uPAR/CD87: A Pivotal Regulator in the Tumor Microenvironment and Beyond

Concept

Urokinase-type plasminogen activator receptor (uPAR), also designated as CD87, is a membrane-anchored glycoprotein receptor encoded by the gene localized on human chromosome 19q13.3-13.4. As the primary receptor for urokinase plasminogen activator (uPA), uPAR exerts multifaceted biological functions, with its core roles centered on mediating extracellular matrix (ECM) degradation and cell migration. Beyond its canonical fibrinolytic activity, uPAR acts as a key modulator of diverse cellular and pathological processes, emerging as a vital research hotspot in oncology, fibrosis, and inflammatory disease research.

Research Frontier

Contemporary life science research has identified uPAR/CD87 as a versatile molecular player with far-reaching implications in the tumor microenvironment (TME) and a spectrum of fibrotic and inflammatory disorders. Cutting-edge studies have deepened the understanding of uPAR’s structural plasticity—including full-length and domain-truncated isoforms—and its context-dependent signaling cascades, uncovering its non-proteolytic signal transduction capabilities independent of uPA-mediated proteolysis. A major research focus now lies in elucidating the mechanistic link between uPAR overexpression and disease progression, as well as validating uPAR as a promising therapeutic target and diagnostic biomarker for solid tumors, cardiac fibrosis, idiopathic pulmonary fibrosis (IPF), and systemic sclerosis (SSc). Additionally, the development of uPAR-targeted drug delivery systems and recombinant uPAR-based research tools has become a burgeoning area for translational biopharmaceutical research.

Research Significance

In-depth investigation and application of uPAR/CD87 hold profound scientific and translational value across basic research and clinical practice, with wide-ranging implications for multiple research fields:

1. Oncology and Disease Mechanism Research: uPAR is a critical mediator of tumor cell invasion and metastasis via ECM degradation and cell migration regulation; its overexpression is closely associated with poor prognosis in various malignancies. Studying uPAR provides a molecular basis for unraveling the regulatory mechanisms of TME remodeling and disease progression in fibrotic and inflammatory disorders.
2. Therapeutic Target Validation: Inhibiting uPAR function can effectively block tumor cell migration and invasion, while targeted modulation of uPAR signaling offers novel therapeutic strategies for fibrotic diseases such as cardiac fibrosis and IPF, addressing unmet clinical needs for refractory diseases.
3. Clinical Diagnostic Development: Ubiquitous uPAR overexpression in tumors and fibrotic disorders makes it a potential diagnostic and prognostic biomarker; detecting uPAR/soluble uPAR (suPAR) levels in biological fluids can aid in early disease diagnosis and progression assessment.
4. Biopharmaceutical Innovation: Recombinant uPAR proteins serve as core tools for developing novel targeted drug carriers and biotherapeutics, enhancing the targeting ability and efficacy of biopharmaceuticals while reducing off-target side effects.

Related Mechanisms and Product Applications

Core Biological Mechanisms of uPAR/CD87

uPAR exerts its biological functions through two major regulatory axes: uPA-dependent proteolytic activity and uPA-independent signal transduction, with wide-ranging involvement in ECM remodeling, cell behavior modulation, and pathological process regulation.

1. Fibrinolytic and ECM degradation mechanism: uPAR binds to its ligand uPA to trigger the conversion of plasminogen to plasmin, a serine protease that degrades key ECM components. This process, coupled with the activation of pro-matrix metalloproteinases (pro-MMPs), facilitates cell migration, invasion, and tumor metastasis, with its activity tightly regulated by plasminogen activator inhibitors 1 and 2 (PAI-1, PAI-2).
2. Intracellular signal transduction mechanism: uPAR mediates proteolysis-independent signaling cascades by interacting with integrins and other cell surface molecules, activating key pathways including PI3K/Akt, focal adhesion kinase (FAK), and JAK-STAT. These pathways regulate cell proliferation, apoptosis, angiogenesis, and immune responses, and are closely associated with inflammation, fibrosis, and tumorigenesis.
3. Receptor trafficking and functional plasticity: uPAR exists in full-length and truncated (e.g., Domain 1) isoforms on the cell membrane, and undergoes internalization and recycling as part of uPA/uPAR/PAI complexes. Its N-terminal extracellular domain can form ternary complexes with proteins such as SORL1, regulating PLAUR internalization and contributing to the pathogenesis of diseases like rheumatoid arthritis.

Tissue Expression and Pathological Dysregulation of uPAR/CD87

uPAR is widely expressed in normal mammalian tissues and cells, including decidua, spleen, fibroblasts, monocytes, macrophages, endothelial cells, and smooth muscle cells, with basal expression levels tightly regulated under physiological conditions. Inflammatory stimuli can induce robust uPAR upregulation, while aberrant overexpression of uPAR/suPAR is a hallmark of multiple pathological conditions:

• Cardiac fibrosis, idiopathic pulmonary fibrosis, and cystic fibrosis
• Chronic liver diseases and chronic hepatitis B
• Focal segmental glomerulosclerosis and renal glomerulosclerosis
• Systemic sclerosis and various solid tumors

Mechanism of uPA/uPAR axis in tumor metastasis

Schematic illustration of uPA/uPAR-mediated proteolytic cascades, ECM degradation, and downstream biological effects in malignant solid tumors, including tumor cell invasion, metastasis, angiogenesis, and cell proliferation. The regulatory role of PAI-1/PAI-2 in uPA/uPAR activity is also depicted.

Structural features and isoforms of uPAR/CD87

Diagram of full-length membrane-bound uPAR (with GPI anchor and D1/D2/D3 domains) and soluble uPAR (suPAR) isoforms, showing protease-mediated cleavage sites and the uPA-binding region within the D1 domain.

 uPAR overexpression in human fibrotic and inflammatory diseases

Summary of uPAR/suPAR upregulation in various organ-specific diseases, including cardiac, hepatic, pulmonary, renal, and cutaneous fibrotic/inflammatory disorders, with corresponding research references.

Application of Recombinant uPAR Protein in Scientific Research

Recombinant uPAR/CD87 protein is an indispensable research tool for investigating uPAR’s structural and functional characteristics, and supports translational research in drug development and diagnostic biomarker validation. Key applications include:

1. Basic mechanistic research: Unraveling the molecular mechanisms of uPAR-mediated ECM degradation, signal transduction, and receptor trafficking; exploring the interaction between uPAR and its binding partners (uPA, integrins, SORL1).
2. Target validation and drug screening: Assessing the efficacy of uPAR-targeted inhibitors and therapeutics; developing uPAR-based drug delivery systems for targeted cancer therapy.
3. Biomarker development: Optimizing detection methods for uPAR/suPAR as diagnostic and prognostic biomarkers for tumors and fibrotic diseases.
4. Structural biology research: Investigating the three-dimensional structure of uPAR and its complexes with ligands/inhibitors to guide rational drug design.

 Bioactivity detection curve of uPAR/CD87 His Tag Protein (SPR assay)

Sensorgram showing the binding kinetics of recombinant uPAR protein with its target ligand, reflecting the high bioactivity of the protein.

 Binding affinity parameters of uPAR/CD87 His Tag Protein

Table of key binding kinetics parameters (Ka, Kd, KD, Rmax) derived from SPR analysis, validating the high binding activity of the recombinant protein.

Concentration-dependent binding curve of uPAR/CD87 His Tag Protein

SPR-based binding curve showing the concentration-dependent interaction between recombinant uPAR protein and its ligand, confirming dose-responsive bioactivity.

Second binding affinity parameter set of uPAR/CD87 His Tag Protein

Additional binding kinetics parameters (KD, Rmax) for recombinant uPAR protein, further verifying its high bioactivity and binding specificity.

Brand Mission of AN BIO PTE. LTD.

ANT BIO PTE. LTD. is a global leading provider of high-quality life science research reagents, dedicated to empowering breakthroughs in biomedical research and biopharmaceutical development by supplying premium antibodies, recombinant proteins, research kits, and general life science reagents. We have built three specialized sub-brands with distinct positioning to comprehensively meet diverse research needs across the life science field:

• Absin: Specializes in general life science reagents and research kits, covering the basic experimental needs of cell biology, molecular biology, and biochemistry research.
• Starter: Focuses on high-performance antibodies for basic research and translational medicine, providing highly specific and sensitive antibody tools for target detection and functional validation.
• UA: Commits to the R&D and production of high-purity, high-activity recombinant proteins, including key target proteins for oncology, fibrosis, and inflammatory disease research such as uPAR/CD87, to support cutting-edge scientific research and drug discovery.

Adhering to the core values of innovation, quality, and customer-centricity, ANT BIO PTE. LTD. leverages advanced protein expression and purification technologies to ensure our recombinant protein products feature high purity, excellent bioactivity, and batch-to-batch consistency. Our professional technical support team provides comprehensive pre-sales and after-sales services, including experimental protocol optimization and technical troubleshooting, to streamline research workflows for scientists worldwide.

Related Product List

ANT BIO PTE. LTD. launches high-activity, high-purity recombinant uPAR/CD87 protein under the UA sub-brand, rigorously validated for bioactivity and specificity, and ideal for uPAR-related mechanistic research, target validation, and drug screening.

ANT BIO PTE. LTD. – Empowering Scientific Breakthroughs

At ANTBIO, we are committed to advancing life science research through high-quality, reliable reagents and comprehensive solutions. Our specialized sub-brands (Absin, Starter, UA) cover a full spectrum of research needs, from general reagents and kits to antibodies and recombinant proteins. With a focus on innovation, quality, and customer-centricity, we strive to be your trusted partner in unlocking scientific mysteries and driving medical progress. Explore our product portfolio today and elevate your research to new heights.