Regulation of Migration and Proliferation of Glioblastoma Cells by Modulating the Acid Sensitive Ion Channel‐1 (ASIC‐1) Activity

Abstract

Inhibition of glioma cell specific cation channels is a promising opportunity for the therapy of glioblastoma multiforme. One of the major features of high grade glioma cells is their extreme ability to migrate and proliferate through brain parenchyma. The movement of cations through ion channels is an important requirement for the metastasis of glioma cells. We have previously reported that high grade malignant glioma cells express an amiloride-sensitive cation conductance which is not present in normal astrocytes or low grade glioma cells. In the present study, we have investigated the potential role of a component of this channel, Acid Sensitive Ion Channel-1 (ASIC-1) to regulate migration and the cell cycle process in glioma cells. We found that the blocking of ASIC-1 by Psalmotoxin-1 (PcTX-1) (100 nM), a tarantula spider toxin, significantly inhibits the migration and proliferation of D54MG and U251 glioma cells both in transwell migration and in-vitro scratch wound assays. Both PcTx-1 and benzamil (100mM), an amiloride analog, caused a significant cell cycle arrest of D54MG cells in G0/G1 phases (by 30% and 40%, respectively) and reduced accumulation in the S phase (by 50% and 86%, respectively), and G2/M phase (by 78% and 80%, respectively) (n=5, P<0.01) at 24h of incubation. An unfolded control peptide (100nM) had no significant effect compared to PcTX-1 and benzamil. PcTX-1 also induced an upregulation of cyclin dependent kinase inhibitor (CDKI) proteins p21Cip1/Waf1 and p27Kip1 in D54MG cells. We also found similar effects in D54MG cells by reducing the [Na+]O in the incubation medium. Knockdown of ASIC-1 expression had similar effects on p21Cip1/Waf1 and p27Kip1 expression and inhibited the cell cycle. Our data implicate the potentialrole of glioma specific cation conductance in migration and in progressionof the cell cycle in glioma cells. This study was supported by NIH grants CA101952 and DK037206.