1
|
Lee MS, Jui J, Sahu A, Goldman D. Mycb and Mych stimulate Müller glial cell reprogramming and proliferation in the uninjured and injured zebrafish retina. Development 2024; 151:dev203062. [PMID: 38984586 PMCID: PMC11369687 DOI: 10.1242/dev.203062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Accepted: 06/26/2024] [Indexed: 07/11/2024]
Abstract
In the injured zebrafish retina, Müller glial cells (MG) reprogram to adopt retinal stem cell properties and regenerate damaged neurons. The strongest zebrafish reprogramming factors might be good candidates for stimulating a similar regenerative response by mammalian MG. Myc proteins are potent reprogramming factors that can stimulate cellular plasticity in differentiated cells; however, their role in MG reprogramming and retina regeneration remains poorly explored. Here, we report that retinal injury stimulates mycb and mych expression and that, although both Mycb and Mych stimulate MG reprogramming and proliferation, only Mych enhances retinal neuron apoptosis. RNA-sequencing analysis of wild-type, mychmut and mycbmut fish revealed that Mycb and Mych regulate ∼40% and ∼16%, respectively, of the genes contributing to the regeneration-associated transcriptome of MG. Of these genes, those that are induced are biased towards regulation of ribosome biogenesis, protein synthesis, DNA synthesis, and cell division, which are the top cellular processes affected by retinal injury, suggesting that Mycb and Mych are potent MG reprogramming factors. Consistent with this, forced expression of either of these proteins is sufficient to stimulate MG proliferation in the uninjured retina.
Collapse
Affiliation(s)
- Mi-Sun Lee
- Michigan Neuroscience Institute and Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jonathan Jui
- Michigan Neuroscience Institute and Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Aresh Sahu
- Michigan Neuroscience Institute and Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Daniel Goldman
- Michigan Neuroscience Institute and Department of Biological Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| |
Collapse
|
2
|
Venkatraman S, Balasubramanian B, Thuwajit C, Meller J, Tohtong R, Chutipongtanate S. Targeting MYC at the intersection between cancer metabolism and oncoimmunology. Front Immunol 2024; 15:1324045. [PMID: 38390324 PMCID: PMC10881682 DOI: 10.3389/fimmu.2024.1324045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
MYC activation is a known hallmark of cancer as it governs the gene targets involved in various facets of cancer progression. Of interest, MYC governs oncometabolism through the interactions with its partners and cofactors, as well as cancer immunity via its gene targets. Recent investigations have taken interest in characterizing these interactions through multi-Omic approaches, to better understand the vastness of the MYC network. Of the several gene targets of MYC involved in either oncometabolism or oncoimmunology, few of them overlap in function. Prominent interactions have been observed with MYC and HIF-1α, in promoting glucose and glutamine metabolism and activation of antigen presentation on regulatory T cells, and its subsequent metabolic reprogramming. This review explores existing knowledge of the role of MYC in oncometabolism and oncoimmunology. It also unravels how MYC governs transcription and influences cellular metabolism to facilitate the induction of pro- or anti-tumoral immunity. Moreover, considering the significant roles MYC holds in cancer development, the present study discusses effective direct or indirect therapeutic strategies to combat MYC-driven cancer progression.
Collapse
Affiliation(s)
- Simran Venkatraman
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Brinda Balasubramanian
- Division of Cancer and Stem Cells, Biodiscovery Institute, School of Medicine, University of Nottingham, Nottingham, United Kingdom
| | - Chanitra Thuwajit
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand
| | - Jaroslaw Meller
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Department of Biomedical Informatics, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Division of Biomedical Informatics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Rutaiwan Tohtong
- Department of Biochemistry, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Somchai Chutipongtanate
- Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, OH, United States
- Milk, microbiome, Immunity and Lactation research for Child Health (MILCH) and Novel Therapeutics Lab, Division of Epidemiology, Department of Environmental and Public Health Sciences, University of Cincinnati College of Medicine, Cincinnati, OH, United States
| |
Collapse
|
3
|
Schütz S, Bergsdorf C, Hänni-Holzinger S, Lingel A, Renatus M, Gossert AD, Jahnke W. Intrinsically Disordered Regions in the Transcription Factor MYC:MAX Modulate DNA Binding via Intramolecular Interactions. Biochemistry 2024. [PMID: 38264995 DOI: 10.1021/acs.biochem.3c00608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2024]
Abstract
The basic helix-loop-helix leucine zipper (bHLH-LZ) transcription factor (TF) MYC is in large part an intrinsically disordered oncoprotein. In complex with its obligate heterodimerization partner MAX, MYC preferentially binds E-Box DNA sequences (CANNTG). At promoters containing these sequence motifs, MYC controls fundamental cellular processes such as cell cycle progression, metabolism, and apoptosis. A vast network of proteins in turn regulates MYC function via intermolecular interactions. In this work, we establish another layer of MYC regulation by intramolecular interactions. We used nuclear magnetic resonance (NMR) spectroscopy to identify and map multiple binding sites for the C-terminal MYC:MAX DNA-binding domain (DBD) on the intrinsically disordered regions (IDRs) in the MYC N-terminus. We find that these binding events in trans are driven by electrostatic attraction, that they have distinct affinities, and that they are competitive with DNA binding. Thereby, we observe the strongest effects for the N-terminal MYC box 0 (Mb0), a conserved motif involved in MYC transactivation and target gene induction. We prepared recombinant full-length MYC:MAX complex and demonstrate that the interactions identified in this work are also relevant in cis, i.e., as intramolecular interactions. These findings are supported by surface plasmon resonance (SPR) experiments, which revealed that intramolecular IDR:DBD interactions in MYC decelerate the association of MYC:MAX complexes to DNA. Our work offers new insights into how bHLH-LZ TFs are regulated by intramolecular interactions, which open up new possibilities for drug discovery.
Collapse
Affiliation(s)
- Stefan Schütz
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Christian Bergsdorf
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Sandra Hänni-Holzinger
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Andreas Lingel
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Martin Renatus
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | | | - Wolfgang Jahnke
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| |
Collapse
|
4
|
Schütz S, Bergsdorf C, Goretzki B, Lingel A, Renatus M, Gossert AD, Jahnke W. The disordered MAX N-terminus modulates DNA binding of the transcription factor MYC:MAX. J Mol Biol 2022; 434:167833. [PMID: 36174765 DOI: 10.1016/j.jmb.2022.167833] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 09/05/2022] [Accepted: 09/17/2022] [Indexed: 11/15/2022]
Abstract
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 Nuclear Magnetic resonance (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.
Collapse
Affiliation(s)
- Stefan Schütz
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Christian Bergsdorf
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Benedikt Goretzki
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Andreas Lingel
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Martin Renatus
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland
| | - Alvar D Gossert
- Department of Biology, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Wolfgang Jahnke
- Novartis Institutes for BioMedical Research, Novartis Campus, CH-4056 Basel, Switzerland.
| |
Collapse
|
5
|
Muto T, Guillamot M, Yeung J, Fang J, Bennett J, Nadorp B, Lasry A, Redondo LZ, Choi K, Gong Y, Walker CS, Hueneman K, Bolanos LC, Barreyro L, Lee LH, Greis KD, Vasyliev N, Khodadadi-Jamayran A, Nudler E, Lujambio A, Lowe SW, Aifantis I, Starczynowski DT. TRAF6 functions as a tumor suppressor in myeloid malignancies by directly targeting MYC oncogenic activity. Cell Stem Cell 2022; 29:298-314.e9. [PMID: 35045331 PMCID: PMC8822959 DOI: 10.1016/j.stem.2021.12.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/05/2021] [Accepted: 12/15/2021] [Indexed: 02/05/2023]
Abstract
Clonal hematopoiesis (CH) is an aging-associated condition characterized by the clonal outgrowth of pre-leukemic cells that acquire specific mutations. Although individuals with CH are healthy, they are at an increased risk of developing myeloid malignancies, suggesting that additional alterations are needed for the transition from a pre-leukemia stage to frank leukemia. To identify signaling states that cooperate with pre-leukemic cells, we used an in vivo RNAi screening approach. One of the most prominent genes identified was the ubiquitin ligase TRAF6. Loss of TRAF6 in pre-leukemic cells results in overt myeloid leukemia and is associated with MYC-dependent stem cell signatures. TRAF6 is repressed in a subset of patients with myeloid malignancies, suggesting that subversion of TRAF6 signaling can lead to acute leukemia. Mechanistically, TRAF6 ubiquitinates MYC, an event that does not affect its protein stability but rather represses its functional activity by antagonizing an acetylation modification.
Collapse
Affiliation(s)
- Tomoya Muto
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Maria Guillamot
- Department of Pathology and Perlmutter Cancer Center, NYU School of Medicine, New York, NY 10016, USA
| | - Jennifer Yeung
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina College of Pharmacy, Columbia, SC 29208, USA
| | - Jing Fang
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina College of Pharmacy, Columbia, SC 29208, USA
| | - Joshua Bennett
- Department of Drug Discovery and Biomedical Sciences, University of South Carolina College of Pharmacy, Columbia, SC 29208, USA
| | - Bettina Nadorp
- Department of Pathology and Perlmutter Cancer Center, NYU School of Medicine, New York, NY 10016, USA
| | - Audrey Lasry
- Department of Pathology and Perlmutter Cancer Center, NYU School of Medicine, New York, NY 10016, USA
| | - Luna Zea Redondo
- Department of Pathology and Perlmutter Cancer Center, NYU School of Medicine, New York, NY 10016, USA
| | - Kwangmin Choi
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Yixiao Gong
- Department of Pathology and Perlmutter Cancer Center, NYU School of Medicine, New York, NY 10016, USA
| | - Callum S Walker
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Kathleen Hueneman
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Lyndsey C Bolanos
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Laura Barreyro
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Lynn H Lee
- Division of Oncology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Kenneth D Greis
- Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA
| | - Nikita Vasyliev
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
| | - Alireza Khodadadi-Jamayran
- Applied Bioinformatics Laboratories and Genome Technology Center, NYU School of Medicine, New York, NY 10016, USA
| | - Evgeny Nudler
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
| | - Amaia Lujambio
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Scott W Lowe
- Department of Cancer Biology and Genetics, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Howard Hughes Medical Institute, Chevy Chase, MD 201815, USA
| | - Iannis Aifantis
- Department of Pathology and Perlmutter Cancer Center, NYU School of Medicine, New York, NY 10016, USA.
| | - Daniel T Starczynowski
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH 45229, USA; Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA; Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH 45229, USA.
| |
Collapse
|
6
|
Campos Gudiño R, Farrell AC, Neudorf NM, McManus KJ. A Comprehensive Assessment of Genetic and Epigenetic Alterations Identifies Frequent Variations Impacting Six Prototypic SCF Complex Members. Int J Mol Sci 2021; 23:ijms23010084. [PMID: 35008511 PMCID: PMC8744973 DOI: 10.3390/ijms23010084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 12/14/2021] [Accepted: 12/20/2021] [Indexed: 11/24/2022] Open
Abstract
The SKP1, CUL1, F-box protein (SCF) complex represents a family of 69 E3 ubiquitin ligases that poly-ubiquitinate protein substrates marking them for proteolytic degradation via the 26S proteasome. Established SCF complex targets include transcription factors, oncoproteins and tumor suppressors that modulate cell cycle activity and mitotic fidelity. Accordingly, genetic and epigenetic alterations involving SCF complex member genes are expected to adversely impact target regulation and contribute to disease etiology. To gain novel insight into cancer pathogenesis, we determined the prevalence of genetic and epigenetic alterations in six prototypic SCF complex member genes (SKP1, CUL1, RBX1, SKP2, FBXW7 and FBXO5) from patient datasets extracted from The Cancer Genome Atlas (TCGA). Collectively, ~45% of observed SCF complex member mutations are predicted to impact complex structure and/or function in 10 solid tumor types. In addition, the distribution of encoded alterations suggest SCF complex members may exhibit either tumor suppressor or oncogenic mutational profiles in a cancer type dependent manner. Further bioinformatic analyses reveal the potential functional implications of encoded alterations arising from missense mutations by examining predicted deleterious mutations with available crystal structures. The SCF complex also exhibits frequent copy number alterations in a variety of cancer types that generally correspond with mRNA expression levels. Finally, we note that SCF complex member genes are differentially methylated across cancer types, which may effectively phenocopy gene copy number alterations. Collectively, these data show that SCF complex member genes are frequently altered at the genetic and epigenetic levels in many cancer types, which will adversely impact the normal targeting and timely destruction of protein substrates, which may contribute to the development and progression of an extensive array of cancer types.
Collapse
Affiliation(s)
- Rubi Campos Gudiño
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada; (R.C.G.); (A.C.F.); (N.M.N.)
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Ally C. Farrell
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada; (R.C.G.); (A.C.F.); (N.M.N.)
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Nicole M. Neudorf
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada; (R.C.G.); (A.C.F.); (N.M.N.)
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Kirk J. McManus
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
- Correspondence: ; Tel.: +1-204-787-2833
| |
Collapse
|
7
|
Thompson LL, Rutherford KA, Lepage CC, McManus KJ. The SCF Complex Is Essential to Maintain Genome and Chromosome Stability. Int J Mol Sci 2021; 22:8544. [PMID: 34445249 PMCID: PMC8395177 DOI: 10.3390/ijms22168544] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 07/29/2021] [Accepted: 08/05/2021] [Indexed: 12/20/2022] Open
Abstract
The SKP1, CUL1, F-box protein (SCF) complex encompasses a group of 69 SCF E3 ubiquitin ligase complexes that primarily modify protein substrates with poly-ubiquitin chains to target them for proteasomal degradation. These SCF complexes are distinguishable by variable F-box proteins, which determine substrate specificity. Although the function(s) of each individual SCF complex remain largely unknown, those that have been characterized regulate a wide array of cellular processes, including gene transcription and the cell cycle. In this regard, the SCF complex regulates transcription factors that modulate cell signaling and ensures timely degradation of primary cell cycle regulators for accurate replication and segregation of genetic material. SCF complex members are aberrantly expressed in a myriad of cancer types, with altered expression or function of the invariable core SCF components expected to have a greater impact on cancer pathogenesis than that of the F-box proteins. Accordingly, this review describes the normal roles that various SCF complexes have in maintaining genome stability before discussing the impact that aberrant SCF complex expression and/or function have on cancer pathogenesis. Further characterization of the SCF complex functions is essential to identify and develop therapeutic approaches to exploit aberrant SCF complex expression and function.
Collapse
Affiliation(s)
- Laura L. Thompson
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada; (L.L.T.); (K.A.R.); (C.C.L.)
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Kailee A. Rutherford
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada; (L.L.T.); (K.A.R.); (C.C.L.)
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Chloe C. Lepage
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada; (L.L.T.); (K.A.R.); (C.C.L.)
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| | - Kirk J. McManus
- CancerCare Manitoba Research Institute, CancerCare Manitoba, Winnipeg, MB R3E 0V9, Canada; (L.L.T.); (K.A.R.); (C.C.L.)
- Department of Biochemistry & Medical Genetics, University of Manitoba, Winnipeg, MB R3E 0J9, Canada
| |
Collapse
|
8
|
Sun XX, Li Y, Sears RC, Dai MS. Targeting the MYC Ubiquitination-Proteasome Degradation Pathway for Cancer Therapy. Front Oncol 2021; 11:679445. [PMID: 34178666 PMCID: PMC8226175 DOI: 10.3389/fonc.2021.679445] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 05/24/2021] [Indexed: 12/23/2022] Open
Abstract
Deregulated MYC overexpression and activation contributes to tumor growth and progression. Given the short half-life and unstable nature of the MYC protein, it is not surprising that the oncoprotein is highly regulated via diverse posttranslational mechanisms. Among them, ubiquitination dynamically controls the levels and activity of MYC during normal cell growth and homeostasis, whereas the disturbance of the ubiquitination/deubiquitination balance enables unwanted MYC stabilization and activation. In addition, MYC is also regulated by SUMOylation which crosstalks with the ubiquitination pathway and controls MYC protein stability and activity. In this mini-review, we will summarize current updates regarding MYC ubiquitination and provide perspectives about these MYC regulators as potential therapeutic targets in cancer.
Collapse
Affiliation(s)
- Xiao-Xin Sun
- Department of Molecular & Medical Genetics, School of Medicine and the OHSU Knight Cancer Institute, Oregon Health & Science University, Portland, OR, United States
| | - Yanping Li
- Department of Molecular & Medical Genetics, School of Medicine and the OHSU Knight Cancer Institute, Oregon Health & Science University, Portland, OR, United States
| | - Rosalie C Sears
- Department of Molecular & Medical Genetics, School of Medicine and the OHSU Knight Cancer Institute, Oregon Health & Science University, Portland, OR, United States
| | - Mu-Shui Dai
- Department of Molecular & Medical Genetics, School of Medicine and the OHSU Knight Cancer Institute, Oregon Health & Science University, Portland, OR, United States
| |
Collapse
|
9
|
Tian Y, Zeng J, Yang Z. MicroRNA-27b inhibits the development of melanoma by targeting MYC. Oncol Lett 2021; 21:370. [PMID: 33747226 PMCID: PMC7967934 DOI: 10.3892/ol.2021.12631] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2020] [Accepted: 02/02/2021] [Indexed: 11/30/2022] Open
Abstract
Cutaneous malignant melanoma is a malignancy with one of the fastest increasing incidence rates worldwide; however, the mechanism underlying the occurrence and development of melanoma remains unclear. The aim of the present study was to identify novel biomarkers for the occurrence and development of melanoma. The results of the present study demonstrated that the expression levels of microRNA (miR)-27b were decreased in melanoma tissue samples compared with those in adjacent noncancerous tissue samples and cells according to online and experimental data. By contrast, MYC expression levels were upregulated in melanoma compared with those in adjacent noncancerous tissue samples. miR-27b overexpression significantly inhibited A375 and A2085 melanoma cell DNA synthesis, viability and invasive ability. Dual-luciferase reporter assay results demonstrated that miR-27b inhibited MYC expression through binding to the 3′-untranslated region of MYC mRNA. MYC knockdown in melanoma cells exerted similar effects to those of miR-27b overexpression on DNA synthesis, cell viability and invasive ability; the effects of miR-27b inhibition were significantly reversed by MYC knockdown. In conclusion, the miR-27b/MYC axis may modulate malignant melanoma cell biological behaviors and may be a potential target for melanoma treatment.
Collapse
Affiliation(s)
- Yi Tian
- Department of Dermatology, The Second Affiliated Hospital, Hunan University of Chinese Medicine, Changsha, Hunan 410005, P.R. China
| | - Juanni Zeng
- Department of Anorectal Disease, The Second Affiliated Hospital, Hunan University of Chinese Medicine, Changsha, Hunan 410005, P.R. China
| | - Zongliang Yang
- Department of Anorectal Disease, The Second Affiliated Hospital, Hunan University of Chinese Medicine, Changsha, Hunan 410005, P.R. China
| |
Collapse
|
10
|
Abstract
To screen and identify ideal leading compounds from a drug library (ZINC15 database) with potential inhibition effect against c-Myc to contribute to medication design and development.A series of computer-aided virtual screening techniques were performed to identify potential inhibitors of c-Myc. LibDock from the software Discovery Studio was used to do a structure-based screening after ADME (absorption, distribution, metabolism, excretion) and toxicity prediction. Molecular docking was utilized to show the binding affinity and potential mechanism between ligands and c-Myc. Stability of the ligand-receptor complex was analyzed by molecular dynamic simulation at the end of the research.Compounds with more interactive energy which are confirmed to be the potential inhibitors for c-Myc were identified from the ZINC15 databases. Additionally, those compounds are also anticipated with fewer ames mutagenicity, rodent carcinogenicity, nondevelopmental toxic potential, and tolerant with cytochrome p450 2D6(CYP2D6). Dynamic simulation analysis also revealed that the very compounds had more favorable potential energy compared with 10058-F4(ZINC12406714). Furthermore, we prove that those compounds are stable and can exist in natural conditions.This study demonstrates that the compounds are potential therapeutic inhibitors for c-Myc. These compounds are safe and stable for drug candidates and may play a critical role in c-Myc inhibitor development.
Collapse
Affiliation(s)
- Junan Ren
- Clinical College, Jilin University, Changchun
| | | | - Junliang Ge
- Clinical College, Jilin University, Changchun
| | - Bo Wu
- Clinical College, Jilin University, Changchun
- Department of Orthopedics
| | - Weihang Li
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xian, China
| | - Xinhui Wang
- Clinical College, Jilin University, Changchun
- Department of Oncology, The First Hospital of Jilin University, Changchun
| | - Liyan Zhao
- Department of Clinical Laboratory, The Second Hospital of Jilin University
| |
Collapse
|
11
|
Ghousein A, Mosca N, Cartier F, Charpentier J, Dupuy JW, Raymond AA, Bioulac-Sage P, Grosset CF. miR-4510 blocks hepatocellular carcinoma development through RAF1 targeting and RAS/RAF/MEK/ERK signalling inactivation. Liver Int 2020; 40:240-251. [PMID: 31612616 DOI: 10.1111/liv.14276] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 09/20/2019] [Accepted: 10/04/2019] [Indexed: 02/06/2023]
Abstract
BACKGROUND Therapeutic outcomes using the multikinase inhibitors, sorafenib and regorafenib, remain unsatisfactory for patients with advanced hepatocellular carcinoma (HCC). Thus, new drug modalities are needed. We recently reported the remarkable capacity of miR-4510 to impede the growth of HCC and hepatoblastoma through Glypican-3 (GPC3) targeting and Wnt pathway inactivation. METHODS To identify new targets of miR-4510, we used a label-free proteomic approach and reported down-regulation of RAF proto-oncogene serine/threonine-protein kinase (RAF1) by miR-4510. Because the tumourigenic role of RAF1 in HCC is controversial, we further studied RAF1:miR-4510 interactions using cellular, molecular as well as functional approaches and a chicken chorioallantoic membrane (CAM) xenograft model. RESULTS We found an increase in RAF1 protein in 59.3% of HCC patients and a specific up-regulation of its transcript in proliferative tumours. We showed that miR-4510 inactivates the RAS/RAF/MEK/ERK pathway and reduces the expression of downstream targets (ie c-Fos proto-oncogene [FOS]) through RAF1 direct targeting. At a cellular level, miR-4510 inhibited HCC cell proliferation and migration and induced senescence in part by lowering RAF1 messenger RNA (mRNA) and protein expression. Finally, we confirmed the pro-tumoural function of RAF1 protein in HCC cells and its ability to sustain HCC tumour progression in vitro and in vivo. CONCLUSIONS In this work, we confirm that RAF1 acts as an oncogene in HCC and further demonstrate that miR-4510 acts as a strong tumour suppressor in the liver by targeting many proto-oncogenes, including GPC3 and RAF1, and subsequently controlling key biological and signalling pathways among which Wnt and RAS/RAF/MEK/ERK signals.
Collapse
Affiliation(s)
| | - Nicola Mosca
- Inserm, BMGIC, U1035, Univ. Bordeaux, Bordeaux, France
| | - Flora Cartier
- Inserm, BMGIC, U1035, Univ. Bordeaux, Bordeaux, France
| | | | - Jean-William Dupuy
- Centre de Génomique Fonctionnelle de Bordeaux, Plateforme Proteome, Univ. Bordeaux, Bordeaux, France
| | | | | | | |
Collapse
|
12
|
Chen Y, Sun XX, Sears RC, Dai MS. Writing and erasing MYC ubiquitination and SUMOylation. Genes Dis 2019; 6:359-371. [PMID: 31832515 PMCID: PMC6889025 DOI: 10.1016/j.gendis.2019.05.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/23/2019] [Accepted: 05/29/2019] [Indexed: 12/22/2022] Open
Abstract
The transcription factor c-MYC (MYC thereafter) controls diverse transcription programs and plays a key role in the development of many human cancers. Cells develop multiple mechanisms to ensure that MYC levels and activity are precisely controlled in normal physiological context. As a short half-lived protein, MYC protein levels are tightly regulated by the ubiquitin proteasome system. Over a dozen of ubiquitin ligases have been found to ubiquitinate MYC whereas a number of deubiquitinating enzymes counteract this process. Recent studies show that SUMOylation and deSUMOylation can also regulate MYC protein stability and activity. Interestingly, evidence suggests an intriguing crosstalk between MYC ubiquitination and SUMOylation. Deregulation of the MYC ubiquitination-SUMOylation regulatory network may contribute to tumorigenesis. This review is intended to provide the current understanding of the complex regulation of the MYC biology by dynamic ubiquitination and SUMOylation and their crosstalk.
Collapse
Affiliation(s)
- Yingxiao Chen
- Departments of Molecular & Medical Genetics, School of Medicine, OHSU Knight Cancer Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Xiao-Xin Sun
- Departments of Molecular & Medical Genetics, School of Medicine, OHSU Knight Cancer Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Rosalie C Sears
- Departments of Molecular & Medical Genetics, School of Medicine, OHSU Knight Cancer Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| | - Mu-Shui Dai
- Departments of Molecular & Medical Genetics, School of Medicine, OHSU Knight Cancer Institute, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
| |
Collapse
|
13
|
Li F, Li X, Qiao L, Liu W, Xu C, Wang X. MALAT1 regulates miR-34a expression in melanoma cells. Cell Death Dis 2019; 10:389. [PMID: 31101802 PMCID: PMC6525244 DOI: 10.1038/s41419-019-1620-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 04/16/2019] [Accepted: 04/29/2019] [Indexed: 12/16/2022]
Abstract
Melanoma is one of the most common skin malignancies. Both microRNAs and long non-coding RNAs (lncRNAs) have critical roles in the progression of cancers, including melanoma. However, the underlying molecular mechanism has not been fully characterized. We demonstrated that miR-34a is negatively correlated with MALAT1 in melanoma cells and tumor specimens. Interestingly, MALAT1, which contains functional sequence-specific miR-34a-binding sites, regulates miR-34a stability in melanoma cells and in vivo. Importantly, MALAT1 was significantly enriched in the Ago2 complex, but not when the MALAT1-binding site of miR-34a was mutated. Furthermore, MALAT1 could be shown to regulate c-Myc and Met expression by functioning as a miR-34a sponge. Our results reveal an unexpected mode of action for MALAT1 as an important regulator of miR-34a.
Collapse
Affiliation(s)
- Fei Li
- Department of Dermatology, Air Force Medical Center, PLA, Beijing, China.
| | - Xinji Li
- Department of Radiation Oncology, Air Force Medical Center, PLA, Beijing, China
| | - Li Qiao
- Department of Dermatology, Air Force Medical Center, PLA, Beijing, China
| | - Wen Liu
- Department of Dermatology, Air Force Medical Center, PLA, Beijing, China
| | - Chengshan Xu
- National Center for Clinical Laboratories, Beijing Hospital, National Center of Gerontology, Beijing, China
| | - Xiaogang Wang
- Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Beihang University, Beijing, China.
| |
Collapse
|
14
|
García-Gutiérrez L, Delgado MD, León J. MYC Oncogene Contributions to Release of Cell Cycle Brakes. Genes (Basel) 2019; 10:E244. [PMID: 30909496 PMCID: PMC6470592 DOI: 10.3390/genes10030244] [Citation(s) in RCA: 113] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2019] [Revised: 03/16/2019] [Accepted: 03/18/2019] [Indexed: 12/12/2022] Open
Abstract
Promotion of the cell cycle is a major oncogenic mechanism of the oncogene c-MYC (MYC). MYC promotes the cell cycle by not only activating or inducing cyclins and CDKs but also through the downregulation or the impairment of the activity of a set of proteins that act as cell-cycle brakes. This review is focused on the role of MYC as a cell-cycle brake releaser i.e., how MYC stimulates the cell cycle mainly through the functional inactivation of cell cycle inhibitors. MYC antagonizes the activities and/or the expression levels of p15, ARF, p21, and p27. The mechanism involved differs for each protein. p15 (encoded by CDKN2B) and p21 (CDKN1A) are repressed by MYC at the transcriptional level. In contrast, MYC activates ARF, which contributes to the apoptosis induced by high MYC levels. At least in some cells types, MYC inhibits the transcription of the p27 gene (CDKN1B) but also enhances p27's degradation through the upregulation of components of ubiquitin ligases complexes. The effect of MYC on cell-cycle brakes also opens the possibility of antitumoral therapies based on synthetic lethal interactions involving MYC and CDKs, for which a series of inhibitors are being developed and tested in clinical trials.
Collapse
Affiliation(s)
- Lucía García-Gutiérrez
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) CSIC-Universidad de Cantabria and Department of Biología Molecular, Universidad de Cantabria, 39011 Santander, Spain.
- Current address: Systems Biology Ireland, University College Dublin, Belfield, Dublin 4, Ireland.
| | - María Dolores Delgado
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) CSIC-Universidad de Cantabria and Department of Biología Molecular, Universidad de Cantabria, 39011 Santander, Spain.
| | - Javier León
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) CSIC-Universidad de Cantabria and Department of Biología Molecular, Universidad de Cantabria, 39011 Santander, Spain.
| |
Collapse
|
15
|
Carabet LA, Rennie PS, Cherkasov A. Therapeutic Inhibition of Myc in Cancer. Structural Bases and Computer-Aided Drug Discovery Approaches. Int J Mol Sci 2018; 20:E120. [PMID: 30597997 PMCID: PMC6337544 DOI: 10.3390/ijms20010120] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/08/2018] [Accepted: 12/21/2018] [Indexed: 12/23/2022] Open
Abstract
Myc (avian myelocytomatosis viral oncogene homolog) represents one of the most sought after drug targets in cancer. Myc transcription factor is an essential regulator of cell growth, but in most cancers it is overexpressed and associated with treatment-resistance and lethal outcomes. Over 40 years of research and drug development efforts did not yield a clinically useful Myc inhibitor. Drugging the "undruggable" is problematic, as Myc inactivation may negatively impact its physiological functions. Moreover, Myc is a disordered protein that lacks effective binding pockets on its surface. It is well established that the Myc function is dependent on dimerization with its obligate partner, Max (Myc associated factor X), which together form a functional DNA-binding domain to activate genomic targets. Herein, we provide an overview of the knowledge accumulated to date on Myc regulation and function, its critical role in cancer, and summarize various strategies that are employed to tackle Myc-driven malignant transformation. We focus on important structure-function relationships of Myc with its interactome, elaborating structural determinants of Myc-Max dimer formation and DNA recognition exploited for therapeutic inhibition. Chronological development of small-molecule Myc-Max prototype inhibitors and corresponding binding sites are comprehensively reviewed and particular emphasis is placed on modern computational drug design methods. On the outlook, technological advancements may soon provide the so long-awaited Myc-Max clinical candidate.
Collapse
Affiliation(s)
- Lavinia A Carabet
- Vancouver Prostate Centre, University of British Columbia, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada.
| | - Paul S Rennie
- Vancouver Prostate Centre, University of British Columbia, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada.
| | - Artem Cherkasov
- Vancouver Prostate Centre, University of British Columbia, 2660 Oak Street, Vancouver, BC V6H 3Z6, Canada.
| |
Collapse
|
16
|
Yang Y, Meng Q, Wang C, Li X, Lu Y, Xin X, Zheng Q, Lu D. MicroRNA 675 cooperates PKM2 to aggravate progression of human liver cancer stem cells induced from embryonic stem cells. J Mol Med (Berl) 2018; 96:1119-1130. [PMID: 30140938 DOI: 10.1007/s00109-018-1687-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Revised: 08/08/2018] [Accepted: 08/13/2018] [Indexed: 01/17/2023]
Abstract
Both miR675 and pyruvate kinase M2 (PKM2) contribute to malignant progression of tumor, but its functions in liver cancer stem cells remain unclear. Herein, our findings indicate that miR675 plus PKM2 strongly promotes the growth of liver cancer stem cells. Mechanistically, miR675 plus PKM2 enhances the transcriptional activity of SUV39h2. On the other hand, the excessive SUV39h2 binds to more substrate histone H3, triggering an increase of tri-methylation of histone H3 on the ninth lysine. Furthermore, the tri-methylation of histone 3 on the ninth lysine (H3K9me3)-heterochromatin protein 1 alpha (HP1α) complex is increased when the complex occupancy ability on the C-myc promoter region is raised, recruiting CREB, P300, and RNApolII to the special position that results in C-myc high abundance. Therefore, miR675 plus PKM2 triggered the upregulation of C-myc by increasing the interaction between H3K9me3 and HP1α. Understanding the signaling pathways that miR675 plus PKM2 epigenetically possesses during the malignant transformation of liver cancer stem cells will contribute to more effective liver cancer therapies.
Collapse
Affiliation(s)
- Yuxin Yang
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China
| | - Qiuyu Meng
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China
| | - Chen Wang
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China
| | - Xiaonan Li
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China
| | - Yanan Lu
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China
| | - Xiaoru Xin
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China
| | - Qidi Zheng
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China
| | - Dongdong Lu
- Research Center for Translational Medicine at Shanghai East Hospital, School of Life Science and Technology, Tongji University, Shanghai, 200092, China.
| |
Collapse
|
17
|
Schaub FX, Dhankani V, Berger AC, Trivedi M, Richardson AB, Shaw R, Zhao W, Zhang X, Ventura A, Liu Y, Ayer DE, Hurlin PJ, Cherniack AD, Eisenman RN, Bernard B, Grandori C. Pan-cancer Alterations of the MYC Oncogene and Its Proximal Network across the Cancer Genome Atlas. Cell Syst 2018; 6:282-300.e2. [PMID: 29596783 PMCID: PMC5892207 DOI: 10.1016/j.cels.2018.03.003] [Citation(s) in RCA: 233] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 02/06/2018] [Accepted: 03/02/2018] [Indexed: 12/19/2022]
Abstract
Although the MYC oncogene has been implicated in cancer, a systematic assessment of alterations of MYC, related transcription factors, and co-regulatory proteins, forming the proximal MYC network (PMN), across human cancers is lacking. Using computational approaches, we define genomic and proteomic features associated with MYC and the PMN across the 33 cancers of The Cancer Genome Atlas. Pan-cancer, 28% of all samples had at least one of the MYC paralogs amplified. In contrast, the MYC antagonists MGA and MNT were the most frequently mutated or deleted members, proposing a role as tumor suppressors. MYC alterations were mutually exclusive with PIK3CA, PTEN, APC, or BRAF alterations, suggesting that MYC is a distinct oncogenic driver. Expression analysis revealed MYC-associated pathways in tumor subtypes, such as immune response and growth factor signaling; chromatin, translation, and DNA replication/repair were conserved pan-cancer. This analysis reveals insights into MYC biology and is a reference for biomarkers and therapeutics for cancers with alterations of MYC or the PMN.
Collapse
Affiliation(s)
- Franz X Schaub
- Cure First, Seattle, WA, USA; SEngine Precision Medicine, Seattle, WA, USA
| | | | - Ashton C Berger
- The Eli and Edythe L. Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, MA, USA
| | | | | | - Reid Shaw
- SEngine Precision Medicine, Seattle, WA, USA
| | - Wei Zhao
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Xiaoyang Zhang
- Dana-Farber Cancer Institute, the Broad Institute of Harvard and MIT, and Harvard Medical School, Boston, MA, USA
| | - Andrea Ventura
- Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Yuexin Liu
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Donald E Ayer
- Department of Oncological Sciences, Huntsman Cancer Institute, University of Utah, Salt Lake City, UT, USA
| | - Peter J Hurlin
- Shriners Hospitals for Children Research Center, Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA
| | - Andrew D Cherniack
- Dana-Farber Cancer Institute, the Broad Institute of Harvard and MIT, and Harvard Medical School, Boston, MA, USA
| | - Robert N Eisenman
- Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Brady Bernard
- Institute for Systems Biology, Seattle, WA, USA; Providence Health and Services, Portland, OR, USA.
| | - Carla Grandori
- Cure First, Seattle, WA, USA; SEngine Precision Medicine, Seattle, WA, USA.
| |
Collapse
|
18
|
De Melo J, Kim SS, Lourenco C, Penn LZ. Lysine-52 stabilizes the MYC oncoprotein through an SCFFbxw7-independent mechanism. Oncogene 2017; 36:6815-6822. [DOI: 10.1038/onc.2017.268] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 06/09/2017] [Accepted: 06/19/2017] [Indexed: 12/11/2022]
|
19
|
MYC Modulation around the CDK2/p27/SKP2 Axis. Genes (Basel) 2017; 8:genes8070174. [PMID: 28665315 PMCID: PMC5541307 DOI: 10.3390/genes8070174] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 06/23/2017] [Accepted: 06/24/2017] [Indexed: 12/20/2022] Open
Abstract
MYC is a pleiotropic transcription factor that controls a number of fundamental cellular processes required for the proliferation and survival of normal and malignant cells, including the cell cycle. MYC interacts with several central cell cycle regulators that control the balance between cell cycle progression and temporary or permanent cell cycle arrest (cellular senescence). Among these are the cyclin E/A/cyclin-dependent kinase 2 (CDK2) complexes, the CDK inhibitor p27KIP1 (p27) and the E3 ubiquitin ligase component S-phase kinase-associated protein 2 (SKP2), which control each other by forming a triangular network. MYC is engaged in bidirectional crosstalk with each of these players; while MYC regulates their expression and/or activity, these factors in turn modulate MYC through protein interactions and post-translational modifications including phosphorylation and ubiquitylation, impacting on MYC's transcriptional output on genes involved in cell cycle progression and senescence. Here we elaborate on these network interactions with MYC and their impact on transcription, cell cycle, replication and stress signaling, and on the role of other players interconnected to this network, such as CDK1, the retinoblastoma protein (pRB), protein phosphatase 2A (PP2A), the F-box proteins FBXW7 and FBXO28, the RAS oncoprotein and the ubiquitin/proteasome system. Finally, we describe how the MYC/CDK2/p27/SKP2 axis impacts on tumor development and discuss possible ways to interfere therapeutically with this system to improve cancer treatment.
Collapse
|
20
|
Zhang Q, West-Osterfield K, Spears E, Li Z, Panaccione A, Hann SR. MB0 and MBI Are Independent and Distinct Transactivation Domains in MYC that Are Essential for Transformation. Genes (Basel) 2017; 8:genes8050134. [PMID: 28481271 PMCID: PMC5448008 DOI: 10.3390/genes8050134] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 04/24/2017] [Accepted: 04/28/2017] [Indexed: 01/05/2023] Open
Abstract
MYC is a transcription factor that is essential for cellular proliferation and development. Deregulation or overexpression of MYC occurs in a variety of human cancers. Ectopic expression of MYC causes hyperproliferation and transformation of cells in culture and tumorigenesis in several transgenic mouse models. Deregulation of MYC can also induce apoptosis through activation of p53 and/or ARF tumor suppressors as a safeguard to prevent tumorigenesis. MYC binds to thousands of genomic sites and regulates hundreds of target genes in a context-dependent fashion to mediate these diverse biological roles. The N-terminal region of MYC contains several conserved domains or MYC Boxes (MB), which influence the different MYC transcriptional and biological activities to varying degrees. However, the specific domains that mediate the ability of MYC to activate transcription remain ill defined. In this report, we have identified a new conserved transactivation domain (TAD), MB0, which is essential for MYC transactivation and target gene induction. We demonstrate that MB0 and MBI represent two distinct and independent TADs within the N-terminal 62 amino acids of MYC. In addition, both MB0 and MBI are essential for MYC transformation of primary fibroblasts in cooperation with activated RAS, while MB0 is necessary for efficient MYC-induced p53-independent apoptosis.
Collapse
Affiliation(s)
- Qin Zhang
- Department of Cell and Developmental Biology, Vanderbilt University, School of Medicine, 1121 21st Ave., Nashville, TN 37232, USA.
| | - Kimberly West-Osterfield
- Department of Cell and Developmental Biology, Vanderbilt University, School of Medicine, 1121 21st Ave., Nashville, TN 37232, USA.
| | - Erick Spears
- Department of Cell and Developmental Biology, Vanderbilt University, School of Medicine, 1121 21st Ave., Nashville, TN 37232, USA.
| | - Zhaoliang Li
- Department of Cell and Developmental Biology, Vanderbilt University, School of Medicine, 1121 21st Ave., Nashville, TN 37232, USA.
| | - Alexander Panaccione
- Department of Cell and Developmental Biology, Vanderbilt University, School of Medicine, 1121 21st Ave., Nashville, TN 37232, USA.
| | - Stephen R Hann
- Department of Cell and Developmental Biology, Vanderbilt University, School of Medicine, 1121 21st Ave., Nashville, TN 37232, USA.
| |
Collapse
|
21
|
Abstract
Ubiquitination plays a key and complex role in the regulation of c-Myc stability, transactivation, and oncogenic activity. c-Myc is ubiquitinated by a number of ubiquitin ligases (E3s), such as SCF(Fbw7) and SCF(Skp2). Depending on the E3s, ubiquitination can either positively or negatively regulate c-Myc levels and activity. Meanwhile, c-Myc ubiquitination can be reversed by deubiquitination. An early study showed that USP28 deubiquitinates c-Myc via interacting with Fbw7α whereas a recent study reveals that USP37 deubiquitinates c-Myc independently of Fbw7 and c-Myc phosphorylation. Consequently, both USP28 and USP37 stabilize c-Myc and enhance its activity. We recently found the nucleolar USP36 as a novel c-Myc deubiquitinase that controls the end-point of c-Myc degradation pathway in the nucleolus. Here we briefly review the current understanding of ubiquitination and deubiquitination regulation of c-Myc and further discuss the USP36-c-Myc regulatory pathway.
Collapse
Affiliation(s)
- Xiao-Xin Sun
- a Departments of Molecular & Medical Genetics ; School of Medicine and the OHSU Knight Cancer Institute; Oregon Health & Science University ; Portland , OR USA
| | - Rosalie C Sears
- a Departments of Molecular & Medical Genetics ; School of Medicine and the OHSU Knight Cancer Institute; Oregon Health & Science University ; Portland , OR USA
| | - Mu-Shui Dai
- a Departments of Molecular & Medical Genetics ; School of Medicine and the OHSU Knight Cancer Institute; Oregon Health & Science University ; Portland , OR USA
| |
Collapse
|
22
|
Definition of a Skp2-c-Myc Pathway to Expand Human Beta-cells. Sci Rep 2016; 6:28461. [PMID: 27380896 PMCID: PMC4933882 DOI: 10.1038/srep28461] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 05/25/2016] [Indexed: 12/20/2022] Open
Abstract
Type 2 diabetes (T2D) is characterized by insulin resistance and reduced functional β-cell mass. Developmental differences, failure of adaptive expansion and loss of β-cells via β-cell death or de-differentiation have emerged as the possible causes of this reduced β-cell mass. We hypothesized that the proliferative response to mitogens of human β-cells from T2D donors is reduced, and that this might contribute to the development and progression of T2D. Here, we demonstrate that the proliferative response of human β-cells from T2D donors in response to cdk6 and cyclin D3 is indeed dramatically impaired. We show that this is accompanied by increased nuclear abundance of the cell cycle inhibitor, p27kip1. Increasing nuclear abundance of p27kip1 by adenoviral delivery decreases the proliferative response of β-cells from non-diabetic donors, mimicking T2D β-cells. However, while both p27kip1 gene silencing and downregulation by Skp2 overexpression increased similarly the proliferative response of human β-cells, only Skp2 was capable of inducing a significant human β-cell expansion. Skp2 was also able to double the proliferative response of T2D β-cells. These studies define c-Myc as a central Skp2 target for the induction of cell cycle entry, expansion and regeneration of human T2D β-cells.
Collapse
|
23
|
Zinc finger factor ZNF121 is a MYC-interacting protein functionally affecting MYC and cell proliferation in epithelial cells. J Genet Genomics 2016; 43:677-685. [PMID: 27988300 DOI: 10.1016/j.jgg.2016.05.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 05/13/2016] [Accepted: 05/17/2016] [Indexed: 12/21/2022]
Abstract
MYC is a potent oncoprotein that modulates multiple cellular processes including proliferation, apoptosis, differentiation, stemness, senescence, and migration. Functioning primarily as a transcriptional factor, MYC interacts with a large number of proteins, and identification and characterization of MYC-interacting proteins are important for understanding how MYC functions. In this study, we used different systems to demonstrate that a novel zinc finger transcription factor, ZNF121, physically interacted with MYC, and the interaction involved their N-terminal regions. Overexpression of ZNF121 increased, while its knockdown decreased, the expression of MYC in multiple epithelial cell lines, and MYC had similar effects on ZNF121 expression. An expression correlation was also detectable in a panel of epithelial cell lines and a cohort of human breast cancer tissues. Functionally, knockdown of ZNF121 in several breast epithelial cell lines attenuated the expressions of MYC and its target genes (e.g., EGR1, CDC2, and nucleolin) and slowed cell proliferation, accompanied by cell cycle arrest in the G1 phase and expression alteration of cell cycle regulators (cyclin D1, p14 and p21). Analysis of publically available databases showed that ZNF121 expression is up-regulated in human breast cancer, and the up-regulation significantly associates with worse patient survival in the luminal A subtype of breast cancer. These findings establish ZNF121 as a MYC-interacting protein with functional effects on MYC and cell proliferation.
Collapse
|
24
|
Li J, Li X, Hou R, Liu R, Zhao X, Dong F, Wang C, Yin G, Zhang K. Psoriatic T cells reduce epidermal turnover time and affect cell proliferation contributed from differential gene expression. J Dermatol 2015; 42:874-80. [PMID: 26046687 DOI: 10.1111/1346-8138.12961] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 04/20/2015] [Indexed: 12/19/2022]
Affiliation(s)
- Junqin Li
- Institute of Dermatology; Taiyuan City Center Hospital; Taiyuan China
| | - Xinhua Li
- Institute of Dermatology; Taiyuan City Center Hospital; Taiyuan China
| | - Ruixia Hou
- Institute of Dermatology; Taiyuan City Center Hospital; Taiyuan China
| | - Ruifeng Liu
- Institute of Dermatology; Taiyuan City Center Hospital; Taiyuan China
| | - Xincheng Zhao
- Institute of Dermatology; Taiyuan City Center Hospital; Taiyuan China
| | - Feng Dong
- Department of Dermatology; Changzhi City Second People's Hospital; Changzhi China
| | - Chunfang Wang
- Laboratory Animal Center; Shanxi Medical University; Taiyuan China
| | - Guohua Yin
- Institute of Dermatology; Taiyuan City Center Hospital; Taiyuan China
| | - Kaiming Zhang
- Institute of Dermatology; Taiyuan City Center Hospital; Taiyuan China
| |
Collapse
|
25
|
Meng X, Carlson NR, Dong J, Zhang Y. Oncogenic c-Myc-induced lymphomagenesis is inhibited non-redundantly by the p19Arf-Mdm2-p53 and RP-Mdm2-p53 pathways. Oncogene 2015; 34:5709-17. [PMID: 25823025 DOI: 10.1038/onc.2015.39] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 11/24/2014] [Accepted: 01/14/2015] [Indexed: 01/01/2023]
Abstract
The multifaceted oncogene c-Myc plays important roles in the development and progression of human cancer. Recent in vitro and in vivo studies have shown that the p19Arf-Mdm2-p53 and the ribosomal protein (RP)-Mdm2-p53 pathways are both essential in preventing oncogenic c-Myc-induced tumorigenesis. Disruption of each pathway individually by p19Arf deletion or by Mdm2(C305F) mutation, which disrupts RP-Mdm2 binding, accelerates Eμ-myc transgene-induced pre-B/B-cell lymphoma in mice at seemingly similar paces with median survival around 10 and 11 weeks, respectively, compared to 20 weeks for Eμ-myc transgenic mice. Because p19Arf can inhibit ribosomal biogenesis through its interaction with nucleophosmin (NPM/B23), RNA helicase DDX5 and RNA polymerase I transcription termination factor (TTF-I), it has been speculated that the p19Arf-Mdm2-p53 and the RP-Mdm2-p53 pathways might be a single p19Arf-RP-Mdm2-p53 pathway, in which p19Arf activates p53 by inhibiting RP biosynthesis; thus, p19Arf deletion or Mdm2(C305F) mutation would result in similar consequences. Here, we generated mice with concurrent p19Arf deletion and Mdm2(C305F) mutation and investigated the compound mice for tumorigenesis in the absence and the presence of oncogenic c-Myc overexpression. In the absence of Eμ-myc transgene, the Mdm2(C305F) mutation did not elicit spontaneous tumors in mice, nor did it accelerate spontaneous tumors in mice with p19Arf deletion. In the presence of Eμ-myc transgene, however, Mdm2(C305F) mutation significantly accelerated p19Arf deletion-induced lymphomagenesis and promoted rapid metastasis. We found that when p19Arf-Mdm2-p53 and RP-Mdm2-p53 pathways are independently disrupted, oncogenic c-Myc-induced p53 stabilization and activation is only partially attenuated. When both pathways are concurrently disrupted, however, c-Myc-induced p53 stabilization and activation are essentially obliterated. Thus, the p19Arf-Mdm2-p53 and the RP-Mdm2-p53 are non-redundant pathways possessing similar capabilities to activate p53 upon c-Myc overexpression.
Collapse
Affiliation(s)
- X Meng
- Department of Radiation Oncology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Hospital and Institute of Hepatobiliary Surgery, Chinese PLA General Hospital, Beijing, China.,Jiangsu Center for the Collaboration and Innovation of Cancer Biotherapy, Cancer Institute, Xuzhou Medical College, Xuzhou, China
| | - N R Carlson
- Department of Radiation Oncology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, USA
| | - J Dong
- Hospital and Institute of Hepatobiliary Surgery, Chinese PLA General Hospital, Beijing, China.,Jiangsu Center for the Collaboration and Innovation of Cancer Biotherapy, Cancer Institute, Xuzhou Medical College, Xuzhou, China
| | - Y Zhang
- Department of Radiation Oncology, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.,Jiangsu Center for the Collaboration and Innovation of Cancer Biotherapy, Cancer Institute, Xuzhou Medical College, Xuzhou, China.,Curriculum in Genetics and Molecular Biology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, USA
| |
Collapse
|
26
|
Peter S, Bultinck J, Myant K, Jaenicke LA, Walz S, Müller J, Gmachl M, Treu M, Boehmelt G, Ade CP, Schmitz W, Wiegering A, Otto C, Popov N, Sansom O, Kraut N, Eilers M. Tumor cell-specific inhibition of MYC function using small molecule inhibitors of the HUWE1 ubiquitin ligase. EMBO Mol Med 2014; 6:1525-41. [PMID: 25253726 PMCID: PMC4287973 DOI: 10.15252/emmm.201403927] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2014] [Revised: 07/30/2014] [Accepted: 08/26/2014] [Indexed: 12/14/2022] Open
Abstract
Deregulated expression of MYC is a driver of colorectal carcinogenesis, necessitating novel strategies to inhibit MYC function. The ubiquitin ligase HUWE1 (HECTH9, ARF-BP1, MULE) associates with both MYC and the MYC-associated protein MIZ1. We show here that HUWE1 is required for growth of colorectal cancer cells in culture and in orthotopic xenograft models. Using high-throughput screening, we identify small molecule inhibitors of HUWE1, which inhibit MYC-dependent transactivation in colorectal cancer cells, but not in stem and normal colon epithelial cells. Inhibition of HUWE1 stabilizes MIZ1. MIZ1 globally accumulates on MYC target genes and contributes to repression of MYC-activated target genes upon HUWE1 inhibition. Our data show that transcriptional activation by MYC in colon cancer cells requires the continuous degradation of MIZ1 and identify a novel principle that allows for inhibition of MYC function in tumor cells.
Collapse
Affiliation(s)
- Stefanie Peter
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Jennyfer Bultinck
- Cytokine Receptor Lab, Department of Biochemistry, Ghent University, Ghent, Belgium
| | | | - Laura A Jaenicke
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Susanne Walz
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Judith Müller
- Department of Molecular Oncology, Netherlands Cancer Institute, Amsterdam, the Netherlands
| | - Michael Gmachl
- Department Lead Discovery, Boehringer Ingelheim RCV GmbH & Co KG, Vienna, Austria
| | - Matthias Treu
- Department Lead Discovery, Boehringer Ingelheim RCV GmbH & Co KG, Vienna, Austria
| | - Guido Boehmelt
- Department Lead Discovery, Boehringer Ingelheim RCV GmbH & Co KG, Vienna, Austria
| | - Carsten P Ade
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Werner Schmitz
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany
| | - Armin Wiegering
- Department of General, Visceral, Vascular and Paediatric Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Christoph Otto
- Department of General, Visceral, Vascular and Paediatric Surgery, University Hospital Würzburg, Würzburg, Germany
| | - Nikita Popov
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany Comprehensive Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany
| | | | - Norbert Kraut
- Department Lead Discovery, Boehringer Ingelheim RCV GmbH & Co KG, Vienna, Austria
| | - Martin Eilers
- Theodor Boveri Institute, Biocenter, University of Würzburg, Würzburg, Germany Comprehensive Cancer Center Mainfranken, University of Würzburg, Würzburg, Germany
| |
Collapse
|
27
|
Chen BJ, Wu YL, Tanaka Y, Zhang W. Small molecules targeting c-Myc oncogene: promising anti-cancer therapeutics. Int J Biol Sci 2014; 10:1084-96. [PMID: 25332683 PMCID: PMC4202025 DOI: 10.7150/ijbs.10190] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 08/25/2014] [Indexed: 02/07/2023] Open
Abstract
The nuclear transcription factor c-Myc is a member of the Myc gene family with multiple functions and located on band q24.1 of chromosome 8. The c-Myc gene is activated by chromosomal translocation, rearrangement, and amplification. Its encoded protein transduces intracellular signals to the nucleus, resulting in the regulation of cell proliferation, differentiation, and apoptosis, and has the ability to transform cells and bind chromosomal DNA. c-Myc also plays a critical role in malignant transformation. The abnormal over-expression of c-Myc is frequently observed in some tumors, including carcinomas of the breast, colon, and cervix, as well as small-cell lung cancer, osteosarcomas, glioblastomas, and myeloid leukemias, therefore making it a possible target for anticancer therapy. In this minireview, we summarize unique characteristics of c-Myc and therapeutic strategies against cancer using small molecules targeting the oncogene, and discuss the prospects in the development of agents targeting c-Myc, in particular G-quadruplexes formed in c-Myc promoter and c-Myc/Max dimerization. Such information will be of importance for the research and development of c-Myc-targeted drugs.
Collapse
Affiliation(s)
- Bing-Jia Chen
- 1. Lab of Chemical Biology and Molecular Drug Design, College of Pharmaceutical Science, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou, 310014, China
| | - Yan-Ling Wu
- 2. Lab of Molecular Immunology, Virus Inspection Department, Zhejiang Provincial Center for Disease Control and Prevention, 630 Xincheng Road, Hangzhou, 310051, China. ; 1. Lab of Chemical Biology and Molecular Drug Design, College of Pharmaceutical Science, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou, 310014, China
| | - Yoshimasa Tanaka
- 3. Center for Innovation in Immunoregulative Technology and Therapeutics, Graduate School of Medicine, Kyoto University, Kyoto, 606-8501, Japan
| | - Wen Zhang
- 1. Lab of Chemical Biology and Molecular Drug Design, College of Pharmaceutical Science, Zhejiang University of Technology, 18 Chaowang Road, Hangzhou, 310014, China
| |
Collapse
|
28
|
Wirth M, Stojanovic N, Christian J, Paul MC, Stauber RH, Schmid RM, Häcker G, Krämer OH, Saur D, Schneider G. MYC and EGR1 synergize to trigger tumor cell death by controlling NOXA and BIM transcription upon treatment with the proteasome inhibitor bortezomib. Nucleic Acids Res 2014; 42:10433-47. [PMID: 25147211 PMCID: PMC4176343 DOI: 10.1093/nar/gku763] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The c-MYC (MYC afterward) oncogene is well known for driving numerous oncogenic programs. However, MYC can also induce apoptosis and this function of MYC warrants further clarification. We report here that a clinically relevant proteasome inhibitor significantly increases MYC protein levels and that endogenous MYC is necessary for the induction of apoptosis. This kind of MYC-induced cell death is mediated by enhanced expression of the pro-apoptotic BCL2 family members NOXA and BIM. Quantitative promoter-scanning chromatin immunoprecipitations (qChIP) further revealed binding of MYC to the promoters of NOXA and BIM upon proteasome inhibition, correlating with increased transcription. Both promoters are further characterized by the presence of tri-methylated lysine 4 of histone H3, marking active chromatin. We provide evidence that in our apoptosis models cell death occurs independently of p53 or ARF. Furthermore, we demonstrate that recruitment of MYC to the NOXA as well as to the BIM gene promoters depends on MYC's interaction with the zinc finger transcription factor EGR1 and an EGR1-binding site in both promoters. Our study uncovers a novel molecular mechanism by showing that the functional cooperation of MYC with EGR1 is required for bortezomib-induced cell death. This observation may be important for novel therapeutic strategies engaging the inherent pro-death function of MYC.
Collapse
Affiliation(s)
- Matthias Wirth
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| | - Natasa Stojanovic
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| | - Jan Christian
- Departments of Medicine and of Microbiology and Immunology, The Research Institute of the McGill University Health Centre, McGill University, Montréal H3A 2B4, Canada
| | - Mariel C Paul
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| | - Roland H Stauber
- Molecular and Cellular Oncology/Mainz Screening Center (MSC), University Hospital of Mainz, Mainz 55101, Germany
| | - Roland M Schmid
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| | - Georg Häcker
- Institut für Medizinische Mikrobiologie und Hygiene, Universitätsklinik Freiburg, Freiburg 79104, Germany
| | - Oliver H Krämer
- Department of Toxicology, University of Mainz Medical Center, Mainz 55131, Germany
| | - Dieter Saur
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| | - Günter Schneider
- Medizinische Klinik, Technische Universität München, München 81675, Germany
| |
Collapse
|
29
|
Hann SR. MYC cofactors: molecular switches controlling diverse biological outcomes. Cold Spring Harb Perspect Med 2014; 4:a014399. [PMID: 24939054 DOI: 10.1101/cshperspect.a014399] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The transcription factor MYC has fundamental roles in proliferation, apoptosis, tumorigenesis, and stem cell pluripotency. Over the last 30 years extensive information has been gathered on the numerous cofactors that interact with MYC and the target genes that are regulated by MYC as a means of understanding the molecular mechanisms controlling its diverse roles. Despite significant advances and perhaps because the amount of information learned about MYC is overwhelming, there has been little consensus on the molecular functions of MYC that mediate its critical biological roles. In this perspective, the major MYC cofactors that regulate the various transcriptional activities of MYC, including canonical and noncanonical transactivation and transcriptional repression, will be reviewed and a model of how these transcriptional mechanisms control MYC-mediated proliferation, apoptosis, and tumorigenesis will be presented. The basis of the model is that a variety of cofactors form dynamic MYC transcriptional complexes that can switch the molecular and biological functions of MYC to yield a diverse range of outcomes in a cell-type- and context-dependent fashion.
Collapse
Affiliation(s)
- Stephen R Hann
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2175
| |
Collapse
|
30
|
BET and HDAC inhibitors induce similar genes and biological effects and synergize to kill in Myc-induced murine lymphoma. Proc Natl Acad Sci U S A 2014; 111:E2721-30. [PMID: 24979794 DOI: 10.1073/pnas.1406722111] [Citation(s) in RCA: 178] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The bromodomain and extraterminal (BET) domain family of proteins binds to acetylated lysines on histones and regulates gene transcription. Recently, BET inhibitors (BETi) have been developed that show promise as potent anticancer drugs against various solid and hematological malignancies. Here we show that the structurally novel and orally bioavailable BET inhibitor RVX2135 inhibits proliferation and induces apoptosis of lymphoma cells arising in Myc-transgenic mice in vitro and in vivo. We find that BET inhibition exhibits broad transcriptional effects in Myc-transgenic lymphoma cells affecting many transcription factor networks. By examining the genes induced by BETi, which have largely been ignored to date, we discovered that these were similar to those induced by histone deacetylase inhibitors (HDACi). HDACi also induced cell-cycle arrest and cell death of Myc-induced murine lymphoma cells and synergized with BETi. Our data suggest that BETi sensitize Myc-overexpressing lymphoma cells partly by inducing HDAC-silenced genes, and suggest synergistic and therapeutic combinations by targeting the genetic link between BETi and HDACi.
Collapse
|
31
|
Myc and its interactors take shape. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2014; 1849:469-83. [PMID: 24933113 DOI: 10.1016/j.bbagrm.2014.06.002] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 06/03/2014] [Accepted: 06/04/2014] [Indexed: 12/11/2022]
Abstract
The Myc oncoprotein is a key contributor to the development of many human cancers. As such, understanding its molecular activities and biological functions has been a field of active research since its discovery more than three decades ago. Genome-wide studies have revealed Myc to be a global regulator of gene expression. The identification of its DNA-binding partner protein, Max, launched an area of extensive research into both the protein-protein interactions and protein structure of Myc. In this review, we highlight key insights with respect to Myc interactors and protein structure that contribute to the understanding of Myc's roles in transcriptional regulation and cancer. Structural analyses of Myc show many critical regions with transient structures that mediate protein interactions and biological functions. Interactors, such as Max, TRRAP, and PTEF-b, provide mechanistic insight into Myc's transcriptional activities, while others, such as ubiquitin ligases, regulate the Myc protein itself. It is appreciated that Myc possesses a large interactome, yet the functional relevance of many interactors remains unknown. Here, we discuss future research trends that embrace advances in genome-wide and proteome-wide approaches to systematically elucidate mechanisms of Myc action. This article is part of a Special Issue entitled: Myc proteins in cell biology and pathology.
Collapse
|
32
|
Abstract
The MYC oncoprotein is an essential transcription factor that regulates the expression of many genes involved in cell growth, proliferation, and metabolic pathways. Thus, it is important to keep MYC activity in check in normal cells in order to avoid unwanted oncogenic changes. Normal cells have adapted several ways to control MYC levels, and these mechanisms can be disrupted in cancer cells. One of the major ways in which MYC levels are controlled in cells is through targeted degradation by the ubiquitin-proteasome system (UPS). Here, we discuss the role of the UPS in the regulation of MYC protein levels and review some of the many proteins that have been shown to regulate MYC protein stability. In addition, we discuss how this relates to MYC transcriptional activity, human cancers, and therapeutic targeting.
Collapse
Affiliation(s)
- Amy S Farrell
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon 97239
| | | |
Collapse
|
33
|
Abstract
The MYC family of proteins is a group of basic-helix-loop-helix-leucine zipper transcription factors that feature prominently in cancer. Overexpression of MYC is observed in the vast majority of human malignancies and promotes an extraordinary set of changes that impact cell proliferation, growth, metabolism, DNA replication, cell cycle progression, cell adhesion, differentiation, and metastasis. The purpose of this review is to introduce the reader to the mammalian family of MYC proteins, highlight important functional properties that endow them with their potent oncogenic potential, describe their mechanisms of action and of deregulation in cancer cells, and discuss efforts to target the unique properties of MYC, and of MYC-driven tumors, to treat cancer.
Collapse
|
34
|
Benetatos L, Vartholomatos G, Hatzimichael E. Polycomb group proteins and MYC: the cancer connection. Cell Mol Life Sci 2014; 71:257-69. [PMID: 23897499 PMCID: PMC11113285 DOI: 10.1007/s00018-013-1426-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/12/2013] [Accepted: 07/15/2013] [Indexed: 01/07/2023]
Abstract
Polycomb group proteins (PcGs) are transcriptional repressors involved in physiological processes whereas PcG deregulation might result in oncogenesis. MYC oncogene is able to regulate gene transcription, proliferation, apoptosis, and malignant transformation. MYC deregulation might result in tumorigenesis with tumor maintenance properties in both solid and blood cancers. Although the interaction of PcG and MYC in cancer was described years ago, new findings are reported every day to explain the exact mechanisms and results of such interactions. In this review, we summarize recent data on the PcG and MYC interactions in cancer, and the putative involvement of microRNAs in the equation.
Collapse
Affiliation(s)
- Leonidas Benetatos
- Blood Bank, General Hospital of Preveza, Selefkias 2, 48100, Preveza, Greece,
| | | | | |
Collapse
|
35
|
Pin1 regulates the dynamics of c-Myc DNA binding to facilitate target gene regulation and oncogenesis. Mol Cell Biol 2013; 33:2930-49. [PMID: 23716601 DOI: 10.1128/mcb.01455-12] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The Myc oncoprotein is considered a master regulator of gene transcription by virtue of its ability to modulate the expression of a large percentage of all genes. However, mechanisms that direct Myc's recruitment to DNA and target gene selection to elicit specific cellular functions have not been well elucidated. Here, we report that the Pin1 prolyl isomerase enhances recruitment of serine 62-phosphorylated Myc and its coactivators to select promoters during gene activation, followed by promoting Myc's release associated with its degradation. This facilitates Myc's activation of genes involved in cell growth and metabolism, resulting in enhanced proproliferative activity, even while controlling Myc levels. In cancer cells with impaired Myc degradation, Pin1 still enhances Myc DNA binding, although it no longer facilitates Myc degradation. Thus, we find that Pin1 and Myc are cooverexpressed in cancer, and this drives a gene expression pattern that we show is enriched in poor-outcome breast cancer subtypes. This study provides new insight into mechanisms regulating Myc DNA binding and oncogenic activity, it reveals a novel role for Pin1 in the regulation of transcription factors, and it elucidates a mechanism that can contribute to oncogenic cooperation between Pin1 and Myc.
Collapse
|