Upregulated cholesterol biosynthesis facilitates the survival of methylation-retaining AML cells following decitabine treatment [single_colony_TEM-Seq]

DNA hypomethylating agents (HMAs) are used to treat acute myeloid leukaemia (AML) and myelodysplasia patients who are unsuitable for intensive chemotherapy, but low response rates and therapy-resistant relapse remain significant challenges. To optimise HMA efficacy, we must understand how resistance and relapse arise from cells that survive treatment. Here we combine single-cell multi-omic analysis with parallel colony-forming assays to link HMA-induced molecular heterogeneity with functional consequences in AML cells. HMAs, azacytidine cytidine (azacytidine ) and decitabine (decitabine ), induced global epigenetic heterogeneity associated with upregulation of inflammatory responses and cell death pathways in a subset of hypomethylated cells. Some AML cells maintained high DNA methylation during treatment, and these methylation-retaining cells had increased self-renewal capacity following decitabine , but not azacytidine . Molecular profiling of individual colonies revealed upregulated cholesterol biosynthesis as an adaptation to HMA treatment, and inhibition by rosuvastatin enhanced decitabine effects in vitro and in vivo. Thus, HMA-induced heterogeneity has important implications for AML cell growth and statins are a candidate co-treatment strategy to delay or prevent HMA-resistant relapse.