TY - JOUR
T1 - Inhibition of Ral GTPases using a stapled peptide approach
AU - Thomas, Jemima C.
AU - Cooper, Jonathan M.
AU - Clayton, Natasha S.
AU - Wang, Chensu
AU - White, Michael A.
AU - Abell, Chris
AU - Owen, Darerca
AU - Mott, Helen R.
N1 - Funding Information:
This work was supported in part by a Cambridge Cancer Centre Pump Priming award (to C. A., D. O., and H. R. M.), a BBSRC (Biotechnology and Biological Sciences Research Council) studentship (to N. S. C.), National Institutes of Health Grant CA71443, and Welch Foundation Grant I-1414 (to M. A. W.). The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. We thank Dr. Nick Pugh and Dr. Stephanie Jung for assistance with confocal microscopy, Dr. Arooj Shafiq for providing RalA, and Dr. Karthik Rajasekar for R-Ras protein. We are also grateful to Dr. Chiara Valenzano and Dr Katherine Stott for helpful discussions.
Publisher Copyright:
© 2016 by The American Society for Biochemistry and Molecular Biology, Inc.
PY - 2016/8/26
Y1 - 2016/8/26
N2 - Aberrant Ras signaling drives numerous cancers, and drugs to inhibit this are urgently required. This compelling clinical need combined with recent innovations in drug discovery including the advent of biologic therapeutic agents, has propelled Ras back to the forefront of targeting efforts. Activated Ras has proved extremely difficult to target directly, and the focus has moved to the main downstream Ras-signaling pathways. In particular, the Ras-Raf and Ras-PI3K pathways have provided conspicuous enzyme therapeutic targets that were more accessible to conventional drug-discovery strategies. The Ras-RalGEF-Ral pathway is a more difficult challenge for traditional medicinal development, and there have, therefore, been few inhibitors reported that disrupt this axis. We have used our structure of a Ral-effector complex as a basis for the design and characterization of α-helical-stapled peptides that bind selectively to active, GTP-bound Ral proteins and that compete with downstream effector proteins. The peptides have been thoroughly characterized biophysically. Crucially, the lead peptide enters cells and is biologically active, inhibiting isoform-specific RalB-driven cellular processes. This, therefore, provides a starting point for therapeutic inhibition of the Ras-RalGEF-Ral pathway.
AB - Aberrant Ras signaling drives numerous cancers, and drugs to inhibit this are urgently required. This compelling clinical need combined with recent innovations in drug discovery including the advent of biologic therapeutic agents, has propelled Ras back to the forefront of targeting efforts. Activated Ras has proved extremely difficult to target directly, and the focus has moved to the main downstream Ras-signaling pathways. In particular, the Ras-Raf and Ras-PI3K pathways have provided conspicuous enzyme therapeutic targets that were more accessible to conventional drug-discovery strategies. The Ras-RalGEF-Ral pathway is a more difficult challenge for traditional medicinal development, and there have, therefore, been few inhibitors reported that disrupt this axis. We have used our structure of a Ral-effector complex as a basis for the design and characterization of α-helical-stapled peptides that bind selectively to active, GTP-bound Ral proteins and that compete with downstream effector proteins. The peptides have been thoroughly characterized biophysically. Crucially, the lead peptide enters cells and is biologically active, inhibiting isoform-specific RalB-driven cellular processes. This, therefore, provides a starting point for therapeutic inhibition of the Ras-RalGEF-Ral pathway.
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U2 - 10.1074/jbc.M116.720243
DO - 10.1074/jbc.M116.720243
M3 - Article
C2 - 27334922
AN - SCOPUS:84984679340
VL - 291
SP - 18310
EP - 18325
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
SN - 0021-9258
IS - 35
ER -