4-Hydroxytamoxifen

4-hydroxytamoxifen (Afimoxifene) Research Standard

4-hydroxytamoxifen (Afimoxifene) is a synthetic selective estrogen receptor modulator (SERM) and the primary active metabolite of Tamoxifen. With an affinity for estrogen receptors (ER) approximately 100 times higher than that of Tamoxifen, it serves as a foundational research tool for investigating estrogen-dependent signaling. Beyond its use in oncology and endocrine research, 4-hydroxytamoxifen is widely utilized in molecular biology as the specific ligand for the inducible Cre-ERT2 recombinase system, allowing for the precise temporal control of gene expression in transgenic research models.

Technical Specifications

Mechanism of Action & Research Context

4-hydroxytamoxifen acts as a high-affinity ligand for both ER-alpha and ER-beta, functioning as a molecular switch for gene transcription.

• Cre-ERT2 Recombinase Induction: The most common laboratory application is the nuclear translocation of the Cre-ERT2 fusion protein. 4-hydroxytamoxifen binds to the mutant estrogen receptor domain (ERT2), inducing a conformational change that forces the fusion protein into the nucleus, where Cre-recombinase can then excise floxed DNA sequences.

• ER Binding & Modulation: It exhibits tissue-specific pharmacology, acting as an antagonist in mammary tissue—making it essential for breast cancer proliferation models—while exerting partial agonist effects in other tissues like bone and endometrium.

• Transcriptional Signaling: It inhibits estrogen-stimulated gene transcription by competitively binding to the receptor, providing a mechanism to study the suppression of hormone-dependent pathways in ER-positive cell lines.

Research Applications

4-hydroxytamoxifen is a specialized reagent essential for modern genetic and oncology research.

Primary fields of in vitro and in vivo laboratory investigation include:

• Conditional Gene Targeting: Utilizing the Cre-ERT2 system for spatiotemporal control of gene deletion or expression in developmental studies.

• Oncology Research: Evaluating the inhibitory effects on estrogen-stimulated cellular growth in ER-positive breast cancer cell lines.

• Comparative SERM Pharmacology: Serving as the benchmark reference for potency and affinity in studies involving novel estrogen receptor ligands.

• Molecular Signaling: Mapping the downstream proteomic and transcriptomic shifts following competitive ER blockade.

Storage & Handling Guidelines

To maintain the chemical stability and experimental reliability of the compound:

• Storage Environment: Maintain at -20 degrees Celsius for long-term stability. The compound is sensitive to degradation.

• Environmental Control: Protect strictly from light (use amber vials) and moisture. Photo-degradation can occur upon prolonged exposure to ambient light.

• Handling: Allow the container to equilibrate to room temperature before opening to minimize condensation. Utilize standard laboratory safety practices and appropriate PPE, as this compound is a biologically active SERM.

• Aseptic Technique: Maintain a sterile work environment to ensure the integrity of the compound for cell culture and genetic model applications.

Research Use Disclaimer

Research Use Only Disclaimer: This product is developed and distributed strictly as a Research Use Only (RUO) laboratory reference chemical intended exclusively for non-clinical analytical and scientific investigation. It is not an FDA-approved drug, medical treatment, dietary supplement, or food ingredient, and is strictly prohibited for human or animal consumption. Kimera Chems supplies this high-purity research material solely to qualified institutions and professional investigators for authorized laboratory research.