title: Transducing properties of a pre-structured α-helical DPT-peptide containing a short canine adenovirus type 2 E4orf4 PP2A1-binding sequence.
abstract: BACKGROUND
  Induction of the death pathway resulting from the specific interaction of the PP2A1 phosphatase with adenoviral E4orf4 protein is a promising approach for cancer therapy. With the aim of deregulating tumor pathways, and mimicking E4orf4 anti-cancer signal, we have previously proposed the DPT technology concept, based on design of specific PP1/PP2A interacting penetrating peptides.
  
  
  METHODS
  Using biochemical, structural and cell survival experiments, we have characterized new DPT-peptides containing short PP2A binding sequences.
  
  
  RESULTS
  We identified overlapping sequences, located within the N-terminal domain E4orf423-46 of canine adenoviral E4orf4 protein, that interact with the PP2A-Bα subunit of PP2A1 holoenzyme. We characterized DPT-E4orf44 and TAT-E4orf44, two bi-partite cell penetrating peptides containing the 12 PP2A1 binding residues of the canine type 2 E4orf427-38 sequence, respectively fused to the DPT-sh1 and TAT shuttle sequences. Surprisingly DPT-E4orf44, in contrast to inactive TAT-E4orf44, adopted a well defined α-helical structure and co-precipitated PP2A1 from HeLa cell extracts. DPT-E4orf44 also internalized streptavidin-HRP and inhibited survival of HeLa cells more efficiently than TAT, TAT-E4orf44 or the previously published anti-tumor TAT-derived peptide shepherdin. DPT-E4orf44 also efficiently inhibited the survival of human adherent transformed cells, including wild type and p53 mutated colonic HCT116 cells, without affecting survival of human non-transformed fibroblasts.
  
  
  CONCLUSIONS
  We characterized the transducing properties of a new α-helical DPT-E4orf44 peptide containing a short PP2A-interacting sequence from canine Adenoviral E4orf4 protein.
  
  
  CONCLUSIONS
  Our results suggest that α-helical structured DPT peptides specifically interacting with PP2A could be a valuable anti-cancer drug design scaffold.
authors.affiliation: Unité Signalisation Moléculaire et Activation Cellulaire, Institut Pasteur, Paris, France.
authors.forename: A
authors.initials: A
authors.lastname: Galioot
authors.forename: A N
authors.initials: AN
authors.lastname: Godet
authors.forename: V
authors.initials: V
authors.lastname: Maire
authors.forename: P B
authors.initials: PB
authors.lastname: Falanga
authors.forename: X
authors.initials: X
authors.lastname: Cayla
authors.forename: B
authors.initials: B
authors.lastname: Baron
authors.forename: P
authors.initials: P
authors.lastname: England
authors.forename: A
authors.initials: A
authors.lastname: Garcia
mesh_terms: D006516:Adenoviruses, Canine; D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects / Q000235:genetics; D002461:Cell Line, Transformed; D004285:Dogs; D006367:HeLa Cells; D006801:Humans; D009154:Mutation; D011485:Protein Binding / Q000187:drug effects / Q000235:genetics; D054648:Protein Phosphatase 2 / Q000378:metabolism*; D017433:Protein Structure, Secondary; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins / Q000138:chemical synthesis / Q000737:chemistry / Q000235:genetics / Q000494:pharmacology
chemical_list: D000970:Antineoplastic Agents; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; D014764:Viral Proteins; D054648:Protein Phosphatase 2