title: Regulation of ciprofloxacin uptake in human promyelocytic leukemia cells and polymorphonuclear leukocytes.
abstract: Polymorphonuclear leukocytes (PMNs) actively internalize ciprofloxacin, a capability that can enhance killing of intracellular bacteria and facilitate delivery of the antimicrobial agent to infection sites by migrating PMNs. In this study we investigated mechanisms for up-regulation of this process. Activation with N-formyl-methionyl-leucyl-phenylalanine (fMLP; 100 nM) enhanced PMN ciprofloxacin uptake by 50% (P < 0.05). Phorbol myristate acetate (PMA; > or = 10 nM) enhanced uptake by at least 36-fold, mainly by stimulating an increase in the Vmax of the ciprofloxacin transporter. This effect of PMA was inhibited by antagonists of protein kinase C (H7 and chelerythrine) and the mitogen-activated protein kinase cascade downstream (PD 098059). Under resting and PMA-activated conditions, ciprofloxacin uptake by immature human promyelocytic leukemia (HL-60) cells was much lower than in PMNs. However, when HL-60 cells were induced to mature into PMN-like cells, their ciprofloxacin uptake activity increased markedly. These findings implicate a role for protein kinase C in up-regulation of the ciprofloxacin transporter and suggest that myeloid cells acquire an enhanced ability to take up ciprofloxacin as they mature to end-stage PMNs.
authors.affiliation: Section of Periodontology, College of Dentistry, The Ohio State University Health Sciences Center, Columbus 43210, USA.
authors.forename: K C
authors.initials: KC
authors.lastname: Loo
authors.forename: A C
authors.initials: AC
authors.lastname: Cario
authors.forename: F
authors.initials: F
authors.lastname: Zhang
authors.forename: J D
authors.initials: JD
authors.lastname: Walters
mesh_terms: D000890:Anti-Infective Agents / Q000097:blood / Q000493:pharmacokinetics*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D002478:Cells, Cultured; D002939:Ciprofloxacin / Q000097:blood / Q000493:pharmacokinetics*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005419:Flavonoids / Q000494:pharmacology; D018922:HL-60 Cells / Q000201:enzymology / Q000378:metabolism*; D006801:Humans; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D018375:Neutrophil Activation / Q000187:drug effects; D009504:Neutrophils / Q000201:enzymology / Q000378:metabolism*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: D000890:Anti-Infective Agents; D004791:Enzyme Inhibitors; D005419:Flavonoids; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002939:Ciprofloxacin; D011493:Protein Kinase C; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one