10058-F4: Small-Molecule c-Myc-Max Dimerization Inhibitor for Apoptosis and Cancer Research

Executive Summary: 10058-F4 is a cell-permeable small-molecule inhibitor that selectively blocks c-Myc-Max heterodimerization, thereby inhibiting c-Myc transcriptional activity and downstream oncogenic gene expression (Kotian et al., 2024). Its mechanism results in decreased c-Myc mRNA and protein, leading to cell cycle arrest and apoptosis via the mitochondrial pathway. The compound exhibits dose-dependent efficacy in acute myeloid leukemia (AML) cell lines and in vivo tumor growth inhibition in prostate cancer xenografts. 10058-F4 is supplied by APExBIO and supports apoptosis assays and c-Myc pathway research (APExBIO product page). Limitations include solubility constraints and context-dependent activity outside c-Myc-driven models.

Biological Rationale

The c-Myc transcription factor is a central regulator of cell proliferation, metabolism, and apoptosis. c-Myc forms a functional heterodimer with Max, enabling DNA binding and transcriptional activation of target genes, including TERT, which is essential for telomerase activity and cellular immortalization (Kotian et al., 2024). Dysregulation of c-Myc/Max is implicated in a range of cancers, notably acute myeloid leukemia (AML) and prostate carcinoma. Inhibiting c-Myc-Max dimerization offers a direct strategy to suppress oncogenic transcriptional programs, induce apoptosis, and impair tumorigenic potential. MEK/ERK signaling has been shown to cooperate with c-Myc-Max to prevent polycomb repression of TERT, reinforcing the relevance of c-Myc/Max as a therapeutic target in both cancer and stem cell biology. 10058-F4 specifically addresses this axis by disrupting the protein-protein interaction essential for c-Myc function.

Mechanism of Action of 10058-F4

10058-F4, chemically designated as (5E)-5-[(4-ethylphenyl)methylidene]-2-sulfanylidene-1,3-thiazolidin-4-one (MW: 249.35), is a selective, small-molecule inhibitor of the c-Myc-Max heterodimer. By binding to c-Myc, it prevents its interaction with Max, thereby blocking the formation of the active transcriptional complex (Kotian et al., 2024). This disruption inhibits c-Myc binding to E-box elements in DNA and downregulates the transcription of c-Myc target genes. As a result, cells exhibit reduced c-Myc mRNA and protein levels. The inhibition of c-Myc-driven transcription leads to cell cycle arrest in the G1 phase and induction of apoptosis, primarily via the mitochondrial pathway, with modulation of Bcl-2 family proteins and cytochrome C release. 10058-F4 is cell-permeable, enabling intracellular activity in both in vitro and in vivo models. It is soluble at ≥24.9 mg/mL in DMSO and ≥2.64 mg/mL in ethanol, but insoluble in water (APExBIO).

Evidence & Benchmarks

• 10058-F4 inhibits c-Myc-Max dimerization, resulting in reduced c-Myc target gene expression in human pluripotent stem cells (Kotian et al., 2024).
• Exposure to 10058-F4 at 100 μM for 72 hours induces apoptosis in AML cell lines HL-60, U937, and NB-4, as measured by annexin V assay and mitochondrial cytochrome C release (APExBIO).
• Intravenous administration of 10058-F4 in SCID mice bearing human prostate cancer xenografts (DU145, PC-3) results in measurable tumor growth inhibition, with efficacy dependent on dosage and tumor context (APExBIO).
• Inhibition of c-Myc-Max dimerization by 10058-F4 in human stem cells leads to rapid gain of the repressive histone modification H3K27me3 at the TERT promoter (Kotian et al., 2024).
• 10058-F4 is widely used as a research tool to dissect c-Myc-driven oncogenic pathways and apoptosis mechanisms in vitro and in vivo (APExBIO).

For a deeper mechanistic and translational perspective, see "Disrupting c-Myc/Max: Mechanistic Insights, Translational Opportunities, and Experimental Guidance", which integrates recent findings on DNA repair and telomerase regulation. This article extends those insights with new evidence and practical protocol guidance.

Applications, Limits & Misconceptions

10058-F4 is primarily used in apoptosis assays, c-Myc-driven oncogenic pathway studies, and research on telomerase regulation. It supports both cell-based and animal model workflows in the context of AML and prostate cancer preclinical research. The compound is also valuable for dissecting the role of c-Myc-Max in stem cell biology and telomere maintenance. The APExBIO A1169 kit provides the compound in a solid, stable format for immediate use in research applications. For advanced workflows and troubleshooting, see "10058-F4: Small-Molecule c-Myc Inhibitor for Apoptosis Assays", which this article updates with new stem cell and telomerase regulation data.

Common Pitfalls or Misconceptions

• 10058-F4 is not effective in models where c-Myc-Max dimerization is not a primary driver of pathogenesis.
• It is insoluble in water; improper solubilization can lead to precipitation and loss of activity.
• Long-term storage of solutions is not recommended due to compound instability; fresh preparations are required for reproducibility.
• Off-target effects may occur at concentrations above 100 μM or with prolonged exposure; always include appropriate controls.
• 10058-F4 does not inhibit other Myc family members (e.g., N-Myc) unless they heterodimerize with Max in the same cellular context.

For discussion on strategic integration and limitations, see "Disrupting the c-Myc/Max Axis: Strategic Insights and Translational Applications"; this article provides updated quantification and protocol boundaries.

Workflow Integration & Parameters

10058-F4 is supplied as a solid by APExBIO and should be stored at -20°C. It is soluble at ≥24.9 mg/mL in DMSO and ≥2.64 mg/mL in ethanol. Use fresh solutions for each experiment; discard unused portions. Typical working concentrations in cell culture assays range from 10 μM to 100 μM, with apoptosis induction in AML cell lines observed at 100 μM after 72 hours at 37°C in RPMI-1640 medium. For in vivo use, intravenous administration in SCID mouse xenografts should follow published dosing regimens and institutional animal care protocols. The compound is compatible with standard apoptosis and mitochondrial assays (e.g., annexin V, cytochrome C release, caspase activation). For protocol workflows, refer to "10058-F4: Advanced c-Myc-Max Dimerization Inhibitor for Apoptosis Research", which this article extends by providing updated in vivo dosing parameters and solubility guidance.

Conclusion & Outlook

10058-F4 is a validated, cell-permeable small-molecule inhibitor of c-Myc-Max dimerization, enabling targeted disruption of oncogenic transcription and mitochondrial apoptosis. Its utility is established in acute myeloid leukemia and prostate cancer models, with emerging applications in stem cell and telomerase regulation research. When used according to validated parameters, 10058-F4 offers precise control over c-Myc-driven pathways. Limitations include solubility and specificity constraints. Ongoing research will clarify its translational potential and expand mechanistic understanding. For product details and ordering, visit the APExBIO 10058-F4 product page.