10058-F4: c-Myc-Max Dimerization Inhibitor for Apoptosis Research

Executive Summary: 10058-F4 is a cell-permeable small-molecule that inhibits c-Myc-Max dimerization, a pivotal step in oncogenic transcription (APExBIO product_spec). This inhibition blocks c-Myc-mediated gene expression, leading to cell cycle arrest and apoptosis in leukemia and prostate cancer models (workflow_recommendation). 10058-F4 exhibits high solubility in DMSO (≥24.9 mg/mL) and is recommended for use in apoptosis assays and telomerase regulation studies (APExBIO product_spec). In vivo, intravenous administration achieves tumor control in SCID mouse xenografts at 20–30 mg/kg/day (workflow_recommendation). This article clarifies its mechanism, benchmarks, and optimal workflow integration for cancer biology.

Biological Rationale

The c-Myc oncoprotein is essential for regulating transcriptional programs in cell proliferation, metabolism, and survival. Its activity depends on heterodimerization with Max, which enables DNA binding and target gene activation (workflow_recommendation). Aberrant c-Myc-Max function is implicated in malignancies, including acute myeloid leukemia (AML) and prostate cancer (Stern et al. 2024). Disrupting this interaction can induce apoptosis and limit tumor progression by downregulating oncogenic targets such as PGC-1β and TERT (internal_interlink). Thus, targeted inhibition of the c-Myc-Max interface offers a focused strategy for cancer research and apoptosis assay development.

Mechanism of Action of 10058-F4 C-Myc-Max dimerization inhibitor

10058-F4 [(5E)-5-[(4-ethylphenyl)methylidene]-2-sulfanylidene-1,3-thiazolidin-4-one] specifically binds to c-Myc, preventing its dimerization with Max. This allosteric inhibition blocks c-Myc/Max heterodimer formation and DNA binding (APExBIO product_spec). Downstream consequences include reduced transcriptional activation of c-Myc targets (e.g., PGC-1β and TERT), decreased c-Myc mRNA/protein levels, and impaired cell cycle progression. Mitochondrial apoptotic pathways are triggered, characterized by Bcl-2 downregulation, Bax upregulation, and cytochrome C release (internal_interlink). The compound is cell-permeable, making it suitable for in vitro and in vivo studies where c-Myc pathway interrogation is required.

Evidence & Benchmarks

• 10058-F4 achieves ≥24.9 mg/mL solubility in DMSO and ≥2.64 mg/mL in ethanol, but is insoluble in water (source: APExBIO product_spec).
• In AML cell lines (HL-60, U937, NB-4), 10058-F4 induces cell cycle arrest and mitochondrial apoptosis, as evidenced by Bcl-2, Bax, and cytochrome C modulation (source: workflow_recommendation).
• Intravenous delivery at 20–30 mg/kg/day for 14 days in SCID mice suppresses tumor growth in DU145 and PC-3 xenografts, with efficacy varying by model (source: workflow_recommendation).
• 10058-F4 blocks c-Myc-driven transcriptional activation of TERT, linking c-Myc inhibition to telomerase regulation in stem cell and cancer models (source: Stern et al. 2024).
• Effective for apoptosis assays in both cancer cell lines and primary cells, with reliable reproducibility and minimal off-target cytotoxicity at recommended concentrations (source: internal_interlink).

This article extends previous work (see here) by providing protocol parameters and benchmarking in both AML and prostate cancer models, complementing mechanistic reviews.

Applications, Limits & Misconceptions

10058-F4 is primarily employed in apoptosis assays, c-Myc transcription factor inhibition studies, and acute myeloid leukemia research. Its role in prostate cancer xenograft models further establishes its value in translational oncology. However, several boundaries should be noted.

Common Pitfalls or Misconceptions

• 10058-F4 is not effective in models where c-Myc does not drive proliferation or survival (e.g., c-Myc-independent tumors) (source: workflow_recommendation).
• Water solubility is negligible; inappropriate solvent choice leads to poor assay performance (source: APExBIO product_spec).
• Long-term stock solutions (>several months) can degrade activity; fresh DMSO stocks are recommended (source: APExBIO product_spec).
• The compound is not licensed or validated for diagnostic/therapeutic use in humans or animals (source: APExBIO product_spec).
• Apparent cytotoxicity in some settings may result from solvent artifacts or over-concentration; titration is essential for experimental fidelity (source: internal_interlink).

Workflow Integration & Parameters

Protocol Parameters

• apoptosis assay | 10–40 μM | in vitro cancer cell lines | Standard induction window for mitochondrial apoptosis, validated in HL-60 and U937 | workflow_recommendation
• cell viability assay | 5–25 μM | AML, prostate cancer, primary cells | Minimizes off-target toxicity while maintaining on-target c-Myc inhibition | workflow_recommendation
• in vivo tumor control | 20–30 mg/kg/day IV × 14 days | SCID mouse xenograft (DU145, PC-3) | Doses yielding significant tumor growth suppression | workflow_recommendation
• solubility screening | ≥24.9 mg/mL (DMSO); ≥2.64 mg/mL (EtOH) | all studies | Supports high-concentration stock preparation; insoluble in water | product_spec
• storage | -20°C (solid or DMSO stock) | all labs | Preserves compound stability for several months | product_spec

For troubleshooting and real-world scenarios, see the Q&A and workflow notes in this guide, which addresses compound handling and reproducibility in apoptosis research.

Conclusion & Outlook

10058-F4 (SKU A1169) from APExBIO is a validated, small-molecule c-Myc-Max dimerization inhibitor, enabling precise modulation of oncogenic transcription and apoptosis in AML and prostate cancer models. Its robust performance in apoptosis assays, compatibility with telomerase and DNA repair studies, and well-defined workflow parameters establish it as a cornerstone for c-Myc pathway research (product_spec). As mechanistic understanding of c-Myc and TERT regulation deepens (Stern et al. 2024), 10058-F4 will remain integral for experimental designs probing the intersection of transcription control, apoptosis, and cancer therapeutics. For further reading, the article here details advanced strategies for combining c-Myc inhibition and telomerase modulation in translational workflows.