Department of Physiology and Biophysics, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA.
J Biol Chem. 2012 Feb 3;287(6):4053-65. doi: 10.1074/jbc.M111.311688. Epub 2011 Nov 30.
In this study, we have investigated the role of a glioma-specific cation channel assembled from subunits of the Deg/epithelial sodium channel (ENaC) superfamily, in the regulation of migration and cell cycle progression in glioma cells. Channel inhibition by psalmotoxin-1 (PcTX-1) significantly inhibited migration and proliferation of D54-MG glioma cells. Both PcTX-1 and benzamil, an amiloride analog, caused cell cycle arrest of D54-MG cells in G(0)/G(1) phases (by 30 and 40%, respectively) and reduced cell accumulation in S and G(2)/M phases after 24 h of incubation. Both PcTX-1 and benzamil up-regulated expression of cyclin-dependent kinase inhibitor proteins p21(Cip1) and p27(Kip1). Similar results were obtained in U87MG and primary glioblastoma multiforme cells maintained in primary culture and following knockdown of one of the component subunits, ASIC1. In contrast, knocking down δENaC, which is not a component of the glioma cation channel complex, had no effect on cyclin-dependent kinase inhibitor expression. Phosphorylation of ERK1/2 was also inhibited by PcTX-1, benzamil, and knockdown of ASIC1 but not δENaC in D54MG cells. Our data suggest that a specific cation conductance composed of acid-sensing ion channels and ENaC subunits regulates migration and cell cycle progression in gliomas.
在这项研究中，我们研究了由 Deg/上皮钠通道（ENaC）超家族亚基组成的神经胶质瘤特异性阳离子通道在调节神经胶质瘤细胞迁移和细胞周期进程中的作用。Psalmotoxin-1 (PcTX-1) 抑制通道显著抑制了 D54-MG 神经胶质瘤细胞的迁移和增殖。PcTX-1 和苯甲脒（一种阿米洛利类似物）均使 D54-MG 细胞周期停滞在 G0/G1 期（分别为 30%和 40%），并减少了孵育 24 小时后 S 和 G2/M 期的细胞积累。PcTX-1 和苯甲脒均上调了细胞周期蛋白依赖性激酶抑制剂蛋白 p21(Cip1) 和 p27(Kip1) 的表达。在原代培养的 U87MG 和原发性多形性成胶质细胞瘤细胞中以及敲低一个组成亚基 ASIC1 后，得到了类似的结果。相比之下，敲低 δENaC（不是神经胶质瘤阳离子通道复合物的组成部分）对细胞周期蛋白依赖性激酶抑制剂的表达没有影响。ERK1/2 的磷酸化也被 PcTX-1、苯甲脒和 ASIC1 的敲低抑制，但 δENaC 的敲低没有抑制 D54MG 细胞中的磷酸化。我们的数据表明，由酸感应离子通道和 ENaC 亚基组成的特定阳离子电导调节神经胶质瘤的迁移和细胞周期进程。
