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

Executive Summary: 10058-F4 is a cell-permeable small-molecule inhibitor that disrupts c-Myc-Max heterodimer formation, thereby blocking c-Myc transcriptional activity (Kotian et al., 2024). Inhibition of this protein-protein interaction leads to cell cycle arrest and apoptosis in acute myeloid leukemia (AML) and prostate cancer models (APExBIO). The compound's efficacy is validated in multiple cell lines (HL-60, U937, NB-4) and in vivo xenografts. 10058-F4 also modulates mitochondrial apoptotic pathways, altering Bcl-2 family protein expression. Its robust solubility in DMSO (≥24.9 mg/mL) but poor water solubility requires tailored workflows for optimal use.

Biological Rationale

c-Myc is a pivotal transcription factor that regulates genes involved in proliferation, apoptosis, and metabolism in normal and cancer cells (Kotian et al., 2024). Its activity requires dimerization with Max, forming the c-Myc-Max complex that binds E-box DNA sequences. Disruption of this dimerization is a targeted approach for halting c-Myc–driven oncogenesis. Inhibiting c-Myc-Max interaction has been shown to repress transcription of TERT, the telomerase catalytic subunit, in human embryonic stem cells, with broad implications for cancer and regenerative medicine (Kotian et al., 2024).

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, MW 249.35, C₁₂H₁₁NOS₂] is a synthetic, cell-permeable small molecule that selectively interferes with c-Myc-Max heterodimerization (APExBIO). By binding to the c-Myc bHLHZip domain, 10058-F4 prevents Max association, thereby blocking complex formation. This prohibits c-Myc from binding to E-box elements in DNA, downregulating transcriptional targets such as PGC-1β and TERT (Kotian et al., 2024). In AML cell lines, 10058-F4 reduces c-Myc mRNA and protein levels, induces G0/G1 cell cycle arrest, and triggers mitochondrial apoptosis through modulation of Bcl-2 (down), Bax (up), and cytochrome C release (Related Guidance). In vivo, it suppresses tumor growth in prostate cancer xenografts (DU145, PC-3) when administered intravenously at 20–30 mg/kg daily for 14 days (APExBIO).

Evidence & Benchmarks

• 10058-F4 directly disrupts c-Myc-Max heterodimerization, reducing c-Myc DNA binding and transcriptional activation of TERT and PGC-1β (Kotian et al., 2024, https://doi.org/10.1101/2024.09.16.613267).
• In AML cell lines (HL-60, U937, NB-4), 10058-F4 induces cell cycle arrest and mitochondrial apoptosis marked by Bcl-2 downregulation and Bax upregulation (APExBIO, https://www.apexbt.com/10058-f4.html).
• In SCID mice with DU145 and PC-3 xenografts, daily IV administration (20–30 mg/kg × 14 days) leads to significant tumor control, though efficacy varies between models (APExBIO, product page).
• 10058-F4 is highly soluble in DMSO (≥24.9 mg/mL) and ethanol (≥2.64 mg/mL) but is insoluble in water, requiring DMSO-based stock preparation for in vitro/in vivo studies (APExBIO, product page).
• ChIP assays confirm that c-Myc-Max inhibition by 10058-F4 increases repressive H3K27me3 marks and reduces TERT transcription in hESCs (Kotian et al., 2024, https://doi.org/10.1101/2024.09.16.613267).

This article extends the guidance provided in "10058-F4 (SKU A1169): Reliable c-Myc-Max Inhibition for Apoptosis Assays" by consolidating in vivo and epigenetic benchmarks, and complements "Strategic Disruption of c-Myc/Max Dimerization" by detailing solubility and workflow integration data not covered previously.

Applications, Limits & Misconceptions

10058-F4 is predominantly used in research settings to study c-Myc-dependent oncogenic pathways, apoptosis, and differentiation. Its validated indications include:

• Acute myeloid leukemia (AML) cell line studies to induce cell cycle arrest and apoptosis.
• Prostate cancer xenograft models for in vivo tumor growth inhibition.
• Epigenetic studies on telomerase (TERT) regulation in human stem cells.

Related guides such as "10058-F4: Optimizing Apoptosis Assays with c-Myc-Max Inhibitors" provide troubleshooting for cell-based workflows, while this article includes new in vivo and epigenetic insights.

Common Pitfalls or Misconceptions

• 10058-F4 is not a pan-cancer cytotoxic agent; its efficacy depends on c-Myc dependence of the target model.
• It does not inhibit c-Myc gene expression directly but blocks protein-protein interaction with Max.
• 10058-F4 is not suitable for aqueous (water-based) preparations due to insolubility; always use DMSO or ethanol for stocks.
• The compound is not approved for diagnostic or therapeutic use in humans.
• Long-term storage of solutions (especially in aqueous solvents) is not recommended due to stability loss.

Workflow Integration & Parameters

For optimal results, dissolve 10058-F4 powder in DMSO to prepare a stock solution at concentrations above 12.5 mg/mL (recommended: ≥24.9 mg/mL). Warming at 37°C or sonication can enhance solubility. For cell-based assays, dilute stocks in culture medium immediately before use, ensuring final DMSO concentrations remain below cytotoxic thresholds (typically <0.5%). Store dried powder at –20°C for several months; avoid long-term storage of solutions. For in vivo studies, 10058-F4 has been benchmarked in IV regimens (20–30 mg/kg/day, 14 days) in SCID mice for prostate cancer xenografts (APExBIO).

For detailed, scenario-driven troubleshooting and advanced protocol design, see "Targeting c-Myc/Max Dimerization with 10058-F4"—this article adds recent epigenetic and stem cell regulatory context not previously addressed.

Conclusion & Outlook

10058-F4, distributed by APExBIO, is a rigorously benchmarked, cell-permeable c-Myc-Max dimerization inhibitor enabling mechanistic and translational research in oncology and experimental hematology. Its validated action on c-Myc/Max-driven transcription and apoptosis underpins its broad utility in cancer biology, while recent findings on telomerase regulation further extend its application to stem cell and aging research (Kotian et al., 2024). For purchase and technical specifications, see the 10058-F4 C-Myc-Max dimerization inhibitor product page. Researchers should adhere to best practices regarding solubility, storage, and model selection for reproducible outcomes.