Department of Biomedicine, Aarhus University, Wilhelm-Meyers-Alle 3, 8000, Aarhus C, Denmark.
Center for Stochastic Geometry and Advanced Bioimaging, Aarhus University, Wilhelm-Meyers-Alle 3, 8000, Aarhus C, Denmark.
Cell Oncol (Dordr). 2017 Jun;40(3):263-279. doi: 10.1007/s13402-017-0319-7. Epub 2017 Apr 20.
Medulloblastomas are aggressive brain malignancies. While considerable progress has been made in the treatment of medulloblastoma patients with respect to overall survival, these patients are still at risk of developing neurologic and cognitive deficits as a result of anti-cancer therapies. It is hypothesized that targeted molecular therapies represent a better treatment option for medulloblastoma patients. Therefore, the aim of the present study was to test a panel of epigenetic drugs for their effect on medulloblastoma cells under mild hypoxic conditions that reflect the physiological concentrations of oxygen in the brain.
Protein levels of histone deacetylase 1 (HDAC1) and DNA methyltransferase 1 (DNMT1) in medulloblastoma-derived cells (Daoy and D283 Med), as well as in developing and differentiated brain cells, were determined and compared. Class I and II histone deacetylase inhibitors (HDACi) and a DNMT inhibitor, 5-aza-2'-deoxycytidine (5-aza-dC), were applied to Daoy and D283 Med cells, and their effects were studied using viability, apoptosis and cancer sphere assays.
We found that in HDAC1 and DNMT1 overexpressing medulloblastoma-derived cells, cell death was induced under various epigenetic drug conditions tested. At low HDACi concentrations, however, a pro-proliferative effect was observed. Parthenolide, a drug that affects cancer stem cells, was found to be efficient in inducing cell death in both cell lines tested. In contrast, we found that Daoy cells were more resistant to 5-aza-dC than D283 Med cells. When suberoylanilide hydroxamic acid (SAHA) and parthenolide were individually applied to both cell lines in combination with 5-aza-dC, a synergistic effect on cell survival was observed.
Our current results suggest that the application of HDACi in combination with drugs that target DNMT may represent a promising option for the treatment of medulloblastoma.
成神经管细胞瘤是一种侵袭性的脑部恶性肿瘤。虽然在提高成神经管细胞瘤患者的总体生存率方面已经取得了相当大的进展，但这些患者仍有罹患神经和认知缺陷的风险，这是抗癌治疗的结果。据推测，针对特定分子的治疗方法可能是成神经管细胞瘤患者的更好治疗选择。因此，本研究的目的是检测一组表观遗传药物在模拟大脑中氧浓度的轻度低氧条件下对成神经管细胞瘤细胞的作用。
检测成神经管细胞瘤衍生细胞（Daoy 和 D283 Med）以及发育中和分化中的脑细胞中组蛋白去乙酰化酶 1（HDAC1）和 DNA 甲基转移酶 1（DNMT1）的蛋白水平，并进行比较。应用 I 类和 II 类组蛋白去乙酰化酶抑制剂（HDACi）和一种 DNA 甲基转移酶抑制剂，5-氮杂-2'-脱氧胞苷（5-aza-dC）处理 Daoy 和 D283 Med 细胞，并通过细胞活力、细胞凋亡和肿瘤球形成试验研究其作用。
我们发现，在 HDAC1 和 DNMT1 过表达的成神经管细胞瘤衍生细胞中，在测试的各种表观遗传药物条件下诱导细胞死亡。然而，在低浓度 HDACi 下，观察到促增殖作用。影响癌症干细胞的药物白头翁内酯在两种测试细胞系中均能有效诱导细胞死亡。相比之下，我们发现 Daoy 细胞对 5-aza-dC 的耐药性强于 D283 Med 细胞。当单独将 SAHA 和白头翁内酯应用于两种细胞系，并与 5-aza-dC 联合应用时，观察到对细胞存活有协同作用。
我们目前的结果表明，HDACi 联合靶向 DNMT 的药物应用可能是治疗成神经管细胞瘤的一种有前途的选择。
