Hull’s magic box: building the case for clinical trials using arginine methylation inhibitors against gbm

Abstract AIMS • Assess/evaluate transcriptomic changes in GBM, maintained on a microfluidics system, in response to treatment with arginine methylation inhibitor GSK3368715, currently in clinical trials, to identify novel therapeutic strategies, synergising with personalised patient care and precision medicine • Investigate molecular differences between healthy brain and GBM maintained on-chip in response to GSK3368715, including proliferation, apoptosis and splicing. METHOD GBM biopsies from Hull Royal Infirmary, or healthy mouse brain tissues, were maintained on-chip for 8- days and perfused with GSK3368715-treated media, at 3 μl/min, mimicking the in vivo environment. RNA- sequencing determined thousands of differentially expressed genes and alternative splicing (AS) events resulting from GSK3368715 treatment. Immunohistochemistry displayed the effect of GSK3368715 on healthy mouse brain tissue to ascertain the specificity of the arginine methylation inhibitor in leading to GBM apoptosis. RESULTS RNA-sequencing showed highly significant GO-term-enrichment in ribosome and translation pathways, suggesting decreased protein synthesis capacity after GSK3368715 treatment. Additionally, several hundreds of genes were found to be undergoing AS, compatible with a mechanism where changes in the arginine methylation pattern of spliceosome member FUS, upon GSK3368715 treatment, contribute to AS. Of these events, 136 (more than expected by chance, χ2 = 7.16, p = 0.007) were known FUS splicing targets. GO-term-enrichment of these AS events was found in DNA damage and cell death . Together these results are consistent with immunohistological findings that GSK3368715 causes apoptosis in GBM-on-chip tissue, in a specific manner. CONCLUSIONS Our results highlight an exciting potential therapeutic target for GBM, via induction of alternative splicing path- ways, through arginine methylation inhibition with GSK3368715.