The molecular interaction of a copper chelate with human P-glycoprotein

• Published in: Molecular and cellular biochemistry 2012-05, Vol.364 (1-2), p.309-320
• Main Authors: Ghosh, Ruma Dey, Chakraborty, Paramita, Banerjee, Kaushik, Adhikary, Arghya, Sarkar, Avijit, Chatterjee, Mitali, Das, Tanya, Choudhuri, Soumitra Kumar
• Format: Article
• Language: English
• Subjects: Adenosine triphosphatase; Adenosine Triphosphatases - metabolism; Animals; Anthracyclines; ATP Binding Cassette Transporter, Sub-Family B; ATP-Binding Cassette, Sub-Family B, Member 1 - biosynthesis; ATP-Binding Cassette, Sub-Family B, Member 1 - genetics; ATP-Binding Cassette, Sub-Family B, Member 1 - metabolism; Biochemistry; Biomedical and Life Sciences; Cardiology; Cell Line; Chelating Agents - chemistry; Chelating Agents - pharmacology; Chromophores; Copper; Copper compounds; Doxorubicin - pharmacology; Drug interactions; Drug resistance; Fibroblasts - metabolism; Gene expression; Glycine - analogs & derivatives; Glycine - chemistry; Glycine - pharmacology; Glycoproteins; Hormones, Sex; Humans; Immunoglobulins; Life Sciences; Medical Biochemistry; Mice; Molecular biology; Monoclonal antibodies; Oncology; Organometallic Compounds - chemistry; Organometallic Compounds - pharmacology; RNA; Toy industry
• ISSN: 0300-8177; 1573-4919
• DOI: 10.1007/s11010-012-1232-z

One of the major reasons for multidrug resistance (MDR) in cancer is the overexpression of P-glycoprotein (P-gp, ABCB1), a drug efflux pump. A novel copper complex, namely, copper (II) N-(2-hydroxyacetophenone) glycinate (CuNG) previously synthesized and characterized by the authors had been tested in this study. In a cell-based assay system with human MDR1 cDNA overexpressed mouse fibroblast NIH MDR1-G185 cell line, we demonstrated that this metal complex can directly interact with this transporter. As CuNG increased cellular accumulation of doxorubicin in P-gp-expressing cells, we presumed that of CuNG may be potential to reverse P-gp-mediated drug resistance probably by lowering the P-gp expression at the protein as well as mRNA level. Interestingly, our studies on UIC2 (a conformation sensitive monoclonal antibody) binding assay indicated the direct interaction of CuNG with P-gp. However, CuNG did not compete for the substrate binding as photoaffinity labeling of P-gp with a substrate analog [ 125 I] iodoarylazidoprazosin ([ 125 I] IAAP) showed approximately twofold increase in [ 125 I] IAAP binding in presence of CuNG. In vitro study showed that CuNG significantly stimulated P-gp-specific ATPase activity in isolated membrane preparations from NIH MDR1-G185 cells. This result further confirmed the CuNG–P-gp direct interaction. This study also demonstrated that CuNG has a drug interaction site different from verapamil-, vinblastine- and progesterone-binding sites on P-gp. Taken together, this is the first report of molecular interaction of any Schiff’s base metal chelate CuNG with human P-gp. This information may be useful to design more efficacious nontoxic metal-based drugs as MDR-reversing agents.