CXCR2 (CXC chemokine receptor 2): SB-265610 is a selective, non-peptide, competitive antagonist of CXCR2. [2]

SB-265610 has an IC50 of 3.7 nM for cytokine-induced neutrophil chemoattractant-1 (CINC-1) activation, and an IC50 of 70 nM for concentration-dependent neutrophil chemotaxis. When CINC-1 is administered at levels not previously attained, SB-265610 diminishes the anti-cellular effects of CINC-1 [1].

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SB-265610 therapy (2 mg/kg/day; i.p.; daily; continued in the afternoon) significantly reduced Gr-1+CD11b+ cell recruitment to Tgfbr2 breast cancer, but did not affect blank tumors [3].

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Inhibition of Neutrophil Recruitment (MPO Assay): Wild-type C57 Black mice were fed a diet containing SB-265610 (100 mg/kg/day) for 5 days prior to nitrogen mustard-induced cutaneous injury. Myeloperoxidase activity (a marker of neutrophil infiltration) in wound lysates was significantly lower in SB-265610-treated mice compared to untreated wild-type mice at post-wound days 1, 2, and 3 (p < 0.05). The reduction in MPO activity with SB-265610 was greater than that observed with prednisolone (glucocorticoid) treatment. [2]
Impairment of Wound Healing: SB-265610 treatment markedly impaired the wound healing process in CXCR2+/+ mice following nitrogen mustard injury. The effect was consistent with the delayed healing observed in CXCR2-/- mice, confirming the role of CXCR2 in wound repair. [2]
Comparison with Glucocorticoid: SB-265610 produced a more pronounced reduction in MPO activity than prednisolone (10 mg/kg/day), indicating greater selectivity for neutrophil recruitment pathways. [2]

Animal/Disease Models: MMTV-PyVmT/Tgfbr2MGKO and MMTV-PyVmT/Tgfbr2flox/flox tumors from donor mice [3]
Doses: 2 mg/kg/day
Doses: Intraperitoneal; Daily; Two-week
Experimental Results: Significant Inhibits the recruitment of Gr-1+CD11b+ cells to breast cancer.

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Animals:** Wild-type C57 Black mice were used. [2]
* **Drug Administration:** Mice were fed for 5 days with food containing SB-265610 at a dose of 100 mg/kg/day. The drug was delivered orally via dietary supplementation. [2]
* **Wounding Model:** After the 5-day pretreatment, mice were anesthetized with ketamine (20 mg/kg) and xylazine (0.32 mg/kg). Dorsal fur was removed, and nitrogen mustard (10 μg of a 2.0% solution in PBS) was applied topically over an area approximately 0.8 cm in diameter. [2]
* **Tissue Collection:** Wounds were harvested at post-wound days 1, 2, 3, 4, 7, and 10. Tissues were snap-frozen in liquid nitrogen for MPO assay. [2]
* **Myeloperoxidase Assay:** Wounded tissue was homogenized in phosphate buffer containing 0.5% hexadecyl trimethyl ammonium bromide (HTAB) in 50 mM phosphate buffer, pH 6.0. Tissues were sonicated on ice, subjected to freeze-thaw cycles, and centrifuged at 15,000 × g for 20 minutes at 4°C. Protein concentration was determined using Bio-Rad protein assay. Aliquots containing 40 μg protein were assayed for MPO activity by mixing with 0.5 mL potassium phosphate buffer (50 mM, pH 6.0) containing 0.167 mg O-dianosidine dihydrochloride and 0.0005% H₂O₂. Change in absorbance at 490 nm was measured spectrophotometrically over 2 minutes. [2]
* **Serum Level Measurement:** Blood samples were collected immediately prior to euthanasia. Serum levels of SB-265610 were assayed and found to be in the range of approximately 700 ng/mL, confirming adequate delivery of the antagonist. [2]

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Animals: Wild-type C57 Black mice were used. [2]
Drug Administration: Mice were fed for 5 days with food containing SB-265610 at a dose of 100 mg/kg/day. The drug was delivered orally via dietary supplementation. [2]
Wounding Model: After the 5-day pretreatment, mice were anesthetized with ketamine (20 mg/kg) and xylazine (0.32 mg/kg). Dorsal fur was removed, and nitrogen mustard (10 μg of a 2.0% solution in PBS) was applied topically over an area approximately 0.8 cm in diameter. [2]
Tissue Collection: Wounds were harvested at post-wound days 1, 2, 3, 4, 7, and 10. Tissues were snap-frozen in liquid nitrogen for MPO assay. [2]
Myeloperoxidase Assay: Wounded tissue was homogenized in phosphate buffer containing 0.5% hexadecyl trimethyl ammonium bromide (HTAB) in 50 mM phosphate buffer, pH 6.0. Tissues were sonicated on ice, subjected to freeze-thaw cycles, and centrifuged at 15,000 × g for 20 minutes at 4°C. Protein concentration was determined using Bio-Rad protein assay. Aliquots containing 40 μg protein were assayed for MPO activity by mixing with 0.5 mL potassium phosphate buffer (50 mM, pH 6.0) containing 0.167 mg O-dianosidine dihydrochloride and 0.0005% H₂O₂. Change in absorbance at 490 nm was measured spectrophotometrically over 2 minutes. [2]
Serum Level Measurement: Blood samples were collected immediately prior to euthanasia. Serum levels of SB-265610 were assayed and found to be in the range of approximately 700 ng/mL, confirming adequate delivery of the antagonist. [2]

Oral Bioavailability: SB-265610 was administered orally via dietary supplementation and achieved serum levels of approximately 700 ng/mL, demonstrating adequate absorption and systemic exposure. [2]
Serum Concentration: At the time of euthanasia (after 5 days of dietary administration at 100 mg/kg/day), serum levels of SB-265610 were measured and found to be in the range of approximately 700 ng/mL. [2]

[1]. Nonpeptide CXCR2 antagonist prevents neutrophil accumulation in hyperoxia-exposed newborn rats. J Pharmacol Exp Ther. 2001 Oct;299(1):90-5.

[2]. Impaired healing of nitrogen mustard wounds in CXCR2 null mice. Wound Repair Regen. 2003 May-Jun;11(3):213-9.

[3]. Abrogation of TGF beta signaling in mammary carcinomas recruits Gr-1+CD11b+ myeloid cells that promote metastasis. Cancer Cell. 2008 Jan;13(1):23-35.

Background: SB-265610 is a selective, non-peptide, competitive antagonist of CXCR2 developed by GlaxoSmithKline. It has been previously shown to inhibit interleukin-8-induced neutrophil migration. [2]
Mechanism of Action: SB-265610 blocks CXCR2, preventing chemokine-mediated neutrophil recruitment to sites of inflammation. In this study, it reduced neutrophil infiltration (measured by MPO activity) and impaired wound healing after nitrogen mustard injury, confirming the critical role of CXCR2 in the inflammatory phase of cutaneous wound repair. [2]
Comparison with Genetic Knockout: The effects of SB-265610 in wild-type mice phenocopied the delayed wound healing observed in CXCR2-/- mice, providing pharmacological validation of the genetic findings. [2]
Selectivity: The study notes that SB-265610 is a selective CXCR2 antagonist, and the effects observed are attributed to specific blockade of this receptor rather than non-specific anti-inflammatory effects. [2]
Therapeutic Implications: The findings suggest that CXCR2 agonists, rather than antagonists, might have therapeutic potential for treating nitrogen mustard-induced skin lesions by facilitating wound repair. However, this study used an antagonist to demonstrate the receptor's importance. [2]

C14H9BRN6O

357.164860486984

356.002

C, 47.08; H, 2.54; Br, 22.37; N, 23.53; O, 4.48

211096-49-0

9841667

Light yellow to yellow solid powder

1.779 g/cm3

527ºC at 760 mmHg

272.5ºC

3.382

3

4

2

22

466

0

SEDUMQWZEOMXSO-UHFFFAOYSA-N

InChI=1S/C14H9BrN6O/c15-9-3-1-2-4-10(9)17-14(22)18-11-6-5-8(7-16)12-13(11)20-21-19-12/h1-6H,(H2,17,18,22)(H,19,20,21)

N-(2-Bromophenyl)-N'-(7-cyano-1H-benzotriazol-4-yl)urea

SB-265610 SB 265610 SB265610.

2934.99.03.00

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~50 mg/mL (~139.99 mM)

Solubility in Formulation 1: ≥ 2.5 mg/mL (7.00 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (7.00 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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 (Please use freshly prepared in vivo formulations for optimal results.)