title: Binding of vinblastine and estramustine to isolated plasma membrane fractions from human prostate and prostatic tumors.
abstract: The binding of vinblastine (VLB) and estramustine (EM) to plasma membranes isolated from human prostate, prostatic tumors as well as from Dunning rat prostatic AT-1 tumors was studied. In addition, the uptake of these drugs in AT-1 tumor cells in culture was examined. Binding of VLB was six-fold lower than that of EM in membrane preparations from all three sources. The uptake of VLB in the intact AT-1 cells was nearly five-fold lower than that of EM. At concentrations comparable to those achieved clinically the binding of EM was 100-fold higher than that of VLB. The data suggest that, owing to a very high membrane concentration of EM relative to that of VLB, the active efflux VLB in drug resistant cells would be impeded. This in turn would lead to a higher accumulation of VLB in cells that actively transport cytotoxic drugs.
authors.affiliation: Department of Obstetrics and Gynecology, University Hospital Lund, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Batra
authors.forename: I
authors.initials: I
authors.lastname: Larsson
mesh_terms: D000818:Animals; D018906:Antineoplastic Agents, Alkylating / Q000378:metabolism*; D000972:Antineoplastic Agents, Phytogenic / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004961:Estramustine / Q000378:metabolism*; D006801:Humans; D008297:Male; D011467:Prostate / Q000378:metabolism*; D011471:Prostatic Neoplasms / Q000378:metabolism*; D051381:Rats; D014407:Tumor Cells, Cultured; D014747:Vinblastine / Q000378:metabolism*
chemical_list: D018906:Antineoplastic Agents, Alkylating; D000972:Antineoplastic Agents, Phytogenic; D004961:Estramustine; D014747:Vinblastine