Rapid Mobilization of Murine Hematopoietic Stem and Progenitor Cells with TG-0054, a Novel CXCR4 Antagonist.

Abstract

3542 Poster Board III-479 Background The interaction between SDF-1 and its receptor, CXCR4, is responsible for retaining of stem cells in the bone marrow. CXCR4 antagonist disrupts the SDF-1/CXCR4 interaction and mobilizes CD34+ hematopoietic stem cells (CD34+ HSCs) and CD133+ endothelial progenitor cells (CD133+ EPCs) from bone marrow into circulation, which can be used as a source for stem cell transplantation and other potential clinical indications. TG-0054 is a novel CXCR4 antagonist. In vitro CXCR4 antagonistic activity and in vivo stem cell mobilization activity of TG-0054 were determined in this study. Materials and Methods In vitro pharmacological assays, including GTP-binding assay, calcium mobilization assay, and chemotaxis assays, were performed to assess the potency of TG-0054 as a CXCR4 antagonist. In addition, receptor-binding assays against a panel of human chemokine receptors as well as other 68 cellular receptors were screened to evaluate the specificity of TG-0054. Kinetics and dose-dependent response of stem cell mobilization by TG-0054 were demonstrated in BALB/c mice. Activity of stem cell mobilization of TG-0054 when used alone or combined with G-CSF was also studied. Results TG-0054 blocked SDF-1-binding to CXCR4 receptor with an IC50 of 10 nM and inhibited SDF-1–induced GTP-binding (IC50 = 6 nM), chemotaxis (IC50 = 43 nM), and calcium mobilization (IC50 = 59 nM). TG-0054 showed greater than 3000-fold selectivity for CXCR4 receptor over other chemokine receptors. It is noteworthy that the IC50 for the inhibitory effect of TG-0054 on hERG potassium currents was greater than 1000 μM when human embryonic kidney (HEK) cells were used to examine the in vitro effects on the hERG potassium channel currents. In animal studies, TG-0054 rapidly and effectively mobilized CD34+ HSCs and CD133+ EPCs into circulation. Single intravenous (IV) administration of TG-0054 resulted in a rapid increase of total white blood cell (WBC) counts, as well as CXCR4+, CD34+, and CD133+ cells in peripheral blood between 1–3 hour post-injection and the cell counts returned to baseline within 6 hours. At their maximum tolerated doses (MTD), TG-0054 increased CXCR4+ cells by 28.7-fold in mice. Furthermore, TG-0054 efficiently mobilized CD34+ (14.5-fold) and CD133+ (7.9-fold) cells. The combined effects of TG-0054 and G-CSF on HSCs and EPCs mobilization from the bone marrow in mice were also investigated. G-CSF (100 μg/kg/day) was administered subcutaneously (SC) from Day 1 to Day 4 followed by a single IV injection of TG-0054 or AMD3100 on Day 5. Synergistic effects were observed in all cell types in mice receiving combination of G-CSF and 50 mg/kg of TG-0054 (total WBC 23.0-fold, CXCR4+ 29.0-fold, CD34+ 37.1-fold, CD133+ 110.8-fold of increase in combination group). Conclusion It was concluded that TG-0054 was a potent and selective CXCR4 antagonist intended for the use of stem cell transplant and other clinical indications. It showed strong stem cell mobilization activity comparable to G-CSF when used alone, and demonstrated synergistic effects when combined with G-CSF in a nonclinical model. Disclosures: Huang: TaiGen Biotechnology Inc.: Employment. Liu:TaiGen Biotechnology Inc.: Employment. Yen:TaiGen Biotechnology Inc.: Employment. Chen:TaiGen Biotechnology Inc.: Consultancy. Chen:TaiGen Biotechnology Inc.: Consultancy. King:TaiGen Biotechnology Inc.: Employment. Hsu:TaiGen Biotechnology, Inc.: Membership on an entity's Board of Directors or advisory committees.

CXCR4 Antagonist TG-0054 Mobilizes Mesenchymal Stem Cells, Attenuates Inflammation, and Preserves Cardiac Systolic Function in a Porcine Model of Myocardial Infarction

“…To ensure that TG-0054, which was shown to mobilize HSCs in mice and humans (11, 22), was effective in mobilizing CXCR4+ stem cells in minipigs, we analyzed PB cell components after TG-0054 treatment (two intravenous doses of 2.85 mg/kg TG-0054 of 72 h apart). TG-0054 increased PB white blood cell (WBC) counts, which peaked at 0.5 and 1 h after the first dose and the second dose, respectively (Fig.…”

“…TG-0054 is a CXCR4 antagonist and was reported to mobilize BM HSCs (22). It is being evaluated for treating human BM malignancies (35, 36).…”

“…The therapeutic effect of AMD3100 was thought to be primarily augmenting endothelial protective function and neovascularization (25, 26). TG-0054, another CXCR4 antagonist, was reported to mobilize BM HSCs (22) and is under clinical trials for cancer therapy (35, 36). Little is known about MSC mobilization and recruitment to cardiac damage sites by CXCR4 antagonists.…”

A Novel CXCR4 antagonist enhances angiogenesis via modifying the ischaemic tissue environment

“…However, this process took several days and the effect of GC‐SF has broad interindividual variability . AMD3100, a representative CXCR4 antagonist, can effectively and rapidly mobilize HSCs, including EPCs . However, HSCs mobilized by AMD3100 showed obviously impaired survival after transplantation , and severe cardiac toxicity has been reported after long‐term AMD3100 administration .…”

Stem Cell Mobilizers Targeting Chemokine Receptor CXCR4: Renoprotective Application in Acute Kidney Injury

“…SDF-1 serves as a specific ligand to CXCR4, a G protein-coupled receptor with seven transmembrane domains on the surface of many stem cell types. , The CXCR4/SDF-1 axis has been well-known to regulate cancer metastasis, stem cell homing, trafficking, and mobilization. − Thus, CXCR4 antagonists that mobilize various stem cells, including hematopoietic stem cells (HSCs), endothelial progenitor cells (EPCs), and mesenchymal stem cells (MSCs), out of the bone marrow into the peripheral blood, might potentially serve as therapeutic agents to treat AKI either via autologous transplantation or simply by raising stem cell levels in blood . Indeed, such cell-based therapy concept has been validated by a selective CXCR4 antagonist, a small molecule known as AMD3100 (Plerixafor, compound 1 ). − Approved by the U.S. FDA in December 2008, a regimen combining compound 1 with granulocyte colony-stimulating factor (G-CSF, Filgrastim) that synergistically augments stem cell mobilization has been used for autologous transplantation of CD34 + cells (HSCs) in patients suffering multiple myeloma or non-Hodgkin’s lymphoma. − Such procedures allowed rapid restoration of immune system after undergoing destructive radio- or chemotherapy. − Moreover, other findings revealed that compound 1 could effectively ameliorate the injured regions caused by myocardial infarction or ischemic stroke, suggesting that CXCR4 antagonists might have great therapeutic potential in anti-inflammation and/or tissue repair. − Though many small molecules and peptidomimetics have been successfully developed to target CXCR4 receptors, , only a fraction of them (Figure ), including TG-0054 (phase II), AMD070 (phase I/II), MSX-122 (phase I), BL8040 (T140) (phase I/II), LY2510924 (phase II), CTCE-9908 (phase I/II), and POL6326 (phase I/II), have entered clinical development. These clinical candidates mainly act as HIV entry inhibitors or stem cell mobilizers for autologous transplantation.…”