Kamnasaran Deepak, Hawkins Cynthia, Guha Abhijit
The Arthur and Sonia Labatts Brain Tumor Research Centre, The Hospital for Sick Children, Research Institute, Toronto, Ontario, Canada M5G 1X8.
Glia. 2008 Mar;56(4):457-70. doi: 10.1002/glia.20631.
Our objective was to determine if murine embryonic stem (ES) cells, which are readily available from repositories, could be developed as a model of gliomagenesis, recognizing the difficulty in obtaining and transforming somatic astrocytes. Using a stringently controlled sequential differentiation procedure on wild type (wt) and p53+/- ES cells, we established GFAP+A2B5-synthetic astrocytes with high efficiency (>90%). The synthetic astrocytes stably express several differentiated astrocyte associated structural proteins and biochemical markers, but lacked expression of differentiated neurons and oligodendrocytes. However, in contrast to somatic differentiated astrocytes, the synthetic astrocytes expressed stem cell markers, with a transcriptome profile similar to astrocytes differentiated from neural stem cells (NSC) and somatic astrocyte cultures established from E13.5-Cortex and P4-hippocampus. In addition, the synthetic astrocytes demonstrated plasticity, with ability to dedifferentiate into neuronal and oligodendrocyte lineages. Intracranial injection of postnatal differentiated somatic astrocytes or synthetic astrocytes of either wt or p53+/- background did not grow tumors, unlike corresponding ES cells that develop teratomas. In contrast, retroviral transduction of either wt or p53+/- synthetic astrocytes and not the postnatal somatic astrocytes, with relevant oncogenes found in human malignant astrocytomas (MDM2, myr-AKT, V12H-RAS), led to intracranial high-grade undifferentiated gliomas. This study demonstrates utilization of readily available ES cells of varying genetic backgrounds to model and further our understanding of gliomagenesis. Large numbers of replenishable derivative synthetic glial lineage cells retain genetic and phenotypic characteristics of progenitor cells and thereby are more amenable to transformation by genetic aberrations involved in gliomagenesis.
我们的目标是确定能否将可从储存库轻松获取的小鼠胚胎干细胞（ES细胞）开发为胶质瘤发生模型，同时认识到获取和转化体细胞星形胶质细胞存在困难。通过对野生型（wt）和p53+/- ES细胞进行严格控制的顺序分化程序，我们高效（>90%）地建立了GFAP+A2B5合成星形胶质细胞。合成星形胶质细胞稳定表达几种分化的星形胶质细胞相关结构蛋白和生化标志物，但缺乏分化神经元和少突胶质细胞的表达。然而，与体细胞分化的星形胶质细胞不同，合成星形胶质细胞表达干细胞标志物，其转录组谱与从神经干细胞（NSC）分化而来的星形胶质细胞以及从E13.5皮质和P4海马体建立的体细胞星形胶质细胞培养物相似。此外，合成星形胶质细胞表现出可塑性，能够去分化为神经元和少突胶质细胞谱系。与相应的能形成畸胎瘤的ES细胞不同，颅内注射出生后分化的体细胞星形胶质细胞或wt或p53+/-背景的合成星形胶质细胞均未生长肿瘤。相反，用人类恶性星形细胞瘤中发现的相关癌基因（MDM2、myr-AKT、V12H-RAS）对wt或p53+/-合成星形胶质细胞而非出生后体细胞星形胶质细胞进行逆转录病毒转导，会导致颅内高级别未分化胶质瘤。这项研究证明了利用具有不同遗传背景的现成ES细胞来模拟并加深我们对胶质瘤发生的理解。大量可补充的衍生合成神经胶质谱系细胞保留了祖细胞的遗传和表型特征，因此更易于被胶质瘤发生过程中涉及的基因畸变转化。
