Multiple Synthetic Routes to the Mini-Protein Omomyc and Coiled-Coil Domain Truncations
Zachary Z Brown1, Claudio Mapelli1, Iman Farasat2
1Discovery Chemistry , Merck & Co., Inc. , 2000 Galloping Hill Road , Kenilworth , New Jersey 07033 , United States.
Abstract:
The Myc transcription factor represents an "undruggable" target of high biological interest due to its central role in various cancers. An abbreviated form of the c-Myc protein, called Omomyc, consists of the Myc DNA-binding domain and a coiled-coil region to facilitate dimerization of the 90 amino acid polypeptide. Here we present our results to evaluate the synthesis of Omomyc using three complementary strategies: linear Fmoc solid-phase peptide synthesis (SPPS) using several advancements for difficult sequences, native chemical ligation from smaller peptide fragments, and a high-throughput bacterial expression and assay platform for rapid mutagenesis. This multifaceted approach allowed access to up to gram quantities of the mini-protein and permitted in vitro and in vivo SAR exploration of this modality. DNA-binding results and cellular activity confirm that Omomyc and analogues presented here, are potent binders of the E-box DNA engaged by Myc for transcriptional activation and that this 90-amino acid mini-protein is cell permeable and can inhibit proliferation of Myc-dependent cell lines. We also present additional results on covalent homodimerization through disulfide formation of the full-length mini-protein and show the coiled-coil region can be truncated while preserving both DNA binding and cellular activity. Altogether, our results highlight the ability of advanced peptide synthesis to achieve SAR tractability in a challenging synthetic modality.
Insights
Researchers developed advanced peptide synthesis methods to create Omomyc, a mini-protein targeting the "undruggable" Myc oncoprotein. This potent mini-protein effectively binds DNA and inhibits cancer cell proliferation, offering a promising new therapeutic strategy.
Area of Science:
- Molecular Biology
- Medicinal Chemistry
- Cancer Research
Background:
- The Myc transcription factor is a critical regulator of cell growth and a key driver in numerous cancers.
- Myc's role in cancer makes it a highly desirable but challenging therapeutic target, often referred to as "undruggable".
Purpose of the Study:
- To develop and evaluate synthesis strategies for Omomyc, a mini-protein inhibitor of Myc.
- To explore the structure-activity relationships (SAR) of Omomyc for potential cancer therapies.
Main Methods:
- Linear Fmoc solid-phase peptide synthesis (SPPS) with specialized techniques for challenging sequences.
- Native chemical ligation for assembling smaller peptide fragments into the full-length Omomyc.
- High-throughput bacterial expression and assay platform for rapid mutagenesis and screening.
Main Results:
- Successfully synthesized Omomyc and analogues in gram quantities using a combination of advanced peptide synthesis techniques.
- Demonstrated potent DNA binding to the E-box element, crucial for Myc-mediated transcriptional activation.
- Confirmed cell permeability and significant inhibition of proliferation in Myc-dependent cancer cell lines.
- Investigated Omomyc's covalent homodimerization via disulfide bonds and identified truncations of the coiled-coil region that preserve activity.
Conclusions:
- Advanced peptide synthesis enables the tractable SAR exploration of challenging mini-protein modalities like Omomyc.
- Omomyc and its analogues are potent inhibitors of Myc transcriptional activity and show promise as anti-cancer agents.
- The development of efficient synthesis routes facilitates the progression of Omomyc as a potential therapeutic candidate.
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