Abstract

TIn this preliminary study the carbohydrate-binding activity of 10 plant lectins from the Diocleinae subtribe Canavalia ensiformis (Con A), Canavalia brasiliensis (Con Br), Canavalia bonariensis (Con Bo), Canavalia grandiflora (Con Gr), Canavalia maritima (Con M), Dioclea grandiflora (DGL), Dioclea guianensis (Dgui), Dioclea virgata (Dvir), Dioclea violacea (Dvio) and Dioclea rostrata (Dros) was studied to determine their capacity to differentiate human colon carcinoma cell variants with respect to cell membrane glyco-receptors. Flow cytometry and confocal microscopy were used to identify the interactions between PITC-labeled lectin and cells. The lectins interacted with cells assayed in a dose-dependent manner. In addition, the fluorescence spectra of Con Bo clearly differentiated the EB3 cells. Furthermore, confocal microscopy showed that Con Bo and Dvio seem to bind greatest to cell variants 8W. These preliminary data suggest a possible use of Diocleinae lectins as tools to identify quantitative and qualitative alterations in membrane glycoproteins during the oncogenic process, facilitating the diagnosis and improving the treatment. However, further experiments involving the use of appropriate controls are in progress.

Key words: Diocleinae lectins, colon carcinoma cells, protein-carbohydrate interactions.