Transcript expression of microdissected xenografted glioblastomas with and without treatment with Lck-I

Migration of human glioma stem cells (hGSCs) within the brain parenchyma makes glioblastoma one of the most aggressive and lethal tumors. Studies of the cellular and molecular mechanisms underlying hGSC migration are hindered by the limitations of existing migration models. Here we developed a dorsal root ganglion axon-oligodendrocyte-hGSC co-culture to study in real time the migration and interaction of hGSCs with their microenvironment. hGSCs interact with myelinated and non-myelinated axons through the formation of pseudopodia. Isolation of pseudopodia-localized polysome-bound RNA reveals transcripts of Lck, Paxillin, Crk-II and Rac1 that undergo local translation. Inhibition of Lck blocks the activation of this pathway, the formation of pseudopodia and the migration of hGSCs. In vivo intraventricular administration of a Lck inhibitor using an orthotopic xenograft mouse model results in significant inhibition of tumor growth and significant down-regulation of stemness gene expression. Targeting this Lck pathway constitutes a novel treatment paradigm for human glioblastomas. Overall design: Human glioma stem cells were orthotopically transplanted in the brain of NU/J mice. Following the cell transplantation, 2 mice were treated with intraventricular delivery of Lck-I for 4 weeks through an ALZET pump, while 3 mice received the diluent (Controls). After 4 weeks of continous treatment the tumors were microdissected and total RNA was isolated to perform RNAseq using Illumina HiSeq 2500. RESULTS: Continuous local treatment with Lck-I for 4 weeks results in significant downregulation of 743 transcripts in human glioblastomas.