Wong Raymond, Turlova Ekaterina, Feng Zhong-Ping, Rutka James T, Sun Hong-Shuo
Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, Canada.
Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada.
Oncotarget. 2017 Feb 14;8(7):11239-11248. doi: 10.18632/oncotarget.14496.
Glioblastoma (GBM), the most common and aggressive brain tumor in the central nervous system, remains a lethal diagnosis with a median survival of < 15 months. Aberrant expression of the TRPM7 channel has been linked to GBM functions. In this study, using the human GBM cell line U87, we evaluated the TRPM7 activator naltriben on GBM viability, migration, and invasiveness. First, using the whole-cell patch-clamp technique, we showed that naltriben enhanced the endogenous TRPM7-like current in U87 cells. In addition, with Fura-2 Ca2+ imaging, we observed robust Ca2+ influx following naltriben application. Naltriben significantly enhanced U87 cell migration and invasion (assessed with scratch wound assays, Matrigel invasion experiments, and MMP-2 protein expression), but not viability and proliferation (evaluated with MTT assays). Using Western immunoblots, we also detected the protein levels of p-Akt/t-Akt, and p-ERK1|2/t-ERK1|2. We found that naltriben enhanced the MAPK/ERK signaling pathway, but not the PI3k/Akt pathway. Therefore, potentiated TRPM7 activity contributes to the devastating migratory and invasive characteristics of GBM.
胶质母细胞瘤（GBM）是中枢神经系统中最常见且侵袭性最强的脑肿瘤，仍然是一种致命的疾病，中位生存期小于15个月。TRPM7通道的异常表达与GBM的功能有关。在本研究中，我们使用人GBM细胞系U87，评估了TRPM7激活剂纳曲苄对GBM活力、迁移和侵袭性的影响。首先，我们使用全细胞膜片钳技术表明，纳曲苄增强了U87细胞中的内源性TRPM7样电流。此外，通过Fura-2 Ca2+成像，我们观察到应用纳曲苄后有强烈的Ca2+内流。纳曲苄显著增强了U87细胞的迁移和侵袭（通过划痕试验、基质胶侵袭实验和MMP-2蛋白表达评估），但对活力和增殖没有影响（通过MTT试验评估）。使用Western免疫印迹法，我们还检测了p-Akt/t-Akt和p-ERK1|2/t-ERK1|2的蛋白水平。我们发现纳曲苄增强了MAPK/ERK信号通路，但没有增强PI3k/Akt通路。因此，增强的TRPM7活性促成了GBM具有破坏性的迁移和侵袭特性。
