Diffuse intrinsic pontine glioma (DIPG) is a highly aggressive type of glial brain tumour found in the pons region of the brainstem. DIPG accounts for about 10% of childhood central nervous system tumours and the prognosis for these children is poor. Resistance to radiation, the only current available therapy for DIPG, is one of the biggest challenges. This resistance could be due to the plasticity of DIPG cells, allowing them to rapidly adapt in response to different conditions. Preliminary RNA sequencing analyses of patient tumours identified the expression of ion channel genes including the GABA family. It is known that ion channels regulate tumour plasticity in other cancers and as such we aimed to investigate and characterise the role of ion channels in DIPG. This study aimed to validate the mRNA and protein expression of the GABA-A receptors associated with ligand-gated chloride channels, in DIPG patient-derived cell lines. The results of the study validated mRNA expression of the GABA-A receptor subunits using semi-quantitative and quantitative RT-PCR. Protein expression of three of the most highly expressed subunits (GABRA2, GABRA4, and GABRA5) was also demonstrated using western blotting and immunocytochemistry. Furthermore, a drug screen and titration showed that some GABA-A receptor modulators significantly inhibited proliferation of DIPG cells. This work confirmed that GABA-A subunits are expressed in DIPG cells and that blocking these ion channels inhibits DIPG cell proliferation. These findings form the foundation for future studies that will investigate GABA-A receptor drugs as potential treatments for DIPG using preclinical models
