Lectin soybean agglutinin: measurements in colonic epithelial cells of human subjects following supplemental dietary calcium

A biomarker of cell differentiation was analyzed in normal and abnormal colonic epithelial cells. Soybean agglutinin (SBA) lectin which binds to specific carbohydrate residues was studied in normal human colonic epithelial cells, in epithelial cells in transitional colonic mucosa adjacent to carcinomas, and in colonic carcinomas. Findings revealed that increased SBA binding occurred maximally in normal, well-differentiated colonic epithelial cells, and least in colonic carcinomas. Further quantitation of SBA lectin binding also was carried out before and after supplemental dietary calcium. Findings revealed that in subjects whose colonic crypt biopsies had normal SBA lectin binding before calcium supplementation, SBA remained unchanged after calcium supplementation. However, in subjects whose biopsies initially had reduced SBA binding, the SBA increased after calcium and became more characteristic of that observed in normal colonic epithelium. In subjects receiving calcium for less than 3 months, the increased SBA was not statistically significant; but when subjects received calcium for durations of 3 months or longer SBA lectin binding was significantly increased, changing towards that observed in normal mucosa containing greater numbers of well-differentiated colonic epithelial cells.