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 that inhibits VEGFR2, PDGFRβ, and FGFR1 with nanomolar potency (IC₅₀s: 5.6 ± 1.2 nM, 8.7 ± 3.4 nM, 11.7 ± 4.1 nM, respectively) (Chen & Feng 2019). It blocks the ERK signaling pathway and suppresses endothelial cell migration and tube formation in vitro. Compared to sunitinib and nintedanib, anlotinib exhibits superior inhibition of angiogenic processes. Pharmacokinetic studies reveal high oral bioavailability in animal models, extensive tissue distribution, and low systemic toxicity. APExBIO supplies validated Anlotinib (hydrochloride) as SKU C8688 (product page).

Biological Rationale

Tumor angiogenesis is essential for tumor growth and metastasis. Vascular endothelial growth factor receptor 2 (VEGFR2), platelet-derived growth factor receptor β (PDGFRβ), and fibroblast growth factor receptor 1 (FGFR1) are central regulators of endothelial cell proliferation, migration, and neovascularization. Inhibiting these kinases disrupts new vessel formation, starving tumors of nutrients and oxygen. Multi-target tyrosine kinase inhibitors (TKIs) are employed to block angiogenic signaling redundancies and overcome resistance seen with single-target agents (see mechanistic masterclass).

This article extends prior coverage by providing updated benchmarks, pharmacokinetic metrics, and comparative insights for Anlotinib (hydrochloride) versus legacy TKIs (see comparative review).

Mechanism of Action of Anlotinib (hydrochloride)

Anlotinib hydrochloride is a selective, orally bioavailable TKI that targets multiple angiogenesis-related receptors:

• VEGFR2: IC₅₀ = 5.6 ± 1.2 nM (ATP-competitive inhibition)
• PDGFRβ: IC₅₀ = 8.7 ± 3.4 nM
• FGFR1: IC₅₀ = 11.7 ± 4.1 nM

Anlotinib also inhibits downstream ERK phosphorylation, which is critical for cell migration and proliferation. It blocks VEGF-, PDGF-BB-, and FGF-2-induced endothelial cell migration and capillary-like tube formation in EA.hy 926 human vascular endothelial cells in a concentration-dependent manner. Compared to sunitinib, sorafenib, and nintedanib, anlotinib demonstrates greater suppression of tube formation (APExBIO product details).

Anlotinib is metabolized mainly by CYP3A in the liver, producing hydroxylated and dealkylated metabolites. It displays high plasma protein binding (93% in humans) and accumulates in tumor, lung, liver, kidney, and heart tissues. It can penetrate the blood-brain barrier (Chen & Feng 2019).

Evidence & Benchmarks

• Anlotinib inhibits VEGFR2, PDGFRβ, and FGFR1 with low nanomolar IC₅₀ values—significantly lower than sunitinib and nintedanib under identical in vitro conditions (Chen & Feng 2019).
• In endothelial cell assays (EA.hy 926), anlotinib blocks VEGF/PDGF-BB/FGF-2-induced migration and tube formation, outperforming comparators at equimolar doses (Mechanistic review).
• Oral bioavailability in rats: 28-58%; dogs: 41-77% (administered as free base, fasted state) (APExBIO).
• Median lethal dose (LD₅₀): 1735.9 mg/kg in 14-day oral administration studies; no significant organ or genetic toxicity observed in preclinical models (Chen & Feng 2019).
• In clinical case reports, anlotinib reduced metastatic lymph node size in intra-abdominal desmoplastic small round cell tumor (IADSRCT) and was well tolerated (main side effects: hypertriglyceridemia, fatigue) (Chen & Feng 2019).

This article updates and synthesizes practical assay data and clinical case insights, extending beyond the mechanistic focus of previous summaries (see strategic guidance).

Applications, Limits & Misconceptions

Anlotinib (hydrochloride) is used in research applications involving:

• Capillary tube formation assays
• Endothelial cell migration and invasion assays
• ERK signaling pathway inhibition studies
• Tumor angiogenesis models (in vitro and in vivo)

It is not approved for diagnostic or therapeutic use in humans or animals. All applications should comply with institutional biosafety and ethical guidelines. For advanced assay optimization and application-specific guidance, see this translational roadmap (which this article updates with new pharmacokinetic and comparative efficacy data).

Common Pitfalls or Misconceptions

• Misconception: Anlotinib is a single-target VEGFR2 inhibitor.
  Correction: It also targets PDGFRβ, FGFR1, c-Kit, and MET at relevant concentrations (DOI).
• Pitfall: Using anlotinib for clinical therapy outside regulated trials.
  Correction: Supplied by APExBIO for research use only; not for diagnostic or therapeutic applications (product info).
• Pitfall: Assuming equal efficacy in all tumor models.
  Correction: Efficacy depends on tumor type, receptor expression profile, and dosing regimen (Chen & Feng 2019).
• Pitfall: Inadequate control of metabolic stability.
  Correction: Anlotinib undergoes CYP3A-dependent metabolism; co-administered compounds may affect activity.

Workflow Integration & Parameters

Anlotinib (hydrochloride), as provided by APExBIO (SKU C8688), is supplied as a powder for reconstitution. For in vitro experiments, it is commonly dissolved in DMSO to ≥10 mM stock concentration and stored at -20°C. Standard working concentrations for endothelial cell assays range from 0.1 nM to 1 μM, depending on cell line sensitivity and endpoint.

Inhibition of VEGFR2, PDGFRβ, and FGFR1 activity should be validated in each system using appropriate positive and negative controls. For cell migration and tube formation assays, pre-incubation for 30–60 minutes before growth factor stimulation is recommended. Pharmacokinetic parameters—including bioavailability, plasma protein binding, and tissue distribution—should be considered in vivo.

For integration with advanced angiogenesis research workflows, see this mechanistic deep-dive, which this article extends by adding new pharmacodynamic and safety metrics for anlotinib.

Conclusion & Outlook

Anlotinib hydrochloride is a state-of-the-art anti-angiogenic small molecule that targets multiple tyrosine kinases central to tumor vascularization. With nanomolar potency, high selectivity, and validated safety in preclinical models, it is a preferred tool for dissecting angiogenic mechanisms and benchmarking new inhibitors. APExBIO’s offering ensures high-quality, reproducible results for research teams advancing cancer biology and translational innovation. Future directions include expanded use in complex tumor models and integration with multi-omics approaches to refine anti-angiogenic targeting (Chen & Feng 2019).