title: Potent and specific peptide inhibitors of human pro-survival protein Bcl-xL.
abstract: The Bcl-2 family of proteins plays a critical role regulating apoptosis, and pro-survival Bcl-2 family members are important therapeutic targets due to their overexpression in different cancers. Pro-apoptotic Bcl-2 homology 3 (BH3)-only proteins antagonize pro-survival Bcl-2 protein functions by binding directly to them, and a sub-class of BH3-only proteins termed sensitizers can initiate apoptosis via this mechanism in response to diverse signals. The five pro-survival proteins Bcl-xL, Mcl-1, Bcl-2, Bcl-w and Bfl-1 differ in their binding preferences, with Bcl-xL, Bcl-2 and Bcl-w sharing similar interaction profiles for many natural sensitizers and small molecules. Peptides that bind selectively to just one or a subset of family members have shown utility in assays that diagnose apoptotic blockades in cancer cells and as reagents for dissecting apoptotic mechanism. Combining computational design, combinatorial library screening and rational mutagenesis, we designed a series of BH3 sensitizer peptides that bind Bcl-xL with sub-nanomolar affinity and selectivity up to 1000-fold over each of the four competing pro-survival proteins. We demonstrate the efficacy of our designed BH3 peptides in assays that differentiate between cancer cells that are dependent on different pro-survival proteins.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Sanjib
authors.initials: S
authors.lastname: Dutta
authors.affiliation: Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA 02215, USA.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Ryan
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: T Scott
authors.initials: TS
authors.lastname: Chen
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Christos
authors.initials: C
authors.lastname: Kougentakis
authors.affiliation: Department of Medical Oncology, Dana Farber Cancer Institute, Boston, MA 02215, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Letai
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA. Electronic address: keating@mit.edu.
authors.forename: Amy E
authors.initials: AE
authors.lastname: Keating
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000037:antagonists & inhibitors*; D001943:Breast Neoplasms / Q000378:metabolism*; D005260:Female; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000494:pharmacology*; D019151:Peptide Library; D011487:Protein Conformation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000037:antagonists & inhibitors*; D012441:Saccharomyces cerevisiae; D014407:Tumor Cells, Cultured; D051020:bcl-X Protein / Q000037:antagonists & inhibitors*
chemical_list: D051017:Apoptosis Regulatory Proteins; C494811:BCL2L1 protein, human; C491073:BCL2L2 protein, human; D010446:Peptide Fragments; D019151:Peptide Library; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein
keywords: BH3 peptides; BH3 profiling; Bcl-2 proteins; peptide design; yeast-surface display