Anti-Mouse CD309 (VEGFR2) [Clone DC101] — Purified in vivo GOLD™ Functional Grade

The most common in vivo applications of the clone DC101 antibody in mice are the blockade of VEGFR-2 (vascular endothelial growth factor receptor 2) signaling, primarily to inhibit angiogenesis and study anti-tumor effects. DC101 is a rat IgG1 monoclonal antibody that specifically targets the mouse VEGFR-2 receptor, a key mediator of blood vessel formation (angiogenesis).

Key in vivo applications include:

• Anti-cancer therapy studies: DC101 is widely used in mouse models to block VEGFR-2 signaling, thereby inhibiting tumor angiogenesis, reducing tumor growth, decreasing microvessel density, and increasing tumor cell apoptosis. Tumor types investigated include melanoma, lung cancer, and breast cancer.
• Tumor vessel normalization: Treatment with DC101 promotes normalization of tumor vessels, which can facilitate better immune cell infiltration and enhance responses to immunotherapies.
• Immune cell infiltration studies: DC101 therapy has been shown to increase the proportion of immune cells (B cells, dendritic cells, CD3+/CD8+ T cells) within tumors, supporting research on the tumor microenvironment and anti-tumor immunity.
• Ischemia and vascular biology research: Conjugated forms of DC101 (e.g., labeled with fluorescent dyes) are used to study VEGFR-2 expression and vascular remodeling in ischemic tissue models.
• General angiogenesis blockade: As an inhibitor of VEGFR-2 signaling, DC101 is used to test hypotheses relating to vascular development and permeability in vivo, beyond cancer models.

Experimental use:

• DC101 is administered to mice to block the VEGF/VEGFR-2 pathway in vivo, usually to investigate the biological role of VEGFR-2 in disease progression and tissue remodeling.
• It is also used as a functional tool in combination with other therapeutic strategies, such as engineered T cells bearing DC101-derived chimeric antigen receptors (DC101-CAR), to target tumor vasculature in mouse models.

DC101’s effectiveness and widespread application in the above research areas are supported by numerous studies and product references, underscoring its role as a standard tool in mouse angiogenesis and tumor biology research.

Commonly used antibodies or proteins combined with DC101 (an anti-VEGFR2 antibody) in the literature include anti-VEGF-A antibodies, cetuximab, and chemotherapeutic agents such as paclitaxel. Other experimental agents mentioned for comparative or combination therapy include VEGF-Trap (aflibercept) and conventional antiangiogenic drugs like vinblastine.

Key combinations and usages:

• Anti-VEGF-A antibodies (e.g., 2G11-2A05): Used alongside DC101 to simultaneously target VEGF-A and its receptor VEGFR2, aiming for a dual blockade to enhance inhibition of angiogenesis and tumor progression.
• Cetuximab: Combined with DC101 to target both VEGFR2 and EGFR pathways, with studies showing improved outcomes in tumor growth and metastasis models.
• Paclitaxel: Chemotherapy agent used in combination with DC101 to achieve greater tumor regression and anti-angiogenic effects in bladder cancer models.
• VEGF-Trap (aflibercept/R1R2): Studied in parallel with DC101 or as a comparator; both agents block VEGF pathways, but through different mechanisms.
• Vinblastine: Used with DC101 in continuous low-dose regimens to enhance anti-tumor efficacy and inhibit endothelial cell proliferation.

Additional markers/proteins analyzed in studies involving DC101:

• CD31 antibodies: For assessing microvessel density (MVD) in angiogenesis studies.
• PCNA and TUNEL assays: For evaluating cell proliferation and apoptosis in treated tumors.

These combinations are chosen to enhance efficacy, overcome resistance mechanisms in anti-angiogenic therapy, and study synergistic effects on tumor progression and microenvironment.

DC101 is a monoclonal antibody targeting VEGFR-2 (also known as Flk-1, KDR, or CD309) that has been extensively studied for its antiangiogenic and antitumor properties. The scientific literature reveals several important findings about this antibody's mechanisms and effects.

Rapid Vascular Regression and Antitumor Effects

DC101 demonstrates remarkably rapid effects on tumor vasculature. Beginning just 24 hours after treatment, the antibody causes decreased vessel density and reduced endothelial cell proliferation. This rapid vascularization reversal continues progressively through 96 hours of treatment, with VEGFR-2 inhibition not only limiting new vessel formation but also causing regression of pre-existing vessels. The reduced tumor vascularization leads to large areas of necrosis in tumor regions distant from underlying stroma.

Stromal Remodeling and Tumor Phenotype Reversion

A particularly striking finding is DC101's ability to induce stromal alterations that fundamentally change tumor behavior. Within 96 hours of VEGFR-2 inhibition, stromal expression of matrix metalloproteinase-9 and -13 is drastically reduced. This protease inhibition results in profound changes to the tumor-stroma border, which transforms from a highly invasive carcinoma to a well-demarcated, premalignant phenotype characterized by regular basement membrane appearance. These findings demonstrate that short-term inhibition of VEGF signaling produces complex stromal alterations with crucial consequences for tumor phenotype.

Effects on Leukemia and Hematologic Malignancies

In leukemia models, DC101 treatment at 800 μg/injection three times weekly prolonged survival by more than 2-fold, though mice eventually died within 42 days. These results demonstrate that blocking VEGF-induced angiogenesis through murine VEGFR-2 delays leukemic growth but is insufficient to eradicate the disease. Notably, targeting VEGFR-1 had no effect on survival, indicating that the VEGF/VEGFR-2 pathway is critical for leukemia proliferation while VEGFR-1 plays only a marginal role.

Cardiovascular Effects

Beyond oncology, DC101 has revealed important physiological roles of VEGFR-2. Blockade of VEGFR-2 with DC101 causes significant hypertension in normal mice, likely mediated by reduced nitric oxide production. This finding indicates that VEGFR-2 signaling plays a crucial role in blood pressure regulation under normal physiological conditions.

Applications in Immunotherapy

DC101 has been utilized as a foundation for engineered cellular therapies. DC101-CAR-modified mouse T cells effectively generate antigen-specific immune responses in vitro, responding specifically to VEGFR-2-expressing targets through proliferation and IFN-γ secretion. These engineered T cells can recognize various mouse cell lines expressing VEGFR-2, with endothelial cell lines showing particularly high expression levels.

Dosing regimens for the VEGFR-2-blocking antibody DC101 differ by mouse model, experimental aim, tumor type, and combination with other therapies. Key variables include dose per injection, frequency of administration, and route.

Common DC101 dosing regimens across mouse models:

• Standard anti-tumor models:
  • 15 mg/kg per day, administered by intraperitoneal (i.p.) injection, once daily for extended durations such as 28 days.
• Dose escalation or comparison studies:
  • Doses such as 10 mg/kg or 40 mg/kg, delivered in four total injections at 3-day intervals (every third day), tailored to testing lower vs. higher anti-angiogenic effects.
  • Some studies compare "quarter-dose" (low dose) to "high dose" effects for enhanced immunogenicity or vascular normalization.
• Leukemia or other non-solid-tumor models:
  • Fixed amount dosing (not weight-based): 800 μg per injection, given three times weekly (e.g., Monday/Wednesday/Friday), for a schedule set by tumor progression.
• Single-dose comparative or mechanistic experiments:
  • A single 800 μg dose in synergy with other immune or chemotherapeutic interventions.
• Alternative regimens:
  • Lower doses (as low as 150 μg per injection) used for specific vascular or blood pressure studies.
  • Combination regimens with chemotherapy or other antibodies generally maintain the DC101 regimen but may adjust dosing/frequency as needed.

Summary Table: DC101 Regimens in Mouse Models

Key considerations:

• Frequency and total treatment duration can vary widely, even at the same dose, depending on disease context and study design.
• Dose adjustments may be made for immunogenic vs. immune-tolerant models, vaccine combination protocols, or in studies assessing vascular normalization.
• Preclinical suppliers and reviews indicate that dose, frequency, and strategy are tailored for each application.

These examples illustrate that DC101 dosing is not fixed; it is optimized for each mouse model and experimental question, with variations in dose, schedule, and combination partners seen throughout the literature.