Anlotinib Hydrochloride: Multi-Target Tyrosine Kinase Inhibitor for Cancer Research

Executive Summary: Anlotinib hydrochloride is a multi-target tyrosine kinase inhibitor (TKI) with nanomolar potency against VEGFR2, PDGFRβ, and FGFR1, supporting its use in anti-angiogenic research (Chen & Feng 2019). It demonstrates superior inhibitory effects compared to sunitinib, sorafenib, and nintedanib in endothelial cell assays (source). The compound exhibits rapid oral absorption and high plasma protein binding (93% in humans), with wide tissue distribution, including tumor and brain tissues. Safety studies show a high median lethal dose (LD₅₀ 1735.9 mg/kg, oral, 14-day, rat) and no significant organ or genetic toxicity (APExBIO). Anlotinib (hydrochloride) is supplied by APExBIO for research use in cellular angiogenesis and migration assays.

Biological Rationale

Tumor angiogenesis is a key process in cancer progression, enabling tumor growth and metastasis by supplying oxygen and nutrients (Chen & Feng 2019). Vascular endothelial growth factor receptors (VEGFRs), platelet-derived growth factor receptors (PDGFRs), and fibroblast growth factor receptors (FGFRs) are principal drivers of angiogenesis in many tumor types. Inhibiting these pathways reduces neovascularization and can suppress tumor proliferation. Multi-target tyrosine kinase inhibitors have become essential tools in preclinical and translational oncology research for dissecting angiogenic mechanisms and validating drug targets.

Mechanism of Action of Anlotinib (hydrochloride)

Anlotinib hydrochloride (CAS 1058157-76-8) is a small-molecule TKI that simultaneously inhibits VEGFR2 (IC₅₀: 5.6 ± 1.2 nM), PDGFRβ (8.7 ± 3.4 nM), and FGFR1 (11.7 ± 4.1 nM) in biochemical assays (APExBIO). It additionally targets VEGFR1/3, FGFR2–4, PDGFRα, c-Kit, and Met receptors (Chen & Feng 2019). These receptors are involved in signaling cascades that promote endothelial cell survival, migration, and tube formation. Anlotinib suppresses downstream pathways such as ERK phosphorylation, resulting in potent anti-angiogenic effects in vitro and in vivo. It inhibits VEGF/PDGF-BB/FGF-2-induced endothelial cell migration and capillary-like tube formation in a concentration-dependent manner. In comparison studies, it demonstrates greater inhibition of angiogenic processes than clinically used agents like sunitinib or nintedanib (source).

Evidence & Benchmarks

• Anlotinib inhibits VEGFR2 kinase activity with an IC₅₀ of 5.6 ± 1.2 nM (in vitro enzymatic assay, pH 7.4, 25°C) (APExBIO).
• Inhibits migration of human vascular endothelial cells (EA.hy 926) in response to VEGF, PDGF-BB, and FGF-2, with significant reduction at 10–100 nM concentrations (cellular migration assay) (Chen & Feng 2019).
• Suppresses capillary-like tube formation in Matrigel assays, outperforming sunitinib and sorafenib at matched concentrations (100 nM, 24 h, 37°C) (source).
• Shows oral bioavailability of 28–58% in rats and 41–77% in dogs (single-dose, fasted, LC-MS/MS quantification) (APExBIO).
• Plasma protein binding reaches 93% in human samples (equilibrium dialysis, 37°C, pH 7.4) (APExBIO).
• Crosses the blood-brain barrier and accumulates in lung, liver, kidney, heart, and tumor tissues (rodent tissue distribution study) (Chen & Feng 2019).
• High median lethal dose (LD₅₀): 1735.9 mg/kg (oral, 14-day, rat), with no significant organ or genetic toxicity (GLP safety evaluation) (APExBIO).
• Demonstrated clinical benefit in metastatic intra-abdominal desmoplastic small round cell tumor (IADSRCT) in case studies (reduction in lymph node size, maintenance therapy) (Chen & Feng 2019).

This article extends prior mechanistic overviews such as 'Systems Biology Insights into Multi-Target Tyrosine Kinase Inhibition' by providing quantitative pharmacokinetic, safety, and benchmarking data validated in independent peer-reviewed sources.

Applications, Limits & Misconceptions

Anlotinib hydrochloride is used in research settings for:

• Anti-angiogenic mechanism studies in cell-based and in vivo models.
• Capillary tube formation and migration assays in human endothelial cells.
• Pharmacological benchmarking against other clinically used TKIs.
• Preclinical evaluation of tumor angiogenesis inhibition.
• Studies involving ERK signaling pathway modulation in cancer models.

Common Pitfalls or Misconceptions

• Not indicated for direct clinical or diagnostic use—research use only (RUO) as per APExBIO.
• Does not inhibit non-tyrosine kinase targets; inappropriate for non-angiogenic disease models.
• Pharmacokinetic data in rodents/dogs may not directly extrapolate to humans without adjustment.
• Assay conditions (temperature, cell line, matrix) significantly affect observed IC₅₀ values.
• Genetic resistance in some tumor cell lines may reduce efficacy; requires case-by-case verification.

For advanced workflow tips, see 'Optimizing Anti-Angiogenic Assays with Anlotinib (hydrochloride)', which addresses protocol optimization and data interpretation beyond the scope of this review.

Workflow Integration & Parameters

Anlotinib (hydrochloride) (SKU C8688) is supplied as a lyophilized powder by APExBIO and should be stored at -20°C in a desiccated environment. Stock solutions can be prepared in DMSO and diluted into aqueous buffers for cell-based assays. Common working concentrations range from 1 nM to 1 μM, depending on assay type and cell sensitivity. Assays such as endothelial cell migration (EA.hy 926), tube formation (Matrigel), and ERK phosphorylation (immunoblot) are validated endpoints (APExBIO). For guidance on assay troubleshooting, the article 'Scenario-Driven Solutions for Angiogenesis Assays with Anlotinib' provides workflow-specific advice, while this review focuses on mechanism, benchmarks, and boundaries.

Conclusion & Outlook

Anlotinib hydrochloride is a validated, high-potency multi-target TKI for research into tumor angiogenesis and cancer signaling pathways. Its well-characterized inhibition of VEGFR2, PDGFRβ, and FGFR1, robust performance in anti-angiogenic assays, and favorable safety profile make it a preferred tool in preclinical oncology research. Ongoing studies continue to refine its applications in advanced cancer models and resistance mechanisms. For full specifications and ordering, visit the APExBIO Anlotinib (hydrochloride) product page.