RT Journal Article SR Electronic T1 The Presence of P-glycoprotein in L1210 Cells Directly Induces Down-Regulation of Cell Surface Saccharide Targets of Concanavalin A JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 3661 OP 3668 VO 30 IS 9 A1 ZDENA SULOVÁ A1 PETER DITTE A1 TATIANA KURUCOVÁ A1 EVA POLÁKOVÁ A1 KRISTÍNA ROGOZANOVÁ A1 LENKA GIBALOVÁ A1 MÁRIO ŠEREŠ A1 LUCIA ŠKVARKOVÁ A1 JÁN SEDLÁK A1 JAROMÍR PASTOREK A1 ALBERT BREIER YR 2010 UL http://ar.iiarjournals.org/content/30/9/3661.abstract AB Overexpression of P-glycoprotein (P-gp), a plasma membrane drug transporter (ABCB1, a member of the ABC transporter family), is the most prevalent cause of multidrug resistance in cancer tissues. Lectin concanavalin A (ConA) induces massive cell death of L1210 leukemia cells (S). Cell sublines of L1210 in which P-gp overexpression was induced by selection with vincristine (R) or by stable transfection with a plasmid encoding full-length human P-gp (T) were less sensitive to ConA. Both P-gp-positive cell lines exhibited typical P-gp-mediated multidrug resistance. Resistance of R and T cells to ConA was associated with lower binding of ConA as compared to S cells when analysed by the following methods: (i) SDS PAGE and electroblotting of proteins in the crude membrane fraction followed by detection with biotinylated ConA and avidin-peroxidase, and (ii) fluorescent cytometry or confocal microscopy of the intact cells with surfaces labeled by FITC-ConA. These data indicated that the presence of P-glycoprotein in L1210 cells independently of the mode of its expression induced down-regulation of cell surface saccharide targets of ConA. Therefore, this feature may be considered as a secondary cellular response to P-glycoprotein expression.