Human GAL3(Galectin-3) ELISA Kit

Background/Aim: The effects of O-linked P-Nacetyl-D-glucosamine (O-GlcNAc) transferase (OGT) and O-GlcNAcase (OGA) inhibitors on galectin gene expression profiles were examined in MCF7, HT-29, and HL-60 cancer cell lines. Materials and Methods: Cell cultures were treated for 24 h with OGA inhibitor thiamet G or OGT inhibitor 2-acetamido-1,3,4,6-tetra-O-acetyl-2-deoxy-5-thio-a-D- glucopyranose, and global O-GlcNAc levels and expression of galectin genes were determined using an immunodot blot assay and real-time quantitative polymerase chain reaction. Results: Two galectin genes, LGALS3 in MCF7 cells and LGALSJ2 in HL-60 cells, were up-regulated by O-GlcNAc, whereas other cell-specific galectins were unresponsive to changes in O-GlcNAc level. Of interest, basal levels of O-GlcNAc in resting HL-60 and HT-29 cells were significantly higher than those in cells differentiated into neutrophilic or enterocytic lineages, respectively. Conclusion: O-GlcNAcmediated signaling pathways may be involved in regulating the expression of only a limited number of galectin genes. Additional O-GlcNAc-dependent mechanisms may work at the protein level (galectin secretion and intracellular localization) and warrant further investigation.

Introduction of the integrin beta 1- but not the beta 3-subunit in GE11 cells induces an epithelial-to-mesenchymal-transition (EMT)-like phenomenon that is characterized by the loss of cell-cell contacts, cell scattering, increased cell migration and RhoA activity, and fibronectin fibrillogenesis. Because galactosebinding lectins (galectins) have been implicated in these phenomena, we investigated whether galectins are involved in the beta-induced phenotype. We examined 9 galectins and, intriguingly, found that the expression of galectin-3 (Gal-3) is specifically induced by beta 1 but not by beta 3. Using beta 1-beta 3 chimeric integrins, we show that the induction of Gal-3 expression requires the hypervariable region in the extracellular domain of beta 1, but not its cytoplasmic tail. Furthermore, Gal-3 expression does not depend on RhoA signaling, serum factors, or any of the major signal transduction pathways involving protein kinase C (PKC), p38 mitogen-activated protein kinase (p38MAPK), extracellular signal-regulated kinase-1/-2 (ERK-1/2), phosphatidylinositol3- OH kinase (PI3-K), or Src kinases. Instead, Gal-3 expression is controlled in an epigenetic manner. Whereas DNA methylation of the Lgals3 promoter maintains Gal-3 silencing in GE11 cells, expression of beta 1 causes its demethylation, leading to transcriptional activation of the Lgals3 gene. In turn, Gal-3 expression enhances beta 1 integrin-mediated cell adhesion to fibronectin (FN) and laminin (LN), as well as cell migration. Gal-3 also promotes beta 1-mediated cell adhesion to LN and Collagen-1 (Col)-1 in cells that endogenously express Gal-3 and beta 1 integrins. In conclusion, we identify a functional feedback-loop between beta 1 integrins and Gal-3 that involves the epigenetic induction of Gal-3 expression during integrin-induced EMT and cell scattering.