Fig. 6

Exportin 1 (XPO1) inhibitor treatment selectively and dramatically decreases colony formation and the serial replating ability of Tet2-mutant murine haematopoietic stem and progenitor cells (HSPCs). Schematic representation of colony-forming unit assay. Bone marrow cells of wild-type (WT) or Tet2-mutant mice were sorted for Lin⁻Sca-1⁺c-Kit⁻ (LSK) and 1000 LSK+ cells were plated on methylcellulose containing eltanexor, selinexor or vehicle. (B) Relative numbers of colonies of murine (WT) or Tet2-deficient HSPC cells surviving after treatment with selinexor or eltanexor. The number of colonies was determined after 7 days of culture in methylcellulose-containing drug or vehicle. Selinexor and eltanexor reduce Tet2-mutant colonies by ~50% or ~ 75% respectively but have little effect on normal HSPC plating efficiency. (C) Representative colony morphology with or without drug treatment. (D) Schematic of serial re-plating of murine WT or Tet2-deficient LSK+ HSPC cells in methylcellulose. Cells were treated with selinexor (50 nM) or eltanexor (50 nM) at each of the four passages (P1–P4). Total number of colony-forming units (CFU) was determined 7 d after each passage. (E, F) Relative number of colonies of murine WT or Tet2−/− € or Tet2+/− (f) HSPC cells surviving after treatment with selinexor (E) or eltanexor (E, F) at each of the four passages (P1–P4). Wild-type colonies do not re-plate beyond three passages (P3). Tet2-deficient HSPCs exhibit increased re-plating capacity, which is dramatically decreased by selinexor or eltanexor treatment.