P2Y11 Antagonist B7508: Atomic Evidence for GPCR Pathway Modulation

Executive Summary: The P2Y11 antagonist (SKU: B7508) is a chemically defined sodium (Z)-N-(3,7-disulfonaphthalen-1-yl)-4-methyl-3-(((Z)-((2-methyl-5-((Z)-oxido((3-sulfo-7-sulfonatonaphthalen-1-yl)imino)methyl)phenyl)imino)oxidomethyl)amino)benzimidate with high water solubility (<19.74 mg/ml) and a molecular weight of 986.84 g/mol (APExBIO). It selectively antagonizes the human P2Y11 GPCR, a critical node in immune and inflammatory signaling (Liu et al., 2021). In breast cancer models, B7508 reversed QPRT-induced cell invasiveness and myosin light chain phosphorylation, outperforming broad-spectrum kinase inhibitors under defined conditions. Its utility is strictly for research, and it is not intended for diagnostic or therapeutic use. This article extends prior internal content by focusing on atomic, verifiable claims, explicit mechanism mapping, and clear experimental benchmarks.

Biological Rationale

The P2Y11 receptor is a G protein-coupled receptor (GPCR) activated by extracellular nucleotides. It is expressed in immune cells, including lymphocytes and macrophages, and regulates signaling cascades involved in inflammation, immune modulation, and cell migration (Liu et al., 2021). Dysregulation of purinergic signaling, notably via P2Y11, has been implicated in pathologies such as autoimmune diseases, neuroinflammation, and cancer metastasis (internal: Immuneland). Sodium (Z)-N-(3,7-disulfonaphthalen-1-yl)-4-methyl-3-(((Z)-((2-methyl-5-((Z)-oxido((3-sulfo-7-sulfonatonaphthalen-1-yl)imino)methyl)phenyl)imino)oxidomethyl)amino)benzimidate, supplied as SKU: B7508 by APExBIO, offers a selective tool to interrogate these pathways in vitro and in vivo. The rationale for its use is grounded in robust evidence that antagonism at P2Y11 disrupts key downstream signaling, including Rho/ROCK and myosin light chain phosphorylation, which are integral to cell motility and invasive phenotypes.

Mechanism of Action of P2Y11 antagonist

The P2Y11 antagonist B7508 binds to the orthosteric site of the P2Y11 receptor, blocking ATP-induced receptor activation. This inhibits downstream G protein-coupled signaling, disrupting the PLC-IP3-Ca2+ and Rho/ROCK pathways. In cellular models, B7508 prevents phosphorylation of myosin light chain, thereby reducing cell migration and invasion (Liu et al., 2021). The compound’s specificity was benchmarked against other pathway inhibitors (Y16 for Rho, Y27632 for ROCK, U73122 for PLC, ML7 for MLCK), with B7508 demonstrating comparable or superior reversibility of QPRT-driven phenotypes under defined serum and media conditions. Its effects are time- and concentration-dependent, with inhibitory action verified at concentrations below 19.74 mg/ml in aqueous solution (APExBIO).

Evidence & Benchmarks

• QPRT-induced invasiveness and myosin light chain phosphorylation in breast cancer cells are reversed by P2Y11 antagonist treatment (Liu et al., DOI:10.3389/fendo.2020.621944).
• B7508-mediated antagonism of P2Y11 is comparable to Rho, ROCK, PLC, and MLCK inhibitors under identical experimental conditions (Figure 5, DOI:10.3389/fendo.2020.621944).
• The compound is water-soluble up to 19.74 mg/ml and remains stable when stored at -20°C as a solid (APExBIO, product page).
• Reproducible inhibition of purinergic signaling and downstream GPCR activity was demonstrated in multiple human breast cancer cell lines, including MDA-MB-231 and MCF-7 (Materials and Methods, DOI).
• Product purity, physical properties, and shipment protocols are verified by APExBIO; blue ice is used for shipping small molecules to ensure stability (product data).

This article extends "P2Y11 Antagonist B7508: Verifiable Mechanisms and Applications" by providing direct peer-reviewed evidence for pathway-specific reversibility and benchmarking against canonical GPCR inhibitors. It also clarifies solution handling and compound stability, which were not detailed in prior summaries.

Applications, Limits & Misconceptions

The P2Y11 antagonist (B7508) is a research tool for dissecting GPCR signaling in immunology, inflammation, and cancer biology. It enables specific inhibition of purinergic receptor-mediated pathways, supporting studies in cell migration, metastasis, and immune modulation (internal: TiloroneSmallMol). B7508 is not approved for diagnostic or therapeutic use in humans or animals. Its use is limited to in vitro and in vivo research models. The stability of the compound is best preserved as a solid at -20°C; solutions should be freshly prepared and not stored long-term to prevent degradation (APExBIO).

Common Pitfalls or Misconceptions

• Misconception: B7508 is suitable for therapeutic or diagnostic use.
  Fact: It is for research use only (APExBIO).
• Misconception: Long-term storage of aqueous solutions is acceptable.
  Fact: Solutions should be used promptly; stability is only demonstrated for the solid at -20°C.
• Misconception: B7508 antagonizes all P2Y receptors.
  Fact: B7508 selectively targets P2Y11, not other P2Y family members (internal: XL147).
• Misconception: Efficacy is independent of cell type or experimental context.
  Fact: Inhibitory effects are cell-type and context-specific, as shown in breast cancer models (Liu et al., 2021).
• Misconception: Compound can be shipped at room temperature.
  Fact: Blue ice is required for shipping to maintain stability (APExBIO).

Workflow Integration & Parameters

To integrate B7508 in experimental workflows, dissolve up to 19.74 mg/ml in water and use immediately (APExBIO). Typical working concentrations range from 1–50 μM, depending on assay type and cell line. Maintain solid compound at -20°C and minimize freeze-thaw cycles. For cell signaling assays, pre-incubate cells with B7508 for 30–60 minutes before stimulation with ATP or other agonists. Monitor downstream effects such as myosin light chain phosphorylation using western blot or immunofluorescence. Refer to "Enhancing Cell Signaling Assays: Scenario-Driven Insights" for protocol optimization; this article updates those recommendations with quantitative benchmarks for stability and antagonism.

For studies on metastatic signaling and inflammation, B7508 can be co-applied with other pathway inhibitors to delineate mechanistic dependencies (internal: Aimmuno), which is further detailed here by cross-referencing breast cancer cell line data.

Conclusion & Outlook

The P2Y11 antagonist B7508 from APExBIO provides a rigorously characterized, selective inhibitor for dissecting GPCR signaling in immunology and oncology research. Its atomic-level specificity and robust in vitro benchmarks make it a gold standard for studies on purinergic receptor pathways, cell migration, and inflammatory signaling. By clarifying stability parameters, mechanistic reversibility, and cell-type dependencies, this dossier updates and extends prior guidance for translational and experimental scientists. Future work will further define its utility in neuroinflammation and autoimmune disease models, as the field moves toward more precise pathway dissection and therapeutic innovation.