National Cancer Institute, Neuro-Oncology Branch, Bethesda, MD, USA.
Macrogen, Seoul, Korea.
Sci Rep. 2017 Mar 3;7:43605. doi: 10.1038/srep43605.
Glioblastoma, the most common primary malignant brain tumor, harbors a small population of tumor initiating cells (glioblastoma stem cells) that have many properties similar to neural stem cells. To investigate common regulatory networks in both neural and glioblastoma stem cells, we subjected both cell types to in-vitro differentiation conditions and measured global gene-expression changes using gene expression microarrays. Analysis of enriched transcription factor DNA-binding sites in the promoters of differentially expressed genes was used to reconstruct regulatory networks involved in differentiation. Computational predictions, which were biochemically validated, show an extensive overlap of regulatory circuitry between cell types including a network centered on the transcription factor KLF4. We further demonstrate that EGR1, a transcription factor previously shown to be downstream of the MAPK pathway, regulates KLF4 expression and that KLF4 in turn transcriptionally activates NOTCH as well as SOX2. These results demonstrate how known genomic alterations in glioma that induce constitutive activation of MAPK are transcriptionally linked to master regulators essential for neural stem cell identify.
胶质母细胞瘤是最常见的原发性恶性脑肿瘤,其中存在一小部分肿瘤起始细胞(胶质母细胞瘤干细胞),它们具有许多与神经干细胞相似的特性。为了研究神经干细胞和胶质母细胞瘤干细胞中的共同调控网络,我们将这两种细胞类型置于体外分化条件下,并使用基因表达微阵列测量其全基因表达变化。对差异表达基因启动子中富集的转录因子 DNA 结合位点进行分析,以重建参与分化的调控网络。计算预测,经生物化学验证,表明细胞类型之间的调控电路有广泛的重叠,包括以转录因子 KLF4 为中心的网络。我们进一步证明,先前显示为 MAPK 通路下游的转录因子 EGR1 调节 KLF4 的表达,而 KLF4 反过来又转录激活 NOTCH 和 SOX2。这些结果表明,已知的诱导 MAPK 持续激活的胶质母细胞瘤中的基因组改变如何与神经干细胞特征所必需的主调控因子在转录水平上联系起来。