title: Platinum(II)-dendrimer conjugates: synthesis and investigations on cytotoxicity, cellular distribution, platinum release, DNA, and protein binding.
abstract: A set of polyamidoamine dendrimers were modified in such a way that they are able to act as carrier and drug delivery systems for cytostatics. The terminal binding of the non-proteinogenic D,L-2,3-diaminopropionic acid allowed the attachment of the cytotoxic PtX(2) moiety (X = Cl, I: A(PtI(2))(2), A(PtCl(2))(2), B(PtI(2))(2), B(PtCl(2))(2)), while the 2-carboxypentanedioic acid acted as leaving group for [meso-1,2-bis(4-fluorophenyl)ethylenediamine]platinum(II) ((m-4F-Pt)(3)C, (m-4F-Pt)(3)D). Poly(ethylene glycol) chains at C(PtI(2))(3) and C(PtCl(2))(3) as well as (m-4F-Pt)(3)C and (m-4F-Pt)(3)D mediated sufficient water solubility. Additional dansyl residues (B(PtI(2))(2) and (m-4F-Pt)(3)D) made a simultaneous determination of platinum (graphite furnace atomic absorption spectroscopy (GF-AAS)) and dendrimer (fluorimetry) possible. The ethylenediamine-terminated dendrimers were typically accumulated into MCF-7 cells in clathrin-dependent pathways and targeted the platinum moieties to the nuclear compartment. The highest intracellular platinum concentration and DNA binding caused the dendrimers A(PtX(2))(2) and B(PtX(2))(2). A coordinative DNA binding, however, is very unlikely because of low cytotoxic effects. (m-4F-Pt)(3)C and (m-4F-Pt)(3)D are labile conjugates and liberated the m-4F-Pt moiety in biological systems. The effects of these dendrimers were similar to that of the reference compounds m-4F-PtCl(2) and m-4F-Pt(H(2)O)(2).
authors.affiliation: Institute of Pharmacy, Freie Universitat Berlin, Konigin Luise Strasse 2 + 4, 14195 Berlin, Germany.
authors.forename: Timo
authors.initials: T
authors.lastname: Kapp
authors.forename: Anja
authors.initials: A
authors.lastname: Dullin
authors.forename: Ronald
authors.initials: R
authors.lastname: Gust
mesh_terms: D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology; D001692:Biological Transport; D045744:Cell Line, Tumor; D004247:DNA / Q000378:metabolism*; D050091:Dendrimers / Q000138:chemical synthesis / Q000737:chemistry*; D004337:Drug Carriers / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D010984:Platinum / Q000737:chemistry* / Q000494:pharmacology*; D011485:Protein Binding; D012709:Serum Albumin / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D050091:Dendrimers; D004337:Drug Carriers; D012709:Serum Albumin; D010984:Platinum; D004247:DNA