Functional characterization of acid-sensing ion channels in the cerebellum-originating medulloblastoma cell line DAOY and in cerebellar granule neurons

Pflugers Arch. 2023 Sep;475(9):1073-1087. doi: 10.1007/s00424-023-02839-3. Epub 2023 Jul 20.

Abstract

Acid-sensing ion channels (ASICs) are Na+ channels that are almost ubiquitously expressed in neurons of the brain. Functional ASIC1a is also expressed in glioblastoma stem cells, where it might sense the acidic tumor microenvironment. Prolonged acidosis induces cell death in neurons and reduces tumor sphere formation in glioblastoma via activation of ASIC1a. It is currently unknown whether ASICs are expressed and involved in acid-induced cell death in other types of brain tumors. In this study, we investigated ASICs in medulloblastoma, using two established cell lines, DAOY and UW228, as in vitro models. In addition, we characterized ASICs in the most numerous neuron of the brain, the cerebellar granule cell, which shares the progenitor cell with some forms of medulloblastoma. We report compelling evidence using RT-qPCR, western blot and whole-cell patch clamp that DAOY and cerebellar granule cells, but not UW228 cells, functionally express homomeric ASIC1a. Additionally, Ca2+-imaging revealed that extracellular acidification elevated intracellular Ca2+-levels in DAOY cells independently of ASICs. Finally, we show that overexpression of RIPK3, a key component of the necroptosis pathway, renders DAOY cells susceptible to acid-induced cell death via activation of ASIC1a. Our data support the idea that ASIC1a is an important acid sensor in brain tumors and that its activation has potential to induce cell death in tumor cells.

Keywords: Cell death; Extracellular acidity; Necroptosis; Tumour microenvironment; Tumour spheroids.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acid Sensing Ion Channels / metabolism
  • Brain Neoplasms* / metabolism
  • Cell Line
  • Cerebellar Neoplasms* / metabolism
  • Cerebellum
  • Glioblastoma* / metabolism
  • Humans
  • Medulloblastoma* / metabolism
  • Neurons / metabolism
  • Tumor Microenvironment

Substances

  • Acid Sensing Ion Channels