Plerixafor (AMD3100)

Plerixafor inhibits CXCL12-mediated chemotaxis with a potency lightly better than its affinity for CXCR4. ^[1]

Plerixafor also antagonizes SDF-1/CXCL12 ligand binding with an IC50 of 651 nM. Plerixafor inhibits SDF-1 mediated GTP-binding, SDF-1 mediated calcium flux and SDF-1 stimulated chemotaxis with IC50 of 27 nM, 572 nM and 51 nM, respectively. Plerixafor does not inhibit calcium flux against cells expressing CXCR3, CCR1, CCR2b, CCR4, CCR5 or CCR7 when stimulated with their cognate ligands, nor does Plerixafor inhibit receptor binding of LTB4. Plerixafor does not, on its own, induce a calcium flux in the CCRF–CEM cells, which express multiple GPCRs including CXCR4, CCR4 and CCR7. ^[2]

A single topical application of Plerixafor promotes wound healing in diabetic mice by increasing cytokine production, mobilizing bone marrow EPCs, and enhancing the activity of fibroblasts and monocytes/macrophages, thereby increasing both angiogenesis and vasculogenesis. ^[3]

Cohorts of mice are administered with PBS, IGF1, PDGF, SCF, or VEGF for five consecutive days and Plerixafor on the 5th day. The number and size of the colonies are highest in IGF1 plus Plerixafor injected mice compared to PDGF, SCF and VEGF treated groups, in combination with Plerixafor. ^[4]

• Receptor binding assays

  For the competition binding studies against CXCR4, a concentration range of Plerixafor is incubated for 3 hours at 4 °C in binding buffer (PBS containing 5 mM MgCl₂, 1 mM Ca Cl₂, 0.25% BSA, pH 7.4) with 5 × 10⁵ CCRF–CEM cells and 100 pM ¹²⁵I-SDF-1α (2200 Ci/mmol) in Milipore Durapore^TM filter plates. Unbound ¹²⁵I-SDF-1α is removed by washing with cold 50 mM HEPES, 0.5 M NaCl pH 7.4. The competition binding assay against BLT1 is performed on membranes from CHO-S cells expressing recombinant BLT1. The membranes are prepared by mechanical cell lysis followed by high speed centrifugation, re-suspended in 50 mm HEPES, 5 mM MgCl₂ buffer and flash frozen. The membrane preparation is incubated with Plerixafor for 1 hour at room temperature in an assay mixture containing 50 mM Tris, pH 7.4, 10 mM MgCl₂, 10 mM CaCl₂, 4 nM LTB₄ mixed with 1 nM ³H-LTB₄ (195.0 Ci/mmol) and 8 μg membrane. The unbound ³H-LTB₄ is separated by filtration on Millipore Type GF-C filter plates.

• Animal Models

  Twelve-week-old C57BL/6 mice with segmental bone defect

• Dosages

  5 mg/kg

• Administration

  Administered via i.p.