10058-F4: Targeted c-Myc-Max Dimerization Inhibition for Apoptosis Research

Executive Summary: 10058-F4 is a small-molecule, cell-permeable inhibitor of c-Myc-Max dimerization, directly disrupting c-Myc-driven transcription and inducing apoptosis via mitochondrial pathways (APExBIO). It demonstrates dose-dependent cytotoxicity in acute myeloid leukemia (AML) cell lines and suppresses tumor growth in human prostate cancer xenograft models (HL-60, U937, NB-4; DU145, PC-3) (Stern et al., 2024). The compound's mechanism includes reduced c-Myc mRNA/protein and altered Bcl-2 family proteins, with cytochrome C release marking mitochondrial apoptosis. Its physicochemical profile allows robust DMSO and ethanol solubility, but not water. 10058-F4 is a research tool for c-Myc pathway inhibition, apoptosis assays, and telomerase-linked cancer investigations.

Biological Rationale

The c-Myc transcription factor is a master regulator of cell proliferation, metabolism, and apoptosis. c-Myc exerts its function primarily by forming a heterodimer with Max, enabling sequence-specific DNA binding and gene transcription. Dysregulation of c-Myc is linked to oncogenesis in diverse cancers, including AML and prostate cancer (Stern et al., 2024). Targeting c-Myc-Max dimerization provides a tractable strategy to suppress c-Myc-driven transcriptional programs. 10058-F4 specifically disrupts this protein-protein interaction, resulting in downregulation of c-Myc target genes and induction of apoptosis in cancer cells. This targeted inhibition is especially relevant for apoptosis assay development and research on mitochondrial apoptosis pathways. The link between c-Myc, telomerase (TERT), and DNA repair underscores the broader relevance of 10058-F4 for cancer biology and stem cell studies (Stern et al., 2024).

Mechanism of Action of 10058-F4

10058-F4 ((5E)-5-[(4-ethylphenyl)methylidene]-2-sulfanylidene-1,3-thiazolidin-4-one) inhibits the formation of the c-Myc-Max heterodimer by binding to c-Myc, thereby preventing its association with Max (APExBIO). This inhibition blocks c-Myc’s binding to E-box sequences in DNA, suppressing the transcription of c-Myc target genes. Loss of c-Myc gene expression leads to decreased mRNA and protein levels, which disrupts cell cycle progression and induces apoptosis. The apoptotic response is characterized by mitochondrial pathway activation, including altered expression of Bcl-2 family proteins and cytochrome C release. 10058-F4 is cell-permeable, enabling intracellular activity in both suspension and adherent cell lines. Its effect is dose- and time-dependent, with significant apoptosis observed at 100 μM after 72 hours in AML cell lines. The compound is not effective at inhibiting other protein-protein interactions outside the c-Myc-Max context, supporting its specificity.

Evidence & Benchmarks

• 10058-F4 induces apoptosis in human AML cell lines (HL-60, U937, NB-4) with significant effects at 100 μM after 72 hours (Stern et al., 2024).
• In vivo, intravenous 10058-F4 administration (dose and schedule as per protocol) inhibits tumor growth in SCID mice bearing DU145 and PC-3 human prostate cancer xenografts, though with variable efficacy (Stern et al., 2024).
• 10058-F4 treatment leads to decreased c-Myc mRNA and protein, mitochondrial membrane potential loss, and cytochrome C release, consistent with mitochondrial apoptosis (APExBIO).
• The compound is soluble at ≥24.9 mg/mL in DMSO and ≥2.64 mg/mL in ethanol but insoluble in water; optimal storage is as a solid at -20°C (APExBIO).
• 10058-F4 does not inhibit TERT expression directly but may provide a tool to dissect c-Myc–driven telomerase regulation, as c-Myc modulates TERT promoter activity (Stern et al., 2024).

For additional mechanistic insights, see 10058-F4: Advanced Insights into c-Myc-Max Dimerization Inhibition, which covers broader applications; this article provides new quantitative benchmarks and clarifies mechanistic specificity.

To compare workflow parameters, 10058-F4: Precise c-Myc-Max Dimerization Inhibition details strict assay conditions; here, we update best practices with recent solubility and storage data.

Applications, Limits & Misconceptions

10058-F4 is a validated research reagent for the following applications:

• Dissecting c-Myc-driven transcriptional programs in cancer biology (Stern et al., 2024).
• Apoptosis assays in cell lines sensitive to c-Myc inhibition, such as AML and prostate cancer models.
• Studies of mitochondrial apoptosis, including cytochrome C release and Bcl-2 family protein modulation.
• Research into the c-Myc/TERT regulatory axis, relevant for telomerase-linked pathologies.

However, its use is subject to several boundaries:

Common Pitfalls or Misconceptions

• 10058-F4 is ineffective in models lacking c-Myc/Max expression or with c-Myc-independent proliferation.
• The compound does not directly inhibit telomerase (TERT) activity; observed effects on TERT are mediated via c-Myc regulation.
• 10058-F4 is not suitable for long-term solution storage; working solutions should be prepared fresh, as per APExBIO guidelines (APExBIO).
• Water-based solvents are not recommended due to insolubility; only DMSO or ethanol should be used for stock preparation.
• Off-target effects at supra-physiological concentrations (>100 μM) have not been exhaustively ruled out in all cell types.

For advanced integration with telomerase pathway research, see 10058-F4: Redefining c-Myc-Max Inhibition for Apoptosis and Telomerase Pathway Research, which links mitochondrial and telomerase regulatory mechanisms; this article focuses on validated apoptosis and c-Myc transcriptional benchmarks.

Workflow Integration & Parameters

Preparation: Dissolve 10058-F4 at ≥24.9 mg/mL in DMSO or ≥2.64 mg/mL in ethanol. Do not use water as a solvent. Stock solutions should be prepared immediately before use and discarded after the experiment. Store the solid compound at -20°C (APExBIO).

Assay recommendations: For in vitro apoptosis assays, treat cells with 10058-F4 at concentrations up to 100 μM for 72 hours. Monitor for cell cycle arrest and apoptosis via flow cytometry, cytochrome C release assays, or Bcl-2/Bax immunoblotting. For in vivo studies, follow established intravenous administration protocols and monitor tumor growth inhibition in xenograft models (DU145, PC-3).

Controls: Include DMSO- or ethanol-only controls to account for solvent effects. Validate c-Myc and Max expression in the intended cell line before use.

For detailed application protocols, refer to the APExBIO 10058-F4 product page and 10058-F4: Small-Molecule c-Myc Inhibitor for Advanced Apoptosis Assays, which describes next-generation assay workflows; this article updates those protocols with the latest solubility and storage guidelines.

Conclusion & Outlook

10058-F4 is a specific, cell-permeable inhibitor of c-Myc-Max dimerization with validated efficacy in apoptosis assays and cancer models. Its well-characterized mechanism, robust solubility in DMSO/ethanol, and ability to induce mitochondrial apoptosis make it an essential tool for dissecting c-Myc-related oncogenic pathways. The compound does not directly affect telomerase activity but provides a valuable means to probe c-Myc’s role in TERT regulation. APExBIO provides high-quality 10058-F4 (SKU: A1169) for research use. Future studies are warranted to further refine concentration ranges, explore off-target effects, and expand its application in telomerase and DNA repair pathway research. For purchase and latest documentation, visit the official product page.