RNA-Seq of GPR56+/- populations

Insights into the complex clonal architecture of acute myeloid leukemia (AML) unravelled by deep sequencing technologies have challenged the concept of AML as a hierarchically organised disease initiated and driven by rare self-renewing leukemic stem cells (LSCs). The lack of clone-specific surface markers, however, precludes prospective isolation and functional characterisation of distinct clones. Here, we performed RNA-Sequencing and assessed LSC frequencies for 56 primary AML samples in xenograft assays. We found that G-protein coupled receptor 56 (GPR56) identified the engrafting fraction in CD34positive samples and was associated with most high-risk mutations and poor outcome. Furthermore, variant allele frequency analysis revealed different clonal composition of engrafting GPR56+ versus non-engrafting GPR56- fractions identifying GPR56 as a discriminator of leukemic sub-clones with high and low leukemia initiating capacity. Our data suggest that the NSG-model rather than reproducing the full clonal diversity of the human disease selects for leukemic sub-clones based on their distinct functional properties. Overall design: RNA-Seq of GPR56+/- populations