Galectin-1 is implicated in the protein kinase c ε/vimentin-controlled trafficking of integrin-β1 in glioblastoma cells

Abstract

Cell motility and resistance to apoptosis characterize glioblastoma (GBM) growth and malignancy. In our current work we report that galectin-1, a homodimeric adhesion molecule and carbohydrate-binding protein with affinity for -galactosides, is linked with cell surface expression of integrin 1 and the process of integrin trafficking. Using immunofluorescence, depletion of galectin-1 through both stable knockdown and transient-targeted small interfering RNA (siRNA) treatment induces an intracellular accumulation of integrin-1 coincident with a diminution of integrin-1 at points of cellular adhesion at the cell membrane. Galectin-1 depletion does not alter the gene expression level of integrin-1. Transient galectin-1 depletion effectuates as well the perinuclear accumulation of protein kinase C epsilon (PKC) and the intermediate filament vimentin, both of which have been shown to mediate integrin recycling in motile cells. Our results argue for the involvement of galectin-1 in the PKCvimentin-controlled trafficking of integrin-1. The understanding of molecular mediators such as galectin-1 and the pathways through which they drive the cell invasion so descriptive of GBM is anticipated to reveal potential therapeutic targets that promote glioma malignancy. © 2008 International Society of Neuropathology.