title: Targetable HPMA copolymer-adriamycin conjugates. Recognition, internalization, and subcellular fate.
abstract: Recognition, internalization, and subcellular trafficking of N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer conjugates containing N-acylated galactosamine (GalN) or monoclonal OV-TL16 antibodies (Ab) have been investigated in human hepatocarcinoma HepG2 and ovarian carcinoma OVCAR-3 cells, respectively. The intrinsic fluorescence of fluorescein or adriamycin (ADR) attached to HPMA copolymers permitted us to follow the subcellular fate of HPMA copolymer conjugates by confocal fluorescence microscopy and fluorescence spectroscopy. The pattern of fluorescence during incubation of HPMA copolymer-ADR-GalN conjugate containing lysosomally degradable tetrapeptide (GFLG) side-chains with HepG2 cells was consistent with conjugate recognition, internalization, localization in lysosomes, followed by the release of ADR from the polymer chains and ultimately diffusion via the cytoplasm into the cell nuclei. A similar pattern was observed in OVCAR-3 cells for Ab targeted HPMA copolymer conjugates. To test our hypothesis that HPMA-copolymer-bound anticancer drugs will be inaccessible to the energy-driven P-glycoprotein efflux pump in multidrug resistant (MDR) cells, we have compared the internalization of the HPMA copolymer-ADR conjugates by sensitive (A2780) and ADR-resistant (A2780/AD) ovarian carcinoma cell lines. Preliminary data on relative retention of ADR in MDR (A2780/AD) cells indicate a higher intracellular ADR concentration after incubation with HPMA copolymer-ADR conjugate when compared to incubation with free (unbound) ADR.
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City 84112, USA.
authors.forename: V
authors.initials: V
authors.lastname: Omelyanenko
authors.forename: P
authors.initials: P
authors.lastname: Kopecková
authors.forename: C
authors.initials: C
authors.lastname: Gentry
authors.forename: J
authors.initials: J
authors.lastname: Kopecek
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism; D000215:Acylation; D000595:Amino Acid Sequence; D000818:Animals; D004317:Doxorubicin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism; D004337:Drug Carriers; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D004705:Endocytosis; D005688:Galactosamine / Q000378:metabolism; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D015394:Molecular Structure; D011109:Polymethacrylic Acids / Q000008:administration & dosage* / Q000138:chemical synthesis / Q000378:metabolism; D013050:Spectrometry, Fluorescence; D013347:Subcellular Fractions / Q000378:metabolism*; D014407:Tumor Cells, Cultured
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D004337:Drug Carriers; D011109:Polymethacrylic Acids; C055176:doxorubicin-N-(2-hydroxypropyl)methacrylamide copolymer conjugate; D005688:Galactosamine; D004317:Doxorubicin