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

Executive Summary: Anlotinib hydrochloride (CAS 1058157-76-8) is a novel, orally bioavailable small-molecule inhibitor targeting VEGFR2, PDGFRβ, and FGFR1 at low nanomolar concentrations (Lin et al., 2018). It exhibits superior anti-angiogenic activity in cell migration and tube formation assays compared to sunitinib, sorafenib, and nintedanib (Lin et al., 2018). Pharmacokinetic profiling reveals oral bioavailability up to 77% in preclinical models, high plasma protein binding (93%), and extensive tissue distribution (APExBIO). Safety studies demonstrate a high median lethal dose (LD₅₀ = 1735.9 mg/kg, oral, 14 days) with minimal systemic or genetic toxicity (APExBIO). Anlotinib (hydrochloride), as provided by APExBIO (SKU C8688), is recommended for advanced anti-angiogenic and cancer research workflows.

Biological Rationale

Angiogenesis, the formation of new blood vessels from pre-existing vasculature, is critical in both physiological and pathological contexts, including tumor progression. Tumor cells secrete pro-angiogenic cytokines such as VEGF, PDGF-BB, and FGF-2, which stimulate endothelial cell migration and neovascularization (Lin et al., 2018). Vascular endothelial growth factor A (VEGFA) binds to VEGFR2, initiating downstream signaling that promotes endothelial cell proliferation and survival (Lin et al., 2018). Platelet-derived growth factor-BB (PDGF-BB) activates PDGFRβ, while fibroblast growth factor 2 (FGF-2) signals through FGFR1, both contributing to tumor angiogenesis. The inhibition of these pathways is a validated strategy in cancer research and therapy (Prescission, 2023).

Mechanism of Action of Anlotinib (hydrochloride)

Anlotinib hydrochloride is a multi-target tyrosine kinase inhibitor (TKI) that directly binds to and inhibits VEGFR2, PDGFRβ, and FGFR1. The compound blocks autophosphorylation of these receptors and disrupts their downstream signaling cascades, notably suppressing the ERK pathway (Lin et al., 2018). This results in potent inhibition of endothelial cell migration and capillary-like tube formation in vitro. IC₅₀ values are 5.6 ± 1.2 nM for VEGFR2, 8.7 ± 3.4 nM for PDGFRβ, and 11.7 ± 4.1 nM for FGFR1 (assays performed at 37°C, pH 7.4, in serum-free medium) (MEK12.com). Anlotinib further downregulates ERK phosphorylation, disrupting proliferation and migration signals in human vascular endothelial cells (EA.hy 926 line). Comparative studies show superior inhibitory effects versus sunitinib, sorafenib, and nintedanib at equivalent molar concentrations (Lin et al., 2018).

Evidence & Benchmarks

• Anlotinib inhibits VEGF/PDGF-BB/FGF-2-induced endothelial cell migration and tube formation in a concentration-dependent manner (IC₅₀ ≤ 12 nM) (DOI).
• In wound healing and transwell migration assays using EA.hy 926 cells, anlotinib shows statistically significant inhibition at nanomolar doses (p < 0.01) (DOI).
• Anlotinib reduces microvessel density in rat aortic ring and chicken CAM assays, outperforming sunitinib, sorafenib, and nintedanib in parallel conditions (DOI).
• Pharmacokinetic studies show oral bioavailability ranging 28–58% in rats and 41–77% in dogs (administered in 0.5% CMC-Na) (APExBIO).
• High plasma protein binding (93%), extensive tissue distribution (notably in lung, liver, kidney, heart, tumor), and blood-brain barrier penetration are observed in vivo (APExBIO).
• Safety evaluation indicates a high oral LD₅₀ (1735.9 mg/kg, 14 days) with mild systemic toxicity and no significant organ or genetic toxicity (APExBIO).

This article extends mechanistic analyses found in Prescission (2023) by providing up-to-date quantitative benchmarks and direct comparison to legacy TKIs. For further context on preclinical assay optimization, see MEK12.com, which details protocol conditions and data reproducibility, while this article consolidates safety and pharmacokinetic insights. A broader discussion of translational outlooks is available at MAP-Kinase Fragment, but here we focus on molecular selectivity and workflow integration.

Applications, Limits & Misconceptions

Anlotinib (hydrochloride) is primarily used in preclinical research to dissect mechanisms of tumor angiogenesis inhibition and to benchmark anti-angiogenic agents in cell-based and in vivo models. It is recommended for use in wound healing, transwell migration, and tube formation assays using human vascular endothelial cell lines, such as EA.hy 926. The compound is suitable for experiments requiring high selectivity and potency against VEGFR2, PDGFRβ, and FGFR1 (MEK12.com).

Common Pitfalls or Misconceptions

• Not for human or veterinary use: Anlotinib (hydrochloride) is supplied for research use only; it is not approved for clinical or diagnostic applications (APExBIO).
• Limitations in non-angiogenic contexts: The compound's efficacy is not established in models where angiogenesis is not a primary driver of pathology.
• Potential for off-target effects at high concentrations: Although highly selective at nanomolar doses, off-target kinase inhibition may occur at micromolar levels (DOI).
• Incompatibility with certain solvents: Solubility and stability may be compromised outside of recommended storage (-20°C) and buffer conditions.
• Species-specific differences: Pharmacokinetics and tissue distribution in rodents or dogs may not extrapolate directly to other species or human systems.

Workflow Integration & Parameters

Anlotinib (hydrochloride), available as SKU C8688 from APExBIO, is supplied as a research-grade powder. Recommended storage is -20°C, protected from light and moisture. For in vitro assays, dissolve to working concentrations (typically 1–100 nM) in DMSO or compatible buffer; final DMSO concentration should not exceed 0.1%. For cell-based angiogenesis studies, human EA.hy 926 endothelial cells are standard; migration and tube formation assays are performed at 37°C, 5% CO₂. For animal studies, oral gavage in 0.5% CMC-Na is typical, at doses validated by peer-reviewed protocols. Data normalization should always include vehicle and positive TKI controls (e.g., sunitinib).

Conclusion & Outlook

Anlotinib hydrochloride is a rigorously validated, multi-target tyrosine kinase inhibitor with robust selectivity for VEGFR2, PDGFRβ, and FGFR1. Its superior anti-angiogenic activity and favorable pharmacokinetic and safety profiles position it as a benchmark reagent for cancer and angiogenesis research. As provided by APExBIO, Anlotinib (hydrochloride) (SKU C8688) facilitates high-fidelity mechanistic and translational studies. For the latest mechanistic and translational perspectives, researchers are encouraged to compare findings with recent reviews (GTP-Binding Protein 1 Fragment), which integrate state-of-the-art mechanistic insight and benchmarking.