1
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Liu Y, Jiang G, Lv C, Yang C. miR-222-5p promotes dysfunction of human vascular smooth muscle cells by targeting RB1. ENVIRONMENTAL TOXICOLOGY 2022; 37:683-694. [PMID: 34862716 DOI: 10.1002/tox.23434] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/04/2021] [Accepted: 11/27/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Coronary atherosclerosis (AS) is characterized by the formation of plaque in the vessel wall. The structural and functional changes of vascular smooth muscle cells (VSMCs) can promote plaque formation and induce plaque instability. OBJECTIVE To investigate the functions and mechanism of miR-222-5p in VSMCs under the treatment of oxidized low-density lipoprotein (ox-LDL). METHODS miR-222-5p expression in ox-LDL-treated VSMCs and the serum of Apolipoprotein E (ApoE) knockout mice was detected by reverse transcription quantitative polymerase chain reaction. The viability and migration of VSMCs were detected by Cell Counting Kit-8 and Transwell assays. Protein levels of proliferation and migration-related factors were evaluated by western blotting. Luciferase reporter assays were performed to explore the binding between miR-222-5p and retinoblastoma susceptibility protein (RB1) gene in VSMCs. ApoE-knockout mice were infected with the lentivirus inhibiting miR-222-5p expression to explore the effect of miR-222-5p on pathological changes. Hematoxylin and eosin (H&E) staining, trichrome staining, and Oil Red O staining were conducted to determine the necrotic core area and atherosclerotic lesion size in the ascending aorta of ApoE-knockout mice. RESULTS With the accumulation of ox-LDL concentration and treatment time, miR-222-5p expression was gradually upregulated in VSMCs. Similarly, miR-222-5p expression was increased in the serum of ApoE-knockout mice. miR-222-5p knockdown inhibited the proliferative and migratory abilities of ox-LDL-treated VSMCs, and the inhibitory effect on cellular behaviors was then significantly reversed by co-knockdown of RB1. RB1 is a downstream target gene of miR-222-5p, and miR-222-5p bound with 3'-untranslated region of RB1 in VSMCs. We further confirmed that miR-222-5p knockdown alleviated pathological changes and inhibited lipid deposition in the serum of ApoE-knockout mice in vivo. CONCLUSION miR-222-5p accelerates the dysfunction of VSMCs and promotes pathological changes and lipid deposition in ApoE-knockout mice by targeting RB1. The study may provide novel therapeutic targets for AS.
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Affiliation(s)
- Yihang Liu
- Department of Cardiovascular Medicine, The Second Hospital of Jilin University, Jilin, China
| | - Guopan Jiang
- Department of Cardiovascular Medicine, Jilin Provincial People's Hospital, Jilin, China
| | - Changzhi Lv
- Department of Second Cardiology, Dandong First Hospital, Dandong, China
| | - Chuang Yang
- Department of Cardiovascular Medicine, The Second Hospital of Jilin University, Jilin, China
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2
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Zluhan-Martínez E, Pérez-Koldenkova V, Ponce-Castañeda MV, Sánchez MDLP, García-Ponce B, Miguel-Hernández S, Álvarez-Buylla ER, Garay-Arroyo A. Beyond What Your Retina Can See: Similarities of Retinoblastoma Function between Plants and Animals, from Developmental Processes to Epigenetic Regulation. Int J Mol Sci 2020; 21:E4925. [PMID: 32664691 PMCID: PMC7404004 DOI: 10.3390/ijms21144925] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/29/2020] [Accepted: 07/07/2020] [Indexed: 12/15/2022] Open
Abstract
The Retinoblastoma protein (pRb) is a key cell cycle regulator conserved in a wide variety of organisms. Experimental analysis of pRb's functions in animals and plants has revealed that this protein participates in cell proliferation and differentiation processes. In addition, pRb in animals and its orthologs in plants (RBR), are part of highly conserved protein complexes which suggest the possibility that analogies exist not only between functions carried out by pRb orthologs themselves, but also in the structure and roles of the protein networks where these proteins are involved. Here, we present examples of pRb/RBR participation in cell cycle control, cell differentiation, and in the regulation of epigenetic changes and chromatin remodeling machinery, highlighting the similarities that exist between the composition of such networks in plants and animals.
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Affiliation(s)
- Estephania Zluhan-Martínez
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
- Posgrado en Ciencias Biomédicas, Universidad Nacional Autónoma de México, Av. Universidad 3000, Coyoacán 04510, Mexico
| | - Vadim Pérez-Koldenkova
- Laboratorio Nacional de Microscopía Avanzada, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Av. Cuauhtémoc, 330. Col. Doctores, Alc. Cuauhtémoc 06720, Mexico;
| | - Martha Verónica Ponce-Castañeda
- Unidad de Investigación Médica en Enfermedades Infecciosas, Centro Médico Nacional SXXI, Instituto Mexicano del Seguro Social, Mexico City 06720, Mexico;
| | - María de la Paz Sánchez
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
| | - Berenice García-Ponce
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
| | - Sergio Miguel-Hernández
- Laboratorio de Citopatología Ambiental, Departamento de Morfología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Campus Zacatenco, Calle Wilfrido Massieu Esquina Cda, Manuel Stampa 07738, Mexico;
| | - Elena R. Álvarez-Buylla
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
| | - Adriana Garay-Arroyo
- Laboratorio de Genética Molecular, Epigenética, Desarrollo y Evolución de Plantas, Instituto de Ecología, Universidad Nacional Autónoma de Mexico, 3er Circuito Ext. Junto a J. Botánico, Ciudad Universitaria, UNAM 04510, Mexico; (E.Z.-M.); (M.d.l.P.S.); (B.G.-P.)
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3
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Fernandez-Nicolas A, Xu D, Yajima M. A tumor suppressor Retinoblastoma1 is essential for embryonic development in the sea urchin. Dev Dyn 2019; 248:1273-1285. [PMID: 31515896 DOI: 10.1002/dvdy.113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/19/2019] [Accepted: 09/06/2019] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Embryonic cells and cancer cells share various cellular characteristics important for their functions. It has been thus proposed that similar mechanisms of regulation may be present in these otherwise disparate cell types. RESULTS To explore how regulative embryonic cells are fundamentally different from cancerous cells, we report here that a fine balance of a tumor suppressor protein Retinoblastoma1 (Rb1) and a germline factor Vasa are important for proper cell proliferation and differentiation of the somatic cells during embryogenesis of the sea urchin. Rb1 knockdown blocked embryonic development and induced Vasa accumulation in the entire embryo, while its overexpression resulted in a smaller-sized embryo with differentiated body structures. These results suggest that a titrated level of Rb1 protein may be essential for a proper balance of cell proliferation and differentiation during development. Vasa knockdown or overexpression, on the other hand, reduced or increased Rb1 protein expression, respectively. CONCLUSIONS Taken together, it appears that Vasa protein positively regulates Rb1 protein while Rb1 protein negatively regulates Vasa protein, balancing the act of these two antagonistic molecules in somatic cells. This mechanism may provide a fine control of cell proliferation and differentiation, which is essential for regulative embryonic development.
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Affiliation(s)
| | - Derek Xu
- MCB Department, Brown University, Providence, Rhode Island
| | - Mamiko Yajima
- MCB Department, Brown University, Providence, Rhode Island
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4
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Erdem C, Nagle AM, Casa AJ, Litzenburger BC, Wang YF, Taylor DL, Lee AV, Lezon TR. Proteomic Screening and Lasso Regression Reveal Differential Signaling in Insulin and Insulin-like Growth Factor I (IGF1) Pathways. Mol Cell Proteomics 2016; 15:3045-57. [PMID: 27364358 PMCID: PMC5013316 DOI: 10.1074/mcp.m115.057729] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 06/23/2016] [Indexed: 01/22/2023] Open
Abstract
Insulin and insulin-like growth factor I (IGF1) influence cancer risk and progression through poorly understood mechanisms. To better understand the roles of insulin and IGF1 signaling in breast cancer, we combined proteomic screening with computational network inference to uncover differences in IGF1 and insulin induced signaling. Using reverse phase protein array, we measured the levels of 134 proteins in 21 breast cancer cell lines stimulated with IGF1 or insulin for up to 48 h. We then constructed directed protein expression networks using three separate methods: (i) lasso regression, (ii) conventional matrix inversion, and (iii) entropy maximization. These networks, named here as the time translation models, were analyzed and the inferred interactions were ranked by differential magnitude to identify pathway differences. The two top candidates, chosen for experimental validation, were shown to regulate IGF1/insulin induced phosphorylation events. First, acetyl-CoA carboxylase (ACC) knock-down was shown to increase the level of mitogen-activated protein kinase (MAPK) phosphorylation. Second, stable knock-down of E-Cadherin increased the phospho-Akt protein levels. Both of the knock-down perturbations incurred phosphorylation responses stronger in IGF1 stimulated cells compared with insulin. Overall, the time-translation modeling coupled to wet-lab experiments has proven to be powerful in inferring differential interactions downstream of IGF1 and insulin signaling, in vitro.
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Affiliation(s)
- Cemal Erdem
- From the ‡Department of Computational & Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania; §University of Pittsburgh Drug Discovery Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Alison M Nagle
- ¶Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania; ‖Women's Cancer Research Center, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania
| | - Angelo J Casa
- **Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas
| | - Beate C Litzenburger
- **Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas
| | - Yu-Fen Wang
- **Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, Texas
| | - D Lansing Taylor
- From the ‡Department of Computational & Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania; §University of Pittsburgh Drug Discovery Institute, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Adrian V Lee
- ¶Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania; ‖Women's Cancer Research Center, University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania; ‡‡Department of Human Genetics, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Timothy R Lezon
- From the ‡Department of Computational & Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania; §University of Pittsburgh Drug Discovery Institute, University of Pittsburgh, Pittsburgh, Pennsylvania;
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5
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Huang PH, Cook R, Zoumpoulidou G, Luczynski MT, Mittnacht S. Retinoblastoma family proteins: New players in DNA repair by non-homologous end-joining. Mol Cell Oncol 2016; 3:e1053596. [PMID: 27308588 PMCID: PMC4905371 DOI: 10.1080/23723556.2015.1053596] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2015] [Revised: 05/17/2015] [Accepted: 05/18/2015] [Indexed: 10/23/2022]
Abstract
Loss of retinoblastoma protein (RB1) function is a major driver in cancer development. We have recently reported that, in addition to its well-documented functions in cell cycle and fate control, RB1 and its paralogs have a novel role in regulating DNA repair by non-homologous end joining (NHEJ). Here we summarize our findings and present mechanistic hypotheses on how RB1 may support the DNA repair process and the therapeutic implications for patients who harbor RB1-negative cancers.
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Affiliation(s)
- Paul H. Huang
- The Institute of Cancer Research, Division of Cancer Biology, Chester Beatty Laboratories, London, UK
| | - Rebecca Cook
- The Institute of Cancer Research, Division of Cancer Biology, Chester Beatty Laboratories, London, UK
- Cancer Cell Signalling, UCL Cancer Institute, University College London, London, UK
| | - Georgia Zoumpoulidou
- The Institute of Cancer Research, Division of Cancer Biology, Chester Beatty Laboratories, London, UK
| | - Maciej T. Luczynski
- The Institute of Cancer Research, Division of Cancer Biology, Chester Beatty Laboratories, London, UK
| | - Sibylle Mittnacht
- The Institute of Cancer Research, Division of Cancer Biology, Chester Beatty Laboratories, London, UK
- Cancer Cell Signalling, UCL Cancer Institute, University College London, London, UK
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6
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Toki H, Inoue M, Minowa O, Motegi H, Saiki Y, Wakana S, Masuya H, Gondo Y, Shiroishi T, Yao R, Noda T. Novel retinoblastoma mutation abrogating the interaction to E2F2/3, but not E2F1, led to selective suppression of thyroid tumors. Cancer Sci 2014; 105:1360-8. [PMID: 25088905 PMCID: PMC4462357 DOI: 10.1111/cas.12495] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 07/18/2014] [Accepted: 07/25/2014] [Indexed: 01/18/2023] Open
Abstract
Mutant mouse models are indispensable tools for clarifying gene functions and elucidating the pathogenic mechanisms of human diseases. Here, we describe novel cancer models bearing point mutations in the retinoblastoma gene (Rb1) generated by N-ethyl-N-nitrosourea mutagenesis. Two mutations in splice sites reduced Rb1 expression and led to a tumor spectrum and incidence similar to those observed in the conventional Rb1 knockout mice. The missense mutant, Rb1D326V/+, developed pituitary tumors, but thyroid tumors were completely suppressed. Immunohistochemical analyses of thyroid tissue revealed that E2F1, but not E2F2/3, was selectively inactivated, indicating that the mutant Rb protein (pRb) suppressed thyroid tumors by inactivating E2F1. Interestingly, Rb1D326V/+ mice developed pituitary tumors that originated from the intermediate lobe of the pituitary, despite selective inactivation of E2F1. Furthermore, in the anterior lobe of the pituitary, other E2F were also inactivated. These observations show that pRb mediates the inactivation of E2F function and its contribution to tumorigenesis is highly dependent on the cell type. Last, by using a reconstitution assay of synthesized proteins, we showed that the D326V missense pRb bound to E2F1 but failed to interact with E2F2/3. These results reveal the effect of the pRb N-terminal domain on E2F function and the impact of the protein on tumorigenesis. Thus, this mutant mouse model can be used to investigate human Rb family-bearing mutations at the N-terminal region.
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Affiliation(s)
- Hideaki Toki
- Team for Advanced Development and Evaluation of Human Disease Models, Riken BioResource Center, Tsukuba, Ibaraki, Japan
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7
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Narasimha AM, Kaulich M, Shapiro GS, Choi YJ, Sicinski P, Dowdy SF. Cyclin D activates the Rb tumor suppressor by mono-phosphorylation. eLife 2014; 3. [PMID: 24876129 PMCID: PMC4076869 DOI: 10.7554/elife.02872] [Citation(s) in RCA: 292] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 05/22/2014] [Indexed: 11/30/2022] Open
Abstract
The widely accepted model of G1 cell cycle progression proposes that cyclin D:Cdk4/6 inactivates the Rb tumor suppressor during early G1 phase by progressive multi-phosphorylation, termed hypo-phosphorylation, to release E2F transcription factors. However, this model remains unproven biochemically and the biologically active form(s) of Rb remains unknown. In this study, we find that Rb is exclusively mono-phosphorylated in early G1 phase by cyclin D:Cdk4/6. Mono-phosphorylated Rb is composed of 14 independent isoforms that are all targeted by the E1a oncoprotein, but show preferential E2F binding patterns. At the late G1 Restriction Point, cyclin E:Cdk2 inactivates Rb by quantum hyper-phosphorylation. Cells undergoing a DNA damage response activate cyclin D:Cdk4/6 to generate mono-phosphorylated Rb that regulates global transcription, whereas cells undergoing differentiation utilize un-phosphorylated Rb. These observations fundamentally change our understanding of G1 cell cycle progression and show that mono-phosphorylated Rb, generated by cyclin D:Cdk4/6, is the only Rb isoform in early G1 phase. DOI:http://dx.doi.org/10.7554/eLife.02872.001 Cells go through a tightly controlled, multi-step procedure before they divide. This cell division program—the cell cycle—is necessary for preventing unrestrained cellular growth, which may lead to cancer. Proteins called cyclins control the progression through each of the phases of the cell cycle, with different cyclins working during different phases. During the G1 phase of the cell cycle, cells grow in size and produce the proteins that are required to copy DNA. Once a cell passes a checkpoint called the 'restriction point' at the end of the G1 phase, it is committed to dividing. It is therefore particularly important to keep events during G1 phase in check. The Retinoblastoma tumor suppresor protein (Rb) is a key player in regulating the G1 phase. Rb sequesters transcription factors that are essential for the cell cycle to progress. Previously, it was thought that a complex called cyclin D added more and more phosphates to the Rb protein during the G1 phase. This process predicted a slow release of transcription factors, which attach to DNA and start the process of DNA replication. While many studies have presented data that is consistent with this model, direct biochemical evidence of these events is lacking. Narasimha, Kaulich, Shapiro et al. now present biochemical analyses of Rb proteins that show—completely unexpectedly—that the cyclin D complex adds just one phosphate group to Rb during the G1 phase, although this group can be added to one of fourteen different sites. The resulting 'mono-phosphorylated' Rb varieties can each sequester different transcription factors and stop them working. At the restriction point, many more phosphate groups are then rapidly added, and the Rb protein is inactivated by a different cyclin. This cyclin—called Cyclin E—then drives cells into the next phase of the cell cycle. Establishing how cyclin E is activated is a priority for future research. DOI:http://dx.doi.org/10.7554/eLife.02872.002
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Affiliation(s)
- Anil M Narasimha
- Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, United States
| | - Manuel Kaulich
- Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, United States
| | - Gary S Shapiro
- Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, United States
| | - Yoon J Choi
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Piotr Sicinski
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Steven F Dowdy
- Department of Cellular and Molecular Medicine, University of California, San Diego School of Medicine, La Jolla, United States
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8
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Desvoyes B, de Mendoza A, Ruiz-Trillo I, Gutierrez C. Novel roles of plant RETINOBLASTOMA-RELATED (RBR) protein in cell proliferation and asymmetric cell division. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:2657-66. [PMID: 24323507 PMCID: PMC4557542 DOI: 10.1093/jxb/ert411] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The retinoblastoma (Rb) protein was identified as a human tumour suppressor protein that controls various stages of cell proliferation through the interaction with members of the E2F family of transcription factors. It was originally thought to be specific to animals but plants contain homologues of Rb, called RETINOBLASTOMA-RELATED (RBR). In fact, the Rb-E2F module seems to be a very early acquisition of eukaryotes. The activity of RBR depends on phosphorylation of certain amino acid residues, which in most cases are well conserved between plant and animal proteins. In addition to its role in cell-cycle progression, RBR has been shown to participate in various cellular processes such as endoreplication, transcriptional regulation, chromatin remodelling, cell growth, stem cell biology, and differentiation. Here, we discuss the most recent advances to define the role of RBR in cell proliferation and asymmetric cell division. These and other reports clearly support the idea that RBR is used as a landing platform of a plethora of cellular proteins and complexes to control various aspects of cell physiology and plant development.
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Affiliation(s)
- Bénédicte Desvoyes
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, Nicolas Cabrera 1, 28049 Madrid, Spain
| | - Alex de Mendoza
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, 08010 Barcelona, Catalonia, Spain
| | - Iñaki Ruiz-Trillo
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, 08003 Barcelona, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, 08010 Barcelona, Catalonia, Spain
| | - Crisanto Gutierrez
- Centro de Biologia Molecular Severo Ochoa, CSIC-UAM, Cantoblanco, Nicolas Cabrera 1, 28049 Madrid, Spain
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9
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Costa C, Paramio JM, Santos M. Skin Tumors Rb(eing) Uncovered. Front Oncol 2013; 3:307. [PMID: 24381932 PMCID: PMC3865458 DOI: 10.3389/fonc.2013.00307] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 12/04/2013] [Indexed: 11/23/2022] Open
Abstract
The Rb1 gene was the first bona fide tumor suppressor identified and cloned more than 25 years ago. Since then, a plethora of studies have revealed the functions of pRb and the existence of a sophisticated and strictly regulated pathway that modulates such functional roles. An emerging paradox affecting Rb1 in cancer connects the relatively low number of mutations affecting Rb1 gene in specific human tumors, compared with the widely functional inactivation of pRb in most, if not in all, human cancers. The existence of a retinoblastoma family of proteins pRb, p107, and p130 and their potential unique and overlapping functions as master regulators of cell cycle progression and transcriptional modulation by similar processes, may provide potential clues to explain such conundrum. Here, we will review the development of different genetically engineered mouse models, in particular those affecting stratified epithelia, and how they have offered new avenues to understand the roles of the Rb family members and their targets in the context of tumor development and progression.
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Affiliation(s)
- Clotilde Costa
- Molecular Oncology Unit, Department of Basic Research, Centro de Investigaciones Energéticas Medioambientales y Teconológicas (ed70A) , Madrid , Spain
| | - Jesús M Paramio
- Molecular Oncology Unit, Department of Basic Research, Centro de Investigaciones Energéticas Medioambientales y Teconológicas (ed70A) , Madrid , Spain
| | - Mirentxu Santos
- Molecular Oncology Unit, Department of Basic Research, Centro de Investigaciones Energéticas Medioambientales y Teconológicas (ed70A) , Madrid , Spain
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10
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Burke JR, Liban TJ, Restrepo T, Lee HW, Rubin SM. Multiple mechanisms for E2F binding inhibition by phosphorylation of the retinoblastoma protein C-terminal domain. J Mol Biol 2013; 426:245-55. [PMID: 24103329 DOI: 10.1016/j.jmb.2013.09.031] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 09/20/2013] [Indexed: 12/22/2022]
Abstract
The retinoblastoma protein C-terminal domain (RbC) is necessary for the tumor suppressor protein's activities in growth suppression and E2F transcription factor inhibition. Cyclin-dependent kinase phosphorylation of RbC contributes to Rb inactivation and weakens the Rb-E2F inhibitory complex. Here we demonstrate two mechanisms for how RbC phosphorylation inhibits E2F binding. We find that phosphorylation of S788 and S795 weakens the direct association between the N-terminal portion of RbC (RbC(N)) and the marked-box domains of E2F and its heterodimerization partner DP. Phosphorylation of these sites and S807/S811 also induces an intramolecular association between RbC and the pocket domain, which overlaps with the site of E2F transactivation domain binding. A reduction in E2F binding affinity occurs with S788/S795 phosphorylation that is additive with the effects of phosphorylation at other sites, and we propose a structural mechanism that explains this additivity. We find that different Rb phosphorylation events have distinct effects on activating E2F family members, which suggests a novel mechanism for how Rb may differentially regulate E2F activities.
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Affiliation(s)
- Jason R Burke
- Department of Chemistry and Biochemistry, University of California Santa Cruz, CA 95064, USA
| | - Tyler J Liban
- Department of Chemistry and Biochemistry, University of California Santa Cruz, CA 95064, USA
| | - Tamara Restrepo
- Department of Chemistry and Biochemistry, University of California Santa Cruz, CA 95064, USA
| | - Hsiau-Wei Lee
- Department of Chemistry and Biochemistry, University of California Santa Cruz, CA 95064, USA
| | - Seth M Rubin
- Department of Chemistry and Biochemistry, University of California Santa Cruz, CA 95064, USA.
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11
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Prediction and analysis of retinoblastoma related genes through gene ontology and KEGG. BIOMED RESEARCH INTERNATIONAL 2013; 2013:304029. [PMID: 23998122 PMCID: PMC3755425 DOI: 10.1155/2013/304029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Accepted: 07/16/2013] [Indexed: 11/18/2022]
Abstract
One of the most important and challenging problems in biomedicine is how to predict the cancer related genes. Retinoblastoma (RB) is the most common primary intraocular malignancy usually occurring in childhood. Early detection of RB could reduce the morbidity and promote the probability of disease-free survival. Therefore, it is of great importance to identify RB genes. In this study, we developed a computational method to predict RB related genes based on Dagging, with the maximum relevance minimum redundancy (mRMR) method followed by incremental feature selection (IFS). 119 RB genes were compiled from two previous RB related studies, while 5,500 non-RB genes were randomly selected from Ensemble genes. Ten datasets were constructed based on all these RB and non-RB genes. Each gene was encoded with a 13,126-dimensional vector including 12,887 Gene Ontology enrichment scores and 239 KEGG enrichment scores. Finally, an optimal feature set including 1061 GO terms and 8 KEGG pathways was obtained. Analysis showed that these features were closely related to RB. It is anticipated that the method can be applied to predict the other cancer related genes as well.
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12
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Chemes LB, Noval MG, Sánchez IE, de Prat-Gay G. Folding of a cyclin box: linking multitarget binding to marginal stability, oligomerization, and aggregation of the retinoblastoma tumor suppressor AB pocket domain. J Biol Chem 2013; 288:18923-38. [PMID: 23632018 DOI: 10.1074/jbc.m113.467316] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The retinoblastoma tumor suppressor (Rb) controls the proliferation, differentiation, and survival of cells in most eukaryotes with a role in the fate of stem cells. Its inactivation by mutation or oncogenic viruses is required for cellular transformation and eventually carcinogenesis. The high conservation of the Rb cyclin fold prompted us to investigate the link between conformational stability and ligand binding properties of the RbAB pocket domain. RbAB unfolding presents a three-state transition involving cooperative secondary and tertiary structure changes and a partially folded intermediate that can oligomerize. The first transition corresponds to unfolding of the metastable B subdomain containing the binding site for the LXCXE motif present in cellular and viral targets, and the second transition corresponds to the stable A subdomain. The low thermodynamic stability of RbAB translates into a propensity to rapidly oligomerize and aggregate at 37 °C (T50 = 28 min) that is suppressed by human papillomavirus E7 and E2F peptide ligands, suggesting that Rb is likely stabilized in vivo through binding to target proteins. We propose that marginal stability and associated oligomerization may be conserved for function as a "hub" protein, allowing the formation of multiprotein complexes, which could constitute a robust mechanism to retain its cell cycle regulatory role throughout evolution. Decreased stability and oligomerization are shared with the p53 tumor suppressor, suggesting a link between folding and function in these two essential cell regulators that are inactivated in most cancers and operate within multitarget signaling pathways.
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Affiliation(s)
- Lucía B Chemes
- Protein Structure-Function and Engineering Laboratory, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas de Buenos Aires-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Avenida Patricias Argentinas 435, 1405 Buenos Aires, Argentina
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Abstract
Inactivation of the RB protein is one of the most fundamental events in cancer. Coming to a molecular understanding of its function in normal cells and how it impedes cancer development has been challenging. Historically, the ability of RB to regulate the cell cycle placed it in a central role in proliferative control, and research focused on RB regulation of the E2F family of transcription factors. Remarkably, several recent studies have found additional tumour-suppressor functions of RB, including alternative roles in the cell cycle, maintenance of genome stability and apoptosis. These advances and new structural studies are combining to define the multifunctionality of RB.
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