Department of Neurosurgery, Charité University Hospital, Chariteplatz 1, 10117, Berlin, Germany.
Department of Neurosurgery, Ernst von Bergmann Hospital, Potsdam, Germany.
J Cancer Res Clin Oncol. 2018 May;144(5):809-819. doi: 10.1007/s00432-018-2600-1. Epub 2018 Feb 9.
Glioblastoma multiforme (GBM) is the most lethal primary brain tumor in adults. The epigenetically active ribonucleoside analog 5-azacitidine is a new therapy option that changes tumor cell chromatin, which is frequently modified by methylation and deacetylation in malignant gliomas.
In vitro, we analyzed cell viability, cell apoptosis, and migration of human GBM cells. In vivo, we established subcutaneous and intracerebral GBM mouse models originating from U87MG, U373MG, and primary GBM cells as well as one patient-derived xenograft. Xenografts were treated with 5-azacitidine as well as valproic acid, bevacizumab, temozolomide, and phosphate buffered saline. The tumor sizes and Ki67 proliferation indices were determined. Glioma angiogenesis was examined immunohistochemically by expression analysis of endothelial cells (CD31) and pericytes (PDGFRβ).
In vitro, 5-azacitidine treatment significantly reduced human glioblastoma cell viability, increased cellular apoptosis, and reduced cellular migration. In vivo, 5-azacitidine significantly reduced growth in two intracerebral GBM models. Notably, this was also shown for a xenograft established from a patient surgery sample; whereas, epigenetically acting valproic acid did not show any growth reduction. Highly vascularized tumors responded to treatment, whereas low-vascularized xenografts showed no response. Furthermore, intracerebral glioblastomas treated with 5-azacitidine showed a clearly visible reduction of tumor angiogenesis and lower numbers of endothelial cells and tumor vessel pericytes.
Our data show significant growth inhibition as well as antiangiogenic effects in intracerebral as well as patient-derived GBM xenografts. This encourages to investigate in detail the multifactorial effects of 5-azacitidine on glioblastomas.
多形性胶质母细胞瘤（GBM）是成人中最致命的原发性脑肿瘤。表观遗传活性核苷类似物 5-氮杂胞苷是一种新的治疗选择，它可以改变肿瘤细胞染色质，而恶性神经胶质瘤中经常发生染色质的甲基化和去乙酰化修饰。
在体外，我们分析了人类 GBM 细胞的细胞活力、细胞凋亡和迁移。在体内，我们建立了源自 U87MG、U373MG 和原发性 GBM 细胞以及一个患者来源的异种移植物的皮下和脑内 GBM 小鼠模型。异种移植物用 5-氮杂胞苷以及丙戊酸、贝伐单抗、替莫唑胺和磷酸盐缓冲盐水进行治疗。测量肿瘤大小和 Ki67 增殖指数。通过内皮细胞（CD31）和周细胞（PDGFRβ）的表达分析，用免疫组织化学方法检查胶质瘤血管生成。
在体外，5-氮杂胞苷处理显著降低了人类胶质母细胞瘤细胞活力，增加了细胞凋亡，并减少了细胞迁移。在体内，5-氮杂胞苷显著降低了两个脑内 GBM 模型的生长。值得注意的是，这也适用于从患者手术样本建立的异种移植物；而具有表观遗传作用的丙戊酸则没有显示出任何生长抑制作用。血管丰富的肿瘤对治疗有反应，而血管较少的异种移植物则没有反应。此外，用 5-氮杂胞苷治疗的脑内胶质母细胞瘤显示出明显的肿瘤血管生成减少以及内皮细胞和肿瘤血管周细胞数量减少。
我们的数据显示，在脑内和患者来源的 GBM 异种移植物中，5-氮杂胞苷具有显著的生长抑制和抗血管生成作用。这鼓励我们详细研究 5-氮杂胞苷对胶质母细胞瘤的多因素作用。
