title: Vincristine-induced overexpression of P-glycoprotein in L1210 cells is associated with remodeling of cell surface saccharides.
abstract: Multidrug resistance of murine leukemic cell line L1210/VCR (R), obtained by adaptation of parental L1210 cells (S) on vincristine, is associated with overexpression of P glycoprotein (P-gp, the ATP-dependent drug efflux pump). Previously, we found that cytochemical staining of negatively charged cell surface binding sites (probably sialic acid) by ruthenium red (RR) revealed a compact layer of RR bound to the external coat of S cells. This is in contrast to R cells and L1210/VCR cells cultured in the presence of vincristine during the last cultivation prior to the experiment (V cells), where the RR layer was either reduced or absent. In the current paper, we observed differences in the interactions of S, R and V cells with Concanavalin A (ConA) and tomato lectin (lycopersicum esculentum agglutinin, LEA). ConA bound and induced cell damage more effectively in S cells than in R or V cells. Both of these effects could be prevented by methyl-manopyranose, but not by N-acetylglucosamine. In contrast, LEA lectin preferentially bound to R and V cells. While LEA agglutinated cells more effectively than ConA, it did not cause cell damage comparable to ConA. Binding of LEA to the cell surface could be prevented by chitooligosaccharides. Both LEA and ConA failed to identify P-gp in lectin blots. Thus, changes in ConA and LEA interactions are not caused by massive expression of P-gp in the plasma membrane and the consequent exposure of the inner saccharides to the external side of the plasma membrane.Taken together, the above facts suggest that S cells differ from R and V cells in the composition of cell surface glycosides not directly linked to P-gp.
authors.affiliation: Institute of Molecular Physiology and Genetics, Centre of Excellence of the Slovak Research and Development Agency, BIOMEMBRANES2008, Slovak Academy of Sciences, Bratislava, Slovakia.
authors.forename: Zdenka
authors.initials: Z
authors.lastname: Sulová
authors.forename: Danica
authors.initials: D
authors.lastname: Mislovicová
authors.forename: Lenka
authors.initials: L
authors.lastname: Gibalová
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Vajcnerová
authors.forename: Eva
authors.initials: E
authors.lastname: Poláková
authors.forename: Branislav
authors.initials: B
authors.lastname: Uhrík
authors.forename: Lucia
authors.initials: L
authors.lastname: Tylková
authors.forename: Annámaria
authors.initials: A
authors.lastname: Kovarova
authors.forename: Ján
authors.initials: J
authors.lastname: Sedlák
authors.forename: Albert
authors.initials: A
authors.lastname: Breier
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D000818:Animals; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D045744:Cell Line, Tumor / Q000187:drug effects*; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism / Q000648:ultrastructure; D002470:Cell Survival; D003208:Concanavalin A / Q000378:metabolism; D018432:Drug Resistance, Multiple / Q000187:drug effects; D051379:Mice; D037121:Plant Lectins / Q000378:metabolism; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism; D014750:Vincristine / Q000494:pharmacology*
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000972:Antineoplastic Agents, Phytogenic; D037121:Plant Lectins; D011134:Polysaccharides; C034981:tomato lectin; D003208:Concanavalin A; D014750:Vincristine