Multiple pathways for fluoroquinolone secretion by human intestinal epithelial (Caco‐2) cells

Abstract

upon Tyne NE2 4HH1 Human intestinal epithelial Caco-2 cells, T84 cells, and MDCKII cells transfected with human MDR1, were used to investigate the mechanistic basis of transintestinal¯uoroquinolone secretion. 2 The¯uoroquinolone grepa¯oxacin was secreted across Caco-2 monolayers by a saturable process (V max =16.9+3.4 nmol.cm 72 .h 71 ). Net secretion was reduced by 2-deoxyglucose/azide treatment to reduce intracellular ATP. 3 Grepa¯oxacin inhibited [ 14 C]-cipro¯oxacin (100 mM) secretion across Caco-2 monolayers (K 0.5 =0.8 mM), and concurrently increased the cellular accumulation of cipro¯oxacin from the basal medium, indicating inhibition of export across the apical membrane. 4 The unconjugated bile acid, cholic acid, was secreted across Caco-2 monolayers, and this secretion was sensitive to inhibition by the MRP-selective inhibitor MK-571, suggesting MRP2 involvement. Secretion of cholic acid (10 mM) across the apical membrane was also inhibited by grepa¯oxacin (K 0.5 =0.3 mM), but not by cipro¯oxacin. 5 In MDCKII-MDR1 monolayers, net secretion of grepa¯oxacin was increased by 3.5 fold compared with untransfected controls. Neither cipro¯oxacin nor cholic acid showed net secretion in either MDCKII or MDCKII-MDR1 monolayers, showing that in contrast to grepa¯oxacin, neither are substrates for MDR1. 6 In T84 monolayers, which express MDR1 but not MRP2, neither cipro¯oxacin nor cholic acid was secreted, whilst the V max for grepa¯oxacin secretion was lower than in Caco-2 cells, which express both MDR1 and MRP2. 7 In conclusion, the transepithelial secretion of grepa¯oxacin is mediated by both MRP2 and MDR1, whereas cipro¯oxacin is a substrate for neither. Grepa¯oxacin also competes for the cipro¯oxacin-sensitive pathway, which remains to be elucidated.

Active Efflux of Ciprofloxacin from J774 Macrophages through an MRP-Like Transporter

“…Conversely, the data presented here unambiguously show that P-gp is not involved in ciprofloxacin efflux, even though J774 macrophages express a functional P-gp that acts on azithromycin (46). A similar conclusion was reached concerning the transport of ciprofloxacin in MDR1 (P-gp)-transfected MDCK-II epithelial cells (29). Interestingly enough, the closely related fluoroquinolone grepafloxacin was found to be a substrate of both P-gp and MRP2 in these cells and to compete for the ciprofloxacinsensitive pathway.…”

Intestinal Ciprofloxacin Efflux: The Role of Breast Cancer Resistance Protein (ABCG2)

“…Previous studies have highlighted the importance of active efflux transporters in the secretion of ciprofloxacin and other fluoroquinolones into the intestinal lumen (Cavet et al, 1997;Lowes and Simmons, 2002), a clinically important route for elimination (Sörgel et al, 1989(Sörgel et al, , 1991. We have confirmed that murine bcrp1 mediates active efflux of ciprofloxacin across the apical membrane of bcrp1-overexpressing MDCKII cell monolayers, which showed a significant increase in secretion relative to that of wild-type cells .…”

“…The pharmacological specificity for Ko143 inhibition of ciprofloxacin secretion indicated by the present data, combined with the segmental distribution of ciprofloxacin secretion and BCRP mRNA expression suggests that, at least in rodent intestine, ciprofloxacin secretion is mediated primarily by BCRP. Previous reports have discounted the involvement of MDR1 and MRP2 in ciprofloxacin secretion (Lowes and Simmons, 2002;Marquez et al, 2009) and the present study has confirmed no involvement of MDR1 in the rat ileum.…”

“…Measurements of basolateral and apical transport suggested the existence of distinct transporters at either membrane domain (Griffiths et al, 1994) although transport characteristics were distinct from those of vinblastine, a known P-glycoprotein (P-gp) substrate (Cavet et al, 1997). Lowes and Simmons (2002) confirmed the lack of involvement of MDR1 in ciprofloxacin secretion using wild-type and MDR1-transfected MDCKII cells. In addition, Merino et al (2006) have shown ciprofloxacin secretion using murine bcrp1-transfected MDCKII epithelial layers, whereas in human BCRPtransfected MDCKII cells ciprofloxacin secretion was evident only at extended incubation times.…”

The ATP-Binding Cassette Transporters and Their Implication in Drug Disposition: A Special Look at the Heart

“…The tissue/plasma concentration ratio was significantly higher in several tissues of mrp1 Ϫ/Ϫ mice such as the heart compared with wild-type animals, which was not the case for mdr1a Ϫ/Ϫ and mdr1a/1b Ϫ/Ϫ mice. This latter finding is surprising considering that grepafloxacin is a well-recognized substrate of P-gp (Tamai et al, 2000;Naruhashi et al, 2001;Lowes and Simmons, 2002). This interesting observation suggested that mrp1 makes a significant contribution to the distribution of its substrates in several tissues including the heart (Sasabe et al, 2004).…”