Rabbit Anti-Human GSK3A Polyclonal antibody

Diffuse intrinsic pontine glioma (or DIPG) are pediatric high-grade gliomas associated with a dismal prognosis. They harbor specific substitution in histone H3 at position K27 that induces major epigenetic dysregulations. Most clinical trials failed so far to increase survival, and radiotherapy remains the most efficient treatment, despite only transient tumor control. We conducted the first lentiviral shRNA dropout screen in newly diagnosed DIPG to generate a cancer-lethal signature as a basis for the development of specific treatments with increased efficacy and reduced side effects compared to existing anticancer therapies. The analysis uncovered 41 DIPG essential genes among the 672 genes of human kinases tested, for which several distinct interfering RNAs impaired cell expansion of three different DIPG stem-cell cultures without deleterious effect on two control neural stem cells. Among them, PLK1, AURKB, CHEK1, EGFR, and GSK3A were previously identified by similar approach in adult GBM indicating common dependencies of these cancer cells and pediatric gliomas. As expected, we observed an enrichment of genes involved in proliferation and cell death processes with a significant number of candidates belonging to PTEN/PI3K/AKT and EGFR pathways already under scrutiny in clinical trials in this disease. We highlighted VRK3, a gene involved especially in cell cycle regulation, DNA repair, and neuronal differentiation, as a non-oncogenic addiction in DIPG. Its repression totally blocked DIPG cell growth in the four cellular models evaluated, and induced cell death in H3.3-1(27M cells specifically but not in H3.1-K27M cells, supporting VRK3 as an interesting and promising target in DIPG.

Here we examine the roles of two isoforms of glycogen synthase kinase-3 (GSK-3), GSK-3 alpha and GSK-3 beta, in skeletal development. Both isoforms were unphosphorylated and active in chondrocyte differentiation stages during SOX9 and type II collagen (COL2A1) expression. Although knock-out of both alleles of Gsk3a (Gsk3a(-/-)) or a single allele of Gsk3b (Gsk3b(+/-)) in mice did not significantly affect skeletal development, compound knock-out (Gsk3a(-/-); Gsk3b(+/-)) caused dwarfism with impairment of chondrocyte differentiation. GSK-3 alpha and GSK-3 beta induced differentiation of cultured chondrocytes with functional redundancy in a cell-autonomous fashion, independently of the Wnt/beta-catenin signal. Computational predictions followed by SOX9 and COL2A1 transcriptional assays identified RelA (NF-kappa B p65) as a key phosphorylation target of GSK-3. Among several phosphorylation residues in RelA, Thr-254 was identified as the critical phosphorylation site for GSK-3 that modulated chondrocyte differentiation. In conclusion, redundant functions of GSK-3 alpha and GSK-3 beta through phosphorylation of RelA at Thr-254 play a crucial role in early stages of chondrocyte differentiation.