Update on acute myeloid leukemia stem cells: New discoveries and therapeutic opportunities

Figure 1 Leukemia stem cells biology and selected therapeutic strategies/agents targeting leukemia stem cell. Leukemia stem cells (LSC) directed therapy targets cell surface markers expressed on LSC (grey boxes), crucial pathways for maintenance of stemness (orange boxes) and interactions between LSC and the bone marrow niche (white boxes). Important LSC surface markers are CD33, CD44, CD123, CD47. Essential pathways are NF-κB, PI3K/AKT/mTOR and bcl-2. LSC mobilization is accomplished with G-CSF and LSC homing to the bone marrow is regulated by the CXCR4–CXCL12 and VCAM-VLA4 axis. VCAM-1: Vascular cell adhesion protein-1; VLA-4: Very late antigen-4; CXCR4: C-X-C chemokine receptor type 4; SDF: Stromal cell-derived factor 1; PI3K: Phosphatidylinositol-4,5-bisphosphate 3-kinase; AKT: Protein kinase B; mTOR: Mechanistic target of rapamycin; bcl-2: B-cell lymphoma 2; G-CSF: Granulocyte-colony stimulating factor.