Inhibition of the P-glycoprotein- and multidrug resistance protein-mediated efflux of anthracyclines and calceinacetoxymethyl ester by PAK-104P

Multidrug resistance (MDR) in tumour cells is often caused by the overexpression of the plasma drug transporter P-glycoprotein (P-gp). This protein is an active efflux pump for chemotherapeutic drugs, natural products and hydrophobic peptides. Despite the advances of recent years, we still have an unclear view of the molecular mechanism by which P-gp transports such a wide diversity of compounds across the membrane. Measurement of the kinetic characteristics of substrate transport is a powerful approach to enhancing our understanding of their function and mechanism. The aim of the present study was to further characterize the transport of several rhodamine analogues, either positively charged or zwitterionic. We took advantage of the intrinsic fluorescence of rhodamines and performed a flow-cytometric analysis of dye accumulation in the wild-type drug sensitive K562 that do not express P-gp and its MDR subline that display high levels of MDR. The measurements were made in real time using intact cells. The kinetic parameter, k a ¼ V M /k m , which is a measure of the efficiency of the P-gp-mediated efflux of a substrate was similar for almost all the rhodamine analogues tested. In addition these values were compared with those determined previously for the P-gp-mediated efflux of anthracycline. Our conclusion is that the compounds of these two classes of molecules, anthracyclines and rhodamines, are substrates of P-gp and that their pumping rates at limiting low substrate concentration are similar. The findings presented here are the first to show quantitative information about the kinetic parameters for P-gp-mediated efflux of rhodamine analogues in intact cells.Keywords: P-glycoprotein; multidrug resistance; membrane transport; rhodamine; efflux. Since 1940, a broad variety of antibiotics active against many infectious organisms were discovered or developed. The widespread, and sometimes uncontrolled, use of these drugs has led to the emergence of defence mechanisms that, at present, are the major drawback of the drug-based treatment of infectious diseases and cancers. Such resistance is not restricted to the drugs (or analogues) used in the treatment but also involves several structurally and functionally unrelated compounds. This phenomenon, which has been termed multidrug resistance (MDR), can be caused by various mechanisms. However, over expression of the P-glycoprotein multidrug transporter (P-gp) in the plasma membrane is believed to be a major cause of resistance to multiple chemotherapeutic drugs [1][2][3][4]. P-gp is an unusual ABC protein in that it appears to be highly promiscuous: hundreds of compounds have been identified as substrates. The spectrum of MDR compounds includes a large number of anticancer drugs (e.g. anthracyclines, vinca alkaloids, taxanes) as well as steroids, fluorescent dyes, rhodamines, and the c-emitting radio pharmaceutical 99m Tc-MIBI. P-gp can transport neutral and positively charged molecules but not negatively charged ones. Despite the advances of recent years, we still h...

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“…Rh123 is also widely used as a structural marker for mitochondria as an indicator of mitochondrial activity [28][29][30].…”

Section: Discussionmentioning

confidence: 99%

New insights into the P‐glycoprotein‐mediated effluxes of rhodamines

Loetchutinat

Saengkhae

Marbeuf-Gueye

et al. 2003

European Journal of Biochemistry

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“…The P-glycoprotein transporter is a 170-kD plasma membrane glycoprotein encoded by the human multidrug resistance gene 1 (MDR1). P-glycoprotein is capable of transporting intracellular drugs out of cells to acquire drug resistance (1)(2)(3). A number of natural and synthetic substances have been tested for their ability to overcome MDR in vitro and in vivo (4).…”

Section: Introductionmentioning

confidence: 99%

Modulation of P-glycoprotein expression by triptolide in adriamycin-resistant K562/A02 cells

Hui

et al. 2011

Oncology Letters

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Abstract. Multidrug resistance is a serious obstacle encountered in leukemia treatment. Previous studies have found drug resistance in human leukemia is mainly associated with overexpression of the multidrug resistance gene 1 (MDR1). The aim of the present study was to investigate the modulation of P-glycoprotein expression by triptolide in adriamycin-resistant K562/A02 cells. The reverse effects of triptolide on drug resistance in K562/A02 cells were assessed by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium bromide (MTT) assay. The percentage of apoptotic cells was obtained from annexin V/fluorescein isothiocyanate (FITC) and propridium iodide (PI) double-staining. The effects of triptolide on P-glycoprotein activity were evaluated by measuring intracellular adriamycin accumulation. The expression of P-glycoprotein was determined by flow cytometry. A luciferase reporter gene assay was used to detect the transcriptional activity of the MDR1 promoter. Results revealed that triptolide decreased the degree of resistance of K562/A02 cells, and significantly inhibited P-glycoprotein expression and drug-transport function, and increased the accumulation of adriamycin in K562/A02 cells as measured by flow cytometry. A luciferase reporter gene assay demonstrated that triptolide was capable of inhibiting the transcriptional activity of the MDR1 promoter. Triptolide may effectively reverse the adriamycin resistance in K562/A02 cells via modulation of the P-glycoprotein expression and by increasing intracellular adriamycin accumulation.

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“…The inhibitors of PgP such as verapamil, quercetin, genistein, and cyclosporine can also suppress the transport activity of MRP1 [Barrand et al, 1993;Versantvoort et al, 1994;Hooijberg et al, 1997Hooijberg et al, , 1999bNguyen et al, 2003]. Other PgP and MRP1 dual inhibitors include the dihydropyridine PAK-104P [Marbeuf-Gueye et al, 2000], the polyhydroxylated sterol acetate agosterol A [Aoki et al, 2001], steroid analogs [Payen et al, 1999;Bandi and Kompella, 2002], and imidazothiazole derivatives [Naito et al, 1998]. The MRP1 inhibiting bioflavonoids, such as genistein, quercetin, biochanin A, and kaempferol, can also decrease the intracellular GSH levels [Versantvoort et al, 1994;Hooijberg et al, 1997Hooijberg et al, , 1999bNguyen et al, 2003].…”

Section: Mrp1mentioning

confidence: 99%

Multidrug resistance proteins (MRPs) and implication in drug development

Tian

Zhang

Chan

et al. 2005

Drug Development Research

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The multidrug resistance protein (MRP)-related ABCC family (MRP1, MRP2, MRP3, MRP4, MRP5, MRP6, MRP7, MRP8, and MRP9) belongs to the ATP-binding cassette (ABC) superfamily of transport proteins. They are capable of transporting a structurally diverse array of endo-and xenobiotics and their metabolites across cell membranes. These transporters play an important role in the absorption, disposition, and elimination of these compounds in the body. In particular, increased expression of these drug transporters in tumor cells is associated with resistance to a number of important chemotherapeutic agents. This review highlights the biochemical and pharmacological properties of MRP1-9 and their implications in drug development. A detailed study on the biochemical function and regulation of MRPs is important in drug development, as this may help to avoid drug toxicity, drug resistance, and drug-drug interactions and to optimize cancer chemotherapy. Drug Dev. Res. 64:1-18, 2005.

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Inhibition of the P-glycoprotein- and multidrug resistance protein-mediated efflux of anthracyclines and calceinacetoxymethyl ester by PAK-104P

Cited by 59 publications

References 19 publications

New insights into the P‐glycoprotein‐mediated effluxes of rhodamines

New insights into the P‐glycoprotein‐mediated effluxes of rhodamines

Modulation of P-glycoprotein expression by triptolide in adriamycin-resistant K562/A02 cells

Multidrug resistance proteins (MRPs) and implication in drug development

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