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Barrett AK, Shingare MR, Rechtsteiner A, Rodriguez KM, Le QN, Wijeratne TU, Mitchell CE, Membreno MW, Rubin SM, Müller GA. HDAC activity is dispensable for repression of cell-cycle genes by DREAM and E2F:RB complexes. Nat Commun 2024; 15:4450. [PMID: 38789411 PMCID: PMC11126580 DOI: 10.1038/s41467-024-48724-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 05/10/2024] [Indexed: 05/26/2024] Open
Abstract
Histone deacetylases (HDACs) play a crucial role in transcriptional regulation and are implicated in various diseases, including cancer. They are involved in histone tail deacetylation and canonically linked to transcriptional repression. Previous studies suggested that HDAC recruitment to cell-cycle gene promoters via the retinoblastoma (RB) protein or the DREAM complex through SIN3B is essential for G1/S and G2/M gene repression during cell-cycle arrest and exit. Here we investigate the interplay among DREAM, RB, SIN3 proteins, and HDACs in the context of cell-cycle gene repression. Knockout of SIN3B does not globally derepress cell-cycle genes in non-proliferating HCT116 and C2C12 cells. Loss of SIN3A/B moderately upregulates several cell-cycle genes in HCT116 cells but does so independently of DREAM/RB. HDAC inhibition does not induce general upregulation of RB/DREAM target genes in arrested transformed or non-transformed cells. Our findings suggest that E2F:RB and DREAM complexes can repress cell-cycle genes without relying on HDAC activity.
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Affiliation(s)
- Alison K Barrett
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Manisha R Shingare
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Andreas Rechtsteiner
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA, USA
| | - Kelsie M Rodriguez
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Quynh N Le
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Tilini U Wijeratne
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Corbin E Mitchell
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Miles W Membreno
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA
| | - Seth M Rubin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA.
| | - Gerd A Müller
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA, USA.
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2
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Zaragoza JZ, Klap K, Heidstra R, Zhou W, Scheres B. The dual role of the RETINOBLASTOMA-RELATED protein in the DNA damage response is coordinated by the interaction with LXCXE-containing proteins. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:1194-1206. [PMID: 38321589 DOI: 10.1111/tpj.16665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 01/10/2024] [Accepted: 01/18/2024] [Indexed: 02/08/2024]
Abstract
Living organisms possess mechanisms to safeguard genome integrity. To avoid spreading mutations, DNA lesions are detected and cell division is temporarily arrested to allow repair mechanisms. Afterward, cells either resume division or respond to unsuccessful repair by undergoing programmed cell death (PCD). How the success rate of DNA repair connects to later cell fate decisions remains incompletely known, particularly in plants. The Arabidopsis thaliana RETINOBLASTOMA-RELATED1 (RBR) protein and its partner E2FA, play both structural and transcriptional functions in the DNA damage response (DDR). Here we provide evidence that distinct RBR protein interactions with LXCXE motif-containing proteins guide these processes. Using the N849F substitution in the RBR B-pocket domain, which specifically disrupts binding to the LXCXE motif, we show that these interactions are dispensable in unchallenging conditions. However, N849F substitution abolishes RBR nuclear foci and promotes PCD and growth arrest upon genotoxic stress. NAC044, which promotes growth arrest and PCD, accumulates after the initial recruitment of RBR to foci and can bind non-focalized RBR through the LXCXE motif in a phosphorylation-independent manner, allowing interaction at different cell cycle phases. Disrupting NAC044-RBR interaction impairs PCD, but their genetic interaction points to opposite independent roles in the regulation of PCD. The LXCXE-binding dependency of the roles of RBR in the DDR suggests a coordinating mechanism to translate DNA repair success to cell survival. We propose that RBR and NAC044 act in two distinct DDR pathways, but interact to integrate input from both DDR pathways to decide upon an irreversible cell fate decision.
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Affiliation(s)
- Jorge Zamora Zaragoza
- Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
- Department of Biotechnology, Rijk Zwaan Breeding B.V., Eerste Kruisweg 9, 4793 RS, Fijnaart, The Netherlands
| | - Katinka Klap
- Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Renze Heidstra
- Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
| | - Wenkun Zhou
- Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Ben Scheres
- Laboratory of Molecular Biology, Department of Plant Sciences, Wageningen University and Research, 6708 PB, Wageningen, The Netherlands
- Department of Biotechnology, Rijk Zwaan Breeding B.V., Eerste Kruisweg 9, 4793 RS, Fijnaart, The Netherlands
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3
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Barrett A, Shingare MR, Rechtsteiner A, Wijeratne TU, Rodriguez KM, Rubin SM, Müller GA. HDAC activity is dispensable for repression of cell-cycle genes by DREAM and E2F:RB complexes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.28.564489. [PMID: 37961464 PMCID: PMC10634886 DOI: 10.1101/2023.10.28.564489] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Histone deacetylases (HDACs) are pivotal in transcriptional regulation, and their dysregulation has been associated with various diseases including cancer. One of the critical roles of HDAC-containing complexes is the deacetylation of histone tails, which is canonically linked to transcriptional repression. Previous research has indicated that HDACs are recruited to cell-cycle gene promoters through the RB protein or the DREAM complex via SIN3B and that HDAC activity is essential for repressing G1/S and G2/M cell-cycle genes during cell-cycle arrest and exit. In this study, we sought to explore the interdependence of DREAM, RB, SIN3 proteins, and HDACs in the context of cell-cycle gene repression. We found that genetic knockout of SIN3B did not lead to derepression of cell-cycle genes in non-proliferating HCT116 and C2C12 cells. A combined loss of SIN3A and SIN3B resulted in a moderate upregulation in mRNA expression of several cell-cycle genes in arrested HCT116 cells, however, these effects appeared to be independent of DREAM or RB. Furthermore, HDAC inhibition did not induce a general upregulation of RB and DREAM target gene expression in arrested transformed or non-transformed cells. Our findings provide evidence that E2F:RB and DREAM complexes can repress cell-cycle genes without reliance on HDAC activity.
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Affiliation(s)
- Alison Barrett
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
- Current Affiliation: Department of Medicine, Division of Immunology and Rheumatology, Stanford University, Stanford, CA 94305, USA
| | - Manisha R. Shingare
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - Andreas Rechtsteiner
- Department of Molecular, Cell, and Developmental Biology, University of California, Santa Cruz, CA 95064, USA
| | - Tilini U. Wijeratne
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
- Current Affiliation: Department of Medicine, Division of Immunology and Rheumatology, Stanford University, Stanford, CA 94305, USA
| | - Kelsie M. Rodriguez
- 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
| | - Gerd A. Müller
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
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4
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León-Ruiz JA, Cruz Ramírez A. Predicted landscape of RETINOBLASTOMA-RELATED LxCxE-mediated interactions across the Chloroplastida. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 112:1507-1524. [PMID: 36305297 DOI: 10.1111/tpj.16012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 09/20/2022] [Accepted: 10/14/2022] [Indexed: 05/16/2023]
Abstract
The colonization of land by a single streptophyte algae lineage some 450 million years ago has been linked to multiple key innovations such as three-dimensional growth, alternation of generations, the presence of stomata, as well as innovations inherent to the birth of major plant lineages, such as the origins of vascular tissues, roots, seeds and flowers. Multicellularity, which evolved multiple times in the Chloroplastida coupled with precise spatiotemporal control of proliferation and differentiation were instrumental for the evolution of these traits. RETINOBLASTOMA-RELATED (RBR), the plant homolog of the metazoan Retinoblastoma protein (pRB), is a highly conserved and multifunctional core cell cycle regulator that has been implicated in the evolution of multicellularity in the green lineage as well as in plant multicellularity-related processes such as proliferation, differentiation, stem cell regulation and asymmetric cell division. RBR fulfills these roles through context-specific protein-protein interactions with proteins containing the Leu-x-Cys-x-Glu (LxCxE) short-linear motif (SLiM); however, how RBR-LxCxE interactions have changed throughout major innovations in the Viridiplantae kingdom is a question that remains unexplored. Here, we employ an in silico evo-devo approach to predict and analyze potential RBR-LxCxE interactions in different representative species of key Chloroplastida lineages, providing a valuable resource for deciphering RBR-LxCxE multiple functions. Furthermore, our analyses suggest that RBR-LxCxE interactions are an important component of RBR functions and that interactions with chromatin modifiers/remodelers, DNA replication and repair machinery are highly conserved throughout the Viridiplantae, while LxCxE interactions with transcriptional regulators likely diversified throughout the water-to-land transition.
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Affiliation(s)
- Jesús A León-Ruiz
- Molecular and Developmental Complexity Group, Unidad de Genómica Avanzada, Laboratorio Nacional de Genómica para la Biodiversidad, Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera, Irapuato-León, Irapuato, 36821, Guanajuato, Mexico
| | - Alfredo Cruz Ramírez
- Molecular and Developmental Complexity Group, Unidad de Genómica Avanzada, Laboratorio Nacional de Genómica para la Biodiversidad, Cinvestav Sede Irapuato, Km. 9.6 Libramiento Norte Carretera, Irapuato-León, Irapuato, 36821, Guanajuato, Mexico
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5
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Putta S, Alvarez L, Lüdtke S, Sehr P, Müller GA, Fernandez SM, Tripathi S, Lewis J, Gibson TJ, Chemes LB, Rubin SM. Structural basis for tunable affinity and specificity of LxCxE-dependent protein interactions with the retinoblastoma protein family. Structure 2022; 30:1340-1353.e3. [PMID: 35716663 PMCID: PMC9444907 DOI: 10.1016/j.str.2022.05.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 04/25/2022] [Accepted: 05/25/2022] [Indexed: 11/25/2022]
Abstract
The retinoblastoma protein (Rb) and its homologs p107 and p130 are critical regulators of gene expression during the cell cycle and are commonly inactivated in cancer. Rb proteins use their "pocket domain" to bind an LxCxE sequence motif in other proteins, many of which function with Rb proteins to co-regulate transcription. Here, we present binding data and crystal structures of the p107 pocket domain in complex with LxCxE peptides from the transcriptional co-repressor proteins HDAC1, ARID4A, and EID1. Our results explain why Rb and p107 have weaker affinity for cellular LxCxE proteins compared with the E7 protein from human papillomavirus, which has been used as the primary model for understanding LxCxE motif interactions. Our structural and mutagenesis data also identify and explain differences in Rb and p107 affinities for some LxCxE-containing sequences. Our study provides new insights into how Rb proteins bind their cell partners with varying affinity and specificity.
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Affiliation(s)
- Sivasankar Putta
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - Lucia Alvarez
- Instituto de Investigaciones Biotecnológicas (IIBiO-CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, Av. 25 de Mayo y Francia, Buenos Aires CP1650, Argentina
| | - Stephan Lüdtke
- Belyntic GmbH, Richard-Willstätter-Str. 11, 12489 Berlin, Germany
| | - Peter Sehr
- Chemical Biology Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Gerd A Müller
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - Samantha M Fernandez
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - Sarvind Tripathi
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA
| | - Joe Lewis
- Chemical Biology Core Facility, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Toby J Gibson
- Structural and Computational Biology Unit, European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | - Lucia B Chemes
- Instituto de Investigaciones Biotecnológicas (IIBiO-CONICET), Escuela de Bio y Nanotecnologías (EByN), Universidad Nacional de San Martín, Av. 25 de Mayo y Francia, Buenos Aires CP1650, Argentina.
| | - Seth M Rubin
- Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064, USA.
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6
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PfARID Regulates P. falciparum Malaria Parasite Male Gametogenesis and Female Fertility and Is Critical for Parasite Transmission to the Mosquito Vector. mBio 2022; 13:e0057822. [PMID: 35638735 PMCID: PMC9239086 DOI: 10.1128/mbio.00578-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sexual reproduction of Plasmodium falciparum parasites is critical to the spread of malaria in the human population. The factors that regulate gene expression underlying formation of fertilization-competent gametes, however, remain unknown. Here, we report that P. falciparum expresses a protein with an AT-rich interaction domain (ARID) which, in other organisms, is part of chromatin remodeling complexes. P. falciparum ARID (PfARID) localized to the parasite nucleus and is critical for the formation of male gametes and fertility of female gametes. PfARID gene deletion (Pfarid–) gametocytes showed downregulation of gene expression important for gametogenesis, antigenic variation, and cell signaling and for parasite development in the mosquito. Our study identifies PfARID as a critical nuclear protein involved in regulating the gene expression landscape of mature gametocytes. This establishes fertility and also prepares the parasite for postfertilization events that are essential for infection of the mosquito vector.
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7
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He K, Li Z, Ye K, Zhou Y, Yan M, Qi H, Hu H, Dai Y, Tang Y. Novel sequential therapy with metformin enhances the effects of cisplatin in testicular germ cell tumours via YAP1 signalling. Cancer Cell Int 2022; 22:113. [PMID: 35264157 PMCID: PMC8905836 DOI: 10.1186/s12935-022-02534-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 02/24/2022] [Indexed: 12/03/2022] Open
Abstract
Background Testicular germ cell tumours (TGCTs) are the most commonly diagnosed malignancy in young men. Although cisplatin has been shown to be effective to treat TGCT patients, long-term follow-up has shown that TGCT survivors who accepted cisplatin treatment suffered from a greater number of adverse reactions than patients who underwent orchiectomy alone. As metformin has shown an anticancer effect in various cancers, we investigated whether metformin could enhance the effects of cisplatin to treat TGCTs. Methods The anticancer effects of different treatment strategies consisting of metformin and cisplatin in TCam-2 and NTERA-2 cells were assessed in vitro and in vivo. First, we used a colony formation assay, CCK-8 and MTT assays to explore the viability of TGCT cells. Flow cytometry was used to assess the cell cycle and apoptosis of TGCTs. Then, Western blotting was used to detect the protein expression of TGCTs cells after different treatments. In addition, a xenograft model was used to investigate the effects of the different treatments on the proliferation of TGCT cells. Immunohistochemistry assays were performed to analyse the expression of related proteins in the tissues from the xenograft model. Results Metformin inhibited the proliferation of TCam-2 and NTERA-2 cells by arresting them in G1 phase, while metformin did not induce apoptosis in TGCT cells. Compared with cisplatin monotherapy, the CCK-8, MTT assay and colony formation assay showed that sequential treatment with metformin and cisplatin produced enhanced anticancer effects. Further study showed that metformin blocked the cells in G1 phase by inducing phosphorylated YAP1 and reducing the expression of cyclin D1, CDK6, CDK4 and RB, which enhanced the chemosensitivity of cisplatin and activated the expression of cleaved caspase 3 in TGCTs. Conclusions Our study discovers the important role of YAP1 in TGCTs and reports a new treatment strategy that employs the sequential administration of metformin and cisplatin, which can reduce the required cisplatin dose and enhance the sensitivity of TGCT cells to cisplatin. Therefore, this sequential treatment strategy may facilitate the development of basic and clinical research for anticancer therapies to treat TGCTs.
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Affiliation(s)
- Kancheng He
- Department of Urology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China.,Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China
| | - Zitaiyu Li
- Department of Urology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China.,Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China
| | - Kun Ye
- Department of Urology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China.,Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China
| | - Yihong Zhou
- Department of Urology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China
| | - Minbo Yan
- Department of Urology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China
| | - Hao Qi
- Department of Urology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China.,Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China
| | - Huating Hu
- State Key Laboratory of Quality Research in Chinese Medicine/Macau Institute for Applied Research in Medicine and Health, Macau University of Science and Technology, Avenida Wai Long, Taipa, Macao, China
| | - Yingbo Dai
- Department of Urology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China. .,Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China.
| | - Yuxin Tang
- Department of Urology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China. .,Guangdong Provincial Key Laboratory of Biomedical Imaging, The Fifth Affiliated Hospital, Sun Yat-Sen University, Zhuhai, 519000, Guangdong, China.
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8
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Ramanujan A, Bansal S, Guha M, Pande NT, Tiwari S. LxCxD motif of the APC/C coactivator subunit FZR1 is critical for interaction with the retinoblastoma protein. Exp Cell Res 2021; 404:112632. [PMID: 33971196 DOI: 10.1016/j.yexcr.2021.112632] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/19/2021] [Accepted: 04/27/2021] [Indexed: 10/21/2022]
Abstract
Retinoblastoma protein (pRB) regulates cell cycle by utilizing different regions of its pocket domain for interacting with E2F family of transcription factors and with cellular and viral proteins containing an LxCxE motif. An LxCxE-like motif, LxCxD, is present in FZR1, an adaptor protein of the multi-subunit E3 ligase complex anaphase-promoting complex/cyclosome (APC/C). The APC/CFZR1 complex regulates the timely degradation of multiple cell cycle proteins for mitotic exit and maintains G1 state. We report that FZR1 interacts with pRB via its LxCxD motif. By using point mutations, we found that the cysteine residue in the FZR1 LxCxD motif is critical for direct interaction with pRb. The direct binding of the LxCxD motif of FZR1 to the pRB LxCxE binding pocket is confirmed by using human papillomavirus protein E7 as a competitor, both in vitro and in vivo. While mutation of the cysteine residue significantly disrupts FZR1 interaction with pRB, this motif does not affect FZR1 and core APC/C association. Expression of the FZR1 point mutant results in accumulation of S-phase kinase-associated protein 2 (SKP2) and Polo-like kinase 1 (PLK1), while p27Kip1 and p21Cip1 proteins are downregulated, indicating a G1 cell cycle defect. Consistently, cells containing point mutant FZR1 enter the S phase prematurely. Together our results suggest that the LxCxD motif of FZR1 is a critical determinant for the interaction between FZR1 and pRB and is important for G1 restriction.
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Affiliation(s)
- Ajeena Ramanujan
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Shivangee Bansal
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Manalee Guha
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Nupur T Pande
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Swati Tiwari
- School of Biotechnology, Jawaharlal Nehru University, New Delhi, 110067, India.
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9
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An RB-Condensin II Complex Mediates Long-Range Chromosome Interactions and Influences Expression at Divergently Paired Genes. Mol Cell Biol 2020; 40:MCB.00452-19. [PMID: 31685548 DOI: 10.1128/mcb.00452-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 10/23/2019] [Indexed: 12/19/2022] Open
Abstract
Interphase chromosomes are organized into topologically associated domains in order to establish and maintain integrity of transcriptional programs that remain poorly understood. Here, we show that condensin II and TFIIIC are recruited to bidirectionally transcribed promoters by a mechanism that is dependent on the retinoblastoma (RB) protein. Long-range chromosome contacts are disrupted by loss of condensin II loading, which leads to altered expression at bidirectional gene pairs. This study demonstrates that mammalian condensin II functions to organize long-range chromosome contacts and regulate transcription at specific genes. In addition, RB dependence of condensin II suggests that widespread misregulation of chromosome contacts and transcriptional alterations are a consequence of RB mutation.
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10
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Eberhardt K, Matthäus C, Marthandan S, Diekmann S, Popp J. Raman and infrared spectroscopy reveal that proliferating and quiescent human fibroblast cells age by biochemically similar but not identical processes. PLoS One 2018; 13:e0207380. [PMID: 30507927 PMCID: PMC6277109 DOI: 10.1371/journal.pone.0207380] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 10/30/2018] [Indexed: 12/22/2022] Open
Abstract
Dermal fibroblast cells can adopt different cell states such as proliferation, quiescence, apoptosis or senescence, in order to ensure tissue homeostasis. Proliferating (dividing) cells pass through the phases of the cell cycle, while quiescent and senescent cells exist in a non-proliferating cell cycle-arrested state. However, the reversible quiescence state is in contrast to the irreversible senescence state. Long-term quiescent cells transit into senescence indicating that cells age also when not passing through the cell cycle. Here, by label-free in vitro vibrational spectroscopy, we studied the biomolecular composition of quiescent dermal fibroblast cells and compared them with those of proliferating and senescent cells. Spectra were examined by multivariate statistical analysis using a PLS-LDA classification model, revealing differences in the biomolecular composition between the cell states mainly associated with protein alterations (variations in the side chain residues of amino acids and protein secondary structure), but also within nucleic acids and lipids. We observed spectral changes in quiescent compared to proliferating cells, which increased with quiescence cultivation time. Raman and infrared spectroscopy, which yield complementary biochemical information, clearly distinguished contact-inhibited from serum-starved quiescent cells. Furthermore, the spectra displayed spectral differences between quiescent cells and proliferating cells, which had recovered from quiescence. This became more distinct with increasing quiescence cultivation time. When comparing proliferating, (in particular long-term) quiescent and senescent cells, we found that Raman as well as infrared spectroscopy can separate these three cellular states from each other due to differences in their biomolecular composition. Our spectroscopic analysis shows that proliferating and quiescent fibroblast cells age by similar but biochemically not identical processes. Despite their aging induced changes, over long time periods quiescent cells can return into the cell cycle. Finally however, the cell cycle arrest becomes irreversible indicating senescence.
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Affiliation(s)
- Katharina Eberhardt
- Spectroscopy and Imaging, Leibniz Institute of Photonic Technology, Jena, Germany
| | - Christian Matthäus
- Spectroscopy and Imaging, Leibniz Institute of Photonic Technology, Jena, Germany
- Institute for Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, Germany
| | - Shiva Marthandan
- Department of Molecular Biology, Leibniz Institute on Aging – Fritz Lipmann Institute, Jena, Germany
| | - Stephan Diekmann
- Department of Molecular Biology, Leibniz Institute on Aging – Fritz Lipmann Institute, Jena, Germany
| | - Jürgen Popp
- Spectroscopy and Imaging, Leibniz Institute of Photonic Technology, Jena, Germany
- Institute for Physical Chemistry and Abbe Center of Photonics, Friedrich Schiller University, Jena, Germany
- * E-mail:
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11
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Abstract
The canonical model of RB-mediated tumour suppression developed over the past 30 years is based on the regulation of E2F transcription factors to restrict cell cycle progression. Several additional functions have been proposed for RB, on the basis of which a non-canonical RB pathway can be described. Mechanistically, the non-canonical RB pathway promotes histone modification and regulates chromosome structure in a manner distinct from cell cycle regulation. These functions have implications for chemotherapy response and resistance to targeted anticancer agents. This Opinion offers a framework to guide future studies of RB in basic and clinical research.
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Affiliation(s)
- Frederick A Dick
- London Regional Cancer Program, Children's Health Research Institute, Western University, London, Ontario, Canada.
- London Regional Cancer Program, Department of Biochemistry, Western University, London, Ontario, Canada.
| | - David W Goodrich
- Department of Pharmacology and Therapeutics, Roswell Park Cancer Institute, Buffalo, NY, USA
| | - Julien Sage
- Departments of Pediatrics and Genetics, Stanford University, Stanford, CA, USA
| | - Nicholas J Dyson
- Massachusetts General Hospital Cancer Center, Laboratory of Molecular Oncology, Harvard Medical School, Charlestown, MA, USA
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12
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Fischer M, Müller GA. Cell cycle transcription control: DREAM/MuvB and RB-E2F complexes. Crit Rev Biochem Mol Biol 2017; 52:638-662. [PMID: 28799433 DOI: 10.1080/10409238.2017.1360836] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The precise timing of cell cycle gene expression is critical for the control of cell proliferation; de-regulation of this timing promotes the formation of cancer and leads to defects during differentiation and development. Entry into and progression through S phase requires expression of genes coding for proteins that function in DNA replication. Expression of a distinct set of genes is essential to pass through mitosis and cytokinesis. Expression of these groups of cell cycle-dependent genes is regulated by the RB pocket protein family, the E2F transcription factor family, and MuvB complexes together with B-MYB and FOXM1. Distinct combinations of these transcription factors promote the transcription of the two major groups of cell cycle genes that are maximally expressed either in S phase (G1/S) or in mitosis (G2/M). In this review, we discuss recent work that has started to uncover the molecular mechanisms controlling the precisely timed expression of these genes at specific cell cycle phases, as well as the repression of the genes when a cell exits the cell cycle.
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Affiliation(s)
- Martin Fischer
- a Molecular Oncology, Medical School, University of Leipzig , Leipzig , Germany.,b Department of Medical Oncology , Dana-Farber Cancer Institute , Boston , MA , USA.,c Department of Medicine, Brigham and Women's Hospital , Harvard Medical School , Boston , MA , USA
| | - Gerd A Müller
- a Molecular Oncology, Medical School, University of Leipzig , Leipzig , Germany
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13
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Thwaites MJ, Cecchini MJ, Talluri S, Passos DT, Carnevale J, Dick FA. Multiple molecular interactions redundantly contribute to RB-mediated cell cycle control. Cell Div 2017; 12:3. [PMID: 28293272 PMCID: PMC5348811 DOI: 10.1186/s13008-017-0029-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 02/28/2017] [Indexed: 02/07/2023] Open
Abstract
Background The G1-S phase transition is critical to maintaining proliferative control and preventing carcinogenesis. The retinoblastoma tumor suppressor is a key regulator of this step in the cell cycle. Results Here we use a structure–function approach to evaluate the contributions of multiple protein interaction surfaces on pRB towards cell cycle regulation. SAOS2 cell cycle arrest assays showed that disruption of three separate binding surfaces were necessary to inhibit pRB-mediated cell cycle control. Surprisingly, mutation of some interaction surfaces had no effect on their own. Rather, they only contributed to cell cycle arrest in the absence of other pRB dependent arrest functions. Specifically, our data shows that pRB–E2F interactions are competitive with pRB–CDH1 interactions, implying that interchangeable growth arrest functions underlie pRB’s ability to block proliferation. Additionally, disruption of similar cell cycle control mechanisms in genetically modified mutant mice results in ectopic DNA synthesis in the liver. Conclusions Our work demonstrates that pRB utilizes a network of mechanisms to prevent cell cycle entry. This has important implications for the use of new CDK4/6 inhibitors that aim to activate this proliferative control network.
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Affiliation(s)
- Michael J Thwaites
- London Regional Cancer Program, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| | - Matthew J Cecchini
- London Regional Cancer Program, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| | - Srikanth Talluri
- London Regional Cancer Program, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| | - Daniel T Passos
- London Regional Cancer Program, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| | - Jasmyne Carnevale
- London Regional Cancer Program, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
| | - Frederick A Dick
- London Regional Cancer Program, London, Canada.,Children's Health Research Institute, London, Canada.,Department of Biochemistry, Western University, London, ON Canada
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14
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Augello MA, Berman-Booty LD, Carr R, Yoshida A, Dean JL, Schiewer MJ, Feng FY, Tomlins SA, Gao E, Koch WJ, Benovic JL, Diehl JA, Knudsen KE. Consequence of the tumor-associated conversion to cyclin D1b. EMBO Mol Med 2016; 7:628-47. [PMID: 25787974 PMCID: PMC4492821 DOI: 10.15252/emmm.201404242] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Clinical evidence suggests that cyclin D1b, a variant of cyclin D1, is associated with tumor progression and poor outcome. However, the underlying molecular basis was unknown. Here, novel models were created to generate a genetic switch from cyclin D1 to cyclin D1b. Extensive analyses uncovered overlapping but non-redundant functions of cyclin D1b compared to cyclin D1 on developmental phenotypes, and illustrated the importance of the transcriptional regulatory functions of cyclin D1b in vivo. Data obtained identify cyclin D1b as an oncogene, wherein cyclin D1b expression under the endogenous promoter induced cellular transformation and further cooperated with known oncogenes to promote tumor growth in vivo. Further molecular interrogation uncovered unexpected links between cyclin D1b and the DNA damage/PARP1 regulatory networks, which could be exploited to suppress cyclin D1b-driven tumors. Collectively, these data are the first to define the consequence of cyclin D1b expression on normal cellular function, present evidence for cyclin D1b as an oncogene, and provide pre-clinical evidence of effective methods to thwart growth of cells dependent upon this oncogenic variant.
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Affiliation(s)
- Michael A Augello
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, PA, USA Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Lisa D Berman-Booty
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, PA, USA Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Richard Carr
- Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Akihiro Yoshida
- Medical University of South Carolina, Charleston, SC, USA Hollings Cancer Center, Charleston, SC, USA
| | - Jeffry L Dean
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, PA, USA Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Matthew J Schiewer
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, PA, USA Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Felix Y Feng
- Michigan Center for Translational Pathology, University of Michigan Medical Center, Ann Arbor, MI, USA Department of Radiation Oncology, University of Michigan Medical Center, Ann Arbor, MI, USA Comprehensive Cancer Center University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Scott A Tomlins
- Michigan Center for Translational Pathology, University of Michigan Medical Center, Ann Arbor, MI, USA Comprehensive Cancer Center University of Michigan Medical Center, Ann Arbor, MI, USA Department of Urology, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Erhe Gao
- Pharmacology & Center for Translational Medicine, Philadelphia, PA, USA
| | - Walter J Koch
- Pharmacology & Center for Translational Medicine, Philadelphia, PA, USA Temple University School of Medicine, Philadelphia, PA, USA
| | - Jeffrey L Benovic
- Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - John Alan Diehl
- Medical University of South Carolina, Charleston, SC, USA Hollings Cancer Center, Charleston, SC, USA
| | - Karen E Knudsen
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, PA, USA Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA Department of Urology, Thomas Jefferson University, Philadelphia, PA, USA Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, PA, USA
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15
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CDK6-a review of the past and a glimpse into the future: from cell-cycle control to transcriptional regulation. Oncogene 2015; 35:3083-91. [PMID: 26500059 DOI: 10.1038/onc.2015.407] [Citation(s) in RCA: 115] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 09/22/2015] [Accepted: 09/22/2015] [Indexed: 12/19/2022]
Abstract
The G1 cell-cycle kinase CDK6 has long been thought of as a redundant homolog of CDK4. Although the two kinases have very similar roles in cell-cycle progression, it has recently become apparent that they differ in tissue-specific functions and contribute differently to tumor development. CDK6 is directly involved in transcription in tumor cells and in hematopoietic stem cells. These functions point to a role of CDK6 in tissue homeostasis and differentiation that is partially independent of CDK6's kinase activity and is not shared with CDK4. We review the literature on the contribution of CDK6 to transcription in an attempt to link the new findings on CDK6's transcriptional activity to cell-cycle progression. Finally, we note that anticancer therapies based on the inhibition of CDK6 kinase activity fail to take into account its kinase-independent role in tumor development.
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16
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Knudsen ES, McClendon AK, Franco J, Ertel A, Fortina P, Witkiewicz AK. RB loss contributes to aggressive tumor phenotypes in MYC-driven triple negative breast cancer. Cell Cycle 2015; 14:109-22. [PMID: 25602521 DOI: 10.4161/15384101.2014.967118] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Triple negative breast cancer (TNBC) is characterized by multiple genetic events occurring in concert to drive pathogenic features of the disease. Here we interrogated the coordinate impact of p53, RB, and MYC in a genetic model of TNBC, in parallel with the analysis of clinical specimens. Primary mouse mammary epithelial cells (mMEC) with defined genetic features were used to delineate the combined action of RB and/or p53 in the genesis of TNBC. In this context, the deletion of either RB or p53 alone and in combination increased the proliferation of mMEC; however, the cells did not have the capacity to invade in matrigel. Gene expression profiling revealed that loss of each tumor suppressor has effects related to proliferation, but RB loss in particular leads to alterations in gene expression associated with the epithelial-to-mesenchymal transition. The overexpression of MYC in combination with p53 loss or combined RB/p53 loss drove rapid cell growth. While the effects of MYC overexpression had a dominant impact on gene expression, loss of RB further enhanced the deregulation of a gene expression signature associated with invasion. Specific RB loss lead to enhanced invasion in boyden chambers assays and gave rise to tumors with minimal epithelial characteristics relative to RB-proficient models. Therapeutic screening revealed that RB-deficient cells were particularly resistant to agents targeting PI3K and MEK pathway. Consistent with the aggressive behavior of the preclinical models of MYC overexpression and RB loss, human TNBC tumors that express high levels of MYC and are devoid of RB have a particularly poor outcome. Together these results underscore the potency of tumor suppressor pathways in specifying the biology of breast cancer. Further, they demonstrate that MYC overexpression in concert with RB can promote a particularly aggressive form of TNBC.
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Affiliation(s)
- Erik S Knudsen
- a Simmons Cancer Center; UT Southwestern ; Dallas , TX USA
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17
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Sun Y, Stine JM, Atwater DZ, Sharmin A, Ross JBA, Briknarová K. Structural and functional characterization of the acidic region from the RIZ tumor suppressor. Biochemistry 2015; 54:1390-400. [PMID: 25640033 DOI: 10.1021/bi501398w] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
RIZ (retinoblastoma protein-interacting zinc finger protein), also denoted PRDM2, is a transcriptional regulator and tumor suppressor. It was initially identified because of its ability to interact with another well-established tumor suppressor, the retinoblastoma protein (Rb). A short motif, IRCDE, in the acidic region (AR) of RIZ was reported to play an important role in the interaction with the pocket domain of Rb. The IRCDE motif is similar to a consensus Rb-binding sequence LXCXE (where X denotes any amino acid) that is found in several viral Rb-inactivating oncoproteins. To improve our understanding of the molecular basis of binding of Rb to RIZ, we investigated the interaction between purified recombinant AR and the pocket domain of Rb using nuclear magnetic resonance spectroscopy, isothermal titration calorimetry, and fluorescence anisotropy experiments. We show that AR is intrinsically disordered and that it binds the pocket domain with submicromolar affinity. We also demonstrate that the interaction between AR and the pocket domain is mediated primarily by the short stretch of residues containing the IRCDE motif and that the contribution of other parts of AR to the interaction with the pocket domain is minimal. Overall, our data provide clear evidence that RIZ is one of the few cellular proteins that can interact directly with the LXCXE-binding cleft on Rb.
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Affiliation(s)
- Yizhi Sun
- Department of Chemistry and Biochemistry, University of Montana , Missoula, Montana 59812, United States
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18
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Carper MB, Denvir J, Boskovic G, Primerano DA, Claudio PP. RGS16, a novel p53 and pRb cross-talk candidate inhibits migration and invasion of pancreatic cancer cells. Genes Cancer 2015; 5:420-35. [PMID: 25568667 PMCID: PMC4279439 DOI: 10.18632/genesandcancer.43] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 11/26/2014] [Indexed: 12/11/2022] Open
Abstract
Data collected since the discovery of p53 and pRb/RB1 suggests these tumor suppressors cooperate to inhibit tumor progression. Patients who have mutations in both p53 and RB1 genes have increased tumor reoccurrence and decreased survival compared to patients with only one tumor suppressor gene inactivated. It remains unclear how p53 and pRb cooperate toward inhibiting tumorigenesis. Using RNA expression profiling we identified 179 p53 and pRb cross-talk candidates in normal lung fibroblasts (WI38) cells exogenously coexpressing p53 and pRb. Regulator of G protein signaling 16 (RGS16) was among the p53 and pRb cross-talk candidates and has been implicated in inhibiting activation of several oncogenic pathways associated with proliferation, migration, and invasion of cancer cells. RGS16 has been found to be downregulated in pancreatic cancer patients with metastases compared to patients without metastasis. Expression of RGS16 mRNA was decreased in the pancreatic cancer cell lines tested compared to control. Expression of RGS16 inhibited migration of the BxPC-3 and AsPC-1 but not PANC-1 cells and inhibited invasion of BxPC-3 and AsPC-1 cells with no impact on cell viability. We have identified for the first time p53 and pRb cross-talk candidates and a role for RGS16 to inhibit pancreatic cancer migration and invasion.
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Affiliation(s)
- Miranda B Carper
- McKown Translational Genomic Research Institute, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, USA ; Department of Biochemistry and Microbiology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, USA
| | - James Denvir
- Department of Biochemistry and Microbiology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, USA
| | - Goran Boskovic
- Department of Biochemistry and Microbiology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, USA
| | - Donald A Primerano
- Department of Biochemistry and Microbiology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, USA
| | - Pier Paolo Claudio
- McKown Translational Genomic Research Institute, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, USA ; Department of Biochemistry and Microbiology, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, USA ; Department of Surgery, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV, USA
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19
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Vormer TL, Hansen JB, Te Riele H. The retinoblastoma protein: multitasking to suppress tumorigenesis. Mol Cell Oncol 2015; 2:e968062. [PMID: 27308398 PMCID: PMC4905230 DOI: 10.4161/23723548.2014.968062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 08/17/2014] [Accepted: 08/18/2014] [Indexed: 11/25/2022]
Abstract
Tumor suppressor activity of the retinoblastoma protein pRB is preserved despite loss of interaction with E2F transcription factors (E2F) or proteins harboring a leucine-x-cysteine-x-glutamic acid motif (LxCxE, where x is any amino acid). This indicates that pRB uses several parallel pathways to suppress tumorigenesis, which may also include E2F- and LxCxE-independent interactions.
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Affiliation(s)
- Tinke L Vormer
- Division of Biological Stress Response; The Netherlands Cancer Institute ; Amsterdam, The Netherlands
| | - Jacob B Hansen
- Department of Biology; University of Copenhagen ; Copenhagen, Denmark
| | - Hein Te Riele
- Division of Biological Stress Response; The Netherlands Cancer Institute ; Amsterdam, The Netherlands
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20
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Kareta MS, Gorges LL, Hafeez S, Benayoun BA, Marro S, Zmoos AF, Cecchini MJ, Spacek D, Batista LFZ, O'Brien M, Ng YH, Ang CE, Vaka D, Artandi SE, Dick FA, Brunet A, Sage J, Wernig M. Inhibition of pluripotency networks by the Rb tumor suppressor restricts reprogramming and tumorigenesis. Cell Stem Cell 2014; 16:39-50. [PMID: 25467916 DOI: 10.1016/j.stem.2014.10.019] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2013] [Revised: 08/18/2014] [Accepted: 10/24/2014] [Indexed: 12/15/2022]
Abstract
Mutations in the retinoblastoma tumor suppressor gene Rb are involved in many forms of human cancer. In this study, we investigated the early consequences of inactivating Rb in the context of cellular reprogramming. We found that Rb inactivation promotes the reprogramming of differentiated cells to a pluripotent state. Unexpectedly, this effect is cell cycle independent, and instead reflects direct binding of Rb to pluripotency genes, including Sox2 and Oct4, which leads to a repressed chromatin state. More broadly, this regulation of pluripotency networks and Sox2 in particular is critical for the initiation of tumors upon loss of Rb in mice. These studies therefore identify Rb as a global transcriptional repressor of pluripotency networks, providing a molecular basis for previous reports about its involvement in cell fate pliability, and implicate misregulation of pluripotency factors such as Sox2 in tumorigenesis related to loss of Rb function.
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Affiliation(s)
- Michael S Kareta
- Department of Pediatrics, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA; Department of Pathology, Stanford University, Stanford, CA 94305, USA; Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA
| | - Laura L Gorges
- Department of Pediatrics, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Sana Hafeez
- Department of Pathology, Stanford University, Stanford, CA 94305, USA; Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA
| | - Bérénice A Benayoun
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Paul F. Glenn Laboratories for the Biology of Aging, Stanford University, Stanford, CA 94305, USA
| | - Samuele Marro
- Department of Pathology, Stanford University, Stanford, CA 94305, USA; Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA
| | - Anne-Flore Zmoos
- Department of Pediatrics, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Matthew J Cecchini
- London Regional Cancer Program, Children's Research Institute, Western University, London, ON N6A 4L6, Canada
| | - Damek Spacek
- Department of Pediatrics, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Luis F Z Batista
- Department of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University, Stanford, CA 94305, USA; Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA
| | - Megan O'Brien
- Department of Pediatrics, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Yi-Han Ng
- Department of Pathology, Stanford University, Stanford, CA 94305, USA; Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA
| | - Cheen Euong Ang
- Department of Pathology, Stanford University, Stanford, CA 94305, USA; Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA
| | - Dedeepya Vaka
- Department of Pediatrics, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Steven E Artandi
- Department of Medicine, Stanford University, Stanford, CA 94305, USA; Department of Biochemistry, Stanford University, Stanford, CA 94305, USA; Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA
| | - Frederick A Dick
- London Regional Cancer Program, Children's Research Institute, Western University, London, ON N6A 4L6, Canada
| | - Anne Brunet
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Paul F. Glenn Laboratories for the Biology of Aging, Stanford University, Stanford, CA 94305, USA
| | - Julien Sage
- Department of Pediatrics, Stanford University, Stanford, CA 94305, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA.
| | - Marius Wernig
- Department of Pathology, Stanford University, Stanford, CA 94305, USA; Stanford Institute for Stem Cell Biology and Regenerative Medicine, Stanford University, Stanford, CA 94305, USA.
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21
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Thangavel C, Boopathi E, Ciment S, Liu Y, O'Neill R, Sharma A, McMahon SB, Mellert H, Addya S, Ertel A, Birbe R, Fortina P, Dicker AP, Knudsen KE, Den RB. The retinoblastoma tumor suppressor modulates DNA repair and radioresponsiveness. Clin Cancer Res 2014; 20:5468-5482. [PMID: 25165096 DOI: 10.1158/1078-0432.ccr-14-0326] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE Perturbations in the retinoblastoma pathway are over-represented in advanced prostate cancer; retinoblastoma loss promotes bypass of first-line hormone therapy. Conversely, preliminary studies suggested that retinoblastoma-deficient tumors may become sensitized to a subset of DNA-damaging agents. Here, the molecular and in vivo consequence of retinoblastoma status was analyzed in models of clinical relevance. EXPERIMENTAL DESIGN Experimental work was performed with multiple isogenic prostate cancer cell lines (hormone sensitive: LNCaP and LAPC4 cells and hormone resistant C42, 22Rv1 cells; stable knockdown of retinoblastoma using shRNA). Multiple mechanisms were interrogated including cell cycle, apoptosis, and DNA damage repair. Transcriptome analysis was performed, validated, and mechanisms discerned. Cell survival was measured using clonogenic cell survival assay and in vivo analysis was performed in nude mice with human derived tumor xenografts. RESULTS Loss of retinoblastoma enhanced the radioresponsiveness of both hormone-sensitive and castrate-resistant prostate cancer. Hypersensitivity to ionizing radiation was not mediated by cell cycle or p53. Retinoblastoma loss led to alteration in DNA damage repair and activation of the NF-κB pathway and subsequent cellular apoptosis through PLK3. In vivo xenografts of retinoblastoma-deficient tumors exhibited diminished tumor mass, lower PSA kinetics, and decreased tumor growth after treatment with ionizing radiation (P < 0.05). CONCLUSIONS Loss of retinoblastoma confers increased radiosensitivity in prostate cancer. This hypersensitization was mediated by alterations in apoptotic signaling. Combined, these not only provide insight into the molecular consequence of retinoblastoma loss, but also credential retinoblastoma status as a putative biomarker for predicting response to radiotherapy.
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Affiliation(s)
| | - Ettickan Boopathi
- Department of Surgery, Division of Urology, Glenolden, Pennsylvania, USA
| | - Steve Ciment
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Yi Liu
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Raymond O'Neill
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Ankur Sharma
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Steve B McMahon
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Hestia Mellert
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Biomedical Graduate Studies, University of Pennsylvania, Philadelphia, Pennsylvania, USA.,Department of Molecular, Cellular and Developmental Biology, University of Colorado at Boulder, Colorado, USA
| | - Sankar Addya
- Cancer Genomics, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Adam Ertel
- Cancer Genomics, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Ruth Birbe
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Paolo Fortina
- Cancer Genomics, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Adam P Dicker
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Karen E Knudsen
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Department of Urology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Robert B Den
- Department of Radiation Oncology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.,Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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22
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Vormer TL, Wojciechowicz K, Dekker M, de Vries S, van der Wal A, Delzenne-Goette E, Naik SH, Song JY, Dannenberg JH, Hansen JB, te Riele H. RB Family Tumor Suppressor Activity May Not Relate to Active Silencing of E2F Target Genes. Cancer Res 2014; 74:5266-76. [DOI: 10.1158/0008-5472.can-13-3706] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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Reed C, Hutcheson J, Mayhew CN, Witkiewicz AK, Knudsen ES. RB tumor suppressive function in response to xenobiotic hepatocarcinogens. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:1853-9. [PMID: 24726645 DOI: 10.1016/j.ajpath.2014.02.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/27/2014] [Accepted: 02/04/2014] [Indexed: 12/30/2022]
Abstract
Diverse etiologic events are associated with the development of hepatocellular carcinoma. During hepatocarcinogenesis, genetic events likely occur that subsequently cooperate with long-term exposures to further drive the progression of hepatocellular carcinoma. In this study, the frequent loss of the retinoblastoma (RB) tumor suppressor in hepatocellular carcinoma was modeled in response to diverse hepatic stresses. Loss of RB did not significantly affect the response to a steatotic stress as driven by a methionine- and choline-deficient diet. In addition, RB status did not significantly influence the response to peroxisome proliferators that can drive hepatomegaly and tumor development in rodents. However, RB loss exhibited a highly significant effect on the response to the xenobiotic1,4-Bis-[2-(3,5-dichloropyridyloxy)] benzene. Loss of RB yielded a unique proliferative response to this agent, which was distinct from both regenerative stresses and genotoxic carcinogens. Long-term exposure to 1,4-Bis-[2-(3,5-dichloropyridyloxy)] benzene yielded profound tumor development in RB-deficient livers that was principally absent in RB-sufficient tissue. These data demonstrate the context specificity of RB and the key role RB plays in the suppression of hepatocellular carcinoma driven by xenobiotic stress.
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Affiliation(s)
- Christopher Reed
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jack Hutcheson
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas
| | | | - Agnieszka K Witkiewicz
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania; Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas; Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Erik S Knudsen
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania; Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas; Simmons Cancer Center, University of Texas Southwestern Medical Center, Dallas, Texas.
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24
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Abstract
Mammalian DREAM is a conserved protein complex that functions in cellular quiescence. DREAM contains an E2F, a retinoblastoma (RB)-family protein, and the MuvB core (LIN9, LIN37, LIN52, LIN54, and RBBP4). In mammals, MuvB can alternatively bind to BMYB to form a complex that promotes mitotic gene expression. Because BMYB-MuvB is essential for proliferation, loss-of-function approaches to study MuvB have generated limited insight into DREAM function. Here, we report a gene-targeted mouse model that is uniquely deficient for DREAM complex assembly. We have targeted p107 (Rbl1) to prevent MuvB binding and combined it with deficiency for p130 (Rbl2). Our data demonstrate that cells from these mice preferentially assemble BMYB-MuvB complexes and fail to repress transcription. DREAM-deficient mice show defects in endochondral bone formation and die shortly after birth. Micro-computed tomography and histology demonstrate that in the absence of DREAM, chondrocytes fail to arrest proliferation. Since DREAM requires DYRK1A (dual-specificity tyrosine phosphorylation-regulated protein kinase 1A) phosphorylation of LIN52 for assembly, we utilized an embryonic bone culture system and pharmacologic inhibition of (DYRK) kinase to demonstrate a similar defect in endochondral bone growth. This reveals that assembly of mammalian DREAM is required to induce cell cycle exit in chondrocytes.
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25
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Stressing the cell cycle in senescence and aging. Curr Opin Cell Biol 2013; 25:765-71. [DOI: 10.1016/j.ceb.2013.07.005] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Revised: 07/08/2013] [Accepted: 07/08/2013] [Indexed: 12/31/2022]
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26
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Blais A. Rb and chromatin remodeling in the maintenance of the post-mitotic state of neurons. Cell Cycle 2013; 12:1661-2. [PMID: 23708446 PMCID: PMC3713122 DOI: 10.4161/cc.25071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- Alexandre Blais
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, Faculty of Medicine, University of Ottawa, Ottawa, ON Canada.
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27
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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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28
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Andrusiak MG, Vandenbosch R, Dick FA, Park DS, Slack RS. LXCXE-independent chromatin remodeling by Rb/E2f mediates neuronal quiescence. Cell Cycle 2013; 12:1416-23. [PMID: 23574720 DOI: 10.4161/cc.24527] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Neuronal survival is dependent upon the retinoblastoma family members, Rb1 (Rb) and Rb2 (p130). Rb is thought to regulate gene repression, in part, through direct recruitment of chromatin modifying enzymes to its conserved LXCXE binding domain. We sought to examine the mechanisms that Rb employs to mediate cell cycle gene repression in terminally differentiated cortical neurons. Here, we report that Rb loss converts chromatin at the promoters of E2f-target genes to an activated state. We established a mouse model system in which Rb-LXCXE interactions could be induciblely disabled. Surprisingly, this had no effect on survival or gene silencing in neuronal quiescence. Absence of the Rb LXCXE-binding domain in neurons is compatible with gene repression and long-term survival, unlike Rb deficiency. Finally, we are able to show that chromatin activation following Rb deletion occurs at the level of E2fs. Blocking E2f-mediated transcription downstream of Rb loss is sufficient to maintain chromatin in an inactive state. Taken together our results suggest a model whereby Rb-E2f interactions are sufficient to maintain gene repression irrespective of LXCXE-dependent chromatin remodeling.
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Affiliation(s)
- Matthew G Andrusiak
- Department of Cellular & Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
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29
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Augello MA, Burd CJ, Birbe R, McNair C, Ertel A, Magee MS, Frigo DE, Wilder-Romans K, Shilkrut M, Han S, Jernigan DL, Dean JL, Fatatis A, McDonnell DP, Visakorpi T, Feng FY, Knudsen KE. Convergence of oncogenic and hormone receptor pathways promotes metastatic phenotypes. J Clin Invest 2012; 123:493-508. [PMID: 23257359 DOI: 10.1172/jci64750] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Accepted: 10/23/2012] [Indexed: 12/11/2022] Open
Abstract
Cyclin D1b is a splice variant of the cell cycle regulator cyclin D1 and is known to harbor divergent and highly oncogenic functions in human cancer. While cyclin D1b is induced during disease progression in many cancer types, the mechanisms underlying cyclin D1b function remain poorly understood. Herein, cell and human tumor xenograft models of prostate cancer were utilized to resolve the downstream pathways that are required for the protumorigenic functions of cyclin D1b. Specifically, cyclin D1b was found to modulate the expression of a large transcriptional network that cooperates with androgen receptor (AR) signaling to enhance tumor cell growth and invasive potential. Notably, cyclin D1b promoted AR-dependent activation of genes associated with metastatic phenotypes. Further exploration determined that transcriptional induction of SNAI2 (Slug) was essential for cyclin D1b-mediated proliferative and invasive properties, implicating Slug as a critical driver of disease progression. Importantly, cyclin D1b expression highly correlated with that of Slug in clinical samples of advanced disease. In vivo analyses provided strong evidence that Slug enhances both tumor growth and metastatic phenotypes. Collectively, these findings reveal the underpinning mechanisms behind the protumorigenic functions of cyclin D1b and demonstrate that the convergence of the cyclin D1b/AR and Slug pathways results in the activation of processes critical for the promotion of lethal tumor phenotypes.
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Affiliation(s)
- Michael A Augello
- Department of Cancer Biology and Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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30
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Wang LL, Meng QH, Jiao Y, Xu JY, Ge CM, Zhou JY, Rosen EM, Wang HC, Fan SJ. High-mobility group boxes mediate cell proliferation and radiosensitivity via retinoblastoma-interaction-dependent and -independent mechanisms. Cancer Biother Radiopharm 2012; 27:329-35. [PMID: 22655796 DOI: 10.1089/cbr.2012.1199] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Our previous studies have shown that high-mobility group box 1 (HMGB1) could physically associate with the retinoblastoma (RB) protein via an LXCXE (leucine-X-cysteine-X-glutamic; X=any amino acid) motif. An identical LXCXE motif is present in the HMGB1-3 protein sequences, whereas a near-consensus LXCXD (leucine-X-cysteine-X-asparagine; X=any amino acid) motif is found in the HMGB4 protein. In this study, we have demonstrated that like HMGB1, HMGB2-3 also associated with the RB in vitro and in vivo, as evidenced by glutathione-s-transferase capture and immunoprecipitation-Western blot assays. A point mutation of the LXCXE or LXCXD motif led to disruption of RB:HMGB1-4 interactions. Enforced expression of HMGB1-3 or HMGB4 by adenoviral-vector-mediated gene transfer resulted in significant inhibition of breast cancer cell proliferation through an LXCXE- or LXCXD-dependent mechanism and an increased radiosensitivity through an LXCXE- or LXCXD-independent mechanism. These results suggest an important role of the LXCXE/D motif in RB:HMGB1-4 association and modulation of cancer cell growth, but not radiosensitivity.
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Affiliation(s)
- Li-Li Wang
- Department of Radiotherapy, The First Affiliated Hospital of Soochow University, Suzhou, China
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31
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Varanasi L, Do PM, Goluszko E, Martinez LA. Rad18 is a transcriptional target of E2F3. Cell Cycle 2012; 11:1131-41. [PMID: 22391204 DOI: 10.4161/cc.11.6.19558] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The E2F family of transcription factors responds to a variety of intracellular and extracellular signals and, as such, are key regulators of cell growth, differentiation and cell death. The cellular response to DNA damage is a multistep process generally involving the initial detection of DNA damage, propagation of signals via posttranslational modifications (e.g., phosphorylation and ubiquitination) and, finally, the implementation of a response. We have previously reported that E2F3 can be induced by DNA damage, and that it plays an important role in DNA damage-induced apoptosis. Here, we demonstrate that E2F3 knockdown compromises two canonical DNA damage modification events, the ubiquitination of H2AX and PCNA. We find that the defect in these posttranscriptional modifications after E2F3 knockdown is due to reduced expression of important DNA damage responsive ubiquitin ligases. We characterized the regulation of one of these ligases, Rad18, and we demonstrated that E2F3 associates with the Rad18 promoter and directly controls its activity. Furthermore, we find that ectopic expression of Rad18 is sufficient to rescue the PCNA ubiquitination defect resulting from E2F3 knockdown. Our study reveals a novel facet of E2F3's control of the DNA damage response.
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Affiliation(s)
- Lakshman Varanasi
- Department of Biochemistry and University of Mississippi Cancer Institute, University of Mississippi Medical Center, Jackson, MS, USA
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32
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Abstract
RB, a well known tumour suppressor that functions in the control of cell cycle progression and proliferation, has recently been shown to have additional functions in the maintenance of genomic stability, such that inactivation of RB family proteins promotes chromosome instability (CIN) and aneuploidy. Several studies have provided potential explanations for these phenomena that occur following RB loss, and they suggest that this new function of RB may contribute to its role in tumour suppression.
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Affiliation(s)
| | - Nicholas J. Dyson
- Corresponding Author: Nicholas Dyson 149 13th Street MB 7330 Charlestown, MA 02129 617-726-7800 617-726-7808 (fax)
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33
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Sachdeva UM, O'Brien JM. Understanding pRb: toward the necessary development of targeted treatments for retinoblastoma. J Clin Invest 2012; 122:425-34. [PMID: 22293180 DOI: 10.1172/jci57114] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Retinoblastoma is a pediatric retinal tumor initiated by biallelic inactivation of the retinoblastoma gene (RB1). RB1 was the first identified tumor suppressor gene and has defined roles in the regulation of cell cycle progression, DNA replication, and terminal differentiation. However, despite the abundance of work demonstrating the molecular function and identifying binding partners of pRb, the challenge facing molecular biologists and clinical oncologists is how to integrate this vast body of molecular knowledge into the development of targeted therapies for treatment of retinoblastoma. We propose that a more thorough genetic understanding of retinoblastoma would inform targeted treatment decisions and could improve outcomes and quality of life in children affected by this disease.
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Affiliation(s)
- Uma M Sachdeva
- Scheie Eye Institute, University of Pennsylvania, 51 N. 39th St., Philadelphia, Pennsylvania 19104, USA
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34
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Conserved RB functions in development and tumor suppression. Protein Cell 2011; 2:864-78. [PMID: 22180086 DOI: 10.1007/s13238-011-1117-z] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 10/18/2011] [Indexed: 12/21/2022] Open
Abstract
The variety of human cancers in which the retinoblastoma protein pRb is inactivated reflects both its broad importance for tumor suppression and its multitude of cellular functions. Accumulating evidence indicates that pRb contributes to a diversity of cellular functions, including cell proliferation, differentiation, cell death, and genome stability. pRb performs these diverse functions through the formation of large complexes that include E2F transcription factors and chromatin regulators. In this review we will discuss some of the recent advances made in understanding the structure and function of pRb as they relate to tumor suppression, and highlight research using Drosophila melanogaster that reveals important, evolutionarily conserved functions of the RB family.
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