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

Executive Summary: 10058-F4 is a selective, cell-permeable inhibitor that disrupts c-Myc-Max heterodimerization, a crucial step for c-Myc transcriptional activity (APExBIO | Kotian et al., 2024). This small molecule blocks c-Myc/Max binding to DNA, suppressing oncogenic transcriptional programs. In AML cell lines, it induces apoptosis in a dose- and time-dependent manner, with significant effects at 100 μM after 72 hours. In vivo, 10058-F4 reduces tumor growth in prostate cancer xenograft models. Its mechanism provides a unique tool for dissecting c-Myc signaling, mitochondrial apoptosis, and telomerase regulation in both cancer and stem cell biology (Cellron, 2023).

Biological Rationale

The c-Myc transcription factor regulates cell proliferation, metabolism, and apoptosis. c-Myc requires heterodimerization with Max to bind DNA and activate or repress gene expression (Kotian et al., 2024). Dysregulation of c-Myc is implicated in multiple cancers, including acute myeloid leukemia (AML) and prostate cancer. The c-Myc/Max dimer directly influences expression of telomerase reverse transcriptase (TERT), a gatekeeper of cellular immortality and genomic stability. Inhibiting c-Myc-Max dimerization disrupts these transcriptional programs, offering a rational strategy to induce apoptosis and block tumorigenesis. 10058-F4 targets this axis, enabling causal studies of oncogenic pathways and telomerase regulation. Recent evidence in human pluripotent stem cells confirms that c-Myc/Max activity is required to prevent polycomb-mediated repression of TERT, establishing the relevance of this target for both cancer and stem cell research (Kotian et al., 2024).

Mechanism of Action of 10058-F4

10058-F4 ((5E)-5-[(4-ethylphenyl)methylidene]-2-sulfanylidene-1,3-thiazolidin-4-one) is a synthetic small molecule with a molecular weight of 249.35 g/mol (APExBIO). It binds to c-Myc, preventing its interaction with Max and thus blocking heterodimer formation. This disruption inhibits c-Myc binding to E-box DNA motifs (CANNTG), halting downstream gene transcription. 10058-F4 treatment leads to reduced c-Myc mRNA and protein levels, cell cycle arrest, and activation of apoptosis, particularly through the mitochondrial pathway. This involves changes in Bcl-2 family protein expression and release of cytochrome C from mitochondria, culminating in caspase activation and programmed cell death. In stem cell models, c-Myc-Max inhibition by 10058-F4 results in increased H3K27me3 at the TERT promoter, diminished TERT transcription, and impaired telomerase function (Kotian et al., 2024).

Evidence & Benchmarks

• 10058-F4 inhibits c-Myc-Max dimerization in vitro with an IC₅₀ of ~42 μM (in EMSA and cell-based assays) (Kotian et al., 2024).
• In AML cell lines (HL-60, U937, NB-4), 10058-F4 induces apoptosis in a dose-dependent manner, with significant effects at 100 μM after 72 hours (Cytochrome C Pigeon, 2023).
• In vivo, intravenous administration of 10058-F4 in SCID mice bearing DU145 and PC-3 prostate cancer xenografts results in measurable tumor growth inhibition, though with variable efficacy depending on the model (APExBIO).
• 10058-F4 increases H3K27me3 and reduces TERT transcription in human pluripotent stem cells, mirroring the effects of c-Myc-Max functional loss (Kotian et al., 2024).
• 10058-F4 is soluble at ≥24.9 mg/mL in DMSO and ≥2.64 mg/mL in ethanol but is insoluble in water, supporting flexible assay integration (APExBIO).

This article extends on Cellron 2023 by detailing TERT and H3K27me3 mechanistic findings in stem cells, providing new translational insight. Additionally, it updates this C-Myc Peptide article by explicitly benchmarking molecular, cellular, and in vivo parameters for AML and prostate cancer models.

Applications, Limits & Misconceptions

Applications: 10058-F4 is widely used to dissect c-Myc-dependent transcriptional programs in cancer biology. It enables apoptosis assays in leukemia and solid tumor models, mechanistic studies of mitochondrial apoptosis, and investigations into telomerase regulation in stem and cancer cells. Its selectivity for c-Myc-Max dimerization makes it a valuable reference tool for evaluating oncogene addiction, tumor progression, and resistance mechanisms. The compound's cell permeability and robust solubility in DMSO and ethanol facilitate its use in diverse in vitro and in vivo workflows (APExBIO).

Common Pitfalls or Misconceptions

• 10058-F4 does not inhibit c-Myc-independent tumor growth or pathways that bypass c-Myc/Max function.
• The compound is not effective in models lacking Max or with c-Myc/Max-independent TERT activation (Kotian et al., 2024).
• 10058-F4 is insoluble in water, requiring organic solvents for stock solutions; aqueous stability is poor (APExBIO).
• Prolonged storage of 10058-F4 solutions is not recommended—fresh preparation ensures potency.
• Not suitable for use as a clinical therapeutic; intended for research use only.

This discussion clarifies boundaries for translational deployment and complements the workflow focus in this benchmark article.

Workflow Integration & Parameters

10058-F4 is typically supplied as a solid and should be stored at -20°C. For cell-based assays, dissolve in DMSO at ≥24.9 mg/mL or in ethanol at ≥2.64 mg/mL. Working concentrations in apoptosis or transcriptional assays range from 10 to 100 μM, with optimal effects at 100 μM after 72 hours in AML models. For in vivo work, intravenous dosing regimens in SCID mice have been validated in prostate cancer xenografts. Solutions should be freshly prepared prior to use; long-term storage in solution is not recommended due to stability limitations (APExBIO). 10058-F4 is compatible with standard apoptosis readouts (Annexin V, TUNEL), mitochondrial assays (cytochrome C release), and transcriptional profiling workflows. APExBIO provides quality-controlled A1169 kits with detailed protocols and storage guidelines (APExBIO product page).

Conclusion & Outlook

10058-F4 enables precise, mechanism-based interrogation of c-Myc-Max-driven transcription and apoptosis in cancer and stem cell biology. Its validated action in AML and prostate cancer models, along with new insights into telomerase and chromatin regulation, support its ongoing use in translational oncology and regenerative medicine research. For further reading, see this strategic overview, which maps future discoveries in c-Myc/Max disruption pathways. As a research tool from APExBIO, 10058-F4 sets a benchmark for apoptosis assay development and c-Myc pathway dissection.