Analysis of the mechanism of invasive growth of human glioblastomas. PART II

点击翻译按钮获取中文摘要

Evidence has accumulated that glioblastoma cells release and exploit glutamate for proliferation and migration by autocrine or paracrine loops.Ca^<2+>-permeable-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA)-type glutamate receptors are important role for the invasive growth of human glioblastomas. Here we show that Ca^<2+> signaling mediated by AMPA receptors regulates the growth and motility of glioblastoma cells via activation of Akt. Ca^<2+> supplied through Ca^<2+>-permeable AMPA receptors phosphorylated Akt at Ser-473, thereby facilitating proliferation and mobility. A dominant negative form of Akt inhibited proliferation and migration accelerated by overexpression of Ca^<2+>-permeable AMPA receptors. In contrast, introduction of a constitutively active form of Akt rescued tumor cells from apoptosis induced by the conversion of Ca^<2+>-permeable AMPA receptors to Ca^<2+>-impermeable receptors by the delivery of GluR2 cDNA.Therefore, Akt functions as a downstream effector for Ca^<2+>-signaling mediated by AMPA receptors in glioblastoma cells. Glutamate released by glioma cells is involved in Akt activity through Ca^<2+>-permeable AMPA receptors and the activation of Glutamate-AMPA-Akt pathway contributes to the high degree of anaplasia and invasive growth of human glioblastoma. Thus this novel pathway might give alternative therapeutic target.