Lectin-Mediated Binding of Engineered to Cancer Cells.

Lectins have been increasingly utilized as carriers for targeted drug delivery based on their specific binding to glycans located on mammalian cells. This study employed two lectins, B subunit of bacterial Shiga holotoxin (Stx1B) and fungal lectin (CNL), for surface display on the lactic acid bacterium . The specific adhesion of these engineered, lectin-displaying to cancer cells was evaluated. The expression and surface display of both lectins on were demonstrated by western blotting and flow cytometry, respectively. MTS assays revealed that recombinant Stx1B had no effect on Caco-2 cell viability at concentrations of ≤25 µg/mL, whereas CNL was non-toxic even at relatively high concentrations of ≤250 µg/mL. Stx1B bound to Caco-2, HT-29 and HeLa cells after 1 h of incubation. CNL bound to Caco-2 cells and recognized several glycoproteins in HT-29 and Caco-2 cell homogenates of which a 70 kDa protein predominated. Confocal microscopy revealed adhesion of Stx1B-displaying to HeLa, Caco-2, and, to a lesser extent, HT-29 cells; CNL-displaying showed a relatively similar level of adherence to HT-29 and Caco-2 cells. Thus, lectin-displaying might serve as a carrier in targeted drug delivery when coupled to a therapeutic moiety.