Sc-37 * the role of ng2 expressing progenitor cells in diffuse intrinsic pontine glioma

We examined NG2 expression in frozen brainstem specimens of DIPGs and observed significant NG2 expression in DIPGs [10 of 14 (71 %), fold change = 33, p < 0.05)] as compared to the adjacent normal tissue. NG2 expression was associated with histone 3 K27M mutation [8 of 10 (80 %)]. Two mechanisms of NG2 regulation in DIPG were identified: i) histone 3 binds to NG2 promoter, and ii) miR 129-2 negatively regulates NG2. We detected downregulation of miR129-2 in 85.7% (6 of 7) of DIPG tumors compared to normal tissue (FC = -30.79, n = 7 pairs). We also found overall hypermethylation at 8 CpG loci corresponding to the miR129-2 promoter. NG2 knockdown in vitro (shRNA, miR129-2 or demethylating drugs) retards cellular migration. Luciferase assay in primary mouse glioma cells co-transfected with 3'UTR of NG2 and miR129-2 revealed regulation of NG2 by miR129-2. This was further confirmed in vivo by injection of NG2-dsRed transgenic mice with mir129-2 lentivirus. Orthotopic injection of NG2+ cells results in rapid tumor formation while NG2-KD cells fail to form tumors. Our study offers a potential model for the expansion of tumor stem cells and their self-renewal properties in DIPGs.
Source: Neuro-Oncology - Category: Cancer & Oncology Authors: Tags: STEM CELLS Source Type: research