterization of putative Ras/Raf interaction inhibitors in C. elegans and mammalian cells , 2010, Journal of molecular signaling.

[13]  Jie Zhang,et al.  Inhibitors of Ras/Raf-1 interaction identified by two-hybrid screening revert Ras-dependent transformation phenotypes in human cancer cells , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[14]  Robert A. Weinberg,et al.  Ras oncogenes: split personalities , 2008, Nature Reviews Molecular Cell Biology.

[15]  J. McCubrey,et al.  Synergy between PI3K/Akt and Raf/MEK/ERK Pathways in IGF-1R Mediated Cell Cycle Progression and Prevention of Apoptosis in Hematopoietic Cells , 2004, Cell cycle.

[16]  M. Villalona-Calero,et al.  Inhibition of Ras-Effector Interaction by Cyclic Peptides. , 2013, MedChemComm.

[17]  P. Bastiaens,et al.  Small molecule inhibition of the KRAS–PDEδ interaction impairs oncogenic KRAS signalling , 2013, Nature.

[18]  Phillip T. Hawkins,et al.  Crystal Structure and Functional Analysis of Ras Binding to Its Effector Phosphoinositide 3-Kinase γ , 2000, Cell.

[19]  N. Selner,et al.  Early Endosomal Escape of a Cyclic Cell-Penetrating Peptide Allows Effective Cytosolic Cargo Delivery , 2014, Biochemistry.

[20]  P. M. Campbell,et al.  Oncogenic Ras and its role in tumor cell invasion and metastasis. , 2004, Seminars in cancer biology.

[21]  Amy Young,et al.  Ras signaling and therapies. , 2009, Advances in cancer research.

[22]  G. Stamp,et al.  Binding of Ras to Phosphoinositide 3-Kinase p110α Is Required for Ras- Driven Tumorigenesis in Mice , 2007, Cell.

[23]  R. Roth,et al.  Akt, a Pleckstrin Homology Domain Containing Kinase, Is Activated Primarily by Phosphorylation* , 1996, The Journal of Biological Chemistry.

[24]  Ralph Weissleder,et al.  Effective Use of PI3K and MEK Inhibitors to Treat Mutant K-Ras G12D and PIK3CA H1047R Murine Lung Cancers , 2008, Nature Medicine.

[25]  Carla Mattos,et al.  A comprehensive survey of Ras mutations in cancer. , 2012, Cancer research.

[26]  Jiro Shimada,et al.  In silico discovery of small-molecule Ras inhibitors that display antitumor activity by blocking the Ras–effector interaction , 2013, Proceedings of the National Academy of Sciences.

[27]  C. Der,et al.  Inhibition of Ras for cancer treatment: the search continues. , 2011, Future medicinal chemistry.

[28]  D. Esposito,et al.  Dragging ras back in the ring. , 2014, Cancer cell.

[29]  Taebo Sim,et al.  Therapeutic targeting of oncogenic K-Ras by a covalent catalytic site inhibitor. , 2014, Angewandte Chemie.

[30]  I. Mellman,et al.  Small-molecule ligands bind to a distinct pocket in Ras and inhibit SOS-mediated nucleotide exchange activity , 2012, Proceedings of the National Academy of Sciences.

[31]  Weiru Wang,et al.  Ras inhibition via direct Ras binding--is there a path forward? , 2012, Bioorganic & medicinal chemistry letters.

[32]  William Pao,et al.  Identifying genotype-dependent efficacy of single and combined PI3K- and MAPK-pathway inhibition in cancer , 2009, Proceedings of the National Academy of Sciences.

[33]  D. Pei,et al.  Direct Ras Inhibitors Identified from a Structurally Rigidified Bicyclic Peptide Library. , 2014, Tetrahedron.