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

Executive Summary: Anlotinib hydrochloride (CAS 1058157-76-8) is a small-molecule inhibitor targeting VEGFR2, PDGFRβ, and FGFR1, with low nanomolar IC₅₀ values (5.6–11.7 nM) under standard kinase assay conditions (Lin et al., 2018). It exhibits superior anti-angiogenic activity compared to sunitinib and sorafenib, efficiently blocking endothelial cell migration and capillary tube formation in vitro (Lin et al., 2018). Anlotinib displays high oral bioavailability (28–77%, species-dependent) and strong plasma protein binding (93% in human plasma) (Lin et al., 2018). Its safety profile includes a high oral LD₅₀ (1735.9 mg/kg, 14-day rat study), with no significant organ or genetic toxicity at research doses. APExBIO provides validated, research-grade Anlotinib (hydrochloride) (SKU C8688) for advanced angiogenesis and tumor signaling studies (product page).

Biological Rationale

Angiogenesis, the formation of new blood vessels from existing vasculature, is critical for tumor progression and metastasis. Tumor cells secrete pro-angiogenic factors such as VEGF, PDGF-BB, and FGF-2, which activate signaling pathways in endothelial cells, promoting proliferation, migration, and tube formation (Lin et al., 2018). Inhibiting these processes disrupts tumor growth and is a validated therapeutic approach. Small-molecule tyrosine kinase inhibitors (TKIs) that target multiple angiogenic pathways—especially VEGFR2, PDGFRβ, and FGFR1—are essential for dissecting complex tumor microenvironment mechanisms and benchmarking anti-angiogenic strategies in preclinical models.

Mechanism of Action of Anlotinib (hydrochloride)

Anlotinib is a multi-target TKI that primarily inhibits VEGFR2, PDGFRβ, and FGFR1, as well as their shared downstream effector, the ERK signaling pathway. In enzyme-based kinase assays, Anlotinib demonstrates IC₅₀ values of 5.6 ± 1.2 nM for VEGFR2, 8.7 ± 3.4 nM for PDGFRβ, and 11.7 ± 4.1 nM for FGFR1 (HEPES buffer, 25°C, 30 min) (Lin et al., 2018, Table 1). It blocks phosphorylation and activation of these receptors in human endothelial cells (EA.hy 926), thereby halting cell migration and capillary-like tube formation in a concentration-dependent manner. Compared to sunitinib, sorafenib, and nintedanib, Anlotinib exhibits superior or comparable inhibition of angiogenic signaling (Lin et al., 2018, Fig. 1B). Downstream, Anlotinib suppresses ERK1/2 phosphorylation, which is a critical node in angiogenic and proliferative signaling cascades.

Evidence & Benchmarks

• Anlotinib inhibits VEGF/PDGF-BB/FGF-2-induced migration of EA.hy 926 endothelial cells with high potency (IC₅₀ <12 nM) under standard wound healing and Boyden chamber assays (Lin et al., 2018, Fig. 2).
• Anlotinib suppresses capillary-like tube formation in endothelial cell assays more efficiently than sunitinib and sorafenib (1–20 nM, 24 h, Matrigel) (Lin et al., 2018, Fig. 3).
• In rat aortic ring and chicken chorioallantoic membrane (CAM) assays, Anlotinib reduces microvessel density and sprouting at nanomolar concentrations (Lin et al., 2018, Fig. 4–5).
• Pharmacokinetic studies show oral bioavailability of 28–58% in rats and 41–77% in dogs, and 93% plasma protein binding in humans (Lin et al., 2018).
• The compound achieves a high safety margin, with an LD₅₀ of 1735.9 mg/kg (oral, 14-day, rat) and no significant adverse organ or genotoxic effects at research doses (Lin et al., 2018).

This article extends the practical guidance found in Solving Lab Challenges with Anlotinib (hydrochloride) by providing quantified pharmacokinetic and safety data, and clarifies comparative efficacy benchmarks described in Enhancing Tumor Angiogenesis Assays with Anlotinib (hydrochloride).

Applications, Limits & Misconceptions

Anlotinib (hydrochloride) from APExBIO is validated for research applications including:

• In vitro endothelial cell migration and tube formation assays (EA.hy 926, HUVEC, 1–20 nM, 24–48 h).
• Preclinical in vivo angiogenesis models (rat aortic ring, CAM, tumor xenograft models).
• Mechanistic studies of VEGFR2, PDGFRβ, FGFR1, and ERK signaling in cancer and vascular biology.
• Comparative benchmarking against other TKIs in translational research.

Common Pitfalls or Misconceptions

• Not for Diagnostic or Therapeutic Use: Anlotinib (hydrochloride) is strictly for scientific research and not approved for clinical diagnostic or therapeutic applications (APExBIO).
• Species-Specific PK Profiles: Pharmacokinetic parameters (bioavailability, metabolism) differ between species and may not directly extrapolate to humans (Lin et al., 2018).
• Assay Context Sensitivity: Efficacy may vary with cell type, matrix, and growth factor concentrations; always validate in the specific experimental system.
• Not a Universal Angiogenesis Blocker: Anlotinib does not inhibit angiogenic pathways independent of VEGFR2, PDGFRβ, or FGFR1.
• Storage and Handling: Compound must be stored at -20°C and protected from moisture for stability (APExBIO).

For a strategic overview of translational implications, Redefining Tumor Angiogenesis Research offers a forward-looking perspective, whereas this article focuses on validated experimental benchmarks and workflow parameters.

Workflow Integration & Parameters

Anlotinib (hydrochloride) (SKU C8688) is supplied as a stable, lyophilized powder for reconstitution in DMSO or aqueous buffers. Recommended working concentrations for cell-based assays range from 1 to 20 nM, with exposure times of 24–48 h. For in vivo studies, dosing regimens should be optimized based on species-specific pharmacokinetics (Lin et al., 2018). The compound is compatible with standard migration, tube formation, and phosphorylation assays. For researchers seeking protocol troubleshooting and assay optimization, Optimizing Tumor Angiogenesis Assays with Anlotinib (hydrochloride) presents practical guidance; this article augments those details with expanded safety and selectivity data.

Conclusion & Outlook

Anlotinib hydrochloride is a potent, validated multi-target TKI with proven superiority in inhibiting VEGFR2, PDGFRβ, and FGFR1-mediated angiogenesis. Its quantitative benchmarks and robust safety profile make it a preferred reagent for cancer research and angiogenesis assay development. While not a clinical therapeutic, its use in mechanistic and translational studies is well-supported. Future research may further define its role in combinatorial pathway inhibition and resistance modeling. For validated supply and technical documentation, refer to APExBIO's Anlotinib (hydrochloride) product page.