Flash Talk + Poster Presentation 38th Lorne Cancer Conference 2026

Linking cell fate determination in the embryonic forebrain to Diffuse Midline Glioma (#103)

Liam M Furst 1 2 , Ryan F Leung 1 , Jessica Tang 3 4 , Enola M Roussel 5 6 , Kyle A France 1 , Ankita M George 1 , Ron Firestein 7 8 , Fernando J Rosello 3 4 , Mirana Ramialison 1 3 , Maree C Faux 1 2 9 , David D Eisenstat 1 2
  1. Murdoch Children's Research Institute, Parkville, Victoria, Australia
  2. Paediatrics, University of Melbourne, Parkville, Victoria, Australia
  3. Novo Nordisk Foundation Center for Stem Cell Medicine, Murdoch Children’s Research Institute, Melbourne, Victoria, Australia
  4. Department of Clinical Pathology, University of Melbourne, Melbourne, Victoria, Australia
  5. Department of Clinical Pathology, University of Melbourne, Melbourne, Victoria, Australia
  6. Cancer Immunology Program, Peter MacCallum Cancer Centre, Parkville, Victoria, Australia
  7. Cancer for Cancer Research, Hudson Institute of Medical Research, Clayton, Victoria, Australia
  8. Molecular and Translational Sciences, Monash University, Clayton, Victoria, Australia
  9. Surgery, Royal Melbourne Hospital, Parkville, Victoria, Australia

Diffuse Midline Gliomas (DMG) are treatment resistant and uniformly fatal paediatric cancers arising predominantly in the brainstem. Most patient tumours harbour mutations in histone variants H3.3/H3.1, leading to global increase in H3K27ac, reduction of H3K27me3 and a stalled oligodendroglial progenitor cell (OPC) cell state. DLX2 is a transcription factor that represses OPC fate and promotes interneuron fate, as well as interneuron tangential migration during neurogenesis. We hypothesized that DLX2 overexpression in human DMG cell lines would reprogram OPC fate, promoting neuronal differentiation and reducing tumourigenicity. Analysis of an RNA-seq database of DMG cell lines revealed an inverse relationship between DLX2 and OLIG2 expression, suggesting a maintained mutually repressive relationship. DLX2 was overexpressed in selected DMG cell lines with an mCherry reporter. The highest proportion of mCherry expressing cells showed significant upregulation of DLX2 target genes by qPCR, suggesting response to the DLX2 cue. Cell fate changes in these cells were assessed by bulk RNA-seq and immunofluorescence. Comparison of these data mapped to an existing foetal brain atlas as well as DMG tumour gene sets suggests overexpression of DLX2 results in activation of the interneuron-lineage genes, but incomplete repression of OPC genes. To better understand how K27M is preventing complete transdifferentiation of the interneuronal lineage, we evaluated changes in specific chromatin accessibility by CUT&RUN targeting major global epigenetic marks as well as methylation sequencing and proteomic analysis. Functional assays assessing proliferation, cell cycle, and clonogenicity to evaluate specific changes to tumourigenicity will be presented. Further, transdifferentiation towards this lineage may be facilitated by additional supplementation, and chemical transdifferentiating agent combinations. Here, we present a biologically relevant method to explore the developmental plasticity of DMG cells. By better understanding the mechanisms maintaining plasticity that exists within these tumour cell states, we hope to demonstrate developmentally linked epigenetic vulnerabilities.