A niche play for stem cells
Aggressive hematologic malignancies like acute lymphoblastic leukemia can blight the bone marrow and severely hamper the growth of healthy blood cells. Indeed, following chemotherapy, even the presence of a few leukemic cells can prevent bone marrow transplants from taking hold, thus impairing resumption of normal hematopoiesis.
A paper by a University of Chicagoteam now shows how leukemic cells impair normal hematopoiesis by reprogramming the hematopoietic stem (HS) cell niche, a specialized region at the edge of the bone marrow. The researchers suggest that inhibiting a tumor-secreted protein that lures HS cells toward these diseased niches could help in bone marrow transplantation and recovery from cancer.1
HS cells in HS cell niches ordinarily proliferate and differentiate to produce myeloid and lymphoid precursor cells that mature deeper within the marrow. Upon bone injury or chemotherapy, HS cells can migrate to the spleen or to injured niches in other bones.2
In cancer patients