Expression and functional relevance of long non-coding RNAs in acute myeloid leukemia stem cells.

In acute myeloid leukemia (AML), novel therapies are needed to target not only the rapidly dividing AML blasts but also the distinct population of leukemia stem cells (LSCs), which have abnormal self-renewal capacity and increased chemotherapy resistance. Elucidation of the expression and function of deregulated genes in LSCs is critical to specifically target LSCs and may consequently lead to improving outcomes of AML patients. Here, we correlated long non-coding RNA (lncRNA) expression profiles obtained from two RNA-seq datasets of 375 younger (aged <60 years) 76 older (≥60 years) adults with cytogenetically normal AML with a 'core enriched' (CE) gene expression signature (GES) associated with LSCs. We identified a LSC-specific signature of 111 lncRNAs that correlated strongly with the CE-GES. Among the top upregulated LSC-associated lncRNAs, we identified the lncRNA DANCR. Further experiments confirmed that DANCR is upregulated in functionally validated LSC-enriched populations. DANCR knock-down in LSCs resulted in decreased stem-cell renewal and quiescence. Furthermore, we showed that targeting Dancr in vivo using a primary murine model of AML (expressing both Mll partial tandem duplication/Flt3 internal tandem duplication) prolonged the survival of mice after serial transplantation. Our data suggest that LSCs have a distinct lncRNA signature with functional relevance and therapeutic potential.