Simulating cellular galectin networks by mixing galectins in vitro reveals synergistic activity

Background: Even though members of the family of adhesion/growth-regulatory galectins are increasingly detected to be co-expressed, they are still being routinely tested separately. The recent discovery of heterodimer formation among galectins-1, -3, and -7 in mixtures prompts further study of their functional activities in mixtures. Methods: Cell agglutination, galectin binding to cells, as well as effects on cell proliferation, onset of apoptosis and migration were determined in assays using various cell types and mixtures of galectins-1, -3, and -7. Results: Evidence for a more than additive increases of experimental parameters was consistently obtained. Conclusion: Testing galectins in mixtures simulates the situation of co-expression in situ and reveals unsuspected over-additive activities. This new insight is relevant for analyzing galectin functionality in (patho)physiological conditions.