Ohannesian D W, Lotan D, Thomas P, Jessup J M, Fukuda M, Gabius H J, Lotan R
Department of Tumor Biology, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA.
Cancer Res. 1995 May 15;55(10):2191-9.
Galectin-1 and galectin-3, galactoside-binding lectins with molecular weights of M(r) 14,500 and 31,000, respectively, are expressed in normal and malignant cells and have been implicated in regulation of cell growth, adhesion, and metastasis. We analyzed the expression of galectins in 21 cultured human colon carcinoma cell lines by immunoblotting. Galectin-1 was detected in only 7, whereas galectin-3 was found in 20 of the cell lines. KM12 cells, which express only galectin-3, were used to isolate this lectin by affinity chromatography, and the purified lectin was used to identify complementary glycoconjugates by blotting. Galectin-3 was shown to bind to human laminin, carcinoembryonic antigen, and lysosome-associated membrane glycoproteins, which are involved in cell adhesion. Galectin-3 was localized on the KM12 cell surface and colocalized with carcinoembryonic antigen. Several endogenous glycoproteins and cell surface proteins of molecular weights in the range M(r) 58,000 to > 200,000, including carcinoembryonic antigen and lysosome-associated membrane glycoproteins, were identified as galectin-3 ligands by coimmunoprecipitation with and affinity chromatography on immobilized galectin-3. These data demonstrate that galectin-3 interacts with several adhesion molecules and suggest that this lectin may have a role in human colon carcinoma cell adhesion.
半乳糖凝集素-1和半乳糖凝集素-3是分子量分别为14,500和31,000的半乳糖苷结合凝集素，在正常细胞和恶性细胞中均有表达，并与细胞生长、黏附和转移的调节有关。我们通过免疫印迹分析了21种培养的人结肠癌细胞系中凝集素的表达。仅在7种细胞系中检测到半乳糖凝集素-1，而在20种细胞系中发现了半乳糖凝集素-3。仅表达半乳糖凝集素-3的KM12细胞用于通过亲和层析分离这种凝集素，纯化的凝集素用于通过印迹鉴定互补糖缀合物。结果表明，半乳糖凝集素-3与人层粘连蛋白、癌胚抗原和溶酶体相关膜糖蛋白结合，这些蛋白都参与细胞黏附。半乳糖凝集素-3定位于KM12细胞表面，并与癌胚抗原共定位。通过与固定化半乳糖凝集素-3进行共免疫沉淀和亲和层析，鉴定出几种分子量在58,000至>200,000范围内的内源性糖蛋白和细胞表面蛋白，包括癌胚抗原和溶酶体相关膜糖蛋白，作为半乳糖凝集素-3的配体。这些数据表明半乳糖凝集素-3与几种黏附分子相互作用，并提示这种凝集素可能在人结肠癌细胞黏附中起作用。
