10058-F4 C-Myc-Max Dimerization Inhibitor: Mechanism, Evidence, and Applications

Executive Summary: 10058-F4 is a selective, cell-permeable small-molecule inhibitor that blocks the c-Myc/Max dimerization necessary for c-Myc transcriptional activity [APExBIO]. In vitro, 10058-F4 induces cell cycle arrest and mitochondrial apoptosis in AML cell lines via downregulation of Bcl-2 and upregulation of Bax [Stern et al., 2024]. In vivo, intravenous dosing at 20–30 mg/kg/day achieves significant tumor growth inhibition in prostate cancer xenograft models. The compound is insoluble in water but demonstrates high solubility in DMSO (≥24.9 mg/mL) and ethanol (≥2.64 mg/mL), requiring specific handling protocols. 10058-F4's validated mechanism and performance parameters make it a benchmark c-Myc inhibitor for cancer biology and apoptosis research.

Biological Rationale

c-Myc is a transcription factor essential for cell proliferation, metabolism, and survival. Aberrant c-Myc expression is a hallmark of diverse cancers, including acute myeloid leukemia (AML) and prostate cancer. c-Myc function requires heterodimerization with Max, enabling DNA binding and transcriptional activation of target genes such as PGC-1β. Disruption of c-Myc/Max dimerization impairs oncogenic signaling and induces cell cycle arrest or apoptosis, making this interaction a validated target for small-molecule inhibitors [Stern et al., 2024]. 10058-F4 was developed to address this gap, providing selective c-Myc/Max inhibition for mechanistic studies and therapeutic modeling.

Mechanism of Action of 10058-F4 C-Myc-Max Dimerization Inhibitor

10058-F4, chemically (5E)-5-[(4-ethylphenyl)methylidene]-2-sulfanylidene-1,3-thiazolidin-4-one (MW 249.35, C₁₂H₁₁NOS₂), selectively binds the c-Myc bHLHZip domain, preventing c-Myc from forming heterodimers with Max. This inhibition blocks c-Myc/Max DNA binding and transcriptional activation. Downstream, 10058-F4 suppresses transcription of c-Myc targets, reduces c-Myc mRNA and protein levels, and triggers mitochondrial apoptosis characterized by Bcl-2 downregulation, Bax upregulation, and cytochrome C release. In AML cell lines (HL-60, U937, NB-4), this pathway culminates in cell cycle arrest and myeloid differentiation. In vivo, 10058-F4 reduces tumor burden in human prostate cancer xenografts (DU145, PC-3) [APExBIO].

Evidence & Benchmarks

• 10058-F4 inhibits c-Myc/Max heterodimer formation in a dose-dependent manner with IC₅₀ values in the low micromolar range under cell-free and cellular conditions (APExBIO).
• Application of 10058-F4 to HL-60, U937, and NB-4 AML cell lines induces G1 cell cycle arrest and mitochondrial apoptosis within 24–48 hours (Stern et al., 2024).
• Upon treatment, Bcl-2 protein levels decrease while Bax increases, and cytochrome C is released from mitochondria, confirming activation of the intrinsic apoptosis pathway (Stern et al., 2024).
• In SCID mice bearing DU145 or PC-3 prostate cancer xenografts, intravenous 10058-F4 at 20–30 mg/kg/day for 14 days significantly reduces tumor volume versus vehicle controls (model-dependent efficacy; see product documentation: APExBIO).
• 10058-F4 does not inhibit APEX2-driven TERT expression, confirming pathway selectivity (Stern et al., 2024).

Compared to prior reviews (e.g., see this application-driven summary), this article synthesizes the most recent in vivo efficacy and selectivity data for 10058-F4, clarifying its utility and limits.

For protocol optimization and troubleshooting, see this workflow-oriented article; the present review additionally provides molecular rationale and context for target selectivity.

For expanded discussion on c-Myc-driven telomerase regulation, this piece contextualizes 10058-F4's role in apoptosis relative to emerging telomerase findings—here, we focus on validated benchmarks and experimental boundaries.

Applications, Limits & Misconceptions

10058-F4 is primarily used in apoptosis assays, c-Myc transcription factor inhibition studies, and cancer models focused on c-Myc/Max pathway interrogation. It is a reference compound for acute myeloid leukemia (AML) research and prostate cancer xenograft studies. Its cell-permeable nature and selectivity enable precise targeting of c-Myc/Max-regulated transcriptional programs.

Common Pitfalls or Misconceptions

• 10058-F4 is not active in water; improper solubilization leads to loss of efficacy. Use DMSO (≥24.9 mg/mL) or ethanol (≥2.64 mg/mL) at recommended temperatures.
• It does not inhibit c-Myc-independent cell proliferation pathways; off-target effects are minimal at recommended concentrations.
• 10058-F4 is not suitable for clinical or diagnostic use; intended for research purposes only.
• Long-term storage of solutions may reduce activity; prepare fresh aliquots and store at -20°C for optimal results.
• It does not affect APEX2-mediated TERT expression, so results should not be interpreted as direct telomerase modulation unless c-Myc is established as a regulatory node in the system.

Workflow Integration & Parameters

For apoptosis and proliferation assays, dissolve 10058-F4 in DMSO to ≥12.5 mg/mL. Warm solutions at 37°C or sonicate to enhance dissolution. Store aliquots at -20°C; avoid repeated freeze-thaw cycles. Use validated concentrations (often 10–50 µM in vitro) and controls. For in vivo studies, administer intravenously at 20–30 mg/kg/day for up to two weeks, monitoring tumor growth and animal health. Refer to the product page for batch-specific technical data and safety information. APExBIO ships 10058-F4 on blue ice to maintain integrity; verify compound appearance and solubility before use.

Conclusion & Outlook

10058-F4, offered by APExBIO, is a benchmark small-molecule c-Myc-Max dimerization inhibitor for apoptosis and oncogenic pathway research. Its well-characterized mechanism, robust in vitro/in vivo efficacy, and defined handling protocols make it indispensable for cancer biology workflows. Emerging research on telomerase and stem cell regulation positions c-Myc/Max inhibition as a strategic axis in experimental hematology and oncology. Ongoing studies will further clarify the boundaries and translational potential of this compound.