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Rozanska A, Cerna-Chavez R, Queen R, Collin J, Zerti D, Dorgau B, Beh CS, Davey T, Coxhead J, Hussain R, Al-Aama J, Steel DH, Benvenisty N, Armstrong L, Parulekar M, Lako M. pRB-Depleted Pluripotent Stem Cell Retinal Organoids Recapitulate Cell State Transitions of Retinoblastoma Development and Suggest an Important Role for pRB in Retinal Cell Differentiation. Stem Cells Transl Med 2022; 11:415-433. [PMID: 35325233 PMCID: PMC9052432 DOI: 10.1093/stcltm/szac008] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/19/2021] [Indexed: 11/12/2022] Open
Abstract
Retinoblastoma (Rb) is a childhood cancer of the developing retina, accounting for up to 17% of all tumors in infancy. To gain insights into the transcriptional events of cell state transitions during Rb development, we established 2 disease models via retinal organoid differentiation of a pRB (retinoblastoma protein)-depleted human embryonic stem cell line (RB1-null hESCs) and a pRB patient-specific induced pluripotent (iPSC) line harboring a RB1 biallelic mutation (c.2082delC). Both models were characterized by pRB depletion and accumulation of retinal progenitor cells at the expense of amacrine, horizontal and retinal ganglion cells, which suggests an important role for pRB in differentiation of these cell lineages. Importantly, a significant increase in the fraction of proliferating cone precursors (RXRγ+Ki67+) was observed in both pRB-depleted organoid models, which were defined as Rb-like clusters by single-cell RNA-Seq analysis. The pRB-depleted retinal organoids displayed similar features to Rb tumors, including mitochondrial cristae aberrations and rosette-like structures, and were able to undergo cell growth in an anchorage-independent manner, indicative of cell transformation in vitro. In both models, the Rb cones expressed retinal ganglion and horizontal cell markers, a novel finding, which could help to better characterize these tumors with possible therapeutic implications. Application of Melphalan, Topotecan, and TW-37 led to a significant reduction in the fraction of Rb proliferating cone precursors, validating the suitability of these in vitro models for testing novel therapeutics for Rb.
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Affiliation(s)
- Agata Rozanska
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | | | - Rachel Queen
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Joseph Collin
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Darin Zerti
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Birthe Dorgau
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Chia Shyan Beh
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Tracey Davey
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Jonathan Coxhead
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Rafiqul Hussain
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Jumana Al-Aama
- Faculty of Medicine, King Abdulaziz University, Riyadh, Saudi Arabia
| | - David H Steel
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Nissim Benvenisty
- The Azrieli Center for Stem Cells and Genetic Research, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Lyle Armstrong
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
| | - Manoj Parulekar
- Birmingham Women's and Children NHS Foundation Trust, Birmingham, UK
| | - Majlinda Lako
- Biosciences Institute, Newcastle University, Newcastle upon Tyne, UK
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2
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Zheng C, Schneider JW, Hsieh J. Role of RB1 in human embryonic stem cell-derived retinal organoids. Dev Biol 2020; 462:197-207. [PMID: 32197890 DOI: 10.1016/j.ydbio.2020.03.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 02/21/2020] [Accepted: 03/11/2020] [Indexed: 01/09/2023]
Abstract
Three-dimensional (3D) organoid models derived from human pluripotent stem cells provide a platform for studying human development and understanding disease mechanisms. Most studies that examine biallelic inactivation of the cell cycle regulator Retinoblastoma 1 (RB1) and the link to retinoblastoma is in mice, however, less is known regarding the pathophysiological role of RB1 during human retinal development. To study the role of RB1 in early human retinal development and tumor formation, we generated retinal organoids from CRISPR/Cas9-derived RB1-null human embryonic stem cells (hESCs). We showed that RB is abundantly expressed in retinal progenitor cells in retinal organoids and loss of RB1 promotes S-phase entry. Furthermore, loss of RB1 resulted in widespread apoptosis and reduced the number of photoreceptor, ganglion, and bipolar cells. Interestingly, RB1 mutation in retinal organoids did not result in retinoblastoma formation in vitro or in the vitreous body of NOD/SCID immunodeficient mice. Together, our work identifies a crucial function for RB1 in human retinal development and suggests that RB1 deletion alone is not sufficient for tumor development, at least in human retinal organoids.
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Affiliation(s)
- Canbin Zheng
- Department of Molecular Biology and Hamon Center for Regenerative Science and Medicine, UT Southwestern Medical Center, Dallas, TX, 75390, USA; Department of Orthopedic and Microsurgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, GD, 510080, China
| | - Jay W Schneider
- Wanek Program for Hypoplastic Left Heart Syndrome, Mayo Clinic, Rochester, Minnesota 55905, USA
| | - Jenny Hsieh
- Department of Biology and Brain Health Consortium, The University of Texas at San Antonio, San Antonio, TX, 78249, USA.
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Munier FL, Beck-Popovic M, Chantada GL, Cobrinik D, Kivelä TT, Lohmann D, Maeder P, Moll AC, Carcaboso AM, Moulin A, Schaiquevich P, Bergin C, Dyson PJ, Houghton S, Puccinelli F, Vial Y, Gaillard MC, Stathopoulos C. Conservative management of retinoblastoma: Challenging orthodoxy without compromising the state of metastatic grace. "Alive, with good vision and no comorbidity". Prog Retin Eye Res 2019; 73:100764. [PMID: 31173880 DOI: 10.1016/j.preteyeres.2019.05.005] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 05/25/2019] [Accepted: 05/29/2019] [Indexed: 12/21/2022]
Abstract
Retinoblastoma is lethal by metastasis if left untreated, so the primary goal of therapy is to preserve life, with ocular survival, visual preservation and quality of life as secondary aims. Historically, enucleation was the first successful therapeutic approach to decrease mortality, followed over 100 years ago by the first eye salvage attempts with radiotherapy. This led to the empiric delineation of a window for conservative management subject to a "state of metastatic grace" never to be violated. Over the last two decades, conservative management of retinoblastoma witnessed an impressive acceleration of improvements, culminating in two major paradigm shifts in therapeutic strategy. Firstly, the introduction of systemic chemotherapy and focal treatments in the late 1990s enabled radiotherapy to be progressively abandoned. Around 10 years later, the advent of chemotherapy in situ, with the capitalization of new routes of targeted drug delivery, namely intra-arterial, intravitreal and now intracameral injections, allowed significant increase in eye preservation rate, definitive eradication of radiotherapy and reduction of systemic chemotherapy. Here we intend to review the relevant knowledge susceptible to improve the conservative management of retinoblastoma in compliance with the "state of metastatic grace", with particular attention to (i) reviewing how new imaging modalities impact the frontiers of conservative management, (ii) dissecting retinoblastoma genesis, growth patterns, and intraocular routes of tumor propagation, (iii) assessing major therapeutic changes and trends, (iv) proposing a classification of relapsing retinoblastoma, (v) examining treatable/preventable disease-related or treatment-induced complications, and (vi) appraising new therapeutic targets and concepts, as well as liquid biopsy potentiality.
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Affiliation(s)
- Francis L Munier
- Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland.
| | - Maja Beck-Popovic
- Unit of Pediatric Hematology-Oncology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Guillermo L Chantada
- Hemato-Oncology Service, Hospital JP Garrahan, Buenos Aires, Argentina; Pediatric Hematology and Oncology, Hospital Sant Joan de Deu, Barcelona, Spain; Institut de Recerca Sant Joan de Deu, Barcelona, Spain
| | - David Cobrinik
- The Vision Center and The Saban Research Institute, Children's Hospital Los Angeles, Los Angeles, CA, USA; USC Roski Eye Institute, Department of Biochemistry & Molecular Medicine, Norris Comprehensive Cancer Center, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Tero T Kivelä
- Department of Ophthalmology, Ocular Oncology and Pediatric Ophthalmology Services, Helsinki University Hospital, Helsinki, Finland
| | - Dietmar Lohmann
- Eye Oncogenetics Research Group, Institute of Human Genetics, University Hospital Essen, Essen, Germany
| | - Philippe Maeder
- Unit of Neuroradiology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Annette C Moll
- UMC, Vrije Universiteit Amsterdam, Department of Ophthalmology, Cancer Center Amsterdam, Amsterdam, Netherlands
| | - Angel Montero Carcaboso
- Pediatric Hematology and Oncology, Hospital Sant Joan de Deu, Barcelona, Spain; Institut de Recerca Sant Joan de Deu, Barcelona, Spain
| | - Alexandre Moulin
- Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
| | - Paula Schaiquevich
- Unit of Clinical Pharmacokinetics, Hospital de Pediatria JP Garrahan, Buenos Aires, Argentina; National Scientific and Technical Research Council (CONICET), Buenos Aires, Argentina
| | - Ciara Bergin
- Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
| | - Paul J Dyson
- Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015, Lausanne, Switzerland
| | - Susan Houghton
- Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
| | - Francesco Puccinelli
- Interventional Neuroradiology Unit, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| | - Yvan Vial
- Materno-Fetal Medicine Unit, Woman-Mother-Child Department, University Hospital of Lausanne, Switzerland
| | - Marie-Claire Gaillard
- Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
| | - Christina Stathopoulos
- Jules-Gonin Eye Hospital, Fondation Asile des Aveugles, University of Lausanne, Lausanne, Switzerland
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Developmental stage-specific proliferation and retinoblastoma genesis in RB-deficient human but not mouse cone precursors. Proc Natl Acad Sci U S A 2018; 115:E9391-E9400. [PMID: 30213853 DOI: 10.1073/pnas.1808903115] [Citation(s) in RCA: 49] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Most retinoblastomas initiate in response to the inactivation of the RB1 gene and loss of functional RB protein. The tumors may form with few additional genomic changes and develop after a premalignant retinoma phase. Despite this seemingly straightforward etiology, mouse models have not recapitulated the genetic, cellular, and stage-specific features of human retinoblastoma genesis. For example, whereas human retinoblastomas appear to derive from cone photoreceptor precursors, current mouse models develop tumors that derive from other retinal cell types. To investigate the basis of the human cone-specific oncogenesis, we compared developmental stage-specific cone precursor responses to RB loss in human and murine retina cultures and in cone-specific Rb1-knockout mice. We report that RB-depleted maturing (ARR3+) but not immature (ARR3-) human cone precursors enter the cell cycle, proliferate, and form retinoblastoma-like lesions with Flexner-Wintersteiner rosettes, then form low or nonproliferative premalignant retinoma-like lesions with fleurettes and p16INK4A and p130 expression, and finally form highly proliferative retinoblastoma-like masses. In contrast, in murine retina, only RB-depleted immature (Arr3-) cone precursors entered the cell cycle, and they failed to progress from S to M phase. Moreover, whereas intrinsically highly expressed MDM2 and MYCN contribute to RB-depleted maturing (ARR3+) human cone precursor proliferation, ectopic MDM2 and Mycn promoted only immature (Arr3-) murine cone precursor cell-cycle entry. These findings demonstrate that developmental stage-specific as well as species- and cell type-specific features sensitize to RB1 inactivation and reveal the human cone precursors' capacity to model retinoblastoma initiation, proliferation, premalignant arrest, and tumor growth.
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Characterisation of retinoblastomas without RB1 mutations: genomic, gene expression, and clinical studies. Lancet Oncol 2013; 14:327-34. [PMID: 23498719 DOI: 10.1016/s1470-2045(13)70045-7] [Citation(s) in RCA: 239] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
BACKGROUND Retinoblastoma is the childhood retinal cancer that defined tumour-suppressor genes. Previous work shows that mutation of both alleles of the RB1 retinoblastoma suppressor gene initiates disease. We aimed to characterise non-familial retinoblastoma tumours with no detectable RB1 mutations. METHODS Of 1068 unilateral non-familial retinoblastoma tumours, we compared those with no evidence of RB1 mutations (RB1(+/+)) with tumours carrying a mutation in both alleles (RB1(-/-)). We analysed genomic copy number, RB1 gene expression and protein function, retinal gene expression, histological features, and clinical data. FINDINGS No RB1 mutations (RB1(+/+)) were reported in 29 (2·7%) of 1068 unilateral retinoblastoma tumours. 15 of the 29 RB1(+/+) tumours had high-level MYCN oncogene amplification (28-121 copies; RB1(+/+)MYCN(A)), whereas none of 93 RB1(-/-) primary tumours tested showed MYCN amplification (p<0·0001). RB1(+/+)MYCN(A) tumours expressed functional RB1 protein, had fewer overall genomic copy-number changes in genes characteristic of retinoblastoma than did RB1(-/-) tumours, and showed distinct aggressive histological features. MYCN amplification was the sole copy-number change in one RB1(+/+)MYCN(A) retinoblastoma. One additional MYCN(A) tumour was discovered after the initial frequencies were determined, and this is included in further analyses. Median age at diagnosis of the 17 children with RB1(+/+)MYCN(A) tumours was 4·5 months (IQR 3·5-10), compared with 24 months (15-37) for 79 children with non-familial unilateral RB1(-/-) retinoblastoma. INTERPRETATION Amplification of the MYCN oncogene might initiate retinoblastoma in the presence of non-mutated RB1 genes. These unilateral RB1(+/+)MYCN(A) retinoblastomas are characterised by distinct histological features, only a few of the genomic copy-number changes that are characteristic of retinoblastoma, and very early age of diagnosis. FUNDING National Cancer Institute-National Institutes of Health, Canadian Institutes of Health Research, German Research Foundation, Canadian Retinoblastoma Society, Hyland Foundation, Toronto Netralaya and Doctors Lions Clubs, Ontario Ministry of Health and Long Term Care, UK-Essen, and Foundations Avanti-STR and KiKa.
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Morin A, Bardot B, Simeonova I, Lejour V, Bouarich-Bourimi R, Toledo F. Of mice and men: fuzzy tandem repeats and divergent p53 transcriptional repertoires. Transcription 2013; 4:67-71. [PMID: 23412358 DOI: 10.4161/trns.23772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The clinical importance of tumor suppressor p53 makes it one of the most studied transcription factors. A comparison of mammalian p53 transcriptional repertoires may help identify fundamental principles in genome evolution and better understand cancer processes. Here we summarize mechanisms underlying the divergence of mammalian p53 transcriptional repertoires, with an emphasis on the rapid evolution of fuzzy tandem repeats containing p53 response elements.
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Simeonova I, Lejour V, Bardot B, Bouarich-Bourimi R, Morin A, Fang M, Charbonnier L, Toledo F. Fuzzy tandem repeats containing p53 response elements may define species-specific p53 target genes. PLoS Genet 2012; 8:e1002731. [PMID: 22761580 PMCID: PMC3386156 DOI: 10.1371/journal.pgen.1002731] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 04/11/2012] [Indexed: 12/21/2022] Open
Abstract
Evolutionary forces that shape regulatory networks remain poorly understood. In mammals, the Rb pathway is a classic example of species-specific gene regulation, as a germline mutation in one Rb allele promotes retinoblastoma in humans, but not in mice. Here we show that p53 transactivates the Retinoblastoma-like 2 (Rbl2) gene to produce p130 in murine, but not human, cells. We found intronic fuzzy tandem repeats containing perfect p53 response elements to be important for this regulation. We next identified two other murine genes regulated by p53 via fuzzy tandem repeats: Ncoa1 and Klhl26. The repeats are poorly conserved in evolution, and the p53-dependent regulation of the murine genes is lost in humans. Our results indicate a role for the rapid evolution of tandem repeats in shaping differences in p53 regulatory networks between mammalian species. TP53, the gene encoding p53, is mutated in more than half of human cancers. Consequently, p53 is one of the most studied transcription factors, shown to directly regulate more than 150 genes. The mouse is a model of choice to study p53 mutants and cancer. However, differences were found between tumorigenesis in mice and humans, and these should be investigated to improve the relevance of mouse models. The distinct mutational events required to initiate retinoblastomas in these species constitute a classic example of such differences. Here we show that p53 regulates the Retinoblastoma-like 2 (Rbl2) gene, encoding tumor suppressor p130, in murine but not human cells. The p53-dependent regulation of murine Rbl2/p130 relies on clustered p53 response elements, located within tandem repeats poorly conserved in evolution. A similar situation was found for two other genes, also p53 targets in mice but not in humans. Thus, tandem repeats may shape differences in mammalian p53 regulatory networks. By uncovering differences in p53 target gene repertoires between mice and humans, our findings may help to improve mice as models of human disease. In addition, the role of tandem repeats in shaping the target gene repertoires of other mammalian transcription factors should be considered.
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Affiliation(s)
- Iva Simeonova
- Institut Curie, Centre de Recherche, Paris, France
- UPMC Univ Paris 06, Paris, France
- CNRS UMR 3244, Paris, France
| | - Vincent Lejour
- Institut Curie, Centre de Recherche, Paris, France
- UPMC Univ Paris 06, Paris, France
- CNRS UMR 3244, Paris, France
| | - Boris Bardot
- Institut Curie, Centre de Recherche, Paris, France
- UPMC Univ Paris 06, Paris, France
- CNRS UMR 3244, Paris, France
| | - Rachida Bouarich-Bourimi
- Institut Curie, Centre de Recherche, Paris, France
- UPMC Univ Paris 06, Paris, France
- CNRS UMR 3244, Paris, France
| | - Aurélie Morin
- Institut Curie, Centre de Recherche, Paris, France
- UPMC Univ Paris 06, Paris, France
- CNRS UMR 3244, Paris, France
| | - Ming Fang
- Institut Curie, Centre de Recherche, Paris, France
- UPMC Univ Paris 06, Paris, France
- CNRS UMR 3244, Paris, France
| | - Laure Charbonnier
- Institut Curie, Centre de Recherche, Paris, France
- UPMC Univ Paris 06, Paris, France
- CNRS UMR 3244, Paris, France
| | - Franck Toledo
- Institut Curie, Centre de Recherche, Paris, France
- UPMC Univ Paris 06, Paris, France
- CNRS UMR 3244, Paris, France
- * E-mail:
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8
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Abstract
In cancer cells, the retinoblastoma tumor suppressor RB is directly inactivated by mutation in the RB gene or functionally inhibited by abnormal activation of cyclin-dependent kinase activity. While variations in RB levels may also provide an important means of controlling RB function in both normal and cancer cells, little is known about the mechanisms regulating RB transcription. Here we show that members of the RB and E2F families bind directly to the RB promoter. To investigate how the RB/E2F pathway may regulate Rb transcription, we generated reporter mice carrying an eGFP transgene inserted into a bacterial artificial chromosome containing most of the Rb gene. Expression of eGFP largely parallels that of Rb in transgenic embryos and adult mice. Using these reporter mice and mutant alleles for Rb, p107, and p130, we found that RB family members modulate Rb transcription in specific cell populations in vivo and in culture. Interestingly, while Rb is a target of the RB/E2F pathway in mouse and human cells, Rb expression does not strictly correlate with the cell cycle status of these cells. These experiments identify novel regulatory feedback mechanisms within the RB pathway in mammalian cells.
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Xu XL, Fang Y, Lee TC, Forrest D, Gregory-Evans C, Almeida D, Liu A, Jhanwar SC, Abramson DH, Cobrinik D. Retinoblastoma has properties of a cone precursor tumor and depends upon cone-specific MDM2 signaling. Cell 2009; 137:1018-31. [PMID: 19524506 DOI: 10.1016/j.cell.2009.03.051] [Citation(s) in RCA: 178] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2008] [Revised: 01/09/2009] [Accepted: 03/13/2009] [Indexed: 01/18/2023]
Abstract
Retinoblastomas result from the inactivation of the RB1 gene and the loss of Rb protein, yet the cell type in which Rb suppresses retinoblastoma and the circuitry that underlies the need for Rb are undefined. Here, we show that retinoblastoma cells express markers of postmitotic cone precursors but not markers of other retinal cell types. We also demonstrate that human cone precursors prominently express MDM2 and N-Myc, that retinoblastoma cells require both of these proteins for proliferation and survival, and that MDM2 is needed to suppress ARF-induced apoptosis in cultured retinoblastoma cells. Interestingly, retinoblastoma cell MDM2 expression was regulated by the cone-specific RXRgamma transcription factor and a human-specific RXRgamma consensus binding site, and proliferation required RXRgamma, as well as the cone-specific thyroid hormone receptor-beta2. These findings provide support for a cone precursor origin of retinoblastoma and suggest that human cone-specific signaling circuitry sensitizes to the oncogenic effects of RB1 mutations.
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Affiliation(s)
- Xiaoliang L Xu
- Dyson Vision Research Institute, Weill Cornell Medical College, New York, NY 10021, USA
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10
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Das G, Choi Y, Sicinski P, Levine EM. Cyclin D1 fine-tunes the neurogenic output of embryonic retinal progenitor cells. Neural Dev 2009; 4:15. [PMID: 19416500 PMCID: PMC2694796 DOI: 10.1186/1749-8104-4-15] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2008] [Accepted: 05/05/2009] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Maintaining the correct balance of proliferation versus differentiation in retinal progenitor cells (RPCs) is essential for proper development of the retina. The cell cycle regulator cyclin D1 is expressed in RPCs, and mice with a targeted null allele at the cyclin D1 locus (Ccnd1-/-) have microphthalmia and hypocellular retinas, the latter phenotype attributed to reduced RPC proliferation and increased photoreceptor cell death during the postnatal period. How cyclin D1 influences RPC behavior, especially during the embryonic period, is unclear. RESULTS In this study, we show that embryonic RPCs lacking cyclin D1 progress through the cell cycle at a slower rate and exit the cell cycle at a faster rate. Consistent with enhanced cell cycle exit, the relative proportions of cell types born in the embryonic period, such as retinal ganglion cells and photoreceptor cells, are increased. Unexpectedly, cyclin D1 deficiency decreases the proportions of other early born retinal neurons, namely horizontal cells and specific amacrine cell types. We also found that the laminar positioning of horizontal cells and other cell types is altered in the absence of cyclin D1. Genetically replacing cyclin D1 with cyclin D2 is not efficient at correcting the phenotypes due to the cyclin D1 deficiency, which suggests the D-cyclins are not fully redundant. Replacement with cyclin E or inactivation of cyclin-dependent kinase inhibitor p27Kip1 restores the balance of RPCs and retinal cell types to more normal distributions, which suggests that regulation of the retinoblastoma pathway is an important function for cyclin D1 during embryonic retinal development. CONCLUSION Our findings show that cyclin D1 has important roles in RPC cell cycle regulation and retinal histogenesis. The reduction in the RPC population due to a longer cell cycle time and to an enhanced rate of cell cycle exit are likely to be the primary factors driving retinal hypocellularity and altered output of precursor populations in the embryonic Ccnd1-/- retina.
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Affiliation(s)
- Gaurav Das
- Department of Ophthalmology and Visual Sciences, John A Moran Eye Center, University of Utah, Salt Lake City, UT 84132, USA.
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11
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Schubert SW, Lamoureux N, Kilian K, Klein-Hitpass L, Hashemolhosseini S. Identification of Integrin-α4, Rb1, and Syncytin A as Murine Placental Target Genes of the Transcription Factor GCMa/Gcm1. J Biol Chem 2008; 283:5460-5. [DOI: 10.1074/jbc.m710110200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
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12
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Dimaras H, Khetan V, Halliday W, Orlic M, Prigoda NL, Piovesan B, Marrano P, Corson TW, Eagle RC, Squire JA, Gallie BL. Loss of RB1 induces non-proliferative retinoma: increasing genomic instability correlates with progression to retinoblastoma. Hum Mol Genet 2008; 17:1363-72. [PMID: 18211953 DOI: 10.1093/hmg/ddn024] [Citation(s) in RCA: 219] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Retinoblastoma clinical observations revealed the role of tumor suppressor genes in human cancer, Knudson's 'two-hit' model of cancer induction. We now demonstrate that loss of both RB1 tumor suppressor gene alleles initiates quiescent RB1(-/-) retinomas with low level genomic instability and high expression of the senescence-associated proteins p16(INK4a) and p130. Although retinomas can remain unchanged throughout life, highly proliferative, clonal and aneuploid retinoblastomas commonly emerge, exhibiting altered gene copy number and expression of oncogenes (MYCN, E2F3, DEK, KIF14 and MDM4) and tumor suppressor genes (CDH11, p75(NTR)) and reduced expression of p16(INK4a) and p130. We suggest that RB1 inactivation in developing retina induces genomic instability, but senescence can block transformation at the stage of retinoma. However, stable retinoma is rarely clinically observed because progressive genomic instability commonly leads to highly proliferative retinoblastoma.
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Affiliation(s)
- Helen Dimaras
- Department of Molecular and Medical Genetics, University of Toronto, Medical Sciences Building, 1 King's College Circle, Toronto, ON, Canada
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Kim TH, Goodman J, Anderson KV, Niswander L. Phactr4 regulates neural tube and optic fissure closure by controlling PP1-, Rb-, and E2F1-regulated cell-cycle progression. Dev Cell 2007; 13:87-102. [PMID: 17609112 DOI: 10.1016/j.devcel.2007.04.018] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2006] [Revised: 02/20/2007] [Accepted: 04/26/2007] [Indexed: 12/11/2022]
Abstract
Here we identify the humpty dumpty (humdy) mouse mutant with failure to close the neural tube and optic fissure, causing exencephaly and retinal coloboma, common birth defects. The humdy mutation disrupts Phactr4, an uncharacterized protein phosphatase 1 (PP1) and actin regulator family member, and the missense mutation specifically disrupts binding to PP1. Phactr4 is initially expressed in the ventral cranial neural tube, a region of regulated proliferation, and after neural closure throughout the dorsoventral axis. humdy embryos display elevated proliferation and abnormally phosphorylated, inactive PP1, resulting in Rb hyperphosphorylation, derepression of E2F targets, and abnormal cell-cycle progression. Exencephaly, coloboma, and abnormal proliferation in humdy embryos are rescued by loss of E2f1, demonstrating the cell cycle is the key target controlled by Phactr4. Thus, Phactr4 is critical for the spatially and temporally regulated transition in proliferation through differential regulation of PP1 and the cell cycle during neurulation and eye development.
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Affiliation(s)
- Tae-Hee Kim
- Cell Biology and Genetics Program, Weill Graduate School of Medical Sciences of Cornell University, New York, NY 10021, USA
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14
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Chen D, Opavsky R, Pacal M, Tanimoto N, Wenzel P, Seeliger MW, Leone G, Bremner R. Rb-mediated neuronal differentiation through cell-cycle-independent regulation of E2f3a. PLoS Biol 2007; 5:e179. [PMID: 17608565 PMCID: PMC1914394 DOI: 10.1371/journal.pbio.0050179] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Accepted: 05/08/2007] [Indexed: 01/19/2023] Open
Abstract
It has long been known that loss of the retinoblastoma protein (Rb) perturbs neural differentiation, but the underlying mechanism has never been solved. Rb absence impairs cell cycle exit and triggers death of some neurons, so differentiation defects may well be indirect. Indeed, we show that abnormalities in both differentiation and light-evoked electrophysiological responses in Rb-deficient retinal cells are rescued when ectopic division and apoptosis are blocked specifically by deleting E2f transcription factor (E2f) 1. However, comprehensive cell-type analysis of the rescued double-null retina exposed cell-cycle–independent differentiation defects specifically in starburst amacrine cells (SACs), cholinergic interneurons critical in direction selectivity and developmentally important rhythmic bursts. Typically, Rb is thought to block division by repressing E2fs, but to promote differentiation by potentiating tissue-specific factors. Remarkably, however, Rb promotes SAC differentiation by inhibiting E2f3 activity. Two E2f3 isoforms exist, and we find both in the developing retina, although intriguingly they show distinct subcellular distribution. E2f3b is thought to mediate Rb function in quiescent cells. However, in what is to our knowledge the first work to dissect E2f isoform function in vivo we show that Rb promotes SAC differentiation through E2f3a. These data reveal a mechanism through which Rb regulates neural differentiation directly, and, unexpectedly, it involves inhibition of E2f3a, not potentiation of tissue-specific factors. The retinoblastoma protein (Rb), an important tumor suppressor, blocks division and death by inhibiting the E2f transcription factor family. In contrast, Rb is thought to promote differentiation by potentiating tissue-specific transcription factors, although differentiation defects in Rb null cells could be an indirect consequence of E2f-driven division and death. Here, we resolve different mechanisms by which Rb controls division, death, and differentiation in the retina. Removing E2f1 rescues aberrant division of differentiating Rb-deficient retinal neurons, as well as death in cells prone to apoptosis, and restores both normal differentiation and function of major cell types, such as photoreceptors. However, Rb-deficient starburst amacrine neurons differentiate abnormally even when E2f1 is removed, providing an unequivocal example of a direct role for Rb in neuronal differentiation. Rather than potentiating a cell-specific factor, Rb promotes starburst cell differentiation by inhibiting another E2f, E2f3a. This cell-cycle–independent activity broadens the importance of the Rb–E2f pathway, and suggests we should reassess its role in the differentiation of other cell types. The retinoblastoma protein (Rb), a tumor suppressor, promotes the differentiation of starburst amacrine cells in the retina by inhibiting the transcription factor E2f3a, whereas it suppresses retinal cell division and death by inhibiting E2f1.
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Affiliation(s)
- Danian Chen
- Genetics and Development Division, Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
- Department of Ophthalmology and Visual Science, University of Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
| | - Rene Opavsky
- Human Cancer Genetics Program, Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University, Columbus, Ohio, United States of America
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio, United States of America
- Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, United States of America
| | - Marek Pacal
- Genetics and Development Division, Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
- Department of Ophthalmology and Visual Science, University of Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
| | - Naoyuki Tanimoto
- Ocular Neurodegeneration Research Group, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Germany
| | - Pamela Wenzel
- Human Cancer Genetics Program, Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University, Columbus, Ohio, United States of America
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio, United States of America
- Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, United States of America
| | - Mathias W Seeliger
- Ocular Neurodegeneration Research Group, Centre for Ophthalmology, Institute for Ophthalmic Research, University of Tuebingen, Germany
| | - Gustavo Leone
- Human Cancer Genetics Program, Department of Molecular Virology, Immunology and Medical Genetics, Ohio State University, Columbus, Ohio, United States of America
- Department of Molecular Genetics, Ohio State University, Columbus, Ohio, United States of America
- Comprehensive Cancer Center, Ohio State University, Columbus, Ohio, United States of America
| | - Rod Bremner
- Genetics and Development Division, Toronto Western Research Institute, University Health Network, University of Toronto, Ontario, Canada
- Department of Ophthalmology and Visual Science, University of Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Ontario, Canada
- * To whom correspondence should be addressed. E-mail:
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15
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Chai J, Lu X, Godfrey V, Fletcher C, Roberts CWM, Van Dyke T, Weissman BE. Tumor-specific cooperation of retinoblastoma protein family and Snf5 inactivation. Cancer Res 2007; 67:3002-9. [PMID: 17409406 DOI: 10.1158/0008-5472.can-06-4207] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Malignant rhabdoid tumors (MRT) are rare aggressive cancers that occur in young children. Seventy-five percent of sporadic MRTs harbor inactivating SNF5 mutations, and mice heterozygous for an Snf5-null allele develop MRTs with partial penetrance. The diagnosis of choroid plexus carcinomas (CPC) in addition to MRTs in families with a single mutant SNF5 allele prompted us to assess the role of SNF5 loss in CPC in genetically engineered mice. With high frequency, TgT(121) mice develop CPCs that are initiated by inactivation of retinoblastoma protein (pRb) and related proteins p107 and p130. However, CPC penetrance and latency were not significantly affected by Snf5 heterozygosity, consistent with recent evidence that CPCs in SNF5 families were, in many cases, misdiagnosed MRTs. Surprisingly, although the CPC phenotype was unaffected, TgT(121);Snf5(+/-) mice developed MRTs with increased penetrance and decreased latency compared with TgT(121);Snf5(+/+) littermates. MRTs expressed the T(121) protein with a concomitant increase in mitotic activity. The predominant appearance of TgT(121);Snf5(+/-) MRTs in the spinal cord led to the discovery that these tumors likely arose from a subset of spinal cord neural progenitor cells expressing T(121) rather than from transdifferentiation of CPC. Significantly, the target cell type(s) for MRT is unknown. Hence, this study not only shows that pRb(f) and SNF5 inactivation cooperate to induce MRTs but also provides new insight into the MRT target population.
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Affiliation(s)
- Jingjing Chai
- Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, North Carolina, USA
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16
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MacPherson D, Conkrite K, Tam M, Mukai S, Mu D, Jacks T. Murine bilateral retinoblastoma exhibiting rapid-onset, metastatic progression and N-myc gene amplification. EMBO J 2007; 26:784-94. [PMID: 17235288 PMCID: PMC1794380 DOI: 10.1038/sj.emboj.7601515] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2006] [Accepted: 11/28/2006] [Indexed: 11/08/2022] Open
Abstract
Human retinoblastoma is a pediatric cancer initiated by RB gene mutations in the developing retina. We have examined the origins and progression of retinoblastoma in mouse models of the disease. Retina-specific inactivation of Rb on a p130-/- genetic background led to bilateral retinoblastoma with rapid kinetics, whereas on a p107-/- background Rb mutation caused predominantly unilateral tumors that arose with delayed kinetics and incomplete penetrance. In both models, retinoblastomas arose from cells at the extreme periphery of the murine retina. Furthermore, late retinoblastomas progressed to invade the brain and metastasized to the cervical lymph nodes. Metastatic tumors lacking Rb and p130 exhibited chromosomal changes revealed by representational oligonucleotide microarray analysis including high-level amplification of the N-myc oncogene. N-myc was found amplified in three of 16 metastatic retinoblastomas lacking Rb and p130 as well as in retinoblastomas lacking Rb and p107. N-myc amplification ranged from 6- to 400-fold and correlated with high N-myc-expression levels. These murine models closely resemble human retinoblastoma in their progression and secondary genetic changes, making them ideal tools for further dissection of steps to tumorigenesis and for testing novel therapies.
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Affiliation(s)
- David MacPherson
- Department of Embryology, Carnegie Institution, Baltimore, MD 21218, USA.
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17
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Macaluso M, Montanari M, Giordano A. Rb family proteins as modulators of gene expression and new aspects regarding the interaction with chromatin remodeling enzymes. Oncogene 2006; 25:5263-7. [PMID: 16936746 DOI: 10.1038/sj.onc.1209680] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The pRb family proteins (pRb1/105, p107, pRb2/p130), collectively referred to as pocket proteins, are believed to function primarily as regulators of the mammalian cell cycle progression, and suppressors of cellular growth and proliferation. In addition, different studies suggest that these pocket proteins are also involved in development and differentiation of various tissues. Several lines of evidence indicate that generally pRb-family proteins function through their effect on the transcription of E2F-regulated genes. In fact, each of Rb family proteins binds to distinct members of the E2F transcription factors, which regulate the expression of genes whose protein products are necessary for cell proliferation and to drive cell-cycle progression. Nevertheless, pocket proteins can affect the G1/S transition through E2F-independent mechanisms. More recently, a broad range of evidences indicate that pRb-family proteins associate with a wide variety of transcription factors and chromatin remodeling enzymes forming transcriptional repressor complexes that control gene expression. This review focuses on the complex regulatory mechanisms by which pRb-family proteins tell genes when to switch on and off.
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Affiliation(s)
- M Macaluso
- Sbarro Institute for Cancer Research and Molecular Medicine, Center of Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA
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18
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Agromayor M, Wloga E, Naglieri B, Abrashkin J, Verma K, Yamasaki L. Visualizing dynamic E2F-mediated repression in vivo. Mol Cell Biol 2006; 26:4448-61. [PMID: 16738312 PMCID: PMC1489115 DOI: 10.1128/mcb.02101-05] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2005] [Revised: 11/30/2005] [Accepted: 03/12/2006] [Indexed: 11/20/2022] Open
Abstract
Although many E2F target genes have been identified recently, very little is known about how any single E2F site controls the expression of an E2F target gene in vivo. To test the requirement for a single E2F site in vivo and to learn how E2F-mediated repression is regulated during development and tumorigenesis, we have constructed a novel series of wild-type and mutant Rb promoter-LacZ transgenic reporter lines that allow us to visualize the activity of a crucial E2F target in vivo, the retinoblastoma tumor suppressor gene (Rb). Two mutant Rb promoter-LacZ constructs were used to evaluate the importance of a single E2F site or a nearby activator (Sp1/Ets) site that is found mutated in low-penetrance retinoblastomas. The activity of the wild-type Rb promoter is dynamic, varying spatially and temporally within the developing nervous system. While loss of the activator site silences the Rb promoter, loss of the E2F site stimulates its activity in the neocortex, retina, and trigeminal ganglion. Surprisingly, E2F-mediated repression of Rb does not act globally or in a static manner but, instead, is a highly dynamic process in vivo. Using neocortical extracts, we detected GA-binding protein alpha (GABPalpha, an Ets family member) bound to the activator site and both E2F1 and E2F4 bound to the repressor site of the Rb promoter in vitro. Additionally, we detected binding of both E2F1 and E2F4 to the Rb promoter in vivo using chromatin immunoprecipitation analysis on embryonic day 13.5 brain. Unexpectedly, we detect no evidence for Rb promoter autoregulation in neuroendocrine tumors from Rb+/-; RbP-LacZ mice that undergo loss of heterozygosity at the Rb locus, in contrast to the situation in human retinoblastomas where high RB mRNA levels are found. In summary, this study provides the first demonstration that loss of an E2F site is critical for target gene repression in vivo and underscores the complexity of the Rb and E2F family network in vivo.
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Affiliation(s)
- Monica Agromayor
- Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, 1102 Fairchild Building, Mail Code 2428, New York, NY 10027, USA
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19
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Donovan SL, Schweers B, Martins R, Johnson D, Dyer MA. Compensation by tumor suppressor genes during retinal development in mice and humans. BMC Biol 2006; 4:14. [PMID: 16672052 PMCID: PMC1481602 DOI: 10.1186/1741-7007-4-14] [Citation(s) in RCA: 84] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2006] [Accepted: 05/03/2006] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The RB1 gene was the first tumor suppressor gene cloned from humans by studying genetic lesions in families with retinoblastoma. Children who inherit one defective copy of the RB1 gene have an increased susceptibility to retinoblastoma. Several years after the identification of the human RB1 gene, a targeted deletion of Rb was generated in mice. Mice with one defective copy of the Rb gene do not develop retinoblastoma. In this manuscript, we explore the different roles of the Rb family in human and mouse retinal development in order to better understand the species-specific difference in retinoblastoma susceptibility. RESULTS We found that the Rb family of proteins (Rb, p107 and p130) are expressed in a dynamic manner during mouse retinal development. The primary Rb family member expressed in proliferating embryonic retinal progenitor cells in mice is p107, which is required for appropriate cell cycle exit during retinogenesis. The primary Rb family member expressed in proliferating postnatal retinal progenitor cells is Rb. p130 protein is expressed redundantly with Rb in postmitotic cells of the inner nuclear layer and the ganglion cell layer of the mouse retina. When Rb is inactivated in an acute or chronic manner during mouse retinal development, p107 is upregulated in a compensatory manner. Similarly, when p107 is inactivated in the mouse retina, Rb is upregulated. No changes in p130 expression were seen when p107, Rb or both were inactivated in the developing mouse retina. In the human retina, RB1 was the primary family member expressed throughout development. There was very little if any p107 expressed in the developing human retina. In contrast to the developing mouse retina, when RB1 was acutely inactivated in the developing human fetal retina, p107 was not upregulated in a compensatory manner. CONCLUSION We propose that intrinsic genetic compensation between Rb and p107 prevents retinoblastoma in Rb- or p107-deficient mice, but this compensation does not occur in humans. Together, these data suggest a model that explains why humans are susceptible to retinoblastoma following RB1 loss, but mice require both Rb and p107 gene inactivation.
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Affiliation(s)
- Stacy L Donovan
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Brett Schweers
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Rodrigo Martins
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Dianna Johnson
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Michael A Dyer
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
- Department of Ophthalmology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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