Poster Presentation 35th Lorne Cancer Conference 2023

Sensitisation and eradication of chemo-resistant T-ALL by repurposing epigenetic and non-conventional cancer drugs (#165)

Jackie Huang 1
  1. Children's Cancer Institute, UNSW Sydney, NSW, Australia

Acute lymphoblastic leukaemia (ALL) is the most common childhood cancer and leading cause of death in children. ALL of the T-cell lineage (T-ALL) is of higher risk and often relapses due to drug resistance which remains a barrier to cure. Significantly, the survival rate for children with drug-resistant T-ALL is only 30-50% and so a strong unmet need remains to restore glucocorticoid sensitivity by developing more effective therapies for these hard-to-treat ALL cases. We have discovered that closure and inaccessibility of certain DNA regions are linked to drug resistance in T-ALL. We now propose that DNA accessibility can be restored through DNA demethylation and demonstrate the in vivo efficacy of a novel drug regimen on drug-resistant T-ALL using a DNA demethylating agent routinely for acute myeloid leukaemia treatment (decitabine) combined with glucocorticoid (dexamethasone). Specifically, two pre-clinical glucocorticoid-resistant T-ALL mouse models were treated with vehicle, decitabine, dexamethasone, or combination at optimised doses to assess decitabine’s action in restoring glucocorticoid sensitivity. Upon tracking the leukaemia burden post-treatment, we observed significantly prolonged survival in the combination group compared to the dexamethasone group. Global changes in DNA methylation and transcriptome between different treatment groups are being assessed using Illumina methylation EPIC array and RNA sequencing, respectively, to identify biomarkers and DNA regulatory mechanisms associated with chemo-resistance in T-ALL and demethylation-induced sensitisation. These findings will advance our knowledge of how the epigenetic alterations in drug-resistant T-ALL impact drug sensitivity and ultimately guide patient profiling for predicting their response to this regimen. By using repurposed drugs with safe clinical profiles, the regimen can be rapidly translated to the clinics to improve the outcome of children with hard-to-treat T-ALL.