Transport properties of the multidrug resistance‐associated protein (MRP) in human tumour cells

FEBS Letters

Homolya, László¹  Hegedüs, Tamás¹  Sarkadi, Balázs¹  Holló, Zsolt¹ 

[1] National Institute of Haematology and Immunology, Daróczi u. 24, H-1113 Budapest, Hungary

关键词: Multidrug resistance-associated protein;    Multidrug-resistance protein;    P-glycoprotein;    Drug resistance;    Calcein;    Fluorometry;    Immunoblotting;    Transport assay;    ADR;    adriamycin (doxorubicin);    AM;    acetoxymethylester;    CCCP;    chlorocarbonyl cyanide phenylhydrazone;    2;    4-DNP;    2;    4-dinitrophenol;    DMEM;    Dulbecco's modified Eagle's medium;    FCS;    fetal calf serum;    GSH;    reduced glutathione;    MDR1;    multidrug-resistance protein;    MRP;    multidrug resistance-associated protein;    NEM;    N-ethylmaleimide;    NPM;    N-pyrenemaleimide;    PGA1;    prostaglandin A1;    PVDF;    polyvinylidene difluoride;    VBL;    vinblastine;   

DOI  :  10.1016/0014-5793(96)00237-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

In this paper we demonstrate that the expression of the multidrug resistance-associated protein (MRP) in a variety of intact human tumour cells results in the ATP-dependent, mutually exclusive extrusion of both the acetoxymethyl ester and the free anion forms of the fluorescent dye calcein, as well as that of a fluorescent pyrenemaleimide-glutathione conjugate. The MRP-dependent transport of all these three model compounds closely correlates with the expression level of MRP and is cross-inhibited by hydrophobic anticancer drugs, by reversing agents for MDR1, and also by compounds not influencing MDR1, such as hydrophobic anions, alkylating agents, and inhibitors of organic anion transporters. Cellular glutathione depletion affects neither the MRP-dependent extrusion of calcein AM or free calcein, nor its modulation by most hydrophobic or anionic compounds, although eliminating the cross-inhibitory effect of glutathione conjugates. These results suggest that the outward pumping of both hydrophobic uncharged and water-soluble anionic compounds, including glutathione conjugates, is an inherent property of MRP, and offer sensitive methods for the functional diagnostics of this transport protein as well as for the rapid screening of drug-resistance modulating agents.

【 授权许可】

Unknown