title: Targeting a c-Myc inhibitory polypeptide to specific intracellular compartments using cell penetrating peptides.
abstract: The therapeutic index of current anti-cancer chemotherapeutics can be improved by two major mechanisms: 1) developing drugs which are specifically toxic to the cancer cells and 2) developing methods to deliver drugs to the tumor site. In an attempt to combine these approaches, we developed a thermally responsive polypeptide inhibitor of c-Myc. This polypeptide is based on the thermally responsive Elastin-like polypeptide (ELP). When injected systemically, ELP-fused drugs will aggregate and accumulate at the tumor site where local hyperthermia is applied. ELP was fused to a peptide which blocks c-Myc/Max dimerization (H1), thereby inhibiting transcription activation by c-Myc (ELP-H1). In this study, the cellular uptake, intracellular distribution, and potency of the Pen, Tat and Bac cell penetrating peptides fused to ELP-H1 were evaluated. While Pen-ELP-H1 and Tat-ELP-H1 were localized in the cytoplasm, Bac-ELP-H1 localized to the nucleus in a subset of the cells and was the most potent inhibitor of MCF-7 cell proliferation. This data demonstrates that ELP can be targeted to the desired cellular compartment simply by choice of the CPP used, resulting in a more potent nuclear targeted c-Myc inhibitory polypeptide which may be beneficial in cancer therapy.
authors.affiliation: Department of Biochemistry, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216, USA.
authors.forename: Gene L
authors.initials: GL
authors.lastname: Bidwell
authors.forename: Aisha N
authors.initials: AN
authors.lastname: Davis
authors.forename: Drazen
authors.initials: D
authors.lastname: Raucher
mesh_terms: D000970:Antineoplastic Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics / Q000494:pharmacology; D045744:Cell Line, Tumor; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics; D005260:Female; D006801:Humans; D006979:Hyperthermia, Induced; D008856:Microscopy, Fluorescence; D009369:Neoplasms / Q000188:drug therapy / Q000378:metabolism; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics; D044367:Phase Transition; D016271:Proto-Oncogene Proteins c-myc / Q000037:antagonists & inhibitors*; D011993:Recombinant Fusion Proteins / Q000138:chemical synthesis / Q000737:chemistry* / Q000493:pharmacokinetics; D013696:Temperature; D013997:Time Factors
chemical_list: D000970:Antineoplastic Agents; D004337:Drug Carriers; C489427:MYC protein, human; D010446:Peptide Fragments; D010455:Peptides; D016271:Proto-Oncogene Proteins c-myc; D011993:Recombinant Fusion Proteins; C033943:elastin polypentapeptide