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Ferrad M, Ghazzaui N, Issaoui H, Cook-Moreau J, Denizot Y. Mouse Models of c-myc Deregulation Driven by IgH Locus Enhancers as Models of B-Cell Lymphomagenesis. Front Immunol 2020; 11:1564. [PMID: 32793219 PMCID: PMC7390917 DOI: 10.3389/fimmu.2020.01564] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 06/15/2020] [Indexed: 01/18/2023] Open
Abstract
Chromosomal translocations linking various oncogenes to transcriptional enhancers of the immunoglobulin heavy chain (IgH) locus are often implicated as the cause of B-cell malignancies. Two major IgH transcriptional enhancers have been reported so far. The Eμ enhancer located upstream of the Cμ gene controls early events in B-cell maturation such as VDJ recombination. The 3' regulatory region (3'RR) located downstream from the Cα gene controls late events in B-cell maturation such as IgH transcription, somatic hypermutation, and class switch recombination. Convincing demonstrations of the essential contributions of both Eμ and 3'RR in B-cell lymphomagenesis have been provided by transgenic and knock-in animal models which bring the oncogene c-myc under Eμ/3'RR transcriptional control. This short review summarizes the different mouse models so far available and their interests/limitations for progress in our understanding of human c-myc-induced B-cell lymphomagenesis.
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Affiliation(s)
- Melissa Ferrad
- Inserm U1262, UMR CNRS 7276, Equipe Labellisée LIGUE 2018, Université de Limoges, Limoges, France
| | - Nour Ghazzaui
- Inserm U1262, UMR CNRS 7276, Equipe Labellisée LIGUE 2018, Université de Limoges, Limoges, France
| | - Hussein Issaoui
- Inserm U1262, UMR CNRS 7276, Equipe Labellisée LIGUE 2018, Université de Limoges, Limoges, France
| | - Jeanne Cook-Moreau
- Inserm U1262, UMR CNRS 7276, Equipe Labellisée LIGUE 2018, Université de Limoges, Limoges, France
| | - Yves Denizot
- Inserm U1262, UMR CNRS 7276, Equipe Labellisée LIGUE 2018, Université de Limoges, Limoges, France
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Ghazzaui N, Issaoui H, Ferrad M, Carrion C, Cook-Moreau J, Denizot Y, Boyer F. Eμ and 3'RR transcriptional enhancers of the IgH locus cooperate to promote c-myc-induced mature B-cell lymphomas. Blood Adv 2020; 4:28-39. [PMID: 31899800 PMCID: PMC6960469 DOI: 10.1182/bloodadvances.2019000845] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Accepted: 11/12/2019] [Indexed: 01/18/2023] Open
Abstract
Numerous B-cell lymphomas feature translocations linking oncogenes to different locations in the immunoglobulin heavy chain (IgH) locus. During Burkitt lymphoma (BL), IgH breakpoints for c-myc translocation stand either close to JH segments or within switch regions. Transcription, accessibility, and remodeling of the IgH locus are under the control of the 2 potent cis-acting enhancer elements: Eμ and the 3' regulatory region (3'RR). To ensure their respective contributions to oncogene deregulation in the context of the endogenous IgH locus, we studied transgenic mice harboring a knock-in of c-myc in various positions of the IgH locus (3' to JH segments, 5' to Cμ with Eμ deletion and Cα). The observed spectrum of tumors, kinetics of emergence, and transcriptome analysis provide strong evidence that both Eμ and 3'RR deregulate c-myc and cooperate together to promote B-cell lymphomagenesis. Transgenics mimicking endemic BL (with c-myc placed 3' to JH segments) exhibited the highest rate of B-cell lymphoma emergence, the highest Ki67 index of proliferation, and the highest transcriptomic similarities to human BL. The 3'RR enhancer alone deregulated c-myc and initiated the development of BL-like lymphomas, suggesting that its targeting would be of therapeutic interest to reduce c-myc oncogenicity in vivo.
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Affiliation(s)
- Nour Ghazzaui
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 7276, Institut National de la Santé et de la Recherche Médicale U1262, Equipe Labellisée Ligue 2018, Université de Limoges, Limoges, France
| | - Hussein Issaoui
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 7276, Institut National de la Santé et de la Recherche Médicale U1262, Equipe Labellisée Ligue 2018, Université de Limoges, Limoges, France
| | - Mélissa Ferrad
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 7276, Institut National de la Santé et de la Recherche Médicale U1262, Equipe Labellisée Ligue 2018, Université de Limoges, Limoges, France
| | - Claire Carrion
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 7276, Institut National de la Santé et de la Recherche Médicale U1262, Equipe Labellisée Ligue 2018, Université de Limoges, Limoges, France
| | - Jeanne Cook-Moreau
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 7276, Institut National de la Santé et de la Recherche Médicale U1262, Equipe Labellisée Ligue 2018, Université de Limoges, Limoges, France
| | - Yves Denizot
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 7276, Institut National de la Santé et de la Recherche Médicale U1262, Equipe Labellisée Ligue 2018, Université de Limoges, Limoges, France
| | - François Boyer
- Unité Mixte de Recherche Centre National de la Recherche Scientifique 7276, Institut National de la Santé et de la Recherche Médicale U1262, Equipe Labellisée Ligue 2018, Université de Limoges, Limoges, France
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The IgH 3' regulatory region and c-myc-induced B-cell lymphomagenesis. Oncotarget 2018; 8:7059-7067. [PMID: 27729620 PMCID: PMC5351691 DOI: 10.18632/oncotarget.12535] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 10/05/2016] [Indexed: 01/18/2023] Open
Abstract
Deregulation and mutations of c-myc have been reported in multiple mature B-cell malignancies such as Burkitt lymphoma, myeloma and plasma cell lymphoma. After translocation into the immunoglobulin heavy chain (IgH) locus, c-myc is constitutively expressed under the control of active IgH cis-regulatory enhancers. Those located in the IgH 3 regulatory region (3RR) are master control elements of transcription. Over the past decade numerous convincing demonstrations of 3RRs contribution to mature c-myc-induced lymphomagenesis have been made using transgenic models with various types of IgH-c-myc translocations and transgenes. This review highlights how IgH 3RR physiological functions play a critical role in c-myc deregulation during lymphomagenesis.
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Efficient role of IgH 3' regulatory region deficient B-cells in the development of oil granulomas. Oncotarget 2018; 7:38741-38749. [PMID: 27231852 PMCID: PMC5122425 DOI: 10.18632/oncotarget.9588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 04/29/2016] [Indexed: 01/18/2023] Open
Abstract
Functional B-cells are essential for the formation of oil granulomas. The IgH 3′ regulatory region (3′RR) activates important check-points during B-cell maturation. We investigated if 3′RR-deficient B-cells remain efficient to develop oil granulomas in response to pristine. B-cells expressing an IgH 3′RR-deficient allele were similarly recruited to wild type allele expressing B-cells in the granuloma. No differences were observed between 3′RR-deficient mice and control mice for granuloma numbers, cellular composition and ability to express mRNA transcripts for several pro- and anti-inflammatory cytokines. Altogether these results suggest a normal role for 3′RR-deficient B-cells in the development of an acute B-cell-mediated inflammatory response.
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Saintamand A, Ghazzaui N, Issaoui H, Denizot Y. [The IgH 3'RR: Doctor Jekyll and Mister Hyde of B-cell maturation and lymphomagenesis]. Med Sci (Paris) 2017; 33:963-970. [PMID: 29200394 DOI: 10.1051/medsci/20173311013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The four transcriptional enhancers located in the 3' regulatory region (3'RR) of the IgH locus control the late phases of B-cell maturation, namely IgH locus transcription, somatic hypermutation and class switch recombination. Doctor Jekyll by nature, the 3'RR acts as Mister Hyde in case of oncogenic translocation at the IgH locus taking under its transcriptional control the translocated oncogene. The aim of this review is to show this duality on the basis of the latest scientific advances in the structure and function of the 3'RR and to hIghlight the targeting of the 3'RR as a potential therapeutic approach in mature B-cell lymphomas.
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Affiliation(s)
- Alexis Saintamand
- UMR CNRS 7276, Université de Limoges, rue Pr Descottes, 87025 Limoges, France
| | - Nour Ghazzaui
- UMR CNRS 7276, Université de Limoges, rue Pr Descottes, 87025 Limoges, France
| | - Hussein Issaoui
- UMR CNRS 7276, Université de Limoges, rue Pr Descottes, 87025 Limoges, France
| | - Yves Denizot
- UMR CNRS 7276, Université de Limoges, rue Pr Descottes, 87025 Limoges, France
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Saintamand A, Garot A, Saad F, Moulinas R, Denizot Y. Pre-germinal center origin for mature mouse B cell lymphomas: a major discrepancy with human mature lymphomas. Cell Cycle 2016; 14:3656-8. [PMID: 26654599 DOI: 10.1080/15384101.2015.1093708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
| | - Armand Garot
- a Université de Limoges; CRIBL; UMR CNRS 7276 ; Limoges , France
| | - Faten Saad
- a Université de Limoges; CRIBL; UMR CNRS 7276 ; Limoges , France
| | - Rémi Moulinas
- b GENOLIM plateform; Université de Limoges ; Limoges, France
| | - Yves Denizot
- a Université de Limoges; CRIBL; UMR CNRS 7276 ; Limoges , France
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Saintamand A, Rouaud P, Garot A, Saad F, Carrion C, Oblet C, Cogné M, Pinaud E, Denizot Y. The IgH 3' regulatory region governs μ chain transcription in mature B lymphocytes and the B cell fate. Oncotarget 2016; 6:4845-52. [PMID: 25742787 PMCID: PMC4467119 DOI: 10.18632/oncotarget.3010] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 12/21/2014] [Indexed: 12/11/2022] Open
Abstract
We report that the IgH 3' regulatory region (3'RR) has no role on μ chain transcription and pre-BCR expression in B cell progenitors. In contrast, analysis of heterozygous IgH aΔ3'RR/bwt mice indicated that the 3'RR controls μ chain transcripts in mature splenocytes and impacts membrane IgM density without obvious effect on BCR signals (colocalisation with lipid rafts and phosphorylation of Erk and Akt after BCR crosslinking). Deletion of the 3'RR modulates the B cell fate to less marginal zone B cells. In conclusion, the 3'RR is dispensable for pre-BCR expression and necessary for optimal commitments toward the marginal zone B cell fate. These results reinforce the concept of a dual regulation of the IgH locus transcription and accessibility by 5' elements at immature B cell stages, and by the 3'RR as early as the resting mature B cell stage and then along further activation and differentiation.
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Affiliation(s)
| | | | | | | | | | | | - Michel Cogné
- CNRS, CRIBL, UMR 7276, Limoges, France.,Université de Limoges, CRIBL, UMR 7276, Limoges, France.,Institut Universitaire de France, Paris, France
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Saad F, Saintamand A, Cogné M, Denizot Y. The IgH 3' regulatory region influences lymphomagenesis in Igλ-Myc mice. Oncotarget 2015; 6:20302-11. [PMID: 25980500 PMCID: PMC4653006 DOI: 10.18632/oncotarget.3963] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 04/10/2015] [Indexed: 01/11/2023] Open
Abstract
The IgH 3′regulatory region (3′RR), encompassing the four transcriptional enhancers hs3a-hs1,2-hs3b-hs4, has a key role on class switch recombination, somatic hypermutation, IgH transcription and B-cell fate. In plasma cells, transcribed IgH and IgL loci often colocalized in transcription factories and an IgL transcription defect might translate into lowered IgH transcription. We explored whether the 3′RR would affect lymphomagenesis in Igλ-Myc transgenic mice prone to lymphoproliferations. Breeding Igλ-Myc transgenics in a background deficient for the 3′RR influences lymphomagenesis toward less mature lymphomas (16% vs 54%, p = 0.01, Z test for two population proportions). In a 3′RR-deficient background mature tumors less often expressed the CD43 antigen (54% vs 0%, p = 0.02), a membrane glycoprotein expressed on activated mature B-cells. In contrast, in a 3′RR-deficient background tumors more often expressed the CD5 antigen (32% vs 12%, p = 0.05) that may serve to control autoimmunity and that is suspected to play a role in leukemic transformation. Lymphoma myc transcript levels, the Ki67 index of proliferation, the clonality, the usage of V(D)J segments, and their somatic hypermutation status were not affected in the 3′RR-deficient background. In conclusion, most probably through its action during the maturation process, the 3′RR can influence lymphomagenesis even when not linked with an oncogene.
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Affiliation(s)
- Faten Saad
- CNRS UMR 7276, CRIBL, Université de Limoges, Limoges, France
| | | | - Michel Cogné
- CNRS UMR 7276, CRIBL, Université de Limoges, Limoges, France
| | - Yves Denizot
- CNRS UMR 7276, CRIBL, Université de Limoges, Limoges, France
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Amin R, Marfak A, Pangault C, Oblet C, Chanut A, Tarte K, Denizot Y, Cogné M. The class-specific BCR tonic signal modulates lymphomagenesis in a c-myc deregulation transgenic model. Oncotarget 2015; 5:8995-9006. [PMID: 25229630 PMCID: PMC4253413 DOI: 10.18632/oncotarget.2297] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Deregulation of c-myc by translocation onto immunoglobulin (Ig) loci can promote B cell malignant proliferations with phenotypes as diverse as acute lymphoid leukemia, Burkitt lymphoma, diffuse large B cell lymphoma, myeloma… The B cell receptor (BCR) normally providing tonic signals for cell survival and mitogenic responses to antigens, can also contribute to lymphomagenesis upon sustained ligand binding or activating mutations. BCR signaling varies among cell compartments and BCR classes. For unknown reasons, some malignancies associate with expression of either IgM or class-switched Ig. We explored whether an IgA BCR, with strong tonic signaling, would affect lymphomagenesis in c-myc IgH 3′RR transgenic mice prone to lymphoproliferations. Breeding c-myc transgenics in a background where IgM expression was replaced with IgA delayed lymphomagenesis. By comparison to single c-myc transgenics, lymphomas from double mutant animals were more differentiated and less aggressive, with an altered transcriptional program. Larger tumor cells more often expressed CD43 and CD138, which culminated in a plasma cell phenotype in 10% of cases. BCR class-specific signals thus appear to modulate lymphomagenesis and may partly explain the observed association of specific Ig classes with human B cell malignancies of differential phenotype, progression and prognosis.
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Affiliation(s)
- Rada Amin
- Centre National de la Recherche Scientifique, Limoges, France. Université de Limoges, Limoges, France. INSERM UMR U917, Rennes, France
| | | | | | - Christelle Oblet
- Centre National de la Recherche Scientifique, Limoges, France. Université de Limoges, Limoges, France
| | - Aurélie Chanut
- Centre National de la Recherche Scientifique, Limoges, France. Université de Limoges, Limoges, France
| | | | - Yves Denizot
- Centre National de la Recherche Scientifique, Limoges, France. Université de Limoges, Limoges, France
| | - Michel Cogné
- Centre National de la Recherche Scientifique, Limoges, France. Université de Limoges, Limoges, France
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Structure and Function of p53-DNA Complexes with Inactivation and Rescue Mutations: A Molecular Dynamics Simulation Study. PLoS One 2015; 10:e0134638. [PMID: 26244575 PMCID: PMC4526489 DOI: 10.1371/journal.pone.0134638] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 07/10/2015] [Indexed: 01/10/2023] Open
Abstract
The tumor suppressor protein p53 can lose its function upon DNA-contact mutations (R273C and R273H) in the core DNA-binding domain. The activity can be restored by second-site suppressor or rescue mutations (R273C_T284R, R273H_T284R, and R273H_S240R). In this paper, we elucidate the structural and functional consequence of p53 proteins upon DNA-contact mutations and rescue mutations and the underlying mechanisms at the atomic level by means of molecular dynamics simulations. Furthermore, we also apply the docking approach to investigate the binding phenomena between the p53 protein and DNA upon DNA-contact mutations and rescue mutations. This study clearly illustrates that, due to DNA-contact mutants, the p53 structure loses its stability and becomes more rigid than the native protein. This structural loss might affect the p53-DNA interaction and leads to inhibition of the cancer suppression. Rescue mutants (R273C_T284R, R273H_T284R and R273H_S240R) can restore the functional activity of the p53 protein upon DNA-contact mutations and show a good interaction between the p53 protein and a DNA molecule, which may lead to reactivate the cancer suppression function. Understanding the effects of p53 cancer and rescue mutations at the molecular level will be helpful for designing drugs for p53 associated cancer diseases. These drugs should be designed so that they can help to inhibit the abnormal function of the p53 protein and to reactivate the p53 function (cell apoptosis) to treat human cancer.
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Saintamand A, Rouaud P, Saad F, Rios G, Cogné M, Denizot Y. Elucidation of IgH 3′ region regulatory role during class switch recombination via germline deletion. Nat Commun 2015; 6:7084. [DOI: 10.1038/ncomms8084] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 04/01/2015] [Indexed: 02/06/2023] Open
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Saintamand A, Saad F, Denizot Y. A new 3'RR regulatory role during lymphomagenesis. Cell Cycle 2015; 14:1987-8. [PMID: 25927676 DOI: 10.1080/15384101.2015.1046789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
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Saintamand A, Saad F, Denizot Y. 3'RR targeting in lymphomagenesis: a promising strategy? Cell Cycle 2015; 14:789-90. [PMID: 25790089 DOI: 10.1080/15384101.2015.1010964] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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Targeting the oncogene B lymphoma deregulator IgH 3' regulatory region does not impede the in vivo inflammatory response in mice. Oncoscience 2014; 1:591-8. [PMID: 25594069 PMCID: PMC4278336 DOI: 10.18632/oncoscience.81] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 09/14/2014] [Indexed: 01/10/2023] Open
Abstract
The IgH 3′ regulatory region (3′RR), encompassing the four transcriptional enhancers hs3a-hs1,2-hs3b-hs4, is a potent lymphoma oncogene deregulator but its role in B cell-mediated inflammatory responses is unknown. We investigated the 3′RR involvement in the in vivo pristane-induced inflammatory response in BALB/c mice. The lack of the 3′RR in BALB/c mice had no wide effect on the incidence, the kinetic of development and the cellular composition of peritoneal ascites. Ascite pro-inflammatory cytokines levels (IL-6, IL-21, IL-12/23, TNF-α) were unchanged while anti-inflammatory cytokines levels (IL-10, interferon-γ) were slightly increased in 3′RR-deficient BALB/c mice as compared to wt BALB/c mice. In conclusion, the 3′RR is dispensable for the efficient recruitment of immune cells and the normal development of an inflammatory response in the in vivo pristane-induced inflammatory model. The 3′RR might be considered as a potential suitable target for anti-lymphoma pharmacological therapy without potent adverse effect on normal immune and inflammatory responses.
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DeMicco A, Yang-Iott K, Bassing CH. Somatic inactivation of Tp53 in hematopoietic stem cells or thymocytes predisposes mice to thymic lymphomas with clonal translocations. Cell Cycle 2013; 12:3307-16. [PMID: 24036547 DOI: 10.4161/cc.26299] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
TP53 protects cells from transformation by responding to stresses including aneuploidy and DNA double-strand breaks (DSBs). TP53 induces apoptosis of lymphocytes with persistent DSBs at antigen receptor loci and other genomic loci to prevent these lesions from generating oncogenic translocations. Despite this critical function of TP53, germline Tp53(-/-) mice succumb to immature T-cell (thymic) lymphomas that exhibit aneuploidy and lack clonal translocations. However, Tp53(-/-) mice occasionally develop B lineage lymphomas and Tp53 deletion in pro-B cells causes lymphomas with oncogenic immunoglobulin (Ig) locus translocations. In addition, human lymphoid cancers with somatic TP53 inactivation often harbor oncogenic IG or T-cell receptor (TCR) locus translocations. To determine whether somatic Tp53 inactivation unmasks translocations or alters the frequency of B lineage tumors in mice, we generated and analyzed mice with conditional Tp53 deletion initiating in hematopoietic stem cells (HSCs) or in lineage-committed thymocytes. Median tumor-free survival of each strain was similar to the lifespan of Tp53(-/-) mice. Mice with HSC deletion of Tp53 predominantly succumbed to thymic lymphomas with clonal translocations not involving Tcr loci; however, these mice occasionally developed mature B-cell lymphomas that harbored clonal Ig translocations. Deletion of Tp53 in thymocytes caused thymic lymphomas with aneuploidy and/or clonal translocations, including oncogenic Tcr locus translocations. Our data demonstrate that the developmental stage of Tp53 inactivation affects karyotypes of lymphoid malignancies in mice where somatic deletion of Tp53 initiating in thymocytes is sufficient to cause thymic lymphomas with oncogenic translocations.
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Affiliation(s)
- Amy DeMicco
- Cell and Molecular Biology Graduate Group; Perelman School of Medicine of the University of Pennsylvania; Philadelphia, PA USA; Division of Cancer Pathobiology; Department of Pathology and Laboratory Medicine; Center for Childhood Cancer Research; Children's Hospital of Philadelphia Research Institute; Philadelphia, PA USA; Abramson Family Cancer Research Institute; Perelman School of Medicine of the University of Pennsylvania; Philadelphia, PA USA
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Chillemi G, Davidovich P, D'Abramo M, Mametnabiev T, Garabadzhiu AV, Desideri A, Melino G. Molecular dynamics of the full-length p53 monomer. Cell Cycle 2013; 12:3098-108. [PMID: 23974096 DOI: 10.4161/cc.26162] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The p53 protein is frequently mutated in a very large proportion of human tumors, where it seems to acquire gain-of-function activity that facilitates tumor onset and progression. A possible mechanism is the ability of mutant p53 proteins to physically interact with other proteins, including members of the same family, namely p63 and p73, inactivating their function. Assuming that this interaction might occurs at the level of the monomer, to investigate the molecular basis for this interaction, here, we sample the structural flexibility of the wild-type p53 monomeric protein. The results show a strong stability up to 850 ns in the DNA binding domain, with major flexibility in the N-terminal transactivations domains (TAD1 and TAD2) as well as in the C-terminal region (tetramerization domain). Several stable hydrogen bonds have been detected between N-terminal or C-terminal and DNA binding domain, and also between N-terminal and C-terminal. Essential dynamics analysis highlights strongly correlated movements involving TAD1 and the proline-rich region in the N-terminal domain, the tetramerization region in the C-terminal domain; Lys120 in the DNA binding region. The herein presented model is a starting point for further investigation of the whole protein tetramer as well as of its mutants.
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Gogolin S, Ehemann V, Becker G, Brueckner LM, Dreidax D, Bannert S, Nolte I, Savelyeva L, Bell E, Westermann F. CDK4 inhibition restores G(1)-S arrest in MYCN-amplified neuroblastoma cells in the context of doxorubicin-induced DNA damage. Cell Cycle 2013; 12:1091-104. [PMID: 23462184 DOI: 10.4161/cc.24091] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Relapse with drug-resistant disease is the main cause of death in MYCN-amplified neuroblastoma patients. MYCN-amplified neuroblastoma cells in vitro are characterized by a failure to arrest at the G(1)-S checkpoint after irradiation- or drug-induced DNA damage. We show that several MYCN-amplified cell lines harbor additional chromosomal aberrations targeting p53 and/or pRB pathway components, including CDK4/CCND1/MDM2 amplifications, p16INK4A/p14ARF deletions or TP53 mutations. Cells with these additional aberrations undergo significantly lower levels of cell death after doxorubicin treatment compared with MYCN-amplified cells, with no additional mutations in these pathways. In MYCN-amplified cells CDK4 expression is elevated, increasing the competition between CDK4 and CDK2 for binding p21. This results in insufficient p21 to inhibit CDK2, leading to high CDK4 and CDK2 kinase activity upon doxorubicin treatment. CDK4 inhibition by siRNAs, selective small compounds or p19(INK4D) overexpression partly restored G(1)-S arrest, delayed S-phase progression and reduced cell viability upon doxorubicin treatment. Our results suggest a specific function of p19(INK4D), but not p16(INK4A), in sensitizing MYCN-amplified cells with a functional p53 pathway to doxorubicin-induced cell death. In summary, the CDK4/cyclin D-pRB axis is altered in MYCN-amplified cells to evade a G(1)-S arrest after doxorubicin-induced DNA damage. Additional chromosomal aberrations affecting the p53-p21 and CDK4-pRB axes compound the effects of MYCN on the G(1) checkpoint and reduce sensitivity to cell death after doxorubicin treatment. CDK4 inhibition partly restores G(1)-S arrest and sensitizes cells to doxorubicin-mediated cell death in MYCN-amplified cells with an intact p53 pathway.
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Affiliation(s)
- Sina Gogolin
- Division of Tumor Genetics, German Cancer Research Center (DKFZ), Heidelberg, Germany
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