1
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Ellenbroek BD, Kahler JP, Evers SR, Pomplun SJ. Synthetic Peptides: Promising Modalities for the Targeting of Disease-Related Nucleic Acids. Angew Chem Int Ed Engl 2024; 63:e202401704. [PMID: 38456368 DOI: 10.1002/anie.202401704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 03/06/2024] [Accepted: 03/08/2024] [Indexed: 03/09/2024]
Abstract
DNA and RNA play pivotal roles in life processes by storing and transferring genetic information, modulating gene expression, and contributing to essential cellular machinery such as ribosomes. Dysregulation and mutations in nucleic acid-related processes are implicated in numerous diseases. Despite the critical impact on health of nucleic acid mutations or dysregulation, therapeutic compounds addressing these biomolecules remain limited. Peptides have emerged as a promising class of molecules for biomedical research, offering potential solutions for challenging drug targets. This review focuses on the use of synthetic peptides to target disease-related nucleic acids. We discuss examples of peptides targeting double-stranded DNA, including the clinical candidate Omomyc, and compounds designed for regulatory G-quadruplexes. Further, we provide insights into both library-based screenings and the rational design of peptides to target regulatory human RNA scaffolds and viral RNAs, emphasizing the potential of peptides in addressing nucleic acid-related diseases.
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Affiliation(s)
| | | | - Sophie R Evers
- Leiden University, 2333 CC, Leiden, The Netherlands
- Present address, Department of Chemistry, University of Zurich, Wintherthurerstrasse 190, 8057, Zurich, Switzerland
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2
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Synthesis and biological evaluation of a novel c-Myc inhibitor against colorectal cancer via blocking c-Myc/Max heterodimerization and disturbing its DNA binding. Eur J Med Chem 2022; 243:114779. [DOI: 10.1016/j.ejmech.2022.114779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 09/05/2022] [Accepted: 09/13/2022] [Indexed: 11/23/2022]
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3
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Lourenco C, Resetca D, Redel C, Lin P, MacDonald AS, Ciaccio R, Kenney TMG, Wei Y, Andrews DW, Sunnerhagen M, Arrowsmith CH, Raught B, Penn LZ. MYC protein interactors in gene transcription and cancer. Nat Rev Cancer 2021; 21:579-591. [PMID: 34188192 DOI: 10.1038/s41568-021-00367-9] [Citation(s) in RCA: 126] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/04/2021] [Indexed: 02/07/2023]
Abstract
The transcription factor and oncoprotein MYC is a potent driver of many human cancers and can regulate numerous biological activities that contribute to tumorigenesis. How a single transcription factor can regulate such a diverse set of biological programmes is central to the understanding of MYC function in cancer. In this Perspective, we highlight how multiple proteins that interact with MYC enable MYC to regulate several central control points of gene transcription. These include promoter binding, epigenetic modifications, initiation, elongation and post-transcriptional processes. Evidence shows that a combination of multiple protein interactions enables MYC to function as a potent oncoprotein, working together in a 'coalition model', as presented here. Moreover, as MYC depends on its protein interactome for function, we discuss recent research that emphasizes an unprecedented opportunity to target protein interactors to directly impede MYC oncogenesis.
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Affiliation(s)
| | - Diana Resetca
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Cornelia Redel
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Peter Lin
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Alannah S MacDonald
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Roberto Ciaccio
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Tristan M G Kenney
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Yong Wei
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - David W Andrews
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Biological Sciences, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Maria Sunnerhagen
- Department of Physics, Chemistry and Biology, Linköping University, Linköping, Sweden
| | - Cheryl H Arrowsmith
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
- Structural Genomics Consortium, Toronto, ON, Canada
| | - Brian Raught
- Princess Margaret Cancer Centre, Toronto, ON, Canada
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Linda Z Penn
- Princess Margaret Cancer Centre, Toronto, ON, Canada.
- Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
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4
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Jbara M, Pomplun S, Schissel CK, Hawken SW, Boija A, Klein I, Rodriguez J, Buchwald SL, Pentelute BL. Engineering Bioactive Dimeric Transcription Factor Analogs via Palladium Rebound Reagents. J Am Chem Soc 2021; 143:11788-11798. [PMID: 34289685 DOI: 10.1021/jacs.1c05666] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transcription factors (TF), such as Myc, are proteins implicated in disease pathogenesis, with dysregulation of Myc expression in 50% of all human cancers. Still, targeting Myc remains a challenge due to the lack of small molecule binding pockets in the tertiary structure. Here, we report synthetic covalently linked TF mimetics that inhibit oncogenic Myc-driven transcription by antagonistic binding of the target DNA-binding site. We combined automated flow peptide chemistry with palladium(II) oxidative addition complexes (OACs) to engineer covalent protein dimers derived from the DNA-binding domains of Myc, Max, and Omomyc TF analogs. Palladium-mediated cross-coupling of synthesized protein monomers resulted in milligram quantities of seven different covalent homo- and heterodimers. The covalent helical dimers were found to bind DNA and exhibited improved thermal stability. Cell-based studies revealed the Max-Max covalent dimer is cell-penetrating and interfered with Myc-dependent gene transcription resulting in reduced cancer cell proliferation (EC50 of 6 μM in HeLa). RNA sequencing and gene analysis of extracted RNA from treated cancer cells confirmed that the covalent Max-Max homodimer interferes with Myc-dependent transcription. Flow chemistry, combined with palladium(II) OACs, has enabled a practical strategy to generate new bioactive compounds to inhibit tumor cell proliferation.
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Affiliation(s)
- Muhammad Jbara
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Sebastian Pomplun
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Carly K Schissel
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Susana Wilson Hawken
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Ann Boija
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Isaac Klein
- Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142, United States.,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Jacob Rodriguez
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Stephen L Buchwald
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States
| | - Bradley L Pentelute
- Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.,The Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, 500 Main Street, Cambridge, Massachusetts 02142, United States.,Center for Environmental Health Sciences, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139, United States.,Broad Institute of MIT and Harvard, 415 Main Street, Cambridge, Massachusetts 02142, United States
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5
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Inamoto I, Sheoran I, Popa SC, Hussain M, Shin JA. Combining Rational Design and Continuous Evolution on Minimalist Proteins That Target the E-box DNA Site. ACS Chem Biol 2021; 16:35-44. [PMID: 33370105 DOI: 10.1021/acschembio.0c00684] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Protein-based therapeutics are part of the next-generation arsenal of drugs being developed against proto-oncoprotein Myc. We designed protein MEF to mimic the basic region/helix-loop-helix/leucine zipper (bHLHZ) domain of Max and Myc, which bind to the E-box motif (enhancer box, CACGTG). To make MEF, we started with our rationally designed ME47, a hybrid of the Max basic region and E47 HLH, that effectively inhibited tumor growth in a mouse model of breast cancer. We used phage-assisted continuous evolution (PACE), which uncovered mutations at Arg12 that contact the DNA phosphodiester backbone. The Arg12 mutations improved ME47's stability. We replaced Cys29 with Ala to eliminate potential undesired disulfide formation and fused the designed FosW leucine zipper to mutated ME47 to increase the dimerization interface and E-box targeting activity. This "franken-protein" MEF comprises the Max basic region, E47 HLH, and FosW leucine zipper. Compared with ME47, MEF gives 2-fold stronger binding to E-box and 4-fold increased specificity for E-box over nonspecific DNA. The synergistic combination of rational design and PACE allowed us to make MEF and demonstrates the power and utility of our two-pronged approach toward development of promising protein drugs with robust structure and DNA-binding function.
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Affiliation(s)
- Ichiro Inamoto
- Department of Chemistry, University of Toronto, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Inder Sheoran
- Department of Chemistry, University of Toronto, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Serban C. Popa
- Department of Chemistry, University of Toronto, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Montdher Hussain
- Department of Chemistry, University of Toronto, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Jumi A. Shin
- Department of Chemistry, University of Toronto, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
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6
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Madden SK, de Araujo AD, Gerhardt M, Fairlie DP, Mason JM. Taking the Myc out of cancer: toward therapeutic strategies to directly inhibit c-Myc. Mol Cancer 2021; 20:3. [PMID: 33397405 PMCID: PMC7780693 DOI: 10.1186/s12943-020-01291-6] [Citation(s) in RCA: 172] [Impact Index Per Article: 57.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 11/29/2020] [Indexed: 02/07/2023] Open
Abstract
c-Myc is a transcription factor that is constitutively and aberrantly expressed in over 70% of human cancers. Its direct inhibition has been shown to trigger rapid tumor regression in mice with only mild and fully reversible side effects, suggesting this to be a viable therapeutic strategy. Here we reassess the challenges of directly targeting c-Myc, evaluate lessons learned from current inhibitors, and explore how future strategies such as miniaturisation of Omomyc and targeting E-box binding could facilitate translation of c-Myc inhibitors into the clinic.
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Affiliation(s)
- Sarah K Madden
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
| | - Aline Dantas de Araujo
- Division of Chemistry and Structural Biology and ARC 1066 Centre of Excellence for Innovations in Peptide and Protein Science, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Mara Gerhardt
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK
| | - David P Fairlie
- Division of Chemistry and Structural Biology and ARC 1066 Centre of Excellence for Innovations in Peptide and Protein Science, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jody M Mason
- Department of Biology & Biochemistry, University of Bath, Claverton Down, Bath, BA2 7AY, UK.
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7
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Popa S, Inamoto I, Thuronyi BW, Shin JA. Phage-Assisted Continuous Evolution (PACE): A Guide Focused on Evolving Protein-DNA Interactions. ACS OMEGA 2020; 5:26957-26966. [PMID: 33134656 PMCID: PMC7593997 DOI: 10.1021/acsomega.0c03508] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 10/06/2020] [Indexed: 05/08/2023]
Abstract
The uptake of directed evolution methods is increasing, as these powerful systems can be utilized to develop new biomolecules with altered/novel activities, for example, proteins with new catalytic functions or substrate specificities and nucleic acids that recognize an intended target. Especially useful are systems that incorporate continuous evolution, where the protein under selective pressure undergoes continuous mutagenesis with little-to-no input from the researcher once the system is started. However, continuous evolution methods can be challenging to implement and a daunting investment of time and resources. Our intent is to provide basic information and helpful suggestions that we have gained from our experience with bacterial phage-assisted continuous evolution (PACE) toward the evolution of proteins that bind to a specific DNA target. We discuss factors to consider before adopting PACE for a given evolution scheme with focus on the PACE bacterial one-hybrid selection system and what optimization of a PACE selection circuit may look like using the evolution of the DNA-binding protein ME47 as a case study. We outline different types of selection circuits and techniques that may be added onto a basic PACE setup. With this information, researchers will be better equipped to determine whether PACE is a valid strategy to adopt for their research program and how to set up a valid selection circuit.
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Affiliation(s)
- Serban
C. Popa
- Department
of Chemistry, University of Toronto, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Ichiro Inamoto
- Department
of Chemistry, University of Toronto, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
| | - Benjamin W. Thuronyi
- Department
of Chemistry, Williams College, 47 Lab Campus Drive, Williamstown, Massachusetts 01267, United States
| | - Jumi A. Shin
- Department
of Chemistry, University of Toronto, 3359 Mississauga Road, Mississauga, ON L5L 1C6, Canada
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8
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Demma MJ, Hohn MJ, Sun A, Mapelli C, Hall B, Walji A, O'Neil J. Inhibition of Myc transcriptional activity by a mini-protein based upon Mxd1. FEBS Lett 2020; 594:1467-1476. [PMID: 32053209 DOI: 10.1002/1873-3468.13759] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 02/07/2020] [Accepted: 02/10/2020] [Indexed: 12/13/2022]
Abstract
Myc, a transcription factor with oncogenic activity, is upregulated by amplification, translocation, and mutation of the cellular pathways that regulate its stability. Inhibition of the Myc oncogene by various modalities has had limited success. One Myc inhibitor, Omomyc, has limited cellular and in vivo activity. Here, we report a mini-protein, referred to as Mad, which is derived from the cellular Myc antagonist Mxd1. Mad localizes to the nucleus in cells and is 10-fold more potent than Omomyc in inhibiting Myc-driven cell proliferation. Similar to Mxd1, Mad also interacts with Max, the binding partner of Myc, and with the nucleolar upstream binding factor. Mad binds to E-Box DNA in the promoters of Myc target genes and represses Myc-mediated transcription to a greater extent than Omomyc. Overall, Mad appears to be more potent than Omomyc both in vitro and in cells.
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Affiliation(s)
- Mark J Demma
- Oncology Discovery, Merck & Co., Inc., Boston, MA, USA
| | - Michael J Hohn
- Biologics Process R&D, Merck & Co., Inc., Kenilworth, NJ, USA
| | - Angie Sun
- Protein Science, Merck & Co., Inc., Boston, MA, USA
| | | | - Brian Hall
- Protein Science, Merck & Co., Inc., Boston, MA, USA
| | - Abbas Walji
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, NJ, USA
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9
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Popa SC, Shin JA. The Intrinsically Disordered Loop in the USF1 bHLHZ Domain Modulates Its DNA-Binding Sequence Specificity in Hereditary Asthma. J Phys Chem B 2019; 123:9862-9871. [PMID: 31670516 DOI: 10.1021/acs.jpcb.9b06719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
USF1, a basic region/helix-loop-helix/leucine zipper (bHLHZ) transcription factor, binds to the E-box in the PAI-1 (plasminogen activator inhibitor) promoter. Two alleles containing the E-box control PAI-1 transcription; these alleles are termed "4G" and "5G" based on the G tract flanking E-box. USF1-governed transcription of PAI-1 is elevated in heritable asthma sufferers: the 4G/4G genotype has the highest plasma levels of PAI-1. While USF1 uses its basic region to bind E-box, we found that it uses its 12 amino-acid loop to recognize the flanking sequence and discern the single-nucleotide difference between the alleles. We used the bacterial one-hybrid and electrophoretic mobility shift assays to assess protein-DNA recognition, and circular dichroism to examine protein secondary structure. We mutated Ser233 and Thr234 in the USF1 bHLHZ loop to Ala to generate S233A and T234A. Interestingly, USF1 bHLHZ, S233A, and T234A prefer the 5G sequence (USF1 bHLHZ Kd values 4.1 ± 0.3 nM and 7.0 ± 0.4 nM for 5G and 4G, respectively), whereas studies in stimulated human mast cells showed a preference for 4G. We replaced the 8 amino-acid loop of transcription factor Max bHLHZ with the 12 amino-acid USF1 loop: this mutant now distinguishes the 4G/5G polymorphism-while Max bHLHZ does not-confirming that USF1 differentiation of the 4G/5G is driven by the loop.
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Affiliation(s)
- Serban C Popa
- Department of Chemistry , University of Toronto , 3359 Mississauga Road , Mississauga , Ontario L5L 1C6 , Canada
| | - Jumi A Shin
- Department of Chemistry , University of Toronto , 3359 Mississauga Road , Mississauga , Ontario L5L 1C6 , Canada
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10
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Omomyc Reveals New Mechanisms To Inhibit the MYC Oncogene. Mol Cell Biol 2019; 39:MCB.00248-19. [PMID: 31501275 PMCID: PMC6817756 DOI: 10.1128/mcb.00248-19] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 08/07/2019] [Indexed: 11/21/2022] Open
Abstract
The MYC oncogene is upregulated in human cancers by translocation, amplification, and mutation of cellular pathways that regulate Myc. Myc/Max heterodimers bind to E box sequences in the promoter regions of genes and activate transcription. The MYC oncogene is upregulated in human cancers by translocation, amplification, and mutation of cellular pathways that regulate Myc. Myc/Max heterodimers bind to E box sequences in the promoter regions of genes and activate transcription. The MYC inhibitor Omomyc can reduce the ability of MYC to bind specific box sequences in promoters of MYC target genes by binding directly to E box sequences as demonstrated by chromatin immunoprecipitation (CHIP). Here, we demonstrate by both a proximity ligation assay (PLA) and double chromatin immunoprecipitation (ReCHIP) that Omomyc preferentially binds to Max, not Myc, to mediate inhibition of MYC-mediated transcription by replacing MYC/MAX heterodimers with Omomyc/MAX heterodimers. The formation of Myc/Max and Omomyc/Max heterodimers occurs cotranslationally; Myc, Max, and Omomyc can interact with ribosomes and Max RNA under conditions in which ribosomes are intact. Taken together, our data suggest that the mechanism of action of Omomyc is to bind DNA as either a homodimer or a heterodimer with Max that is formed cotranslationally, revealing a novel mechanism to inhibit the MYC oncogene. We find that in vivo, Omomyc distributes quickly to kidneys and liver and has a short effective half-life in plasma, which could limit its use in vivo.
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11
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Inamoto I, Shin JA. Peptide therapeutics that directly target transcription factors. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24048] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ichiro Inamoto
- Department of Chemistry; University of Toronto, 3359 Mississauga Road; Mississauga Ontario L5L 1C6 Canada
| | - Jumi A. Shin
- Department of Chemistry; University of Toronto, 3359 Mississauga Road; Mississauga Ontario L5L 1C6 Canada
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12
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Inhibiting MYC binding to the E-box DNA motif by ME47 decreases tumour xenograft growth. Oncogene 2017; 36:6830-6837. [PMID: 28806396 DOI: 10.1038/onc.2017.275] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 04/21/2017] [Accepted: 05/27/2017] [Indexed: 02/07/2023]
Abstract
Developing therapeutics to effectively inhibit the MYC oncoprotein would mark a key advance towards cancer patient care as MYC is deregulated in over 50% of human cancers. MYC deregulation is correlated with aggressive disease and poor patient outcome. Despite strong evidence in mouse models that inhibiting MYC would significantly impact tumour cell growth and patient survival, traditional approaches have not yet yielded the urgently needed therapeutic agents that directly target MYC. MYC functions through its interaction with MAX to regulate gene transcription by binding to E-box DNA response elements of MYC target genes. Here we used a structure-based strategy to design ME47, a small minimalist hybrid protein (MHP) able to disrupt the MAX:E-box interaction/binding and block transcriptional MYC activity. We show that inducing ME47 expression in established tumour xenografts inhibits tumour growth and decreases cellular proliferation. Mechanistically, we show by chromatin immunoprecipitation that ME47 binds to E-box binding sites of MYC target genes. Moreover, ME47 occupancy decreases MYC:DNA interaction at its cognate E-box binding sites. Taken together, ME47 is a prototypic MHP inhibitor that antagonizes tumour cell growth in vitro and in vivo and inhibits the interaction of MYC with DNA E-box elements. These results support ME47's role as a MYC inhibitor and suggest that MHPs provide an alternative therapeutic targeting system that can be used to target transcription factors important in human diseases, including cancer.
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13
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Inamoto I, Chen G, Shin JA. The DNA target determines the dimerization partner selected by bHLHZ-like hybrid proteins AhRJun and ArntFos. MOLECULAR BIOSYSTEMS 2017; 13:476-488. [DOI: 10.1039/c6mb00795c] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The molecular basis of protein–partner selection and DNA binding of the basic helix–loop–helix (bHLH) and basic region-leucine zipper (bZIP) superfamilies of dimeric transcription factors is fundamental toward understanding gene regulation.
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Affiliation(s)
- Ichiro Inamoto
- Department of Chemistry
- University of Toronto
- Mississauga
- Canada L5L 1C6
| | - Gang Chen
- Department of Chemistry
- University of Toronto
- Mississauga
- Canada L5L 1C6
| | - Jumi A. Shin
- Department of Chemistry
- University of Toronto
- Mississauga
- Canada L5L 1C6
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14
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Verzele D, Madder A. Synthetic Progress in cMyc-Max Oncoprotein Miniaturization: Semi-Online Monitoring Gives Solid-Phase Access to Hydrophobic b(-HLH-)ZIP Peptidosteroid Tweezers. European J Org Chem 2012. [DOI: 10.1002/ejoc.201201235] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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15
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Ahmadpour F, Ghirlando R, De Jong AT, Gloyd M, Shin JA, Guarné A. Crystal structure of the minimalist Max-E47 protein chimera. PLoS One 2012; 7:e32136. [PMID: 22389683 PMCID: PMC3289634 DOI: 10.1371/journal.pone.0032136] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 01/20/2012] [Indexed: 01/07/2023] Open
Abstract
Max-E47 is a protein chimera generated from the fusion of the DNA-binding basic region of Max and the dimerization region of E47, both members of the basic region/helix-loop-helix (bHLH) superfamily of transcription factors. Like native Max, Max-E47 binds with high affinity and specificity to the E-box site, 5'-CACGTG, both in vivo and in vitro. We have determined the crystal structure of Max-E47 at 1.7 Å resolution, and found that it associates to form a well-structured dimer even in the absence of its cognate DNA. Analytical ultracentrifugation confirms that Max-E47 is dimeric even at low micromolar concentrations, indicating that the Max-E47 dimer is stable in the absence of DNA. Circular dichroism analysis demonstrates that both non-specific DNA and the E-box site induce similar levels of helical secondary structure in Max-E47. These results suggest that Max-E47 may bind to the E-box following the two-step mechanism proposed for other bHLH proteins. In this mechanism, a rapid step where protein binds to DNA without sequence specificity is followed by a slow step where specific protein:DNA interactions are fine-tuned, leading to sequence-specific recognition. Collectively, these results show that the designed Max-E47 protein chimera behaves both structurally and functionally like its native counterparts.
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Affiliation(s)
- Faraz Ahmadpour
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Rodolfo Ghirlando
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Antonia T. De Jong
- Department of Chemistry, University of Toronto, Mississauga, Ontario, Canada
| | - Melanie Gloyd
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Jumi A. Shin
- Department of Chemistry, University of Toronto, Mississauga, Ontario, Canada
| | - Alba Guarné
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
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16
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Chen G, De Jong AT, Shin JA. Forced homodimerization of the c-Fos leucine zipper in designed bHLHZ-like hybrid proteins MaxbHLH-Fos and ArntbHLH-Fos. MOLECULAR BIOSYSTEMS 2012; 8:1286-96. [DOI: 10.1039/c2mb05354c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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17
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Shahravan SH, Li ITS, Truong K, Shin JA. FRep: A Fluorescent Protein-Based Bioprobe for in Vivo Detection of Protein–DNA Interactions. Anal Chem 2011; 83:9643-50. [DOI: 10.1021/ac2024602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- S. Hesam Shahravan
- Department of Chemical and Physical Sciences, University of Toronto at Mississauga, Mississauga, Ontario, Canada L5L 1C6
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6
| | - Isaac T. S. Li
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G9
| | - Kevin Truong
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G9
| | - Jumi A. Shin
- Department of Chemical and Physical Sciences, University of Toronto at Mississauga, Mississauga, Ontario, Canada L5L 1C6
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada M5S 3G9
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Aguado-Llera D, Goormaghtigh E, de Geest N, Quan XJ, Prieto A, Hassan BA, Gómez J, Neira JL. The basic helix-loop-helix region of human neurogenin 1 is a monomeric natively unfolded protein which forms a "fuzzy" complex upon DNA binding. Biochemistry 2010; 49:1577-89. [PMID: 20102160 DOI: 10.1021/bi901616z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Neuronal specification is regulated by the activity of transcription factors containing the basic helix-loop-helix motif (bHLH); these regulating proteins include, among others, the neurogenin (Ngn) family, related to the atonal family of genes. Neurogenin 1 (NGN1) is a 237-residue protein that contains a bHLH domain and is involved in neuronal differentiation. In this work, we synthesized the bHLH region of NGN1 (bHLHN) comprising residues 90-150 of the full-length NGN1. The domain is a monomeric natively unfolded protein with a pH-dependent premolten globule conformation, as shown by several spectroscopic techniques (namely, NMR, fluorescence, FTIR, and circular dichroism). The unfolded character of the domain also explains, first, the impossibility of its overexpression in several Escherichia coli strains and, second, its insolubility in aqueous buffers. To the best of our knowledge, this is the first extensive study of the conformational preferences of a bHLH domain under different solution conditions. Upon binding to two DNA E-boxes, the protein forms "fuzzy" complexes (that is, the complexes were not fully folded). The affinities of bHLHN for both DNA boxes were smaller than those of other bHLH domains, which might explain why the protein-DNA complexes were not fully folded.
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Affiliation(s)
- David Aguado-Llera
- Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elche (Alicante), Spain
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Xu J, De Jong AT, Chen G, Chow HK, Damaso CO, Schwartz Mittelman A, Shin JA. Reengineering natural design by rational design and in vivo library selection: the HLH subdomain in bHLHZ proteins is a unique requirement for DNA-binding function. Protein Eng Des Sel 2010; 23:337-46. [PMID: 20086039 DOI: 10.1093/protein/gzp082] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
To explore the role of the HLH subdomain in bHLHZ proteins, we designed sets of minimalist proteins based on bHLHZ protein Max, bHLH/PAS protein Arnt and bZIP protein C/EBP. In the first, the Max bHLH and C/EBP leucine zipper were fused such that the leucine heptad repeats were not in register; therefore, the protein dimerization interface was disrupted. Max1bHLH-C/EBP showed little ability to activate transcription from the E-box (5'-CACGTG) in the yeast one-hybrid assay, and no E-box binding by quantitative fluorescence anisotropy. Max1bHLH-C/EBP's activity was significantly improved after library selection (three amino acids randomized between HLH and leucine zipper), despite the Max bHLH and C/EBP zipper still being out of register: a representative mutant gave a high nanomolar K(d) value for E-box binding. Thus, selection proved to be a powerful tool for salvaging the flawed Max1bHLH-C/EBP, although the out-of-register mutants still did not achieve the strong DNA-binding affinities displayed by their in-register counterparts. ArntbHLH-C/EBP hybrids further demonstrated the importance of maintaining register, as out-of-register mutants showed no E-box-responsive activity, whereas the in-register hybrid showed moderate activity. In another design, we eliminated the HLH altogether and fused the Max basic region to the C/EBP zipper to generate bZIP-like hybrids. Despite numerous designs and selections, these hybrids possessed no E-box-responsive activity. Finally, we tested the importance of the loop sequence in MaxbHLHZ by fluorescence and circular dichroism. In one mutant, the loop was shortened by two residues; in the other, the Lys57:DNA-backbone interaction was abolished by mutation to Gly57. Both showed markedly decreased E-box-binding relative to MaxbHLHZ. Our results suggest that, in contrast to the more rigid bZIP, the HLH is capable of significant conformational adaptation to enable gene-regulatory function and is required for protein dimerization and positioning the basic region for DNA recognition.
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Affiliation(s)
- Jing Xu
- Department of Chemistry, University of Toronto, Mississauga, ON L5L1C6, Canada
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