The Interaction between wheat germ agglutinin and other plant lectins withprostate cancer cells Du-145

The bioadhesive properties of fluorescein-labeled plant lectins with differ ent carbohydrate specificities were investigated by flow cytometry at 4 and 37 degreesC using Du-145 prostate cancer cells. At both temperatures the l ectin association rate increased following the order: Dolichos biflorus agg lutinin (DBA) < peanut agglutinin < Ulex europaeus isoagglutinin I < Lens c ulinaris agglutinin < Solanum tuberosum lectin much less than wheat germ ag glutinin (WGA), reflecting the glycosylation pattern of Du-145 cells. Both, the BSA-binding capacity of the cells referring to nonspecific binding and inhibition studies using the complementary carbohydrate, assured specifici ty of the lectin-cell interactions except for DBA. The WGA-association rate of Du-145 cells was dependent on temperature indicative for cellular uptak e of membrane-bound WGA. Intracellular enrichment of WGA was confirmed by c onfocal microscopy. As resulted from experiments in presence of ouabain act ive transport mechanisms were involved in cellular uptake of WGA. Equilibra tion of the intracellular pH with monensin pointed to accumulation of intra cellular located WGA within acidic compartments of Du-145 cells such as the lysosomes or the trans-Golgi complex. Consequently the interaction of WGA with Du-145 cells at 37 degreesC is a one way process due to immediate acti ve transport of membrane-bound lectin into acidic compartments of prostate cancer cells. (C) 2001 Elsevier Science B.V. All rights reserved.