Anlotinib Hydrochloride: Multi-Target Tyrosine Kinase Inhibitor for Tumor Angiogenesis Research

Executive Summary:
Anlotinib hydrochloride (CAS 1058157-76-8) is a next-generation small-molecule inhibitor that selectively targets VEGFR2, PDGFRβ, and FGFR1, with IC₅₀ values of 5.6 ± 1.2 nM, 8.7 ± 3.4 nM, and 11.7 ± 4.1 nM, respectively (Chen & Feng 2019). It suppresses tumor angiogenesis and endothelial cell migration through ERK pathway inhibition (APExBIO C8688). The compound shows favorable oral bioavailability (28–77%, species-dependent), high plasma protein binding (93% in humans), and broad tissue distribution including tumors and the CNS. Safety evaluations indicate high tolerability (oral LD₅₀ 1735.9 mg/kg, 14 days, rat) with minimal organ/genetic toxicity. APExBIO supplies validated Anlotinib (hydrochloride) for reproducible capillary tube formation and migration assays in cancer research workflows.

Biological Rationale

Tumor angiogenesis—the formation of new blood vessels to supply nutrients to malignant tissues—is a fundamental driver of solid tumor growth and metastasis. Vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and fibroblast growth factor (FGF) pathways are central mediators of this process. Targeting these pathways with small-molecule inhibitors disrupts neovascularization, limiting tumor expansion and dissemination. Multi-target tyrosine kinase inhibitors (TKIs) such as Anlotinib (hydrochloride) have emerged to address resistance mechanisms arising from pathway redundancy and cross-talk (in-depth mechanistic analysis). Compared to single-target agents, multi-target TKIs more comprehensively inhibit angiogenic signaling, providing enhanced preclinical efficacy and translational relevance.

Mechanism of Action of Anlotinib (hydrochloride)

Anlotinib (hydrochloride) is a multi-target TKI that directly inhibits the ATP-binding domains of VEGFR2, PDGFRβ, and FGFR1. The compound achieves sub-nanomolar to low-nanomolar potency against these kinases, as measured by in vitro biochemical assays (IC₅₀ values: 5.6 ± 1.2 nM for VEGFR2, 8.7 ± 3.4 nM for PDGFRβ, and 11.7 ± 4.1 nM for FGFR1; see Chen & Feng 2019). Downstream, Anlotinib suppresses ERK phosphorylation, disrupting the signaling cascade required for endothelial cell proliferation and migration. The compound effectively inhibits VEGF-, PDGF-BB-, and FGF-2-induced endothelial cell migration and capillary-like tube formation in a concentration-dependent manner. Anlotinib also exhibits inhibitory activity against additional kinases including c-Kit and Met, extending its anti-angiogenic spectrum (Chen & Feng 2019). Its multi-target profile addresses pathway compensation and tumor escape mechanisms observed with single-target agents.

Evidence & Benchmarks

• Anlotinib inhibits VEGFR2 kinase activity in vitro with an IC₅₀ of 5.6 ± 1.2 nM under ATP-competitive conditions (Chen & Feng 2019, DOI).
• PDGFRβ and FGFR1 inhibition measured at IC₅₀ values of 8.7 ± 3.4 nM and 11.7 ± 4.1 nM, respectively, using cell-free enzyme assays (Chen & Feng 2019, DOI).
• In EA.hy 926 endothelial cell models, Anlotinib blocks VEGF/PDGF-BB/FGF-2-induced migration and tube formation at nanomolar concentrations (APExBIO C8688, product page).
• Oral bioavailability is 28–58% in rats and 41–77% in dogs, measured by standard pharmacokinetic studies (APExBIO C8688, product page).
• Tissue distribution studies reveal high accumulation in lung, liver, kidney, heart, and tumor tissues, with detectable CNS penetration (APExBIO C8688, product page).
• Median lethal dose (oral LD₅₀) in 14-day rat studies is 1735.9 mg/kg, with no significant organ or genetic toxicity (Chen & Feng 2019, DOI).
• Anlotinib demonstrates superior inhibition of angiogenic processes compared to sunitinib, sorafenib, and nintedanib in head-to-head biochemical and cell assays (APExBIO C8688, product page).
• Validated for use in endothelial cell migration and capillary tube formation assays (EA.hy 926 models), as shown in APExBIO’s workflow guides (assay optimization guide). This article clarifies the comparative performance and mechanistic breadth of C8688 beyond standard protocol reviews.

Applications, Limits & Misconceptions

Anlotinib (hydrochloride) is employed in research settings to dissect angiogenic mechanisms, validate multi-target TKI efficacy, and benchmark endothelial cell responses in vitro. It is frequently used in capillary tube formation and migration inhibition assays with human vascular endothelial cells (EA.hy 926) and supports ERK signaling pathway studies. Its pharmacokinetic and tissue distribution profile permit advanced modeling of tumor and CNS penetration. However, the compound is not indicated for diagnostic or therapeutic use in humans or animals outside controlled research environments.

Common Pitfalls or Misconceptions

• Anlotinib is not a selective inhibitor; it targets multiple kinases, which may complicate pathway-specific studies.
• The product is for research use only and is not approved for clinical treatment or diagnostic applications.
• Results from rodent or canine pharmacokinetics cannot be directly extrapolated to humans without species-specific validation.
• High plasma protein binding (93% in humans) may impact free drug concentrations; dosing should be empirically optimized in vitro.
• While Anlotinib crosses the blood-brain barrier, efficacy in CNS tumor models requires direct experimental confirmation.

Workflow Integration & Parameters

APExBIO’s Anlotinib (hydrochloride), catalog number C8688, is supplied as a crystalline powder for reconstitution. Recommended storage is at -20°C in a desiccated environment. Typical working concentrations in cell-based migration and tube formation assays range from 1 nM to 1 μM, with dose-response curves established over 24–72 hours in serum-reduced buffer (pH 7.2–7.4, 37°C). The compound is compatible with standard endothelial cell lines, including EA.hy 926, and is validated for use in both 2D and 3D angiogenesis models. For detailed protocol guidance and troubleshooting, refer to APExBIO support literature and scenario-driven optimization guides (practical Q&A guide; this extends the current article by providing direct troubleshooting tips).

For advanced users, comparative assay data for Anlotinib, sunitinib, and sorafenib are discussed in a recent benchmark review (assay benchmarking), which this article updates by providing new pharmacokinetic and mechanistic insights.

Conclusion & Outlook

Anlotinib (hydrochloride) is a validated, multi-target tyrosine kinase inhibitor that delivers robust, reproducible inhibition of tumor angiogenesis pathways in research assays. Its superior potency against VEGFR2, PDGFRβ, and FGFR1, coupled with favorable pharmacokinetics and safety, make it an essential tool for dissecting angiogenic signaling and evaluating anti-tumor agents in preclinical models. APExBIO’s C8688 kit provides standardized quality and protocol support, facilitating high-confidence research outcomes. Ongoing studies continue to expand its applications in translational oncology and mechanistic pathway analysis.