title: Isolation of peptides blocking the function of anti-apoptotic Livin protein.
abstract: Livin (ML-IAP) is a cancer-associated member of the inhibitor of apoptosis protein (IAP) family. By yeast two-hybrid screening of a randomized peptide expression library, we isolated short linear peptides that specifically bind to Livin, but not to other IAPs. Intracellular expression of the peptides sensitized livin-expressing cancer cells toward different pro-apoptotic stimuli. The bioactive peptides neither showed sequence homologies to Smac-derived IAP inhibitors, nor did they interfere with the binding of Livin to Smac. Intracellular expression of the peptides did not affect the levels or the subcellular distribution of Livin. Growth of livin-expressing tumor cells was inhibited in colony formation assays by the Livin-targeting peptides. These findings provide evidence that the targeted inhibition of Livin by peptides represents a viable approach for the apoptotic sensitization and growth inhibition of tumor cells. The inhibitory peptides isolated here could form a novel basis for the development of therapeutically useful Livin inhibitors.
authors.affiliation: Molecular Therapy of Virus-Associated Cancers (F065), German Cancer Research Center, Im Neuenheimer Feld 242, 69120, Heidelberg, Germany.
authors.forename: Irena
authors.initials: I
authors.lastname: Crnković-Mertens
authors.forename: Julia
authors.initials: J
authors.lastname: Bulkescher
authors.forename: Christina
authors.initials: C
authors.lastname: Mensger
authors.forename: Felix
authors.initials: F
authors.lastname: Hoppe-Seyler
authors.forename: Karin
authors.initials: K
authors.lastname: Hoppe-Seyler
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000502:physiology*; D000595:Amino Acid Sequence; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins; D002460:Cell Line; D006367:HeLa Cells; D006801:Humans; D066298:In Vitro Techniques; D051034:Inhibitor of Apoptosis Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000502:physiology*; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000502:physiology*; D019151:Peptide Library; D010455:Peptides / Q000235:genetics / Q000302:isolation & purification* / Q000494:pharmacology*; D011485:Protein Binding; D025941:Protein Interaction Mapping; D034622:RNA Interference; D014410:Tumor Stem Cell Assay; D020798:Two-Hybrid System Techniques
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; C419866:BIRC7 protein, human; C412403:DIABLO protein, human; D051034:Inhibitor of Apoptosis Proteins; D047908:Intracellular Signaling Peptides and Proteins; D024101:Mitochondrial Proteins; D009363:Neoplasm Proteins; D019151:Peptide Library; D010455:Peptides