Effect of silencing thymosin beta 4 gene expression on stemness and invasiveness in glioblastoma.

2081 Background: Thymosin β4 (TB4) is a pleiotropic actin-sequestering polypeptide that is involved in wound healing and developmental processes. TB4 gene silencing promotes differentiation of neural progenitor cells whereas TB4 overexpression initiates cortical folding of developing brain hemispheres. However, a role of TB4 in malignant gliomas has not yet been investigated. Methods: We first analyzed TB4 expression on tissue microarrays and performed REMBRANDT and TCGA database interrogations. We analyzed TB4 expression in a panel of 8 long-term glioma cell lines and 7 glioma-initiating cell lines. Using lentiviral transduction, we modulated TB4 expression in LNT-229, U87MG and the glioma-initiating cell line GS-2. We studied clonogenic survival, migration, invasion, self-renewal, differentiation capacity of TB4-depleted or TB4-overexpressing glioma cells in vitro and tumorigenicity upon orthotopic implantation in vivo. Finally, we performed an Affymetrix gene chip analysis to unravel the molecular netw...