title: Reduction of doxorubicin resistance in P-glycoprotein overexpressing cells by hybrid cell-penetrating and drug-binding peptide.
abstract: Drug efflux by the membrane transporter P-glycoprotein (P-gp) plays a key role in multidrug resistance (MDR). In order to bypass P-gp, thus overcoming MDR, a hybrid peptide comprising a cell penetrating peptide (Tat) and a drug binding motif (DBM) has been developed to noncovalently bind and deliver doxorubicin (Dox) into MDR cells. The uptake of Dox into the leukemia cell line K562 and its P-gp overexpressing subline KD30 increased in the presence of DBM-Tat peptide. Confocal microscopy indicated that DBM-Tat associated Dox was directed to a perinuclear area of KD30 cells, while this was not observed in parent K562 cells. When KD30 cells were pretreated with the endosomotropic agent chloroquine (CLQ), peptide associated Dox redistributed into the cytosol, indicating that endocytosis was the predominant uptake route. Altered drug uptake kinetics observed by cellular accumulation assay also supported an endocytic uptake. In the presence of CLQ, DBM-Tat was able to enhance the cytotoxicity of Dox by 68.4% at 5 microM peptide concentration in KD30 cells but there were only minor effects on Dox cytotoxicity in K562 cells even in the presence of CLQ. Thus, combining Dox with DBM-Tat reduces P-gp mediated drug efflux, without a requirement for drug modification or inhibiting P-gp function.
authors.affiliation: School of Pharmacy and Pharmaceutical Sciences, The University of Manchester, Stopford Building, Oxford Road, Manchester, UK. joyce.zheng@gmail.com
authors.forename: Zhaohua
authors.initials: Z
authors.lastname: Zheng
authors.forename: Harmesh
authors.initials: H
authors.lastname: Aojula
authors.forename: David
authors.initials: D
authors.lastname: Clarke
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis*; D000903:Antibiotics, Antineoplastic / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004317:Doxorubicin / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000494:pharmacology*; D004337:Drug Carriers / Q000737:chemistry*; D018432:Drug Resistance, Multiple / Q000187:drug effects*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D005434:Flow Cytometry; D006801:Humans; D020014:K562 Cells; D018613:Microscopy, Confocal; D010446:Peptide Fragments / Q000737:chemistry*; D010539:Permeability; D012995:Solubility; D013050:Spectrometry, Fluorescence; D054322:tat Gene Products, Human Immunodeficiency Virus / Q000737:chemistry*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000903:Antibiotics, Antineoplastic; D004337:Drug Carriers; D010446:Peptide Fragments; D054322:tat Gene Products, Human Immunodeficiency Virus; C490722:tat peptide (49-57), Human immunodeficiency virus 1; D004317:Doxorubicin