CD44 Monoclonal Antibody
Description
CD44 as a Therapeutic Target
CD44 is overexpressed in various cancers (e.g., esophageal, breast, and leukemia) and contributes to tumor cell adhesion, migration, survival, and chemo-resistance . Its interaction with hyaluronic acid (HA) and role in cancer stem cell maintenance make it a high-priority target .
Diagnostic Applications of CD44 mAbs
CD44 mAbs are widely used for detecting CD44 isoforms in research and clinical settings:
Key Findings:
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C44Mab-46 demonstrated strong staining in formalin-fixed esophageal squamous cell carcinoma (ESCC) tissues .
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Anti-CD44v antibodies (e.g., BIWA-4/8) labeled with Re showed efficacy in head and neck squamous cell carcinoma (SCC) xenografts .
Therapeutic Mechanisms and Preclinical Data
CD44 mAbs exert antitumor effects through multiple mechanisms:
Direct Cytotoxicity and Immune Activation
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C44Mab-46-mG2a: Induced 88% complement-dependent cytotoxicity (CDC) in CD44s-overexpressing cells .
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RG7356: Promoted macrophage activation and reduced leukemia engraftment in mice .
Inhibition of Tumor Progression
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IM7: Reduced metastasis in breast cancer models by blocking HA-induced signaling .
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5-mG2a: Suppressed xenograft tumor growth in esophageal cancer models by 60% compared to controls .
RG7356 in Solid Tumors
CD44v-Targeted Combinations
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Sulfasalazine (xCT inhibitor) combined with cisplatin reduced CD44v-positive gastric cancer cells in clinical trials .
Comparative Analysis of CD44 mAbs
Challenges and Future Directions
Product Specs
This monoclonal antibody targeting CD44 was generated using a recombinant human CD44 antigen protein. Mouse spleen cells, producing antibodies against CD44, were fused with myeloma cells. This resulted in hybridomas capable of sustained growth and high-yield CD44 monoclonal antibody production. Antibody functionality has been validated using ELISA, Western blotting, immunohistochemistry (IHC), immunofluorescence (IF), and flow cytometry (FC).
CD44, a transmembrane single-chain glycoprotein, belongs to the family of cell adhesion molecules and is widely expressed on cell surfaces. Initially identified as a granulocyte-T lymphocyte antigen, it was designated CD44 by the Third International Workshop on Human Leukocyte Differentiation Antigens. Encoded by a single gene on chromosome 11p13, CD44 exhibits a molecular weight ranging from 80 to 200 kDa due to extensive N-linked, O-linked glycosylation, and chondroitin sulfate modification. The product is heparinized.
As a crucial adhesion molecule expressed on lymphocytes, monocytes, endothelial cells, and other cell types, CD44's diverse ligands contribute to its multifaceted functions. It acts as a receptor for various cytokines and proteases, playing significant roles in organogenesis, hematopoiesis, inflammation, and autoimmune responses. Given the importance of early diagnosis in cancer treatment, understanding CD44's involvement in tumorigenesis is critical.
Target Background
CD44 is a cell-surface receptor pivotal in cell-cell interactions, cell adhesion, and migration. It enables cells to sense and respond to their tissue microenvironment, participating in diverse cellular processes. These include T-lymphocyte activation, recirculation, and homing; hematopoiesis; inflammation; and responses to bacterial infections. Through its ectodomain, CD44 interacts with extracellular matrix components such as hyaluronan (HA), collagen, growth factors, cytokines, and proteases. Its cytoplasmic domain facilitates signal transduction by assembling protein complexes containing receptor kinases and membrane proteases. These effectors—including PKN2, the RhoGTPases RAC1 and RHOA, Rho-kinases, and phospholipase C—orchestrate signaling pathways that trigger calcium mobilization and actin-mediated cytoskeletal reorganization, essential for cell migration and adhesion.
- Interleukin-4 induces a CD44high/CD49bhigh PC3 subpopulation with tumor-initiating characteristics. PMID: 29236307
- miR-711-mediated downregulation of CD44 inhibited epithelial-mesenchymal transition (EMT) in gastric cancer cells in vitro and in vivo by modulating vimentin and E-cadherin expression. PMID: 30226620
- Expression levels of MACC1, CD44, Twist1, and KiSS-1 correlate with overall survival duration in patients with colonic adenocarcinoma. PMID: 30021598
- miR-218-5p, downregulated in invasion front cells, negatively regulates oral squamous cell carcinoma invasiveness by targeting the CD44-ROCK pathway. PMID: 29990854
- miR-520b inhibits head and neck cancer malignancy by regulating cancer stemness conversion through CD44 targeting. PMID: 28515423
- CD44 and CD55 have been identified as potential host receptors for *Plasmodium falciparum* during invasion (Review). PMID: 29249333
- High CD44 expression in ascites tumor cells correlates with cancer stem cell (CSC) and EMT phenotypes, regulated by the tumor microenvironment through pathways including TGF-beta signaling. PMID: 30142697
- Twist1 and CD44 are identified as novel REST-targeted genes, providing insights into their epigenetic regulation by REST. PMID: 28256535
- Increased CD44 levels in ovarian cancer correlate with enhanced CD44s (standard) expression and decreased epithelial variants (CD44v). CD44s upregulation during TGFβ1-induced EMT is mediated by ESRP1 downregulation. CD44s overexpression induces EMT, invasion, and chemoresistance. PMID: 29130517
- CD44 is a significant prognostic factor in pancreatic cancer. PMID: 29683068
- The CD44-NRF2 axis may be a therapeutic target for controlling stress resistance and survival of CD44high CSCs in breast tumors. PMID: 29729523
- A positive feedback loop exists between CD44s and YAP1 in hepatocellular carcinoma, with CD44s acting as both upstream regulator and downstream effector of YAP1. PMID: 29649630
- CHI3L1 expression is a prognostic biomarker for gastric cancer, identifying the CHI3L1/CD44 axis as a potential therapeutic target. PMID: 30165890
- HA-CH-NP/siRNA selectively binds to CD44-positive tumor endothelial cells. PMID: 29890852
- IGF1R expression correlates with ABCG2 in osteosarcoma and with CD44 in osteosarcoma patients under age 10. PMID: 29892839
- CD44 polymorphisms are associated with gastric cancer. PMID: 29802692
- Oct-4 and CD44 immunopositivity identifies stem cell-like cells in benign odontogenic lesions with varying biological behaviors. PMID: 29971493
- CD44 rs13347 genotypes CT, CT+TT, TT, and allele T may be breast cancer risk factors. PMID: 29748526
- Circulating CD44+ and CD54+ lymphocytes may predict survival in lung cancer patients undergoing chemotherapy. PMID: 29148014
- Immunohistochemistry using pan-CD44 may not detect all cancer stem cells. PMID: 29682524
- CD44 regulates TLR2 responses in human macrophages; reduced CD44 levels or CD44 ligand engagement decrease NF-κB translocation and proinflammatory cytokine production. PMID: 29196459
- CD44 expression predicts gastric cancer development, particularly in patients with precancerous lesions carrying AG or GG genotypes. PMID: 29445738
- CD44 polymorphism rs13347 is a cancer risk factor, especially in Chinese populations, while rs11821102's minor allele may decrease susceptibility. PMID: 28000766
- Intermediate molecular mass hyaluronan and CD44 interactions on polymorphonuclear leukocytes (PMNs) enhance PMN function via F-actin polymerization and MAPK phosphorylation. PMID: 28730511
- CD44v9 is a potential biomarker for identifying cisplatin-chemoresistant urothelial cancer, contributing to reactive oxygen species defenses and chemoresistance via xCT. PMID: 29385995
- CD44 standard isoform is upregulated after high-dose X-ray irradiation. PMID: 29106581
- Upregulated miR-373 and downregulated CD44 and E-cadherin are observed in this study. PMID: 29307338
- MiRNA-34a suppresses invasion and metastasis in esophageal squamous cell carcinoma by regulating CD44. PMID: 29094237
- Near-infrared photothermal immunotherapy (NIR-PIT) with anti-CD44-IR700 shows potential for treating oral cavity squamous cell carcinoma. PMID: 28923838
- miR-214 represses CD44 expression by targeting its 3' untranslated region in HeLa, Raji, and Jurkat cells. PMID: 29138813
- Corilagin inhibits glycolysis by downregulating CD44 and STAT3. PMID: 28791374
- HYAL2 plays a role in CD44 alternative splicing. PMID: 29162741
- CD146 suppresses breast cancer progression as a target of CD44-downstream signaling. PMID: 29121955
- CD44 and CD24 do not reliably reflect cancer stem cell features or prognosis. PMID: 28967636
- CD44s levels correlate with EGFR signature and predict poor prognosis in glioblastomas. PMID: 28716909
- CD44s and splice variants CD44V3, CD44V6, and CD44V10 are significantly upregulated in Alzheimer's disease (AD) patients compared to controls. PMID: 28550248
- Network analysis reveals effects on tubulins, Nfe2l2, S100a4, Cd44, and Nfkb2, linked to traumatic brain injury (TBI) outcomes. PMID: 27530814
- Hepatic CD44 is upregulated in non-alcoholic steatohepatitis (NASH) patients, correlating with NAFLD activity score and inflammation markers. NASH correction reduces liver CD44+ cells. PMID: 28323124
- CD44v and CD44s play distinct roles in gallbladder cancer (GBC) progression and metastasis, with isoform switching triggering EMT. PMID: 28677740
- CD44 variants (rs13347, rs187115, and rs11821102) significantly modulate cancer susceptibility in Asians (meta-analysis). PMID: 27521214
- CD44v9 may be a prognostic biomarker for early gastric cancer and is associated with lymph node metastasis. PMID: 25779358
- Tunicamycin inhibits CD44s overexpression-associated cell migration. PMID: 29377347
- Osteopontin and CD44 are important in meningioma development and progression, serving as prognostic markers and therapeutic targets. PMID: 29504367
- CD24 and CD44 are upregulated in pancreatic cancer compared to chronic pancreatitis and may be related to cancer development. PMID: 28659655
- CD44v6 regulates gastric cancer tumorigenesis, angiogenesis, and survival in an IL-6-mediated, pSTAT3-dependent manner. PMID: 28507278
- CD44 is expressed by rheumatoid synovial fibroblasts in a MIF allele-dependent manner and is regulated by autocrine/paracrine MIF. PMID: 27872288
- Circulating tumor cells expressing ALDH, CD133, and CD44 are associated with poor prognosis and recurrence in pancreatic adenocarcinoma. PMID: 27789528
- High CD44 expression is associated with renal cell carcinoma. PMID: 27588469
- FAM83D promotes hepatocellular carcinoma (HCC) recurrence by promoting CD44 expression and CD44+ CSC malignancy. PMID: 27769048
- Intraperitoneal enrichment of cancer stem-like cells from ovarian cancer using CD44 and CD133 as markers. PMID: 27655682
Q&A
How do I select an appropriate CD44 monoclonal antibody for flow cytometry?
When selecting a CD44 mAb for flow cytometry, prioritize clones validated for your target species and isoform. For murine studies, IM7 demonstrates pan-isoform reactivity with an EC₅₀ of ≤0.25 µg/test . In human systems, C44Mab-46 binds CD44 standard isoforms (CD44s) with an apparent KD of 4.1 × 10⁻⁸ M in KYSE770 ESCC cells . Validate specificity through peptide blocking assays using wild-type (WT) vs. mutant epitopes (e.g., D175A) . Always compare staining intensity against CD44-knockout cells or isotype controls to minimize off-target artifacts .
What controls are essential for CD44 immunohistochemistry (IHC)?
For IHC, include:
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Isotype-matched negative controls to assess nonspecific binding
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Preabsorption controls with recombinant CD44 protein (≥10 µg/mL)
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Tissue microarray validation across ≥3 independent cohorts to confirm staining consistency
How can I resolve contradictory data on CD44 mAb cytotoxicity across studies?
Contradictions often arise from isoform specificity and microenvironmental factors. For example:
To reconcile discrepancies:
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Quantify CD44 isoform expression via Western blot using clone-specific antibodies (C44Mab-46 detects CD44s/variants)
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Model tumor-stroma interactions using MSC co-culture systems
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Compare ADCC activity using NK cell activation assays (e.g., CD107a degranulation)
What methodologies improve CD44 mAb therapeutic efficacy in vivo?
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Xenograft optimization: Use RAG-2⁻/⁻/γc⁻/⁻ mice engrafted with primary CLL cells to bypass immune clearance
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Dose stratification:
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Combinatorial approaches: Pair with HA synthesis inhibitors (e.g., 4-methylumbelliferone) to block compensatory survival pathways
How do CD44 mAbs disrupt HA-mediated signaling?
RO5429083 inhibits HA binding through competitive antagonism, quantified via:
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Phospho-kinase arrays: Reduces ERK1/2 and AKT phosphorylation by ≥60%
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Transcriptomic profiling: Downregulates BCL2L1 (4.2-fold) and MCL1 (3.7-fold)
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Atomic force microscopy: Measures HA-CD44 binding force reduction from 52 pN to <15 pN post-treatment
What criteria confirm CD44 mAb specificity?
Adopt a multi-platform validation framework:
