title: Synthesis and characterization of macromolecular rhodamine tethers and their interactions with P-glycoprotein.
abstract: Rhodamine dyes are well-known P-glycoprotein (P-gp) substrates that have played an important role in the detection of inhibitors and other substrates of P-gp, as well as in the understanding of P-gp function. Macromolecular conjugates of rhodamines could prove useful as tethers for further probing of P-gp structure and function. Two macromolecular derivatives of rhodamine, methoxypolyethylene glycol-rhodamine6G and methoxypolyethylene glycol-rhodamine123, were synthesized through the 2'-position of rhodamine6G and rhodamine123, thoroughly characterized, and then evaluated by inhibition with verapamil for their ability to interact with P-gp and to act as efflux substrates. To put the results into context, the P-gp interactions of the new conjugates were compared to the commercially available methoxypolyethylene glycol-rhodamineB. FACS analysis confirmed that macromolecular tethers of rhodamine6G, rhodamine123, and rhodamineB were accumulated in P-gp expressing cells 5.2 ± 0.3%, 26.2 ± 4%, and 64.2 ± 6%, respectively, compared to a sensitive cell line that does not overexpress P-gp. Along with confocal imaging, the efflux analysis confirmed that the macromolecular rhodamine tethers remain P-gp substrates. These results open potential avenues for new ways to probe the function of P-gp both in vitro and in vivo.
authors: School of Chemical and Biomolecular Engineering and ‡Department of Biomedical Engineering, Cornell University , Ithaca, New York 14853, United States.
authors: Lindsey
authors: L
authors: Crawford
authors: David
authors: D
authors: Putnam
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000378:metabolism*; D045744:Cell Line, Tumor; D060326:Chemistry Techniques, Synthetic; D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D011092:Polyethylene Glycols / Q000737:chemistry; D011485:Protein Binding; D020112:Rhodamine 123 / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*; D012235:Rhodamines / Q000138:chemical synthesis* / Q000737:chemistry / Q000378:metabolism*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D005456:Fluorescent Dyes; D012235:Rhodamines; C026188:rhodamine 6G; D020112:Rhodamine 123; D011092:Polyethylene Glycols; C028210:monomethoxypolyethylene glycol