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1.
J Phys Chem Lett ; 15(34): 8706-8714, 2024 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-39159468

RESUMO

We investigated the binding between the c-MYC G-quadruplex (GQ) and berberine chloride (BCl) in an aqueous two-phase system (ATPS) with 12.3 wt % polyethylene glycol and 5.6 wt % dextran, mimicking the highly crowded intracellular biomolecular condensates formed via liquid-liquid phase separation. We found that in the ATPS, complex formation is significantly altered, leading to an increase in affinity and a change in the stoichiometry of the complex with respect to neat buffer conditions. Thermodynamic studies reveal that binding becomes more thermodynamically favorable in the ATPS due to entropic effects, as the strong excluded volume effect inside ATPS droplets reduces the entropic penalty associated with binding. Finally, the binding affinity of BCl for the c-MYC GQ is higher than those for other DNA structures, indicating potential specific interactions. Overall, these findings will be helpful in the design of potential drugs targeting the c-MYC GQ structures in cancer-related biocondensates.


Assuntos
Berberina , Quadruplex G , Proteínas Proto-Oncogênicas c-myc , Berberina/química , Dextranos/química , DNA/química , Polietilenoglicóis/química , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Termodinâmica , Água/química
2.
Chem Commun (Camb) ; 60(60): 7769-7772, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-38973676

RESUMO

The microperoxidase-11 hemopeptide exhibits configuration-dependent selectivity for guanine-quadruplexes by specifically uncaging c-MYC guanine-quadruplexes from a duplex DNA.


Assuntos
DNA , Quadruplex G , DNA/química , DNA/metabolismo , Peptídeos/química , Peptídeos/metabolismo , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Peroxidases/química , Peroxidases/metabolismo , Humanos
3.
Nucleic Acids Res ; 52(16): 9397-9406, 2024 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-39077944

RESUMO

G-quadruplex (G4) structures play integral roles in modulating biological functions and can be regulated by small molecules. The MYC gene is critical during tumor initiation and malignant progression, in which G4 acts as an important modulation motif. Herein, we reported the MYC promoter G4 recognized by a platinum(II) compound Pt-phen. Two Pt-phen-MYC G4 complex structures in 5 mM K+ were determined by NMR. The Pt-phen first strongly binds the 3'-end of MYC G4 to form a 1:1 3'-end binding complex and then binds 5'-end to form a 2:1 complex with more Pt-phen. In the complexes, the Pt-phen molecules are well-defined and stack over four bases at the G-tetrad for a highly extensive π-π interaction, with the Pt atom aligning with the center of the G-tetrad. The flanking residues were observed to rearrange and cover on top of Pt-phen to stabilize the whole complex. We further demonstrated that Pt-phen targets G4 DNA in living cells and represses MYC gene expression in cancer cells. Our work elucidated the structural basis of ligand binding to MYC promoter G4. The platinum compound bound G4 includes multiple complexes formation, providing insights into the design of metal ligands targeting oncogene G4 DNA.


Assuntos
Quadruplex G , Regiões Promotoras Genéticas , Proteínas Proto-Oncogênicas c-myc , Quadruplex G/efeitos dos fármacos , Humanos , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/química , DNA/química , DNA/metabolismo , Compostos de Platina/química , Genes myc , Platina/química
4.
Proc Natl Acad Sci U S A ; 121(25): e2322452121, 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38861600

RESUMO

Intrinsically disordered proteins (IDPs) play a crucial role in various biological phenomena, dynamically changing their conformations in response to external environmental cues. To gain a deeper understanding of these proteins, it is essential to identify the determinants that fix their structures at the atomic level. Here, we developed a pipeline for rapid crystal structure analysis of IDP using a cell-free protein crystallization (CFPC) method. Through this approach, we successfully demonstrated the determination of the structure of an IDP to uncover the key determinants that stabilize its conformation. Specifically, we focused on the 11-residue fragment of c-Myc, which forms an α-helix through dimerization with a binding partner protein. This fragment was strategically recombined with an in-cell crystallizing protein and was expressed in a cell-free system. The resulting crystal structures of the c-Myc fragment were successfully determined at a resolution of 1.92 Å and we confirmed that they are identical to the structures of the complex with the native binding partner protein. This indicates that the environment of the scaffold crystal can fix the structure of c-Myc. Significantly, these crystals were obtained directly from a small reaction mixture (30 µL) incubated for only 72 h. Analysis of eight crystal structures derived from 22 mutants revealed two hydrophobic residues as the key determinants responsible for stabilizing the α-helical structure. These findings underscore the power of our CFPC screening method as a valuable tool for determining the structures of challenging target proteins and elucidating the essential molecular interactions that govern their stability.


Assuntos
Sistema Livre de Células , Cristalização , Proteínas Intrinsicamente Desordenadas , Proteínas Proto-Oncogênicas c-myc , Proteínas Intrinsicamente Desordenadas/química , Cristalografia por Raios X/métodos , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Humanos , Conformação Proteica , Modelos Moleculares , Ligação Proteica
5.
J Chem Inf Model ; 64(13): 5328-5343, 2024 Jul 08.
Artigo em Inglês | MEDLINE | ID: mdl-38635316

RESUMO

Research in the human genome sciences generates a substantial amount of genetic data for hundreds of thousands of individuals, which concomitantly increases the number of variants of unknown significance (VUS). Bioinformatic analyses can successfully reveal rare variants and variants with clear associations with disease-related phenotypes. These studies have had a significant impact on how clinical genetic screens are interpreted and how patients are stratified for treatment. There are few, if any, computational methods for variants comparable to biological activity predictions. To address this gap, we developed a machine learning method that uses protein three-dimensional structures from AlphaFold to predict how a variant will influence changes to a gene's downstream biological pathways. We trained state-of-the-art machine learning classifiers to predict which protein regions will most likely impact transcriptional activities of two proto-oncogenes, nuclear factor erythroid 2 (NFE2L2)-related factor 2 (NRF2) and c-Myc. We have identified classifiers that attain accuracies higher than 80%, which have allowed us to identify a set of key protein regions that lead to significant perturbations in c-Myc or NRF2 transcriptional pathway activities.


Assuntos
Aprendizado de Máquina , Humanos , Fator 2 Relacionado a NF-E2/metabolismo , Fator 2 Relacionado a NF-E2/química , Conformação Proteica , Variação Genética , Genoma Humano , Modelos Moleculares , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Biologia Computacional/métodos
6.
Nat Commun ; 14(1): 5203, 2023 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-37626077

RESUMO

Intrinsically disordered proteins (IDPs) play crucial roles in cellular processes and hold promise as drug targets. However, the dynamic nature of IDPs remains poorly understood. Here, we construct a single-molecule electrical nanocircuit based on silicon nanowire field-effect transistors (SiNW-FETs) and functionalize it with an individual disordered c-Myc bHLH-LZ domain to enable label-free, in situ, and long-term measurements at the single-molecule level. We use the device to study c-Myc interaction with Max and/or small molecule inhibitors. We observe the self-folding/unfolding process of c-Myc and reveal its interaction mechanism with Max and inhibitors through ultrasensitive real-time monitoring. We capture a relatively stable encounter intermediate ensemble of c-Myc during its transition from the unbound state to the fully folded state. The c-Myc/Max and c-Myc/inhibitor dissociation constants derived are consistent with other ensemble experiments. These proof-of-concept results provide an understanding of the IDP-binding/folding mechanism and represent a promising nanotechnology for IDP conformation/interaction studies and drug discovery.


Assuntos
Sistemas de Liberação de Medicamentos , Proteínas Intrinsicamente Desordenadas/química , Modelos Moleculares , Estrutura Terciária de Proteína , Proteínas Proto-Oncogênicas c-myc/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-myc/química , Ligação Proteica
7.
Nature ; 619(7969): 385-393, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37407816

RESUMO

The basic helix-loop-helix (bHLH) family of transcription factors recognizes DNA motifs known as E-boxes (CANNTG) and includes 108 members1. Here we investigate how chromatinized E-boxes are engaged by two structurally diverse bHLH proteins: the proto-oncogene MYC-MAX and the circadian transcription factor CLOCK-BMAL1 (refs. 2,3). Both transcription factors bind to E-boxes preferentially near the nucleosomal entry-exit sites. Structural studies with engineered or native nucleosome sequences show that MYC-MAX or CLOCK-BMAL1 triggers the release of DNA from histones to gain access. Atop the H2A-H2B acidic patch4, the CLOCK-BMAL1 Per-Arnt-Sim (PAS) dimerization domains engage the histone octamer disc. Binding of tandem E-boxes5-7 at endogenous DNA sequences occurs through direct interactions between two CLOCK-BMAL1 protomers and histones and is important for circadian cycling. At internal E-boxes, the MYC-MAX leucine zipper can also interact with histones H2B and H3, and its binding is indirectly enhanced by OCT4 elsewhere on the nucleosome. The nucleosomal E-box position and the type of bHLH dimerization domain jointly determine the histone contact, the affinity and the degree of competition and cooperativity with other nucleosome-bound factors.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos , DNA , Histonas , Fatores de Transcrição ARNTL/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , DNA/genética , DNA/metabolismo , Sequências Hélice-Alça-Hélice/genética , Histonas/química , Histonas/metabolismo , Nucleossomos/química , Nucleossomos/genética , Nucleossomos/metabolismo , Ligação Proteica , Proteínas CLOCK/química , Proteínas CLOCK/metabolismo , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Regulação Alostérica , Zíper de Leucina , Fator 3 de Transcrição de Octâmero/metabolismo , Multimerização Proteica
8.
J Am Chem Soc ; 145(6): 3259-3269, 2023 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-36734615

RESUMO

The MYC family of oncogenes (MYC, MYCN, and MYCL) encodes a basic helix-loop-helix leucine zipper (bHLHLZ) transcriptional regulator that is responsible for moving the cell through the restriction point. Through the HLHZIP domain, MYC heterodimerizes with the bHLHLZ protein MAX, which enables this MYC-MAX complex to bind to E-box regulatory DNA elements thereby controlling transcription of a large group of genes and their proteins. Translationally, MYC is one of the foremost oncogenic targets, and deregulation of expression of the MYC family gene/proteins occurs in over half of all human tumors and is recognized as a hallmark of cancer initiation and maintenance. Additionally, unexpected roles for this oncoprotein have been found in cancers that nominally have a non-MYC etiology. Although MYC is rarely mutated, its gain of function in cancer results from overexpression or from amplification. Moreover, MYC is a pleiotropic transcription factor possessing broad pathogenic prominence making it a coveted cancer target. A widely held notion within the biomedical research community is that the reliable modulation of MYC represents a tremendous therapeutic opportunity given its role in directly potentiating oncogenesis. However, the MYC-MAX heterodimer interaction contains a large surface area with a lack of well-defined binding sites creating the perception that targeting of MYC-MAX is forbidding. Here, we discuss the biochemistry behind MYC and MYC-MAX as it relates to cancer progression associated with these transcription factors. We also discuss the notion that MYC should no longer be regarded as undruggable, providing examples that a therapeutic window is achievable despite global MYC inhibition.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Neoplasias , Humanos , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , Proteínas Proto-Oncogênicas c-myc/química , Fatores de Transcrição/metabolismo , Oncogenes , Neoplasias/tratamento farmacológico , Neoplasias/genética
9.
Nat Biotechnol ; 41(4): 541-551, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36302987

RESUMO

Despite unequivocal roles in disease, transcription factors (TFs) remain largely untapped as pharmacologic targets due to the challenges in targeting protein-protein and protein-DNA interactions. Here we report a chemical strategy to generate modular synthetic transcriptional repressors (STRs) derived from the bHLH domain of MAX. Our synthetic approach yields chemically stabilized tertiary domain mimetics that cooperatively bind the MYC/MAX consensus E-box motif with nanomolar affinity, exhibit specificity that is equivalent to or beyond that of full-length TFs and directly compete with MYC/MAX protein for DNA binding. A lead STR directly inhibits MYC binding in cells, downregulates MYC-dependent expression programs at the proteome level and inhibits MYC-dependent cell proliferation. Co-crystallization and structure determination of a STR:E-box DNA complex confirms retention of DNA recognition in a near identical manner as full-length bHLH TFs. We additionally demonstrate structure-blind design of STRs derived from alternative bHLH-TFs, confirming that STRs can be used to develop highly specific mimetics of TFs targeting other gene regulatory elements.


Assuntos
Proteínas Proto-Oncogênicas c-myc , Fatores de Transcrição , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Sequências Hélice-Alça-Hélice , Sequências Reguladoras de Ácido Nucleico , DNA/genética , DNA/metabolismo
10.
Methods Enzymol ; 675: 193-205, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36220270

RESUMO

The c-Myc oncogene is a master regulator of cancer cell metabolism, which controls a variety of pathways, including cell proliferation, cell cycle, apoptosis, and epigenetics. Belonging to the bHLH family of transcription factors, c-Myc forms a heterodimeric complex with another bHLH family protein MAX. c-Myc deregulation is reported in most cancers. This heterodimeric complex is a potent transcription factor that controls the expression of the target gene by binding to the E-box sequence and thereby controlling cancer cell proliferation. c-Myc in isolation has a partially folded structure and cannot carry the transcription. However, its heterodimerization provides the ability to bind DNA and carry out the regulatory function. Therefore, heterodimerization of c-Myc and Max is of great interest for cancers, and it has always been considered a target for cancer therapy. This book chapter will present a detailed protocol of cellular experiments employed to validate the in vitro potency of c-Myc inhibitor candidates to search for a novel c-Myc-targeted neoplastic drug.


Assuntos
Proteínas Proto-Oncogênicas c-myc , Fatores de Transcrição , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/genética , DNA/metabolismo , Dimerização , Regulação da Expressão Gênica , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Fatores de Transcrição/genética
11.
J Mol Biol ; 434(22): 167833, 2022 11 30.
Artigo em Inglês | MEDLINE | ID: mdl-36174765

RESUMO

The intrinsically disordered protein MYC belongs to the family of basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factors (TFs). In complex with its cognate binding partner MAX, MYC preferentially binds to E-Box promotor sequences where it controls fundamental cellular processes such as cell cycle progression, metabolism, and apoptosis. Intramolecular regulation of MYC:MAX has not yet been investigated in detail. In this work, we use Nuclear Magnetic Resonance (NMR) spectroscopy to identify and map interactions between the disordered MAX N-terminus and the MYC:MAX DNA binding domain (DBD). We find that this binding event is mainly driven by electrostatic interactions and that it is competitive with DNA binding. Using NMR spectroscopy and Surface Plasmon Resonance (SPR), we demonstrate that the MAX N-terminus serves to accelerate DNA binding kinetics of MYC:MAX and MAX:MAX dimers, while it simultaneously provides specificity for E-Box DNA. We also establish that these effects are further enhanced by Casein Kinase 2-mediated phosphorylation of two serine residues in the MAX N-terminus. Our work provides new insights how bHLH-LZ TFs are regulated by intramolecular interactions between disordered regions and the folded DNA binding domain.


Assuntos
Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Proteínas Intrinsicamente Desordenadas , Domínios e Motivos de Interação entre Proteínas , Proteínas Proto-Oncogênicas c-myc , Caseína Quinase II/química , DNA/química , Proteínas Intrinsicamente Desordenadas/química , Proteínas Proto-Oncogênicas c-myc/química , Serina/química , Mapeamento de Interação de Proteínas , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/química , Ligação Proteica , Fosforilação
12.
J Mol Model ; 28(10): 329, 2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-36149511

RESUMO

Myc is a bHLHZip protein involved in growth control and cancer, which does not form a homodimer. Myc operates in a network with its heterodimerization partner Max, the latter of which can form homodimer and heterodimer. Omomyc, a polypeptide, can block Myc to treat cancers because it can both homodimerize as efficiently as Max and heterodimerize with both Myc and Max. However, the binding efficiencies to DNA for the mentioned two homodimers (Omomyc-Omomyc and Max-Max) and three heterodimers (Myc-Max, Omomyc-Myc, and Omomyc-Max) are still controversial. By molecular dynamics simulations and MM/GBSA free energy calculation, we ranked the binding affinities of five dimers to DNA and analyzed the contribution of single amino acids to the molecular recognition of dimers to DNA. Our simulation showed that the Omomyc-Omomyc dimer exhibited the highest binding energy to DNA, followed by the Omomyc-Myc, Max-Max, Omomyc-Max, and Myc-Max dimers. Moreover, five Arg residues (i.e., 7, 8, 15, 17, and 18 numbered by Omomyc) and five Lys residues (i.e., 6, 22, 40, 43, and 48 numbered by Omomyc) dominated the binding of various dimers to DNA while the residues Asp23 and Asp37 weakened the affinities via repulsive interaction. Our simulation would provide worthy information for further development of the structure-based design of novel Omomyc-like peptide inhibitors against Myc in the future.


Assuntos
Neoplasias , Proteínas Proto-Oncogênicas c-myc , Aminoácidos/metabolismo , DNA/metabolismo , Dimerização , Humanos , Neoplasias/genética , Ligação Proteica , Proteínas/metabolismo , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo
13.
Chemistry ; 28(54): e202201497, 2022 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-35726630

RESUMO

Organometallic molecules offer some of the most promising scaffolds for interaction with G-quadruplex nucleic acids. We report the efficient synthesis of a family of organoplatinum(II) complexes, featuring a 2-([2,2'-bipyridin]-6-yl)phenyl tridentate (N∧ N∧ C) ligand, that incorporates peripheral side-chains aiming at enhancing and diversifying its interaction capabilities. These include a di-isopropyl carbamoyl amide, a morpholine ethylenamide, two enantiomeric proline imides and an oxazole. The binding affinities of the Pt-complexes were evaluated via UV-vis and fluorescence titrations, against 5 topologically-distinct DNA structures, including c-myc G-quadruplex, two telomeric (22AG) G-quadruplexes, a duplex (ds26) and a single-stranded (polyT) DNA. All compounds exhibited binding selectivity in favour of c-myc, with association constants (Ka ) in the range of 2-5×105  M-1 , lower affinity for both folds of 22AG and for ds26 and negligible affinity for polyT. Remarkable emission enhancements (up to 200-fold) upon addition of excess DNA were demonstrated by a subset of the compounds with c-myc, providing a basis for optical selectivity, since optical response to all other tested DNAs was low. A c-myc DNA-melting experiment showed significant stabilizing abilities for all compounds, with the most potent binder, the morpholine-Pt-complex, exhibiting a ΔTm >30 °C, at 1 : 5 DNA-to-ligand molar ratio. The same study implied contributions of the diverse side-chains to helix stabilization. To gain direct evidence of the nature of the interactions, mixtures of c-myc with the four most promising compounds were studied via UV Resonance Raman (UVRR) spectroscopy, which revealed end-stacking binding mode, combined with interactions of side-chains with loop nucleobase residues. Docking simulations were conducted to provide insights into the binding modes for the same four Pt-compounds, suggesting that the binding preference for two alternative orientations of the c-myc G-quadruplex thymine 'cap' ('open' vs. 'closed'), as well as the relative contributions to affinity from end-stacking and H-bonding, are highly dependent on the nature of the interacting Pt-complex side-chain.


Assuntos
Quadruplex G , Radiossensibilizantes , Amidas , DNA/química , Genes myc , Imidas , Ligantes , Morfolinas , Oxazóis , Compostos de Platina , Prolina , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/genética , Timina
14.
Nucleic Acids Res ; 50(8): 4246-4257, 2022 05 06.
Artigo em Inglês | MEDLINE | ID: mdl-35412611

RESUMO

Ligand-Induced duplex-quadruplex transition within the c-MYC promoter region is one of the most studied and advanced ideas for c-MYC regulation. Despite its importance, there is a lack of methods for monitoring such process in cells, hindering a better understanding of the essence of c-MYC G-quadruplex as a drug target. Here we developed a new fluorescent probe ISCH-MYC for specific c-MYC G-quadruplex recognition based on GTFH (G-quadruplex-Triggered Fluorogenic Hybridization) strategy. We validated that ISCH-MYC displayed distinct fluorescence enhancement upon binding to c-MYC G-quadruplex, which allowed the duplex-quadruplex transition detection of c-MYC G-rich DNA in cells. Using ISCH-MYC, we successfully characterized the induction of duplex to G-quadruplex transition in the presence of G-quadruplex stabilizing ligand PDS and further monitored and evaluated the altered interactions of relevant transcription factors Sp1 and CNBP with c-MYC G-rich DNA. Thus, our study provides a visualization strategy to explore the mechanism of G-quadruplex stabilizing ligand action on c-MYC G-rich DNA and relevant proteins, thereby empowering future drug discovery efforts targeting G-quadruplexes.


Assuntos
Quadruplex G , Proteínas Proto-Oncogênicas c-myc , DNA/química , DNA/genética , Ligantes , Hibridização de Ácido Nucleico , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/genética
15.
J Biol Chem ; 298(5): 101898, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35378126

RESUMO

Protein-protein interactions drive various biological processes in healthy as well as disease states. The transcription factor c-Myc plays a crucial role in maintaining cellular homeostasis, and its deregulated expression is linked to various human cancers; therefore, it can be considered a viable target for cancer therapeutics. However, the structural heterogeneity of c-Myc due to its disordered nature poses a major challenge to drug discovery. In the present study, we used an in silico alanine scanning mutagenesis approach to identify "hot spot" residues within the c-Myc/Myc-associated factor X interface, which is highly disordered and has not yet been systematically analyzed for potential small molecule binding sites. We then used the information gained from this analysis to screen potential inhibitors using a conformation ensemble approach. The fluorescence-based biophysical experiments showed that the identified hit molecules displayed noncovalent interactions with these hot spot residues, and further cell-based experiments showed substantial in vitro potency against diverse c-Myc-expressing cancer/stem cells by deregulating c-Myc activity. These biophysical and computational studies demonstrated stable binding of the hit compounds with the disordered c-Myc protein. Collectively, our data indicated effective drug targeting of the disordered c-Myc protein via the determination of hot spot residues in the c-Myc/Myc-associated factor X heterodimer.


Assuntos
Descoberta de Drogas , Fator X , Técnicas Genéticas , Proteínas Proto-Oncogênicas c-myc , Fator X/metabolismo , Humanos , Conformação Molecular , Mutagênese , Ligação Proteica , Domínios e Motivos de Interação entre Proteínas , Proteínas Proto-Oncogênicas c-myc/química
16.
J Mol Model ; 28(4): 92, 2022 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-35294626

RESUMO

Myc is a master transcriptional regulator that controls almost all cellular processes, whose function is dependent on dimerization with its obligate partner Max. Stabilization of Max homodimer by small molecules (such as compound NSC13728) has proven an effective way to reduce the availability of Myc-Max dimer. Omomyc, a peptide inhibitor of Myc, is able to form Omomyc homodimer, which can competitively inhibit the binding of Myc-Max to the E-box of DNA. Considering the high amino acid sequence homology between Omomyc and Max, we put forward the hypothesis that Max-Max stabilizers could stabilize the Omomyc homodimer. Hence, through molecular dynamics (MD) simulation and molecular mechanics/generalized Born surface area (MM/GBSA) free energy calculation, we discovered that the stability of Omomyc-Omomyc is remarkably higher than that of Max-Max. Moreover, after adding the compound NSC13728 into the well-defined "Site 3," the binding affinity between two Omomyc monomers can be further increased. Compound NSC13728 has stronger binding interaction to Omomyc-Omomyc than to Max-Max. "Site 3" of Omomyc is more hydrophobic than that of Max, which enlightens us that the more potent Omomyc-Omomyc stabilizers may be hydrophobic in structure.


Assuntos
Simulação de Dinâmica Molecular , Proteínas Proto-Oncogênicas c-myc , DNA/metabolismo , Dimerização , Ligação Proteica , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo
17.
J Biomol Struct Dyn ; 40(20): 10203-10219, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34192476

RESUMO

c-MYC is deregulated in triple negative breast cancer (TNBC) pointing to be a promising biomarker for breast cancer treatment. Precise level of MYC expression is important in the control of cellular growth and proliferation. Designing of c-MYC-targeted antidotes to restore its basal level of cellular expression holds an optimistic approach towards anti-cancer treatment. MYC transcription is dominantly controlled by Nuclear Hypersensitive Element III-1 (NHEIII1) upstream of the promoter region possessing G-Quadruplex silencer element (Pu-27). We have investigated the selective binding-interaction profile of a natural phytophenolic compound Curcumin with native MYC G-quadruplex by conducting an array of biophysical experiments and in silico based Molecular Docking and Molecular Dynamic (MDs) simulation studies. Curcumin possesses immense anti-cancerous properties. We have observed significantly increased stability of MYC-G Quadruplex and thermodynamic spontaneity of Curcumin-MYC GQ binding with negative ΔG value. Transcription of MYC is tightly regulated by a complex mechanism involving promoters, enhancers and multiple transcription factors. We have used Curcumin as a model drug to understand the innate mechanism of controlling deregulated MYC back to its basal expression level. We have checked MYC-expression at transcriptional and translational level and proceeded for Chromatin Immuno-Precipitation assay (ChIP) to study the occupancy level of SP1, Heterogeneous nuclear ribonucleoprotein K (hnRNPK), Nucleoside Diphosphate Kinase 2 (NM23-H2) and Nucleolin at NHEIII1 upon Curcumin treatment of MDA-MB-231 cells. We have concluded that Curcumin binding tends to drive the equilibrium towards stable G-quadruplex formation repressing MYC back to its threshold-level. On retrospection of the synergistic effect of upregulated c-MYC and BCL-2 in cancer, we have also reported a new pathway [MYC-E2F-1-BCL-2-axis] through which Curcumin trigger apoptosis in cancer cells.Communicated by Ramaswamy H. Sarma.


Assuntos
Neoplasias da Mama , Curcumina , Quadruplex G , Feminino , Humanos , Apoptose , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Curcumina/farmacologia , Genes myc , Simulação de Acoplamento Molecular , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Células MDA-MB-231
18.
Eur J Pharmacol ; 912: 174586, 2021 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-34710368

RESUMO

Herein, a derivate from tanshinone IIA, 1,6,6-trimethyl-11-phenyl-7,8,9,10-tetrahydro-6H-furo[2',3':1,2]phenanthro[3,4-d]imidazole (TA25), has been synthesized and investigated as potential inhibitor against the proliferation, migration and invasion of lung cancer cells. MTT assay and cell colony formation assay results showed that TA25 exhibits acceptable inhibitory effect against the proliferation of lung cancer A549 cells, and the value of IC50 was about 17.9 µM. This result was further confirmed by the inhibition of TA25 against the growth of xenograft lung cancer cells on zebrafish bearing tumor (A549 lung cancer cells). The results of wound-healing assay and FITC-gelatin invasion assay displayed that TA25 could inhibit the migration and invasion of lung cancer A549 cells. Moreover, the studies on the binding properties of TA25 interact with c-myc G-quadruplex DNA suggested that TA25 can bind in the G-quarter plane formed from G7, G11, G16 and G20 with c-myc G-quadruplex DNA through π-π stacking. Further study of the potential anti-cancer mechanism indicated that TA25 can induce S-phase arrest in lung cancer A549 cells, and this phenomenon resulted from the promotion of the production of reactive oxygen species and DNA damage in A549 cells under the action of TA25. Further research revealed that TA25 could inhibit the PI3K/Akt/mTOR signal pathway and increase the expression of p53 protein. Overall, TA25 can be developed into a promising inhibitor against the proliferation, migration and invasion of lung cancer cells and has potential clinical application in the near future.


Assuntos
Abietanos/farmacologia , Antineoplásicos/farmacologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Proteínas Proto-Oncogênicas c-myc/genética , Fase S/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismo , Abietanos/química , Abietanos/uso terapêutico , Abietanos/toxicidade , Animais , Antineoplásicos/química , Antineoplásicos/uso terapêutico , Antineoplásicos/toxicidade , Sítios de Ligação/efeitos dos fármacos , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Modelos Animais de Doenças , Quadruplex G/efeitos dos fármacos , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Modelos Moleculares , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Peixe-Zebra
19.
Oncogene ; 40(46): 6417-6429, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34601505

RESUMO

Tumor cells must rewire cellular metabolism to satisfy the demands of unbridled growth and proliferation. How these metabolic processes are integrated to fuel cancer cell growth remains largely unknown. Deciphering the regulatory mechanisms is vital to develop targeted strategies for tumor-selective therapies. We herein performed an unbiased and functional siRNA screen against 96 deubiquitinases, which play indispensable roles in cancer and are emerging as therapeutic targets, and identified USP29 as a top candidate essential for metabolic reprogramming that support biosynthesis and survival in tumor cells. Integrated metabolic flux analysis and molecular investigation reveal that USP29 directly deubiquitinates and stabilizes MYC and HIF1α, two master regulators of metabolic reprogramming, enabling adaptive response of tumor cells in both normoxia and hypoxia. Systemic knockout of Usp29 depleted MYC and HIF1α in MYC-driven neuroblastoma and B cell lymphoma, inhibited critical metabolic targets and significantly prolonged survival of tumor-bearing mice. Strikingly, mice homozygous null for the Usp29 gene are viable, fertile, and display no gross phenotypic abnormalities. Altogether, these results demonstrate that USP29 selectively coordinates MYC and HIF1α to integrate metabolic processes critical for cancer cell growth, and therapeutic targeting of USP29, a potentially targetable enzyme, could create a unique vulnerability given deregulation of MYC and HIF1α frequently occurs in human cancers.


Assuntos
Subunidade alfa do Fator 1 Induzível por Hipóxia/química , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Linfoma de Células B/patologia , Neuroblastoma/patologia , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteases Específicas de Ubiquitina/metabolismo , Células A549 , Animais , Linhagem Celular Tumoral , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Técnicas de Inativação de Genes , Humanos , Linfoma de Células B/genética , Linfoma de Células B/metabolismo , Camundongos , Transplante de Neoplasias , Neuroblastoma/genética , Neuroblastoma/metabolismo , RNA Interferente Pequeno/farmacologia , Hipóxia Tumoral , Proteases Específicas de Ubiquitina/genética , Ubiquitinação
20.
Cells ; 10(8)2021 08 03.
Artigo em Inglês | MEDLINE | ID: mdl-34440739

RESUMO

Tumor recurrence from cancer stem cells (CSCs) and metastasis often occur post-treatment in colorectal cancer (CRC), leading to chemoresistance and resistance to targeted therapy. MYC is a transcription factor in the nuclei that modulates cell growth and development, and regulates immune response in an antitumor direction by mediating programmed death ligand 1 (PD-L1) and promoting CRC tumor recurrence after adjuvant chemotherapy. However, the molecular mechanism through which c-MYC maintains stemness and confers treatment resistance still remains elusive in CRC. In addition, recent reports demonstrated that CRC solid colon tumors expresses C-X-C motif chemokine ligand 8 (CXCL8). Expression of CXCL8 in CRC was reported to activate the expression of PD-L1 immune checkpoint through c-MYC, this ultimately induces chemoresistance in CRC. Accumulating studies have also demonstrated increased expression of CXCL8, matrix metalloproteinase 7 (MMP7), tissue inhibitor of metalloproteinase 1 (TIMP1), and epithelial-to-mesenchymal transition (EMT) components, in CRC tumors suggesting their potential collaboration to promote EMT and CSCs. TIMP1 is MMP-independent and regulates cell development and apoptosis in various cancer cell types, including CRC. Recent studies showed that TIMP1 cleaves CXCL8 on its chemoattractant, thereby influencing its mechanistic response to therapy. This therefore suggests crosstalk among the c-MYC/CXCL8/TIMP1 oncogenic signatures. In this study, we explored computer simulations through bioinformatics to identify and validate that the MYC/CXCL8/TIMP1 oncogenic signatures are overexpressed in CRC, Moreover, our docking results exhibited putative binding affinities of the above-mentioned oncogenes, with our novel small molecule, RV59, Finally, we demonstrated the anticancer activities of RV59 against NCI human CRC cancer cell lines both as single-dose and dose-dependent treatments, and also demonstrated the MYC/CXCL8/TIMP1 signaling pathway as a potential RV59 drug target.


Assuntos
Biologia Computacional/métodos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Acrilamidas/química , Compostos de Anilina/química , Antineoplásicos/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Antígeno B7-H1/metabolismo , Sítios de Ligação , Linhagem Celular Tumoral , Neoplasias Colorretais/tratamento farmacológico , Neoplasias Colorretais/patologia , Ensaios de Seleção de Medicamentos Antitumorais , Transição Epitelial-Mesenquimal , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Meia-Vida , Humanos , Interleucina-8/química , Interleucina-8/genética , Interleucina-8/metabolismo , Simulação de Acoplamento Molecular , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/metabolismo , Mapas de Interação de Proteínas/efeitos dos fármacos , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/metabolismo , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas c-myc/química , Proteínas Proto-Oncogênicas c-myc/genética , Proteínas Proto-Oncogênicas c-myc/metabolismo , Inibidor Tecidual de Metaloproteinase-1/química , Inibidor Tecidual de Metaloproteinase-1/genética , Inibidor Tecidual de Metaloproteinase-1/metabolismo
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