A robust approach for the generation of functional hematopoietic progenitor cell lines to model leukemic transformation

Studies of molecular mechanisms of hematopoiesis and leukemogenesis are hampered by the unavailability of progenitor cell lines that accurately mimic the situation in vivo. We now report a robust method to generate and maintain LSK (Lin(-), Sca-1(+), c-Kit(+)) cells, which closely resemble MPP1 cells. HPCLSKs reconstitute hematopoiesis in lethally irradiated recipient mice over >8 months. Upon transformation with different oncogenes including BCR/ABL, FLT3-ITD, or MLL-AF9, their leukemic counterparts maintain stem cell properties in vitro and recapitulate leukemia formation in vivo. The method to generate HPCLSKs can be applied to transgenic mice, and we illustrate it for CDK6-deficient animals. Upon BCR/ABL(p210) transformation, HPCLSKs Cdk6(-/-) induce disease with a significantly enhanced latency and reduced incidence, showing the importance of CDK6 in leukemia formation. Studies of the CDK6 transcriptome in murine HPCLSK and human BCR/ABL(+) cells have verified that certain pathways depend on CDK6 and have uncovered a novel CDK6-dependent signature, suggesting a role for CDK6 in leukemic progenitor cell homing. Loss of CDK6 may thus lead to a defect in homing. The HPCLSK system represents a unique tool for combined in vitro and in vivo studies and enables the production of large quantities of genetically modifiable hematopoietic or leukemic stem/progenitor cells.

Automated summary

A robust method has been developed to generate and maintain LSK cells that closely resemble MPP1 cells, allowing for the study of hematopoiesis and leukemogenesis. By transforming these cells with different oncogenes, including BCR/ABL, FLT3-ITD, or MLL-AF9, researchers have demonstrated the importance of CDK6 in leukemia formation and identified novel CDK6-dependent pathways. The HPCLSK system provides a unique tool for in vitro and in vivo studies of hematopoietic or leukemic stem/progenitor cells.