Proserpio Carla, Galardi Silvia, Desimio Maria Giovanna, Michienzi Alessandro, Doria Margherita, Minutolo Antonella, Matteucci Claudia, Ciafrè Silvia Anna
Department of Biomedicine and Prevention, University of Rome Tor Vergata, 00133 Rome, Italy.
Research Unit of Primary Immunodeficiencies, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy.
Cancers (Basel). 2022 May 6;14(9):2304. doi: 10.3390/cancers14092304.
The most widely accepted hypothesis for the development of glioblastoma suggests that glioblastoma stem-like cells (GSCs) are crucially involved in tumor initiation and recurrence as well as in the occurrence of chemo- and radio-resistance. Mesenchyme homeobox 2 (MEOX2) is a transcription factor overexpressed in glioblastoma, whose expression is negatively correlated with patient survival. Starting from our observation that MEOX2 expression is strongly enhanced in six GSC lines, we performed shRNA-mediated knock-down experiments in two different GSC lines and found that MEOX2 depletion resulted in the inhibition of cell growth and sphere-forming ability and an increase in apoptotic cell death. By a deep transcriptome analysis, we identified a core group of genes modulated in response to MEOX2 knock-down. Among these genes, the repressed ones are largely enriched in genes involved in the hypoxic response and glycolytic pathway, two strictly related pathways that contribute to the resistance of high-grade gliomas to therapies. An in silico study of the regulatory regions of genes differentially expressed by MEOX2 knock-down revealed that they mainly consisted of GC-rich regions enriched for Sp1 and Klf4 binding motifs, two main regulators of metabolism in glioblastoma. Our results show, for the first time, the involvement of MEOX2 in the regulation of genes of GSC metabolism, which is essential for the survival and growth of these cells.
关于胶质母细胞瘤发生发展最广泛接受的假说表明，胶质母细胞瘤干细胞（GSCs）在肿瘤起始、复发以及化疗和放疗抗性的发生中起着关键作用。间充质同源盒2（MEOX2）是一种在胶质母细胞瘤中过表达的转录因子，其表达与患者生存率呈负相关。基于我们观察到MEOX2在六种GSC系中表达强烈增强，我们在两种不同的GSC系中进行了shRNA介导的敲低实验，发现MEOX2缺失导致细胞生长和球形成能力受到抑制，凋亡细胞死亡增加。通过深度转录组分析，我们确定了一组因MEOX2敲低而被调控的核心基因。在这些基因中，被抑制的基因在很大程度上富集于参与低氧反应和糖酵解途径的基因中，这两个紧密相关的途径有助于高级别胶质瘤对治疗产生抗性。对因MEOX2敲低而差异表达的基因调控区域进行的计算机研究表明，它们主要由富含GC的区域组成，这些区域富含Sp1和Klf4结合基序，这是胶质母细胞瘤中两个主要的代谢调节因子。我们的结果首次表明MEOX2参与了GSC代谢基因的调控，这对这些细胞的存活和生长至关重要。
