title: Synthesis, characterization, and metabolic stability of porphyrin-peptide conjugates bearing bifunctional signaling sequences.
abstract: A series of four porphyrin-peptide conjugates bearing one linear bifunctional sequence containing a cell penetrating peptide (CPP) and a nuclear localization signal (NLS) were synthesized and their in vitro biological and stability properties investigated. All conjugates accumulated within human HEp2 cells to a significantly higher extent than their porphyrin-PEG precursor, and the extent of their uptake and cytotoxicity depends on the nature and sequence of the amino acids. Conjugates 2 and 5 bearing a NLS-CPP accumulated the most within cells and were the most phototoxic (IC50 approximately 7 microM at 1 J/cm2). All conjugates localized preferentially within the cell lysosomes, and in addition, conjugate 2 was also found in the ER. All conjugates were highly stable under nonenzymatic conditions, but their peptide sequences were cleaved to some extent (ca. 50% after 24 h) by proteolytic enzymes, such as cathepsin B, cathepsin D, prolidase, and plasmin.
authors.affiliation: Department of Chemistry, Louisiana State University, Baton Rouge, LA 70803, USA.
authors.forename: Martha
authors.initials: M
authors.lastname: Sibrian-Vazquez
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Jensen
authors.forename: M Graça H
authors.initials: MG
authors.lastname: Vicente
mesh_terms: D002460:Cell Line; D045744:Cell Line, Tumor; D002942:Circular Dichroism; D006801:Humans; D008027:Light; D008856:Microscopy, Fluorescence; D019913:Nuclear Localization Signals; D009687:Nuclear Proteins / Q000737:chemistry; D056489:Nucleoplasmins; D009842:Oligopeptides / Q000737:chemistry; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology; D010750:Phosphoproteins / Q000737:chemistry; D017319:Photosensitizing Agents / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D011166:Porphyrins / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology; D011487:Protein Conformation; D021382:Protein Sorting Signals; D013329:Structure-Activity Relationship; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000737:chemistry
chemical_list: D019913:Nuclear Localization Signals; D009687:Nuclear Proteins; D056489:Nucleoplasmins; D009842:Oligopeptides; D010455:Peptides; D010750:Phosphoproteins; D017319:Photosensitizing Agents; D011166:Porphyrins; D021382:Protein Sorting Signals; C402304:SV40 nuclear localization peptide; D054322:tat Gene Products, Human Immunodeficiency Virus