Lectin Binding Characteristics of Squamous Cell Carcinomas of the Head and Neck

Abstract

Lectins are polyvalent proteins of non-immune origin with exquisite carbohydrate binding specificity making them ideal for investigation of cell surface glycoprotein and glycolipid antigens. We examined the cell surface lectin binding phenotypes of 20 UM-SCC squamous cell carcinoma cell lines established from 17 patients with head and neck cancers using a panel of fluorescein-conjugated lectins and inhibition by the appropriate monosaccharide to confirm specificity of binding. Conconavalin A (Con A) from Canavalia ensiformis and the peanut agglutinin (PNA) from Arachis hypogaea bound all SCC cell lines tested and wheat germ agglutinin (WGA) from Triticum vulgaris bound to 12 of 13 tumor cell lines. the blood group O specific lectin UEA 1 from Ulex europeus also bound to all cell lines regardless of the donor blood type. Lectins of Dolichos biflorus (DBA) and Griffonia simplicifolia (GS I-B4 or BSA I-B4) with binding specificity for glycoproteins associated with blood group A and B respectively, had reactivity that did not directly correlate with blood group antigen expression. in contrast to the other lectins in our panel which exhibited broad reactivity with SCC antigens, the BSA-II lectin from Griffonia simplicfolia (GS II or BSA II) which has sugar binding specificity for terminal non-reducing GlcNAc, did not bind to any of the screened cell lines. Our results demonstrate a common pattern of lectin-defined carbohydrate expression on the cell surface of squamous cell carcinomas of head and neck that appears promising in defining the malignant cellular phenotype. Lectin binding profile may be useful in differentiating benign from malignant histopathology.

Key Words:

• cell surface glycoprotein
• fluorescein-conjugated lectins
• blood group antigens