title: A sychnological cell penetrating peptide mimic of p21(WAF1/CIP1) is pro-apoptogenic.
abstract: Targeting chemotherapeutic agents directly to sites of DNA replication and repair within cancerous cells is problematic. This study attempts to address the issue of nuclear delivery of biologically active peptides with the potential to disrupt cancer cell growth. Herein, the protein transduction domain of the HIV-1 transactivator of transcription, Tat (Tat(48-60)), is used to deliver a cytotoxic peptide mimic of the cyclin-dependent kinase inhibitor, p21(WAF1/CIP1) into the nucleus. This construct, which we designate as Tat(48-60)-P10, contains the PCNA interacting protein (PIP) box. We demonstrate the utility of Tat(48-60) for peptide delivery to the nucleus and show that Tat(48-60)-P10 induces apoptosis specific to the inclusion of the wild type PIP box containing sequence. Colocalization of Tat(48-60)-P10 with nuclear PCNA was observed by immunofluorescence analysis, supporting the hypothesis that cytotoxicity is potentially related to disruption of nuclear PCNA function. The U251 and U373 glioma cell lines exhibited particular sensitivity to the construct.
authors.affiliation: Research Institute in Healthcare Science, School of Applied Sciences, University of Wolverhampton, Wolverhampton WV1 1SB, United Kingdom.
authors.forename: Rachael D
authors.initials: RD
authors.lastname: Baker
authors.forename: John
authors.initials: J
authors.lastname: Howl
authors.forename: Iain D
authors.initials: ID
authors.lastname: Nicholl
mesh_terms: D000595:Amino Acid Sequence; D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000737:chemistry*; D004305:Dose-Response Relationship, Drug; D015696:Gene Products, tat / Q000737:chemistry; D006801:Humans; D015151:Immunoblotting; D020287:In Situ Nick-End Labeling; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D011485:Protein Binding
chemical_list: D050759:Cyclin-Dependent Kinase Inhibitor p21; D015696:Gene Products, tat; D010455:Peptides; D018809:Proliferating Cell Nuclear Antigen