LECTIN-MEDIATED BIOADHESION - BINDING CHARACTERISTICS OF PLANT-LECTINS ON THE ENTEROCYTE-LIKE CELL-LINES CACO-2, HT-29 AND HCT-8

In order to take advantage of the biorecognition between lectins and s pecific carbohydrates for targeted drug delivery, fluorescein-labelled lectins of different carbohydrate specificities were screened for bin ding to human colorectal carcinoma cell lines by flow cytometry and co nfocal microscopy. The lectin-binding rate increased as follows: Dolic hos biflorus agglutinin, DBA<peanut agglutinin, PNA<Lens culinaris agg lutinin, LCA<Solanum tuberosum lectin, STL<Ulex europaeus isoagglutini n I, UEA-I<wheat germ agglutinin, WGA (Caco-2); PNA<UEA-I<WGA (HT-29); DBA<UEA-I< WGA (HCT-8), thus reflecting the glycosylation pattern of the cells. Compared to the BSA-binding capacity of the cells, the exte nt of nonspecific binding was strongly dependent on the type of cell l ine and lectin under investigation being lower than 2% in the case of WGA, STL and UEA-I/Caco-2 and HT-29 cells. Whereas 50% of DBA was boun d nonspecifically to Caco-2 cells, the interactions DBA/HCT-8 and PNA/ HT-29 were due to nonspecific binding. By competitive inhibition of le ctin-adhesion to the cells upon addition of the complementary carbohyd rate, specificity of lectin-binding was confirmed except for the inter action of DBA/HCT-8 and PNA/HT-29. Following on from this work, we con sider WGA-, STL- and UEA-I-mediated drug delivery to be a promising ap proach for peroral bioadhesive formulations adhering to absorptive ent erocytes. (C) 1998 Elsevier Science B.V. All rights reserved.