Allogeneic stem cell transplantation in the treatment of acute myeloid leukemia: An overview of obstacles and opportunities

Table 1 Molecules that mediate hematopoietic stem and progenitor cell adhesion and chemotaxis during transplantation

HSPC receptor	Bone marrow ligands	Effect	Ref.
PSGL-1/CD162	Selectins (P and E)	Promote HSPC homing	[10]
β1 integrin	Opn	Contribute to HSC trans-marrow migration toward the endosteal region	[17,18]
VLA-4/α4 β1	VCAM-1, fibronectin	Promote HSPC homing	[7,11]
VLA-5/α5 β1	Fibronectin	Promote HSPC homing and proliferation	[19,20]
LFA-1/αL β2	ICAM-1	Promote HSPC homing	[7,11]
LPAM-1/α4 β7	MAdCAM-1	Promote HSPC homing and engraftment	[21]
Cx43		Participate in the formation of intercellular transmembrane channels, facilitate the transportation of mitochondria or other substances, and promote bone marrow regeneration and HSPC engraftment	[22]
CXCR4	SDF-1	Promote HSPC homing and engraftment and participate in the regulation of HSPC survival and proliferation	[7]
c-kit	SCF	The transmembrane isoform of SCF is critical in the lodgment and detainment of HSCs within the bone marrow niche	[23]
c-MPL	TPO	TPO promotes the survival and proliferation of HSPCs and upregulates SDF-1 in the bone marrow niche, thereby contributing to HSPC homing and engraftment	[24,25]
CD44/Pgp-1	Selectins (P, E and L), HA	CD44 and HA play a key role in SDF-1-dependent transendothelial migration of HSPCs and their final anchorage within the bone marrow niche	[26]
CD82/KAI1		CD82 modulates HSPC bone marrow maintenance, homing, and engraftment	[27]
Anxa2r	Annexin II/Anxa2	Regulate stem cell adhesion, homing, and engraftment	[28]
CaR	Ca2+	Enhance HSC lodgment and engraftment in the bone marrow niche	[29]
N-cadherin	N-cadherin	N-cadherin-mediated cell adhesion is functionally required for the establishment of hematopoiesis in the bone marrow niche after bone marrow transplantation	[30]

Anxa2r: Annexin II receptor; c-kit: Tyrosine-protein kinase kit; c-MPL: Thrombopoietin receptor; Ca²⁺: Calcium; CaR: Calcium-sensing receptor; CD162: cluster of differentiation 162; CD44: Cluster of differentiation 44; CD82: Cluster of differentiation 82; Cx43: Connexin 43; CXCR4: C-X-C chemokine receptor 4; HA: Hyaluronic acid; HSC: Hematopoietic stem cell; HSPC: Hematopoietic stem and progenitor cells; ICAM-1: Intercellular adhesion molecule 1; KAI1: Kangai 1; LFA-1: Lymphocyte function-associated antigen-1; LPAM-1: Lymphocyte Peyer's patch adhesion molecule-1; MAdCAM-1: Mucosal addressin cell adhesion molecule-1; MPL: Myeloproliferative leukemia gene; Opn: Osteopontin; Pgp-1: Phagocytic glycoprotein-1; PSGL-1: P-selectin glycoprotein ligand-1; Ref.: Reference; SCF: Stem cell factor; SDF-1: Stromal cell-derived factor-1; TPO: Thrombopoietin; VCAM-1: Vascular cellular adhesion molecule-1; VLA-4: Very late antigen 4; VLA-5: Very late antigen 5.