Hierarchical Lineage Tracing Reveals Diverse Pathways of AML Treatment Resistance [scRNA-seq]

Cancer cells adapt to treatment, leading to the emergence of clones that are more aggressive and resistant to anti-cancer therapies. We have a limited understanding of the evolution of treatment resistance as we have lacked technologies to map the evolution of cancer under the selective pressures. To address this, we developed a hierarchical, dynamic lineage tracing method called FLARE (Following Lineage Adaptation and Resistance Evolution). We use this technique to track the progression of acute myeloid leukemia (AML) cell lines through exposure to Cytarabine (AraC), a front-line treatment in AML, in vitro and in vivo. We map distinct cellular lineages in murine and human AML cell lines that are predisposed to AraC persistence and/or resistance via upregulation of cell adhesion and motility pathways. Additionally, we highlight heritable increased expression of immunoproteasome 11S regulatory cap subunits as a potential mechanism aiding AML cell survival, proliferation, and immune escape in vivo. Finally, we validate the clinical relevance of these signatures in the TARGET-AML cohort, with a bisected response in blood and bone marrow. Our findings reveal a broad spectrum of resistance signatures attributed to significant cell transcriptional changes, and we expect this high-resolution profiling of treatment response to be a useful tool to dissect the evolution of treatment response in a wide range of tumor types.