ABCMdb

PMID: 22115866

Telbisz A, Hegedus C, Ozvegy-Laczka C, Goda K, Varady G, Takats Z, Szabo E, Sorrentino BP, Varadi A, Sarkadi B
Antibody binding shift assay for rapid screening of drug interactions with the human ABCG2 multidrug transporter.
Eur J Pharm Sci. 2012 Jan 23;45(1-2):101-9. Epub 2011 Nov 17., [PubMed]

Sentences

No. Mutations Sentence Comment

18 ABCG2 p.Arg482Gly ABCG2 p.Arg482Met The mutants, containing R482G, T (or R482M or S in the mouse Abcg2), showed altered substrate specificities. Login to comment 57 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly Cytotoxicity assays Cytotoxicity assays were performed using PLB cells expressing the wild-type or the mutant (R482G, R482T) ABCG2 proteins. Login to comment 64 ABCG2 p.Arg482Gly Measurement of imatinib accumulation by HPLC-MS Imatinib accumulation was measured in intact parental and wild-type or R482G mutant ABCG2 expressing PLB cells. Login to comment 133 ABCG2 p.Arg482Thr In cytotoxicity assays VX710 (biricodar) showed higher reversing effect in cell lines expressing the wild type than the R482T variant of ABCG2 (Minderman et al., 2004). Login to comment 134 ABCG2 p.Arg482Thr GF120918 (elacridar), strongly inhibited the ATPase activity of the wild type ABCG2 in Sf9 membranes, whereas the same compound rather stimulated this activity in the case of the R482T mutant (Ahmed-Belkacem et al., 2005). Login to comment 135 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly Therefore, in the next set of experiments, we performed comparative studies for several compounds by using isolated membranes for measuring their modulation of ABCG2 ATPase activity and intact cells expressing the wild type or mutant (R482G and R482T) ABCG2 variants for antibody binding studies. Login to comment 140 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly In contrast, elacridar greatly stimulated the ATPase activities of both ABCG2-R482G and ABCG2-R482T. Login to comment 143 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly Namely, while this compound inhibited the ATPase activity of the wild type protein, it exerted an ATPase stimulatory effect on ABCG2-R482G and ABCG2-R482T (Fig. 3E). Login to comment 148 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly Concentration-dependent modulation of the ATPase activity and 5D3 immunoreactivity of the wild type (j), R482G (d) and R482T (.) Login to comment 155 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly These types of drugs seem to be mutant selective, they can be potent inhibitors of the wild type ABCG2 while still be transported efficiently by ABCG2-R482G and ABCG2-R482T mutants in the same concentration range. Login to comment 157 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly PLB/ABCG2-wild-type, PLB/ABCG2-R482G and PLB/ABCG2-R482T cells were treated with the cytotoxic topoisomerase inhibitor compounds, topotecan and mitoxantrone. Login to comment 166 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly Both in the case of mitoxantrone (Fig. 4A) and topotecan (Fig. 4B), much higher concentrations of elacridar were required to produce a 50% decrease of the IC50 values measured in PLB/ ABCG2-R482G or PLB/ABCG2-R482T cells than in PLB/ABCG2- wild-type cells. Login to comment 167 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly These results confirm that ABCG2-R482G and ABCG2-R482T have decreased sensitivity to the ABCG2 inhibitor drug elacridar, as compared to that of the wild type protein. Login to comment 170 ABCG2 p.Arg482Gly ABCG2 p.Arg482Gly Detailed examination of imatinib accumulation in PLB/ABCG2-wild-type and PLB/ABCG2-R482G at different imatinib concentrations revealed that the R482G variant can lower the accumulation of imatinib with significantly higher capacity, than the wild-type ABCG2 (at similar expression level). Login to comment 171 ABCG2 p.Arg482Gly These data confirm that although imatinib is a transported substrate at low nanomolar concentrations of both ABCG2-types, when imatinib is applied at higher doses (0.2-1 lM), it is not as effectively extruded by wild-type ABCG2 than by the R482G variant. Login to comment 174 ABCG2 p.Arg482Thr ABCG2 p.Arg482Gly Reversal of (A) mitoxantrone and (B) topotecan resistance by elacridar in PLB/ABCG2-wild-type (j), PLB/ABCG2-R482G (d) and PLB/ABCG2-R482T (.) Login to comment 181 ABCG2 p.Arg482Gly Effect of the wild type ABCG2 (j) and the ABCG2/R482G (d) proteins on the intracellular accumulation of imatinib in the absence (-) or in the presence (---) of 1 lM Ko143. Login to comment 185 ABCG2 p.Arg482Gly The star denotes statistically significant difference (95% confidence interval) between imatinib accumulation measured in PLB/ABCG2-wild-type and PLB/ ABCG2-R482G cells. Login to comment