In
leukemia, a distinct subpopulation of
cancer-initiating cells called
leukemia stem cells (LSCs) is believed to drive population expansion and
tumor growth. Failing to eliminate LSCs may result in disease relapse regardless of the amount of non-LSCs destroyed. The first step in targeting and eliminating LSCs is to identify and characterize them. Acute precursor B
lymphoblastic leukemia (B-ALL) cells derived from patients were incubated with fluorescent
glucose analog 2-(N-(7-Nitrobenz-2-oxa-1, 3-diazol-4-yl) Amino)-2-Deoxyglucose (
NBDG) and sorted based on
NBDG uptake. Cell subpopulations defined by
glucose uptake were then serially transplanted into mice and evaluated for
leukemia initiating capacity. Gene expression profiles of these cells were characterized using
RNA-Sequencing (
RNA-Seq). A distinct population of
NBDG-low cells was identified in patient B-ALL samples. These cells are a small population (1.92% of the entire
leukemia population), have lower HLA expression, and are smaller in size (4.0 to 7.0 μm) than the rest of the
leukemia population. All mice transplanted with
NBDG-low cells developed
leukemia between 5 and 14 weeks, while those transplanted with
NBDG-high cells did not develop
leukemia (p ≤ 0.0001-0.002). Serial
transplantation of the
NBDG-low mouse model resulted in successful
leukemia development.
NBDG-medium (
NBDG-med) populations also developed
leukemia. Interestingly, comprehensive molecular characterization of
NBDG-low and
NBDG-med cells from patient-derived xenograft (PDX) models using
RNA-Seq revealed a distinct profile of 2,162 differentially-expressed transcripts (
DETs) (p<0.05) with 70.6% down-regulated in
NBDG-low cells. Hierarchical clustering of
DETs showed distinct segregation of
NBDG-low from
NBDG-med and
NBDG-high groups with marked transcription expression alterations in the
NBDG-low group consistent with
cancer survival. In conclusion, A unique subpopulation of cells with low
glucose uptake (
NBDG-low) in B-ALL was discovered. These cells, despite their quiescence characteristics, once transplanted in mice, showed potent
leukemia initiating capacity. Although
NBDG-med cells also initiated
leukemia, gene expression profiling revealed a distinct signature that clearly distinguishes
NBDG-low cells from
NBDG-med and the rest of the
leukemia populations. These results suggest that
NBDG-low cells may represent quiescent LSCs. These cells can be activated in the appropriate environment in vivo, showing
leukemia initiating capacity. Our study provides insight into the
biologic mechanisms of B-ALL initiation and survival.