Moinfar Zahra, Dambach Hannes, Schoenebeck Bodo, Förster Eckart, Prochnow Nora, Faustmann Pedro Michael
Department of Neuroanatomy and Molecular Brain Research, Ruhr-Universität Bochum, 44801, Bochum, Germany.
International Graduate School of Neuroscience (IGSN), Ruhr-Universität Bochum, 44801, Bochum, Germany.
PLoS One. 2016 Feb 26;11(2):e0150007. doi: 10.1371/journal.pone.0150007. eCollection 2016.
Glioma is the most common malignant primary brain tumour with male preponderance and poor prognosis. Glioma cells express variable amounts of connexin 43 (Cx43) and estrogen receptors (ERs). Both, Cx43 and ERs, play important roles in cell proliferation and migration. Therefore, we investigated the effects of 17-ß estradiol (E2) on Cx43 expression in two glioma cell lines with variable native expression of Cx43.
F98 and C6 rat glioma cells were cultured for 24 h in the presence of 10 nM or 100 nM E2, and the E2-antagonist, Fulvestrant. An MTT assay was performed to evaluate cell viability. ERα, ERβ and Cx43 protein expressions were analysed by western blotting and Cx43 mRNA expression was analysed by real-time polymerase chain reaction. To quantify cell migration, an exclusive zone migration assay was used. Functional coupling of cells via gap junctions was examined using whole-cell patch-clamp technique.
E2 reduced Cx43 expression in C6 cells, but increased Cx43 expression in F98 cultures. These effects were mediated via ERs. Moreover, E2 promoted C6 cell migration, but it did not affect F98 cell migration. The expression level of ERα was found to be high in C6, but low in F98 cells. ERβ was exclusively expressed in C6 cells. In addition, E2 treatment induced a significant decrease of ERβ in C6 cultures, while it decreased ERα expression in F98 glioma cells.
These findings show that E2 differentially modulates Cx43 expression in F98 and C6 glioma cells, likely due to the differential expression of ERs in each of these cell lines. Our findings point to the molecular mechanisms that might contribute to the gender-specific differences in the malignancy of glioma and could have implications for therapeutic strategies against glioma.
胶质瘤是最常见的原发性恶性脑肿瘤，男性居多且预后较差。胶质瘤细胞表达不同量的连接蛋白43（Cx43）和雌激素受体（ERs）。Cx43和ERs在细胞增殖和迁移中均发挥重要作用。因此，我们研究了17-β雌二醇（E2）对两种Cx43天然表达量不同的胶质瘤细胞系中Cx43表达的影响。
将F98和C6大鼠胶质瘤细胞在10 nM或100 nM E2以及E2拮抗剂氟维司群存在的情况下培养24小时。进行MTT试验以评估细胞活力。通过蛋白质印迹法分析ERα、ERβ和Cx43蛋白表达，通过实时聚合酶链反应分析Cx43 mRNA表达。为了量化细胞迁移，使用了专属区域迁移试验。使用全细胞膜片钳技术检查细胞通过缝隙连接的功能偶联。
E2降低了C6细胞中Cx43的表达，但增加了F98培养物中Cx43的表达。这些作用是通过ERs介导的。此外，E2促进了C6细胞的迁移，但不影响F98细胞的迁移。发现ERα的表达水平在C6细胞中较高，而在F98细胞中较低。ERβ仅在C6细胞中表达。此外，E2处理导致C6培养物中ERβ显著降低，而在F98胶质瘤细胞中降低了ERα的表达。
这些发现表明，E2对F98和C6胶质瘤细胞中Cx43的表达具有不同的调节作用，这可能是由于这些细胞系中ERs的差异表达所致。我们的发现指出了可能导致胶质瘤恶性程度性别差异的分子机制，并且可能对胶质瘤的治疗策略产生影响。
