Rho GTPase Rac1: Molecular Switch within the Galectin Network and for N-Glycan α2,6-Sialylation/O-Glycan Core 1 Sialylation in Colon Cancer in Vitro (apoptosis/cancer/glycosylation/invasion/lectin/migration)

The Rho GTPase Rac1 is a multifunctional protein working through different effector pathways. The emerging physiological significance of glycan- lectin recognition gives reason to testing the possibil- ity for an influence of modulation of Rac1 expression on these molecular aspects. Using human colon ade- nocarcinoma (SW620) cells genetically engineered for its up- and down-regulation (Rac1 + and Rac1 - cells) along with wild-type and mock-transfected control cells, the questions are addressed whether the presence of adhesion/growth-regulatory galec- tins and distinct aspects of cell surface glycosylation are affected. Proceeding from RT-PCR data to Western blotting after two-dimensional gel electro- phoresis and flow cytofluorimetry with non-crossre- active antibodies against six members of this lectin family (i.e. galectins-1, -3, -4, -7, -8 and -9), a reduced extent of the presence of galectins-1, -7 and -9 was