Mechanism of Action

ENMD-2076 is a small-molecule kinase inhibitor with a multi-targeted mechanism of action. Its primary molecular target is Aurora A kinase, a serine/threonine kinase that plays a critical role in mitotic spindle assembly, centrosome maturation, and chromosome segregation. Dysregulation of Aurora A is frequently observed in a broad range of human malignancies, making it a clinically validated oncology target.

Beyond Aurora A, ENMD-2076 demonstrates inhibitory activity against a panel of angiogenic receptor tyrosine kinases, including vascular endothelial growth factor receptors (VEGFR), fibroblast growth factor receptors (FGFR), and FMS-like tyrosine kinase 3 (FLT3). This dual anti-mitotic and anti-angiogenic profile distinguishes ENMD-2076 from single-target Aurora inhibitors and may contribute to broader antitumor efficacy in preclinical models.

Mechanistically, Aurora A inhibition leads to mitotic arrest, induction of apoptosis, and suppression of tumor cell proliferation. The concurrent inhibition of angiogenic kinases is expected to impair tumor vascularization, thereby restricting nutrient and oxygen supply to rapidly dividing tumor cells.

Physicochemical Properties and the Role of the Tartrate Salt

ENMD-2076 L-(+)-Tartaric acid is formulated as the tartrate salt of the parent compound ENMD-2076. Salt formation with L-(+)-tartaric acid — a naturally occurring, pharmaceutically acceptable organic acid — is a widely employed strategy in medicinal chemistry to improve the physicochemical properties of basic drug candidates.

The principal benefit of the tartrate salt form is enhanced aqueous solubility relative to the free base. Improved solubility is critical for: (1) preparation of consistent stock solutions in aqueous or aqueous-co-solvent systems for in vitro cell-based assays; (2) formulation of dosing solutions for in vivo pharmacological and pharmacokinetic studies; and (3) ensuring reproducible compound delivery across experimental conditions.

Researchers should prepare stock solutions in DMSO or sterile water where solubility permits, and validate concentration by UV absorbance or an equivalent method. Long-term storage under desiccated, low-temperature conditions is recommended to preserve compound integrity. Specific solubility values and storage recommendations should be confirmed from the certificate of analysis (CoA) supplied with the product lot.

Research Applications in Oncology

ENMD-2076 L-(+)-Tartaric acid is primarily used as a pharmacological tool compound in preclinical oncology research. Its multi-kinase inhibitory profile makes it suitable for investigating the biological consequences of simultaneous Aurora A and angiogenic kinase inhibition in cancer cell lines and animal models.

Cell-based assays: ENMD-2076 tartrate can be applied in proliferation assays (e.g., MTT, CellTiter-Glo), apoptosis assays (e.g., Annexin V/PI staining, caspase activation), cell cycle analysis (e.g., propidium iodide staining, flow cytometry), and mitotic marker immunofluorescence to assess Aurora A substrate phosphorylation.

In vivo models: The improved solubility of the tartrate salt facilitates formulation for oral or intraperitoneal administration in xenograft or syngeneic tumor models. Researchers studying tumor angiogenesis may combine ENMD-2076 with vessel density quantification (e.g., CD31 immunohistochemistry) to evaluate anti-angiogenic effects.

Hematological malignancies: Given its FLT3 inhibitory activity, ENMD-2076 has been investigated in models of acute myeloid leukemia (AML), where FLT3 mutations are among the most common oncogenic drivers. Researchers working in this area should note that combination studies with standard-of-care agents may reveal synergistic interactions.

Handling, Storage, and Quality Considerations

Proper handling and storage of ENMD-2076 L-(+)-Tartaric acid are essential to maintain compound activity and ensure experimental reproducibility. The following general guidelines apply; always defer to the product-specific CoA and Safety Data Sheet (SDS) for authoritative specifications.

• Storage temperature: Store at -20 °C under desiccated conditions. Protect from light and moisture.
• Stock solution preparation: Dissolve in DMSO to prepare a concentrated stock solution. For aqueous formulations, use warm sterile water or appropriate aqueous vehicles. Avoid repeated freeze-thaw cycles by preparing single-use aliquots.
• Purity: Aladdin Scientific supplies ENMD-2076 L-(+)-Tartaric acid (SKU: E129946) with purity documentation. Confirm lot-specific purity via the accompanying CoA prior to experimental use.
• Safety: Handle as a potent biologically active compound. Use appropriate personal protective equipment (PPE) including gloves, lab coat, and eye protection. Consult the SDS for full hazard information.

For research use only. Not intended for diagnostic, therapeutic, or veterinary use.