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

Executive Summary: Anlotinib hydrochloride (CAS 1058157-76-8) is a novel, research-grade small molecule inhibitor provided by APExBIO, exhibiting high selectivity for VEGFR2, PDGFRβ, and FGFR1, with IC₅₀ values of 5.6 nM, 8.7 nM, and 11.7 nM, respectively (APExBIO product page). It demonstrates superior anti-angiogenic activity compared to sunitinib and sorafenib under standardized cell-based assays (see Dovitinib.com). Anlotinib acts by inhibiting VEGF/PDGF-BB/FGF-2-induced endothelial cell migration and capillary formation, and downstream ERK signaling. Pharmacokinetic studies show rapid oral absorption, high plasma protein binding, and wide tissue distribution, including the ability to cross the blood-brain barrier (Chen & Feng 2019, DOI). Validated in multiple tumor models, it offers a safe profile for preclinical research, with a high oral LD₅₀ and minimal systemic toxicity.

Biological Rationale

Angiogenesis, the formation of new blood vessels, is essential for tumor growth and metastasis. Tumor vasculature is predominantly regulated by the VEGF, PDGF, and FGF signaling axes. Receptor tyrosine kinases (RTKs) such as VEGFR2, PDGFRβ, and FGFR1 mediate these pathways. Aberrant activation of RTKs leads to enhanced endothelial cell migration, proliferation, and neovascularization, facilitating malignant progression. Inhibiting these RTKs has emerged as a validated strategy for tumor angiogenesis inhibition (PMID: 31275974). Multi-target inhibition is favored to overcome compensatory mechanisms and resistance seen with single-pathway blockade. Anlotinib hydrochloride was developed to address this gap, combining potent, selective inhibition of key angiogenic RTKs with a favorable pharmacological profile (APExBIO).

Mechanism of Action of Anlotinib (hydrochloride)

Anlotinib hydrochloride directly inhibits the kinase activity of VEGFR2 (IC₅₀ = 5.6 ± 1.2 nM), PDGFRβ (IC₅₀ = 8.7 ± 3.4 nM), and FGFR1 (IC₅₀ = 11.7 ± 4.1 nM) in vitro (APExBIO datasheet). By binding to the ATP-binding pocket of these RTKs, anlotinib prevents autophosphorylation and downstream signaling. This disrupts the VEGF/PDGF/FGF-driven ERK pathway, resulting in the inhibition of endothelial cell migration and capillary-like tube formation. These effects are concentration-dependent, with maximal inhibition observed at nanomolar concentrations in EA.hy 926 human endothelial cell assays. Anlotinib also targets other kinases implicated in tumor progression, including c-Kit and Met, broadening its anti-angiogenic spectrum (Chen & Feng 2019, DOI).

Evidence & Benchmarks

• Anlotinib hydrochloride inhibits VEGFR2 kinase activity with an IC₅₀ of 5.6 ± 1.2 nM in cell-free assays (APExBIO).
• In cellular models, anlotinib blocks VEGF/PDGF-BB/FGF-2-induced migration and tube formation in human endothelial cells in a dose-dependent manner (dovitinib.com).
• Compared to sunitinib, sorafenib, and nintedanib, anlotinib demonstrates higher potency against VEGFR2, PDGFRβ, and FGFR1 in head-to-head assays (angiotensin-iii.com).
• Pharmacokinetic studies in rats and dogs show oral bioavailability of 28–58% and 41–77%, respectively, with high plasma protein binding (93% in humans) (Chen & Feng 2019, DOI).
• Anlotinib exhibits a high median lethal dose (LD₅₀ = 1735.9 mg/kg) after 14-day oral administration in rodent models, with mild, reversible toxicity (prescission.com).
• In a clinical case report, anlotinib reduced lymph node metastases in intra-abdominal desmoplastic small round cell tumor, providing the first evidence for its efficacy in this rare cancer (Chen & Feng 2019, DOI).

This article extends the mechanistic detail and application scope discussed in Anlotinib Hydrochloride: Multi-Target Tyrosine Kinase Inhibitor by providing direct benchmark data and updated clinical context. It also clarifies workflow and toxicity parameters, building upon the experimental protocols covered in Advanced Applied Workflows for Mechanistic Studies.

Applications, Limits & Misconceptions

Anlotinib (hydrochloride) is widely used in research applications focusing on tumor angiogenesis inhibition, endothelial cell migration, and mechanistic cancer studies. It is deployed in in vitro assays with human vascular endothelial cells (e.g., EA.hy 926), capillary tube formation assays, and in vivo models for pharmacokinetics and biodistribution. The compound is not intended for diagnostic or clinical therapeutic use and is distributed for research purposes only (APExBIO).

Common Pitfalls or Misconceptions

• Anlotinib is not a clinical drug product: It is provided for research use only and not approved for human therapy (APExBIO).
• Single-pathway inhibition is insufficient: Anlotinib’s multi-target approach is essential to circumvent compensatory angiogenic signaling, unlike single-kinase inhibitors (prescission.com).
• Not all tumor models respond equally: Efficacy in rare cancers such as IADSRCT is emerging, but broad clinical generalization is not supported (Chen & Feng 2019, DOI).
• Pharmacokinetics may vary by species: Absorption, distribution, and metabolism parameters can differ between rodents, dogs, and humans (Chen & Feng 2019, DOI).
• Not suitable for all angiogenic assays: Careful titration is required, as high concentrations may elicit off-target effects (dovitinib.com).

Workflow Integration & Parameters

Anlotinib (hydrochloride) is typically stored at -20°C in desiccated conditions. It is reconstituted in DMSO or aqueous buffer before use. Standard endothelial cell migration and tube formation assays employ concentrations from 1–100 nM, with maximal inhibition observed near IC₅₀ values. For in vivo pharmacokinetics, oral dosing regimens are guided by species-specific bioavailability and LD₅₀ data. Metabolism via CYP3A should be accounted for in compound interaction studies. Tissue distribution analyses have demonstrated high levels in lung, liver, kidney, heart, and tumor tissue, supporting translational cancer models (Chen & Feng 2019, DOI).

Compared to the guidance in Mechanistic Innovation and Strategic Application, this article provides more detailed storage, handling, and dosing information for reproducible research outcomes.

Conclusion & Outlook

Anlotinib hydrochloride, as supplied by APExBIO, is a validated, research-grade multi-target tyrosine kinase inhibitor for advanced anti-angiogenic studies. Its superior selectivity for VEGFR2, PDGFRβ, and FGFR1, robust cellular potency, and favorable pharmacokinetic and safety profile make it a preferred tool for cancer research. Ongoing mechanistic and translational investigations will clarify its full applicability and limitations in diverse tumor contexts. For detailed protocols and product specifications, visit the Anlotinib (hydrochloride) product page. For expanded mechanistic context, see Expanding the Frontiers of Tumor Angiogenesis Inhibition, which explores broader translational strategies beyond the scope of this article.