B-Cell Precursor Acute Lymphoblastic Leukemia elicits an Interferon-α/β response in Bone Marrow-derived Mesenchymal Stroma

Abstract

SummaryB-cell precursor acute lymphoblastic leukemia (BCP-ALL) can hijack the normal bone marrow microenvironment to create a leukemic niche which facilitates blast cell survival and promotes drug resistance. Bone marrow-derived mesenchymal stromal cells (MSCs) mimic this protective environment inex vivoco-cultures with leukemic cells obtained from children with newly diagnosed BCP-ALL. We examined the potential mechanisms of this protection by RNA sequencing of flow-sorted MSCs after co-culture with BCP-ALL cells. Leukemic cells induced an interferon (IFN)-related gene signature in MSCs, which was partially dependent on cell-cell signaling by tunneling nanotubes. The signature was selectively induced by BCP-ALL cells, most profoundly byETV6-RUNX1positive ALL cells, as co-culture of MSCs with healthy immune cells did not provoke a similar IFN signature. Leukemic cells and MSCs both secreted IFNα and IFNβ, but no IFNγ. In line, the IFN-gene signature was sensitive to blockade of IFNα/β signaling, but less to that of IFNγ. The viability of leukemic cells and level of resistance to three chemotherapeutic agents was not affected by interference with IFN signaling using selective IFNα/β inhibitors or silencing of IFN-related genes. Taken together, our data suggest that the leukemia-induced expression of IFNα/β-related genes by MSCs does not support survival of BCP-ALL cells but may serve a different role in the pathobiology of BCP-ALL.