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Hammond T, Sage J. Monitoring the Cell Cycle of Tumor Cells in Mouse Models of Human Cancer. Cold Spring Harb Perspect Med 2023; 13:a041383. [PMID: 37460156 PMCID: PMC10691483 DOI: 10.1101/cshperspect.a041383] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/27/2023]
Abstract
Cell division is obligatory to tumor growth. However, both cancer cells and noncancer cells in tumors can be found in distinct stages of the cell cycle, which may inform the growth potential of these tumors, their propensity to metastasize, and their response to therapy. Hence, it is of utmost importance to monitor the cell cycle of tumor cells. Here we discuss well-established methods and new genetic advances to track the cell cycle of tumor cells in mouse models of human cancer. We also review recent genetic studies investigating the role of the cell-cycle machinery in the growth of tumors in vivo, with a focus on the machinery regulating the G1/S transition of the cell cycle.
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Affiliation(s)
- Taylar Hammond
- Department of Pediatrics, Stanford University, Stanford, California 94305, USA
- Department of Biology, and Stanford University, Stanford, California 94305, USA
| | - Julien Sage
- Department of Pediatrics, Stanford University, Stanford, California 94305, USA
- Department of Genetics, Stanford University, Stanford, California 94305, USA
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Quiñonez-Silva G, Dávalos-Salas M, Recillas-Targa F, Ostrosky-Wegman P, Aranda DA, Benítez-Bribiesca L. "Monoallelic germline methylation and sequence variant in the promoter of the RB1 gene: a possible constitutive epimutation in hereditary retinoblastoma". Clin Epigenetics 2016; 8:1. [PMID: 26753011 PMCID: PMC4706693 DOI: 10.1186/s13148-015-0167-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 12/25/2015] [Indexed: 11/10/2022] Open
Abstract
Background Retinoblastoma is a malignant tumor of the retina in children <5 years of age and occurs after two mutations in the RB1 gene. The first mutation (M1) is germinal and confers predisposition to the hereditary type, which is transmitted as an autosomal dominant highly penetrant trait, so 90 % of carriers develop retinoblastoma; however, 10 % of carriers either do not develop the tumor or develop it unilaterally. Most mutations are point mutations. Inactivation of the RB1 gene is usually caused by mutations affecting the coding region. Silencing by methylation of the RB1 promoter has been observed in retinoblastoma tumors as a second mutation (M2) and is classified as somatic epimutation. Germline methylation of the RB1 gene promoter was studied in a particular pedigree of six generations from the paternal side, with incomplete penetrance and bias towards healthy male carriers and those affected with unilateral retinoblastoma. Results The methylation status of the 27 CpGs dinucleotides that constitute the core of the RB1 gene promoter, analyzed by cloning and genomic sequencing after DNA sodium bisulfite conversion, demonstrated a monoallelic methylation pattern which coincides with a c. [−187T > G; −188T > G] sequence variant that is found in peripheral blood lymphocytes and tumor DNA. Unexpectedly, it was the mother who transmitted this variant to two more generations. Microsatellite markers of D chromosome showed a biparental contribution of both D13 chromosomes to the retinoblastoma phenotype, conferring double heterozygosity in the affected cases. Conclusions The monoallelic genetic-epigenetic finding, the sequence variant, and methylation suggest a constitutive epimutation and probably a genetic-epigenetic hereditary predisposition for retinoblastoma in this family.
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Affiliation(s)
- Guadalupe Quiñonez-Silva
- Hospital de Pediatría, Centro Médico Nacional Siglo XXI, IMSS, Unidad de Investigación Médica en Genética Humana, México, D.F. Mexico
| | - Mercedes Dávalos-Salas
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), México, D.F. Mexico
| | - Félix Recillas-Targa
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México (UNAM), México, D.F. Mexico
| | - Patricia Ostrosky-Wegman
- Laboratorio de Genómica, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), México, D.F. Mexico
| | - Diego Arenas Aranda
- Hospital de Pediatría, Centro Médico Nacional Siglo XXI, IMSS, Unidad de Investigación Médica en Genética Humana, México, D.F. Mexico
| | - Luis Benítez-Bribiesca
- Hospital de Oncología, CMNS-XXI, IMSS, Unidad de Investigación Médica en Enfermedades Oncológicas, Av. Cuauhtémoc 330, 06725 México, D.F. Mexico
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Tarin C, Lavin B, Gomez M, Saura M, Diez-Juan A, Zaragoza C. The extracellular matrix metalloproteinase inducer EMMPRIN is a target of nitric oxide in myocardial ischemia/reperfusion. Free Radic Biol Med 2011; 51:387-95. [PMID: 21570464 DOI: 10.1016/j.freeradbiomed.2011.04.021] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2011] [Revised: 03/29/2011] [Accepted: 04/11/2011] [Indexed: 12/20/2022]
Abstract
Nitric oxide (NO) is an important defense against myocardial ischemia/reperfusion (I/R) injury. Although matrix metalloproteinase (MMP)-mediated necrosis of cardiac myocytes is well characterized, the role of inducible NO synthase (iNOS)-derived NO in this process is poorly understood. I/R injury was increased in iNOS-deficient mice and in mice treated with 1400 W (a pharmacological iNOS inhibitor) and was associated with significantly increased expression of extracellular matrix metalloproteinase inducer (EMMPRIN) and EMMPRIN-associated MMPs. Transcriptional activity of an EMMPRIN luciferase promoter reporter expressed in cardiac myocytes was inhibited by NO in a cGMP-dependent manner, and this transcriptional inhibition was abolished by mutation of a putative E2F site. Consistent with these findings, EMMPRIN null mice, in which iNOS is normally induced, are partially protected against I/R injury. Pharmacological inhibition of iNOS in EMMPRIN null mice had no additional protective effect, suggesting that EMMPRIN is a downstream target of NO. Administration of anti-EMMPRIN neutralizing antibodies partly reduced the excess heart damage and MMP-9 expression induced by I/R in iNOS null mice, indicating that regulation of EMMPRIN is an important mechanism of NO-mediated cardioprotection.
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Affiliation(s)
- Carlos Tarin
- Fundación Centro Nacional de Investigaciones Cardiovasculares, Madrid 28029, Spain
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Abstract
In cancer cells, the retinoblastoma tumor suppressor RB is directly inactivated by mutation in the RB gene or functionally inhibited by abnormal activation of cyclin-dependent kinase activity. While variations in RB levels may also provide an important means of controlling RB function in both normal and cancer cells, little is known about the mechanisms regulating RB transcription. Here we show that members of the RB and E2F families bind directly to the RB promoter. To investigate how the RB/E2F pathway may regulate Rb transcription, we generated reporter mice carrying an eGFP transgene inserted into a bacterial artificial chromosome containing most of the Rb gene. Expression of eGFP largely parallels that of Rb in transgenic embryos and adult mice. Using these reporter mice and mutant alleles for Rb, p107, and p130, we found that RB family members modulate Rb transcription in specific cell populations in vivo and in culture. Interestingly, while Rb is a target of the RB/E2F pathway in mouse and human cells, Rb expression does not strictly correlate with the cell cycle status of these cells. These experiments identify novel regulatory feedback mechanisms within the RB pathway in mammalian cells.
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Burkhart DL, Viatour P, Ho VM, Sage J. GFP reporter mice for the retinoblastoma-related cell cycle regulator p107. Cell Cycle 2008; 7:2544-52. [PMID: 18719374 DOI: 10.4161/cc.7.16.6441] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The RB tumor suppressor gene is mutated in a broad range of human cancers, including pediatric retinoblastoma. Strikingly, however, Rb mutant mice develop tumors of the pituitary and thyroid glands, but not retinoblastoma. Mouse genetics experiments have demonstrated that p107, a protein related to pRB, is capable of preventing retinoblastoma, but not pituitary tumors, in Rb-deficient mice. Evidence suggests that the basis for this compensatory function of p107 is increased transcription of the p107 gene in response to Rb inactivation. To begin to address the context-dependency of this compensatory role of p107 and to follow p107 expression in vivo, we have generated transgenic mice carrying an enhanced GFP (eGFP) reporter inserted into a bacterial artificial chromosome (BAC) containing the mouse p107 gene. Expression of the eGFP transgene parallels that of p107 in these transgenic mice and identifies cells with a broad range of expression level for p107, even within particular organs or tissues. We also show that loss of Rb results in the upregulation of p107 transcription in specific cell populations in vivo, including subpopulations of hematopoietic cells. Thus, p107 BAC-eGFP transgenic mice serve as a useful tool to identify distinct cell types in which p107 is expressed and may have key functions in vivo, and to characterize changes in cellular networks accompanying Rb deficiency.
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Affiliation(s)
- Deborah L Burkhart
- Department of Pediatrics and Genetics, Cancer Biology Program, Stanford Medical School, Stanford, California, USA
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The chemokine CXCL12 promotes survival of postmitotic neurons by regulating Rb protein. Cell Death Differ 2008; 15:1663-72. [PMID: 18583990 DOI: 10.1038/cdd.2008.95] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Postmitotic neurons need to keep their cell cycle under control to survive and maintain a differentiated state. This study aims to test the hypothesis that the chemokine CXCL12 regulates neuronal survival and differentiation by promoting Rb function, as suggested by previous studies showing that CXCL12 protects neurons from apoptosis induced by Rb loss. To this end, the effect of CXCL12 on Rb expression and transcriptional activity and the role of Rb in CXCL12-induced neuronal survival were studied. CXCL12 increases Rb protein and RNA levels in rat cortical neurons. The chemokine also stimulates an exogenous Rb promoter expressed in these neurons and counteracts the inhibition of the Rb promoter induced by E2F1 overexpression. Furthermore CXCL12 stimulates Rb activity as a transcription repressor. The effects of CXCL12 are mediated by its specific receptor CXCR4, and do not require the presence of glia. Finally, shRNA studies show that Rb expression is crucial to the neuroprotective activity of CXCL12 as indicated by NMDA-neurotoxicity assays. These findings suggest that proper CXCR4 stimulation in the mature CNS can prevent impairment of the Rb-E2F pathway and support neuronal survival. This is important to maintain CNS integrity in physiological conditions and prevent neuronal injury and loss typical of many neurodegenerative and neuroinflammatory conditions.
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De Bleser P, Hooghe B, Vlieghe D, van Roy F. A distance difference matrix approach to identifying transcription factors that regulate differential gene expression. Genome Biol 2007; 8:R83. [PMID: 17504544 PMCID: PMC1929144 DOI: 10.1186/gb-2007-8-5-r83] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2006] [Revised: 03/30/2007] [Accepted: 05/16/2007] [Indexed: 01/10/2023] Open
Abstract
We introduce a method that considers target genes of a transcription factor, and searches for transcription factor binding sites (TFBSs) of secondary factors responsible for differential responses among these targets. Based on the distance difference matrix concept, the method simultaneously integrates statistical overrepresentation and co-occurrence of TFBSs. Our approach is validated on datasets of differentially regulated human genes and is shown to be highly effective in detecting TFBSs responsible for the observed differential gene expression.
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Affiliation(s)
- Pieter De Bleser
- Bioinformatics Core, VIB, B-9052 Ghent, Belgium
- Department for Molecular Biomedical Research, VIB, B-9052 Ghent, Belgium
- Department of Molecular Biology, Ghent University, B-9052 Ghent, Belgium
| | - Bart Hooghe
- Bioinformatics Core, VIB, B-9052 Ghent, Belgium
- Department for Molecular Biomedical Research, VIB, B-9052 Ghent, Belgium
- Department of Molecular Biology, Ghent University, B-9052 Ghent, Belgium
| | - Dominique Vlieghe
- Bioinformatics Core, VIB, B-9052 Ghent, Belgium
- Department for Molecular Biomedical Research, VIB, B-9052 Ghent, Belgium
- Department of Molecular Biology, Ghent University, B-9052 Ghent, Belgium
| | - Frans van Roy
- Department for Molecular Biomedical Research, VIB, B-9052 Ghent, Belgium
- Department of Molecular Biology, Ghent University, B-9052 Ghent, Belgium
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