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

Executive Summary: Anlotinib hydrochloride (CAS 1058157-76-8) is a small-molecule, multi-target tyrosine kinase inhibitor with high potency for VEGFR2 (IC₅₀: 5.6 ± 1.2 nM), PDGFRβ (IC₅₀: 8.7 ± 3.4 nM), and FGFR1 (IC₅₀: 11.7 ± 4.1 nM) under cell-free assay conditions (Xie et al., 2018). It exhibits robust inhibition of angiogenic processes in endothelial cells, including migration and capillary-like tube formation, surpassing sunitinib and sorafenib in comparative studies (Xie et al., 2018). Anlotinib is orally bioavailable, demonstrates high plasma protein binding (93% in humans), and distributes to tumor and key organ tissues, including the lung and brain (APExBIO). Safety profiles indicate a high LD₅₀ (1735.9 mg/kg, 14-day oral, rat), with mild systemic toxicity and no significant organ or genotoxicity detected (APExBIO). These properties position Anlotinib hydrochloride as a validated, reproducible tool for mechanistic and translational cancer research targeting angiogenesis.

Biological Rationale

Angiogenesis is essential for tumor growth, invasion, and metastasis. It is regulated by vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and fibroblast growth factor (FGF) signaling through their respective receptor tyrosine kinases: VEGFR2, PDGFRβ, and FGFR1 (Xie et al., 2018). VEGFR2 is the principal regulator of endothelial cell proliferation, migration, and neovascularization. Persistent angiogenesis is a hallmark of tumor progression, and tumors exceeding ~1 mm³ require active neovascularization for sustenance. Inhibiting these signaling pathways disrupts tumor vascularization and limits cancer progression. Monoclonal antibodies (e.g., bevacizumab) have shown efficacy but are limited by delivery and specificity challenges. Small-molecule inhibitors like Anlotinib offer oral bioavailability and multi-target coverage, addressing redundancy in angiogenic signaling (Xie et al., 2018).

Mechanism of Action of Anlotinib (hydrochloride)

Anlotinib hydrochloride directly binds the ATP-binding pocket of VEGFR2, PDGFRβ, and FGFR1 tyrosine kinases, blocking autophosphorylation and downstream ERK pathway activation (Xie et al., 2018). In biochemical kinase assays, Anlotinib exhibits low-nanomolar inhibitory concentration (IC₅₀) values: 5.6 ± 1.2 nM for VEGFR2, 8.7 ± 3.4 nM for PDGFRβ, and 11.7 ± 4.1 nM for FGFR1. In cell-based systems, it suppresses VEGF/PDGF-BB/FGF-2-induced endothelial cell migration and tube formation in a concentration-dependent manner. Anlotinib also reduces phosphorylation of ERK and Akt, downstream effectors of angiogenic signaling. Comparative studies show that Anlotinib inhibits these targets more effectively than sunitinib, sorafenib, and nintedanib (Xie et al., 2018).

Evidence & Benchmarks

• Anlotinib exhibits an IC₅₀ of 5.6 ± 1.2 nM against VEGFR2, outperforming sunitinib and sorafenib in kinase inhibition assays (Xie et al., 2018).
• In human endothelial cell migration assays (EA.hy 926), Anlotinib inhibits VEGF-induced migration with sub-10 nM potency (Xie et al., 2018).
• Capillary tube formation is blocked in vitro at concentrations as low as 10 nM, suppressing angiogenic morphogenesis (Xie et al., 2018).
• In vivo, daily oral administration in nude mouse xenograft models yields significant tumor regression and reduced vascular density, with broader efficacy than sunitinib (Xie et al., 2018).
• Pharmacokinetic studies reveal oral bioavailability of 28–58% in rats and 41–77% in dogs, with high plasma protein binding (93% in human plasma) (APExBIO).
• Safety profiles show a median lethal dose (LD₅₀) of 1735.9 mg/kg (14-day oral, rat); no significant genotoxicity or organ toxicity observed (APExBIO).

This article builds on 'Anlotinib Hydrochloride: Multi-Target TKI for Tumor Angiogenesis' by providing updated comparative benchmarks and pharmacokinetic data not previously detailed.

For practical workflow optimization, see also 'Solving Lab Challenges with Anlotinib (hydrochloride): Evidence-Based Q&A', which offers troubleshooting for assay fidelity—this article extends by providing mechanistic underpinnings and comparative efficacy data.

'Redefining Tumor Angiogenesis Inhibition: Strategic Perspectives' explores translational and clinical aspects; here, we focus on atomic, preclinical benchmarks and mechanistic scope.

Applications, Limits & Misconceptions

Validated Research Applications

• Anti-angiogenic assays: Inhibition of VEGF/PDGF-BB/FGF-2-driven endothelial cell migration and tube formation.
• Cell signaling studies: Modulation of ERK and Akt phosphorylation in endothelial and tumor cell models.
• In vivo tumor models: Evaluation of anti-tumor and anti-angiogenic efficacy in xenograft and syngeneic systems.
• Pharmacokinetic and tissue distribution studies: Assessment of oral absorption, plasma protein binding, and tissue accumulation (lung, liver, kidney, heart, brain, tumor).

Common Pitfalls or Misconceptions

• Anlotinib hydrochloride is not suitable for direct tumor cytotoxicity studies at sub-micromolar concentrations; its primary action is anti-angiogenic.
• It is not validated for diagnostic or therapeutic use in humans—research use only (RUO).
• Cross-reactivity with non-target kinases may occur at supra-pharmacological concentrations.
• Interpretation of results in high-protein or serum-rich media requires consideration of its 93% plasma protein binding.
• Genetic background and VEGFR2 expression levels in cell lines may affect assay sensitivity.

Workflow Integration & Parameters

Anlotinib hydrochloride (SKU: C8688) from APExBIO is supplied as a lyophilized powder, recommended for storage at -20°C. Reconstitution in DMSO yields stock solutions stable for up to one month at -20°C. In cellular assays (e.g., EA.hy 926), working concentrations typically range from 1–100 nM for anti-angiogenic endpoints. For in vivo studies, oral dosing solutions should be freshly prepared in compatible vehicles (e.g., 0.5% CMC-Na) and dosed at 1–5 mg/kg/day, as per cited preclinical protocols (Xie et al., 2018). High plasma protein binding (93%) necessitates careful interpretation when translating in vitro data to in vivo systems. Tissue distribution studies confirm brain penetration and preferential accumulation in tumor and highly perfused organs. Minimal parent compound is recovered in excreta, reflecting extensive CYP3A-mediated metabolism.

For detailed troubleshooting and workflow optimization, refer to 'Scenario-Driven Solutions with Anlotinib (hydrochloride)', which provides data-driven guidance for assay reproducibility; this article complements it by supplying mechanistic and benchmarking context.

To purchase or review technical specifications, visit the Anlotinib (hydrochloride) product page.

Conclusion & Outlook

Anlotinib hydrochloride is a validated, potent, multi-target tyrosine kinase inhibitor with superior anti-angiogenic and pharmacokinetic properties versus established agents. It is best deployed for mechanistic and translational studies in tumor angiogenesis, vascular signaling, and in vivo cancer models. Continued comparative benchmarking and mechanistic mapping will refine its utility in preclinical research. For advanced applications, integrating Anlotinib into multi-parametric studies and inter-laboratory benchmarking is recommended, with adherence to RUO labeling and robust assay controls.