Dual targeting of p53 and c-MYC selectively eliminates leukaemic stem cells

Chronic myeloid leukaemia (CML) arises after transformation of a haemopoietic stem cell (HSC) by the protein-tyrosine kinase BCR–ABL. Direct inhibition of BCR–ABL kinase has revolutionized disease management, but fails to eradicate leukaemic stem cells (LSCs), which maintain CML. LSCs are independent of BCR–ABL for survival, providing a rationale for identifying and targeting kinase-independent pathways. Here we show—using proteomics, transcriptomics and network analyses—that in human LSCs, aberrantly expressed proteins, in both imatinib-responder and non-responder patients, are modulated in concert with p53 (also known as TP53) and c-MYC regulation. Perturbation of both p53 and c-MYC, and not BCR–ABL itself, leads to synergistic cell kill, differentiation, and near elimination of transplantable human LSCs in mice, while sparing normal HSCs. This unbiased systems approach targeting connected nodes exemplifies a novel precision medicine strategy providing evidence that LSCs can be eradicated. Leukaemic stem cells (LSCs) are responsible for BCR–ABL-driven chronic myeloid leukaemia relapse; here, p53 and MYC signalling networks are shown to regulate LSCs concurrently, and targeting both these pathways has a synergistic effect in managing the disease. Dual targeting of p53 and c-Myc pathways Tyrosine kinase inhibitors are a first-line therapy in patients with chronic myeloid leukaemia (CML), where they target the oncogenic BCR-ABL fusion gene. However, relapse inevitably occurs, probably driven by a drug-resistant population of leukaemic stem cells (LSCs). This study uncovers the concurrent involvement of p53 and Myc signalling networks in regulating LSCs. The authors demonstrate that genetic and/or pharmacological targeting of both the p53 and c-Myc pathways achieves more effective disease neutralization in mouse and human cell models of CML.