551
|
Ndy1/KDM2B immortalizes mouse embryonic fibroblasts by repressing the Ink4a/Arf locus. Proc Natl Acad Sci U S A 2009; 106:2641-6. [PMID: 19202064 DOI: 10.1073/pnas.0813139106] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The histone H3 demethylase Not dead yet-1 (Ndy1/KDM2B) is a physiological inhibitor of senescence. Here, we show that Ndy1 is down-regulated during senescence in mouse embryonic fibroblasts (MEFs) and that it represses the Ink4a/Arf locus. Ndy1 counteracts the senescence-associated down-regulation of Ezh2, a component of polycomb-repressive complex (PRC) 2, via a JmjC domain-dependent process leading to the global and Ink4a/Arf locus-specific up-regulation of histone H3K27 trimethylation. The latter promotes the Ink4a/Arf locus-specific binding of Bmi1, a component of PRC1. Ndy1, which interacts with Ezh2, also binds the Ink4a/Arf locus and demethylates the locus-associated histone H3K36me2 and histone H3K4me3. The combination of histone modifications driven by Ndy1 interferes with the binding of RNA Polymerase II, resulting in the transcriptional silencing of the Ink4a/Arf locus and contributing to the Ndy1 immortalization phenotype. Other studies show that, in addition to inhibiting replicative senescence, Ndy1 inhibits Ras oncogene-induced senescence via a similar molecular mechanism.
Collapse
|
552
|
Coppé JP, Patil CK, Rodier F, Sun Y, Muñoz DP, Goldstein J, Nelson PS, Desprez PY, Campisi J. Senescence-associated secretory phenotypes reveal cell-nonautonomous functions of oncogenic RAS and the p53 tumor suppressor. PLoS Biol 2009; 6:2853-68. [PMID: 19053174 PMCID: PMC2592359 DOI: 10.1371/journal.pbio.0060301] [Citation(s) in RCA: 2702] [Impact Index Per Article: 180.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2008] [Accepted: 10/22/2008] [Indexed: 11/18/2022] Open
Abstract
Cellular senescence suppresses cancer by arresting cell proliferation, essentially permanently, in response to oncogenic stimuli, including genotoxic stress. We modified the use of antibody arrays to provide a quantitative assessment of factors secreted by senescent cells. We show that human cells induced to senesce by genotoxic stress secrete myriad factors associated with inflammation and malignancy. This senescence-associated secretory phenotype (SASP) developed slowly over several days and only after DNA damage of sufficient magnitude to induce senescence. Remarkably similar SASPs developed in normal fibroblasts, normal epithelial cells, and epithelial tumor cells after genotoxic stress in culture, and in epithelial tumor cells in vivo after treatment of prostate cancer patients with DNA-damaging chemotherapy. In cultured premalignant epithelial cells, SASPs induced an epithelial–mesenchyme transition and invasiveness, hallmarks of malignancy, by a paracrine mechanism that depended largely on the SASP factors interleukin (IL)-6 and IL-8. Strikingly, two manipulations markedly amplified, and accelerated development of, the SASPs: oncogenic RAS expression, which causes genotoxic stress and senescence in normal cells, and functional loss of the p53 tumor suppressor protein. Both loss of p53 and gain of oncogenic RAS also exacerbated the promalignant paracrine activities of the SASPs. Our findings define a central feature of genotoxic stress-induced senescence. Moreover, they suggest a cell-nonautonomous mechanism by which p53 can restrain, and oncogenic RAS can promote, the development of age-related cancer by altering the tissue microenvironment. Cells with damaged DNA are at risk of becoming cancerous tumors. Although “cellular senescence” can suppress tumor formation from damaged cells by blocking the cell division that underlies cancer growth, it has also been implicated in promoting cancer and other age-related diseases. To understand how this might happen, we measured proteins that senescent human cells secrete into their local environment and found many factors associated with inflammation and cancer development. Different types of cells secrete a common set of proteins when they senesce. This senescence-associated secretory phenotype (SASP) occurs not only in cultured cells, but also in vivo in response to DNA-damaging chemotherapy. Normal cells that acquire a highly active mutant version of the RAS protein, which is known to contribute to tumor growth, undergo cellular senescence, and develop a very intense SASP, with higher levels of proteins secreted. Likewise, the SASP is more intense when cells lose the functions of the tumor suppressor p53. Senescent cells promote the growth and aggressiveness of nearby precancerous or cancer cells, and cells with a more intense SASP do so more efficiently. Our findings support the idea that cellular senescence can be both beneficial, in preventing damaged cells from dividing, and deleterious, by having effects on neighboring cells; this balance of effects is predicted by an evolutionary theory of aging. By controlling how damaged cells modify their surrounding tissue environment, a tumor suppressor gene can restrain, and an oncogene can promote, the development of cancer.
Collapse
Affiliation(s)
- Jean-Philippe Coppé
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Christopher K Patil
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Francis Rodier
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- Buck Institute for Age Research, Novato, California, United States of America
| | - Yu Sun
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Denise P Muñoz
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- Buck Institute for Age Research, Novato, California, United States of America
| | - Joshua Goldstein
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
| | - Peter S Nelson
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America
| | - Pierre-Yves Desprez
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- California Pacific Medical Center Research Institute, San Francisco, California, United States of America
| | - Judith Campisi
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America
- Buck Institute for Age Research, Novato, California, United States of America
- * To whom correspondence should be addressed. E-mail:
| |
Collapse
|
553
|
Abstract
Mammalian aging results from a replicative decline in the function of somatic stem cells and other self-renewing cells. Recent studies (Monzen et al., 2008; Nishino et al., 2008; Sanna et al., 2008; Weedon et al., 2008) link a chromatin-associated protein, HMGA2, to development, height, and mouse stem cell aging during late fetal development and young adulthood.
Collapse
Affiliation(s)
- Scott M Hammond
- Department of Cell and Developmental Biology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| | | |
Collapse
|
554
|
Senescence and immortality in hepatocellular carcinoma. Cancer Lett 2008; 286:103-13. [PMID: 19070423 DOI: 10.1016/j.canlet.2008.10.048] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 06/23/2008] [Accepted: 10/29/2008] [Indexed: 12/31/2022]
Abstract
Cellular senescence is a process leading to terminal growth arrest with characteristic morphological features. This process is mediated by telomere-dependent, oncogene-induced and ROS-induced pathways, but persistent DNA damage is the most common cause. Senescence arrest is mediated by p16(INK4a)- and p21(Cip1)-dependent pathways both leading to retinoblastoma protein (pRb) activation. p53 plays a relay role between DNA damage sensing and p21(Cip1) activation. pRb arrests the cell cycle by recruiting proliferation genes to facultative heterochromatin for permanent silencing. Replicative senescence that occurs in hepatocytes in culture and in liver cirrhosis is associated with lack of telomerase activity and results in telomere shortening. Hepatocellular carcinoma (HCC) cells display inactivating mutations of p53 and epigenetic silencing of p16(INK4a). Moreover, they re-express telomerase reverse transcriptase required for telomere maintenance. Thus, senescence bypass and cellular immortality is likely to contribute significantly to HCC development. Oncogene-induced senescence in premalignant lesions and reversible immortality of cancer cells including HCC offer new potentials for tumor prevention and treatment.
Collapse
|
555
|
Raina D, Ahmad R, Chen D, Kumar S, Kharbanda S, Kufe D. MUC1 oncoprotein suppresses activation of the ARF-MDM2-p53 pathway. Cancer Biol Ther 2008; 7:1959-67. [PMID: 18981727 DOI: 10.4161/cbt.7.12.6956] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The MUC1 oncoprotein interacts with the c-Abl tyrosine kinase and blocks nuclear targeting of c-Abl in the apoptotic response to DNA damage. Mutation of the MUC1 cytoplasmic domain at Tyr-60 disrupts the MUC1-c-Abl interaction. The present results demonstrate that the MUC1(Y60F) mutant is a potent inducer of the ARF tumor suppressor. MUC1(Y60F) induces transcription of the ARF locus by a c-Abl-dependent mechanism that promotes CUL-4A-mediated nuclear export of the replication protein Cdc6. The functional significance of these findings is that MUC1(Y60F)-induced ARF expression and thereby inhibition of MDM2 results in the upregulation of p53 and the homeodomain interacting protein kinase 2 (HIPK2) serine/threonine kinase. HIPK2-mediated phosphorylation of p53 on Ser-46 was further associated with a shift from expression of the cell cycle arrest-related p21 gene to the apoptosis-related PUMA gene. We also show that the MUC1(Y60F) mutant functions as dominant negative inhibitor of tumorigenicity. These findings indicate that the oncogenic function of MUC1 is conferred by suppressing activation of the ARF-MDM2-p53 pathway.
Collapse
Affiliation(s)
- Deepak Raina
- Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | | | | | | | | | | |
Collapse
|
556
|
Paulson TG, Galipeau PC, Xu L, Kissel HD, Li X, Blount PL, Sanchez CA, Odze RD, Reid BJ. p16 mutation spectrum in the premalignant condition Barrett's esophagus. PLoS One 2008; 3:e3809. [PMID: 19043591 PMCID: PMC2585012 DOI: 10.1371/journal.pone.0003809] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2008] [Accepted: 11/06/2008] [Indexed: 02/08/2023] Open
Abstract
Background Mutation, promoter hypermethylation and loss of heterozygosity involving the tumor suppressor gene p16 (CDKN2a/INK4a) have been detected in a wide variety of human cancers, but much less is known concerning the frequency and spectrum of p16 mutations in premalignant conditions. Methods and Findings We have determined the p16 mutation spectrum for a cohort of 304 patients with Barrett's esophagus, a premalignant condition that predisposes to the development of esophageal adenocarcinoma. Forty seven mutations were detected by sequencing of p16 exon 2 in 44 BE patients (14.5%) with a mutation spectrum consistent with that caused by oxidative damage and chronic inflammation. The percentage of patients with p16 mutations increased with increasing histologic grade. In addition, samples from 3 out of 19 patients (15.8%) who underwent esophagectomy were found to have mutations. Conclusions The results of this study suggest the environment of the esophagus in BE patients can both generate and select for clones with p16 mutations.
Collapse
Affiliation(s)
- Thomas G Paulson
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, Washington, United States of America.
| | | | | | | | | | | | | | | | | |
Collapse
|
557
|
Xi L, Feber A, Gupta V, Wu M, Bergemann AD, Landreneau RJ, Litle VR, Pennathur A, Luketich JD, Godfrey TE. Whole genome exon arrays identify differential expression of alternatively spliced, cancer-related genes in lung cancer. Nucleic Acids Res 2008; 36:6535-47. [PMID: 18927117 PMCID: PMC2582617 DOI: 10.1093/nar/gkn697] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alternative processing of pre-mRNA transcripts is a major source of protein diversity in eukaryotes and has been implicated in several disease processes including cancer. In this study we have performed a genome wide analysis of alternative splicing events in lung adenocarcinoma. We found that 2369 of the 17 800 core Refseq genes appear to have alternative transcripts that are differentially expressed in lung adenocarcinoma versus normal. According to their known functions the largest subset of these genes (30.8%) is believed to be cancer related. Detailed analysis was performed for several genes using PCR, quantitative RT-PCR and DNA sequencing. We found overexpression of ERG variant 2 but not variant 1 in lung tumors and overexpression of CEACAM1 variant 1 but not variant 2 in lung tumors but not in breast or colon tumors. We also identified a novel, overexpressed variant of CDH3 and verified the existence and overexpression of a novel variant of P16 transcribed from the CDKN2A locus. These findings demonstrate how analysis of alternative pre-mRNA processing can shed additional light on differences between tumors and normal tissues as well as between different tumor types. Such studies may lead to the development of additional tools for tumor diagnosis, prognosis and therapy.
Collapse
Affiliation(s)
- Liqiang Xi
- Department of Pathology, Mount Sinai School of Medicine, New York, NY 10029, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
558
|
He J, Kallin EM, Tsukada YI, Zhang Y. The H3K36 demethylase Jhdm1b/Kdm2b regulates cell proliferation and senescence through p15(Ink4b). Nat Struct Mol Biol 2008; 15:1169-75. [PMID: 18836456 PMCID: PMC2612995 DOI: 10.1038/nsmb.1499] [Citation(s) in RCA: 234] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2008] [Accepted: 09/15/2008] [Indexed: 12/15/2022]
Abstract
The Ink4a/Arf/Ink4b locus plays a critical role in both cellular senescence and tumorigenesis. Jhdm1b/Kdm2b/Fbxl10, the mammalian paralogue of the histone demethylase Jhdm1a/Kdm2a/Fbxl11, has been implicated in cell cycle regulation and tumorigenesis. In this report, we demonstrate that Jhdm1b is an H3K36 demethylase. Knockdown of Jhdm1b in primary MEFs inhibits cell proliferation and induces cellular senescence in a pRb and p53 pathway-dependent manner. Importantly, the effect of Jhdm1b on cell proliferation and cellular senescence is mediated through de-repression of p15Ink4b as loss of p15Ink4b function rescues cell proliferation defects in Jhdm1b knockdown cells. Chromatin immunoprecipitation on ectopically expressed Jhdm1b demonstrates that Jhdm1b targets the p15Ink4b locus and regulates its expression in an enzymatic activity-dependent manner. Alteration of Jhdm1b level affects Ras-induced neoplastic transformation. Collectively, our results indicate that Jhdm1b is an H3K36 demethylase that regulates cell proliferation and senescence through p15Ink4b.
Collapse
Affiliation(s)
- Jin He
- Howard Hughes Medical Institute, Chapel Hill, North Carolina 27599-7295, USA
| | | | | | | |
Collapse
|
559
|
Li J, Warner B, Casto BC, Knobloch TJ, Weghorst CM. Tumor suppressor p16(INK4A)/Cdkn2a alterations in 7, 12-dimethylbenz(a)anthracene (DMBA)-induced hamster cheek pouch tumors. Mol Carcinog 2008; 47:733-8. [PMID: 18247379 DOI: 10.1002/mc.20424] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The prevalence of p16(INK4A)/Cdkn2a genetic alterations in human oral cancers indicates that the p16 gene could be a potent and appropriate target for novel intervention. While chemically induced hamster cheek pouch (HCP) tumors are regarded as an appropriate surrogate model for human oral cancers because of their similarities to human oral cancers in both histology and genetics, little is known about the genetic events in the p16 gene in the HCP tumor model. The purpose of this study was to evaluate chemically induced HCP tumor specimens for potential inactivating p16 alterations. HCP tumors were induced with 7, 12-dimethylbenz(a)anthracene (DMBA), and DNA extracted from 34 such specimens were analyzed for homozygous/hemizygous deletions, aberrant methylation of 5' CpG islands, and point mutations using real-time multiplex PCR, methylation-specific PCR, and direct sequencing/cold single strand conformation polymorphism (SSCP), respectively. Homozygous deletions, hemizygous deletions, aberrant methylation of 5'-CpG islands, and point mutation were identified in 11, 4, 9, and 1 of 34 specimens, respectively. While the overall incidence of p16 alterations was 70.6% (24 of 34 specimens), the majority of inactivating events (67.6%) stemmed from deletion or methylation, which is consistent with the observations found in human oral SCCs. Our results show the resemblance between chemically induced HCP tumors and their human counterparts in p16 genetic alterations, and strongly support the use of DMBA-induced HCP tumor model in evaluating novel p16-targeted therapy and prevention of human oral SCCs.
Collapse
Affiliation(s)
- Junan Li
- Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, Ohio 43210, USA
| | | | | | | | | |
Collapse
|
560
|
Abstract
Arf and p53 are regarded among the most relevant tumor suppressors based on their ubiquitous and frequent inactivation in human cancer. The Arf/p53 pathway protects cells against several types of damage and this is the basis of its tumor suppressor activity. Interestingly, aging is a process associated with the accumulation of damage derived from chronic stresses of small magnitude. In agreement with its damage protection role, it has been recently described that the Arf/p53 pathway not only protects mammalian organisms from cancer but also from aging. However, there is also evidence that p53, under certain circumstances, such as when constitutively active, can induce aging. We discuss here the current evidence linking the Arf/p53 pathway to the process of aging and present a unified model.
Collapse
Affiliation(s)
- Ander Matheu
- Tumor Suppression Group, Spanish National Cancer Research Center, Madrid, Spain
| | | | | |
Collapse
|
561
|
Abstract
The retinoblastoma tumour suppressor (RB) is a crucial regulator of cell-cycle progression that is invoked in response to a myriad of anti-mitogenic signals. It has been hypothesized that perturbations of the RB pathway confer a synonymous proliferative advantage to tumour cells; however, recent findings demonstrate context-specific outcomes associated with such lesions. Particularly, loss of RB function is associated with differential response to wide-ranging therapeutic agents. Thus, the status of this tumour suppressor may be particularly informative in directing treatment regimens.
Collapse
Affiliation(s)
- Erik S Knudsen
- Department of Cancer Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA.
| | | |
Collapse
|
562
|
In vitro genetic screen identifies a cooperative role for LPA signaling and c-Myc in cell transformation. Oncogene 2008; 27:6806-16. [PMID: 18762810 DOI: 10.1038/onc.2008.294] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
c-Myc drives uncontrolled cell proliferation in various human cancers. However, in mouse embryo fibroblasts (MEFs), c-Myc also induces apoptosis by activating the p19Arf tumor suppressor pathway. Tbx2, a transcriptional repressor of p19Arf, can collaborate with c-Myc by suppressing apoptosis. MEFs overexpressing c-Myc and Tbx2 are immortal but not transformed. We have performed an unbiased genetic screen, which identified 12 oncogenes that collaborate with c-Myc and Tbx2 to transform MEFs in vitro. One of them encodes the LPA2 receptor for the lipid growth factor lysophosphatidic acid (LPA). We find that LPA1 and LPA4, but not LPA3, can reproduce the transforming effect of LPA2. Using pharmacological inhibitors, we show that the in vitro cell transformation induced by LPA receptors is dependent on the Gi-linked ERK and PI3K signaling pathways. The transforming ability of LPA1, LPA2 and LPA4 was confirmed by tumor formation assays in vivo and correlated with prolonged ERK1/2 activation in response to LPA. Our results reveal a direct role for LPA receptor signaling in cell transformation and tumorigenesis in conjunction with c-Myc and reduced p19Arf expression.
Collapse
|
563
|
Zhuang D, Mannava S, Grachtchouk V, Tang WH, Patil S, Wawrzyniak JA, Berman AE, Giordano TJ, Prochownik EV, Soengas MS, Nikiforov MA. C-MYC overexpression is required for continuous suppression of oncogene-induced senescence in melanoma cells. Oncogene 2008; 27:6623-34. [PMID: 18679422 DOI: 10.1038/onc.2008.258] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Malignant melanomas often harbor activating mutations in BRAF (V600E) or, less frequently, in NRAS (Q61R). Intriguingly, the same mutations have been detected at higher incidences in benign nevi, which are largely composed of senescent melanocytes. Overexpression of BRAF(V600E) or NRAS(Q61R) in human melanocytes in vitro has been shown to induce senescence, although via different mechanisms. How oncogene-induced senescence is overcome during melanoma progression remains unclear. Here, we report that in the majority of analysed BRAF(V600E)- or NRAS(Q61R)-expressing melanoma cells, C-MYC depletion induced different yet overlapping sets of senescence phenotypes that are characteristic of normal melanocytes undergoing senescence due to overexpression of BRAF(V600E) or NRAS(Q61R), respectively. These senescence phenotypes were p16(INK4A)- or p53-independent, however, several of them were suppressed by genetic or pharmacological inhibition of BRAF(V600E) or phosphoinositide 3-kinase pathways, including rapamycin-mediated inhibition of mTOR-raptor in NRAS(Q61R)-expressing melanoma cells. Reciprocally, overexpression of C-MYC in normal melanocytes suppressed BRAF(V600E)-induced senescence more efficiently than NRAS(Q61R)-induced senescence, which agrees with the generally higher rates of activating mutations in BRAF than NRAS gene in human cutaneous melanomas. Our data suggest that one of the major functions of C-MYC overexpression in melanoma progression is to continuous suppress BRAF(V600E)- or NRAS(Q61R)-dependent senescence programs.
Collapse
Affiliation(s)
- D Zhuang
- Department of Cell Stress Biology, Roswell Park Cancer Institute, Buffalo, NY 14263, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
564
|
Mullighan CG, Williams RT, Downing JR, Sherr CJ. Failure of CDKN2A/B (INK4A/B-ARF)-mediated tumor suppression and resistance to targeted therapy in acute lymphoblastic leukemia induced by BCR-ABL. Genes Dev 2008; 22:1411-5. [PMID: 18519632 DOI: 10.1101/gad.1673908] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Deletions of the CDKN2A/B tumor suppressor locus and of the IKAROS and PAX5 genes that promote B-lineage development occur frequently in lymphoid, but not myeloid leukemias initiated by the BCR-ABL tyrosine kinase. Why is this the case, and how do these genetic lesions contribute to an aggressive disease that fails to durably respond to targeted kinase inhibitors?
Collapse
Affiliation(s)
- Charles G Mullighan
- Department of Pathology, St. Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | | | | | | |
Collapse
|
565
|
Mori M, Yoneda-Kato N, Yoshida A, Kato JY. Stable form of JAB1 enhances proliferation and maintenance of hematopoietic progenitors. J Biol Chem 2008; 283:29011-21. [PMID: 18667426 DOI: 10.1074/jbc.m804539200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Overexpression of JAB1 is observed in a variety of human cancers, but how JAB1 is involved in tumor development remained to be investigated. Here we analyzed mice with modified Jab1 expression. Mice ectopically expressing a more stable form of JAB1 protein under the control of a constitutive promoter were rescued from the embryonic lethality caused by the Jab1(-/-) allele and developed a myeloproliferative disorder in a gene dosage-dependent manner. Hematopoietic cells from the bone marrow of Jab1 transgenic mice had a significantly larger stem cell population and exhibited higher and transplantable proliferative potential. In contrast, Jab1(+/-) mice, which express approximately 70% as much JAB1 protein as their wild-type littermates, showed inefficient hematopoiesis. Expression of the tumor suppressor p16(INK4a) was inversely correlated with that of JAB1, and the oncoprotein SMYD3, a newly identified JAB1 interactor, suppressed transcription of p16 in cooperation with JAB1. Thus, the expression and function of JAB1 are critical for the proliferation and maintenance of hematopoietic progenitors.
Collapse
Affiliation(s)
- Masaaki Mori
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101, Japan
| | | | | | | |
Collapse
|
566
|
Bhatia B, Jiang M, Suraneni M, Patrawala L, Badeaux M, Schneider-Broussard R, Multani AS, Jeter CR, Calhoun-Davis T, Hu L, Hu J, Tsavachidis S, Zhang W, Chang S, Hayward SW, Tang DG. Critical and distinct roles of p16 and telomerase in regulating the proliferative life span of normal human prostate epithelial progenitor cells. J Biol Chem 2008; 283:27957-27972. [PMID: 18662989 DOI: 10.1074/jbc.m803467200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Normal human prostate (NHP) epithelial cells undergo senescence in vitro and in vivo, but the underlying molecular mechanisms remain obscure. Here we show that the senescence of primary NHP cells, which are immunophenotyped as intermediate basal-like cells expressing progenitor cell markers CD44, alpha2beta1, p63, hTERT, and CK5/CK18, involves loss of telomerase expression, up-regulation of p16, and activation of p53. Using genetically defined manipulations of these three signaling pathways, we show that p16 is the primary determinant of the NHP cell proliferative capacity and that hTERT is required for unlimited proliferative life span. Hence, suppression of p16 significantly extends NHP cell life span, but both p16 inhibition and hTERT are required to immortalize NHP cells. Importantly, immortalized NHP cells retain expression of most progenitor markers, demonstrate gene expression profiles characteristic of proliferating progenitor cells, and possess multilineage differentiation potential generating functional prostatic glands. Our studies shed important light on the molecular mechanisms regulating the proliferative life span of NHP progenitor cells.
Collapse
Affiliation(s)
- Bobby Bhatia
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957
| | - Ming Jiang
- Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37232, the Departments of
| | - Mahipal Suraneni
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957
| | - Lubna Patrawala
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957
| | - Mark Badeaux
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957
| | - Robin Schneider-Broussard
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957
| | - Asha S Multani
- Cancer Genetics, University of Texas M.D Anderson Cancer Center, Houston, Texas 77030
| | - Collene R Jeter
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957
| | - Tammy Calhoun-Davis
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957
| | - Limei Hu
- Pathology, University of Texas M.D Anderson Cancer Center, Houston, Texas 77030
| | - Jianhua Hu
- Biostatistics, University of Texas M.D Anderson Cancer Center, Houston, Texas 77030
| | - Spiridon Tsavachidis
- Biostatistics, University of Texas M.D Anderson Cancer Center, Houston, Texas 77030
| | - Wei Zhang
- Pathology, University of Texas M.D Anderson Cancer Center, Houston, Texas 77030
| | - Sandy Chang
- Cancer Genetics, University of Texas M.D Anderson Cancer Center, Houston, Texas 77030; Hematopathology, University of Texas M.D Anderson Cancer Center, Houston, Texas 77030
| | - Simon W Hayward
- Department of Urologic Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37232, the Departments of
| | - Dean G Tang
- Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957; Program in Molecular Carcinogenesis, Graduate School of Biomedical Sciences, Houston, Texas 77030.
| |
Collapse
|
567
|
Guo Y, Pajovic S, Gallie BL. Expression of p14ARF, MDM2, and MDM4 in human retinoblastoma. Biochem Biophys Res Commun 2008; 375:1-5. [PMID: 18644346 DOI: 10.1016/j.bbrc.2008.07.055] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2008] [Accepted: 07/09/2008] [Indexed: 12/19/2022]
Abstract
It is still not clear whether the p53 pathway is altered in retinoblastoma development. We assessed the expression of the p53 pathway genes p14(ARF), mouse double minute 2 (MDM2), and mouse double minute 4 (MDM4) in human retinoblastoma compared to normal retina. Primary human retinoblastomas, retinoblastoma cell lines and normal retinas were assessed for p14(ARF) and MDM4 mRNA by quantitative RT-PCR. p14(ARF), MDM2, and MDM4 protein were measured by immunoblot and immunohistochemistry. Compared to retina, p14(ARF) mRNA expression was notably increased in retinoblastoma but p14(ARF) protein was undetectable. MDM2 and MDM4 proteins were expressed in 22/22 retinoblastomas. MDM2 was expressed in 3/10 retinas tested, and MDM4 in 10/10 retinas. The expression level of MDM2 protein in retinoblastomas and retina was comparable, while MDM4 protein was overexpressed in one retinoblastoma cell line Y79 and two primary retinoblastomas. We observe that overexpression of MDM2 and MDM4 is not a necessary step in retinoblastoma development. However, loss of detectable p14(ARF) protein and resultant lack of functional inactivation of these p53 inhibitors may contribute to retinoblastoma development by constitutive inhibition of p53.
Collapse
Affiliation(s)
- Ying Guo
- Division of Applied Molecular Oncology, Ontario Cancer Institute/Princess Margaret Hospital, University Health Network, Room 8-415, 610 University Avenue, Toronto, ON, Canada
| | | | | |
Collapse
|
568
|
Sakurada K, McDonald F, Shimada F. Regenerative Medicine and Stem Cell Based Drug Discovery. Angew Chem Int Ed Engl 2008; 47:5718-38. [DOI: 10.1002/anie.200700724] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
|
569
|
|
570
|
Ewing SJ, Zhu S, Zhu F, House JS, Smart RC. C/EBPbeta represses p53 to promote cell survival downstream of DNA damage independent of oncogenic Ras and p19(Arf). Cell Death Differ 2008; 15:1734-44. [PMID: 18636078 DOI: 10.1038/cdd.2008.105] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
CCAAT/enhancer-binding protein-beta (C/EBPbeta) is a mediator of cell survival and tumorigenesis. When C/EBPbeta(-/-) mice are treated with carcinogens that produce oncogenic Ras mutations in keratinocytes, they respond with abnormally elevated keratinocyte apoptosis and a block in skin tumorigenesis. Although this aberrant carcinogen-induced apoptosis results from abnormal upregulation of p53, it is not known whether upregulated p53 results from oncogenic Ras and its ability to induce p19(Arf) and/or activate DNA-damage response pathways or from direct carcinogen-induced DNA damage. We report that p19(Arf) is dramatically elevated in C/EBPbeta(-/-) epidermis and that C/EBPbeta represses a p19(Arf) promoter reporter. To determine whether p19(Arf) is responsible for the proapoptotic phenotype in C/EBPbeta(-/-) mice, C/EBPbeta(-/-);p19(Arf-/-) mice were generated. C/EBPbeta(-/-);p19(Arf-/-) mice responded to carcinogen treatment with increased p53 and apoptosis, indicating p19(Arf) is not essential. To ascertain whether oncogenic Ras activation induces aberrant p53 and apoptosis in C/EBPbeta(-/-) epidermis, we generated K14-ER:Ras;C/EBPbeta(-/-) mice. Oncogenic Ras activation induced by 4-hydroxytamoxifen did not produce increased p53 or apoptosis. Finally, when C/EBPbeta(-/-) mice were treated with differing types of DNA-damaging agents, including alkylating chemotherapeutic agents, they displayed aberrant levels of p53 and apoptosis. These results indicate that C/EBPbeta represses p53 to promote cell survival downstream of DNA damage and suggest that inhibition of C/EBPbeta may be a target for cancer cotherapy to increase the efficacy of alkylating chemotherapeutic agents.
Collapse
Affiliation(s)
- S J Ewing
- Cell Signaling and Cancer Group, Department of Environmental and Molecular Toxicology, North Carolina State University, Raleigh, NC 27695-7633, USA
| | | | | | | | | |
Collapse
|
571
|
Genome analysis identifies the p15ink4b tumor suppressor as a direct target of the ZNF217/CoREST complex. Mol Cell Biol 2008; 28:6066-77. [PMID: 18625718 DOI: 10.1128/mcb.00246-08] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The ZNF217 oncoprotein is a constituent of a core transcriptional complex that includes CoREST, histone deacetylase 1/2, lysine demethylase 1, and the C-terminal binding protein 1/2. We have combined genome-wide expression profiling and chromatin immunoprecipitation with directed selection and ligation (ChIP-DSL) to identify a subset of genes directly regulated by ZNF217. Our results establish p15(ink4b) as a direct target of the ZNF217 complex. Downregulation of ZNF217 in MCF-7 breast cancer cells resulted in a dramatic increase in p15(ink4b) expression and coincided with increases in dimethylation of H3-K4 and, surprisingly, a decrease in K9/K14-H3 acetylation. Stimulation of HaCaT cells with transforming growth factor beta (TGF-beta) resulted in a release of ZNF217 and a concomitant binding of SMAD2 to the proximal promoter, which preceded increases in ink4b protein expression. Furthermore, the changes in chromatin marks at the p15(ink4b) promoter following TGF-beta stimulation were similar to those observed following ZNF217 downregulation. Collectively, these results establish the ZNF217 complex as a novel negative regulator of the p15(ink4b) gene and may constitute an important link between amplification of ZNF217 and the loss of TGF-beta responsiveness in breast cancer.
Collapse
|
572
|
Ha L, Merlino G, Sviderskaya EV. Melanomagenesis: overcoming the barrier of melanocyte senescence. Cell Cycle 2008; 7:1944-8. [PMID: 18604170 PMCID: PMC2678050 DOI: 10.4161/cc.7.13.6230] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Although melanoma ultimately progresses to a highly aggressive and metastatic disease that is typically resistant to currently available therapy, it often begins as a benign nevus consisting of a clonal population of hyperplastic melanocytes that cannot progress because they are locked in a state of cellular senescence. Once senescence is overcome, the nevus can exhibit dysplastic features and readily progress to more lethal stages. Recent advances have convincingly demonstrated that senescence represents a true barrier to the progression of many types of cancer, including melanoma. Thus, understanding the mechanism(s) by which melanoma evades senescence has become a priority in the melanoma research community. Senescence in most cells is regulated through some combination of activities within the RB and p53 pathways. However, differences discovered among various tumor types, some subtle and others quite profound, have revealed that senescence frequently operates in a context-dependent manner. Here we review what is known about melanocyte senescence, and how such knowledge may provide a much-needed edge in our struggles to contain or perhaps vanquish this often-fatal malignancy.
Collapse
Affiliation(s)
- Linan Ha
- Division of Monoclonal Antibody, Center of Drug Evaluation and Research, Food and Drug Administration, Bethesda, Maryland, USA
| | | | | |
Collapse
|
573
|
Andreassi MG. DNA damage, vascular senescence and atherosclerosis. J Mol Med (Berl) 2008; 86:1033-43. [DOI: 10.1007/s00109-008-0358-7] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2008] [Revised: 03/07/2008] [Accepted: 03/31/2008] [Indexed: 01/21/2023]
|
574
|
Ma Y, Lu B, Ruan W, Wang H, Lin J, Hu H, Deng H, Huang Q, Lai M. Tumor suppressor gene insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) induces senescence-like growth arrest in colorectal cancer cells. Exp Mol Pathol 2008; 85:141-5. [PMID: 18701096 DOI: 10.1016/j.yexmp.2008.04.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2008] [Revised: 03/26/2008] [Accepted: 04/29/2008] [Indexed: 01/11/2023]
Abstract
Insulin-like growth factor binding protein-related protein 1 (IGFBP-rP1) is a potential tumor suppressor gene. This study attempted to explore a potential senescence-like role for IGFBP-rP1 in suppressing human colorectal cancer. Recombinant IGFBP-rP1 inhibited cell proliferation and induced G1 cell cycle arrest in RKO and CW2 cells. It induced a senescence-like phenotype by showing 2-fold higher beta-galactosidase activity in IGFBP-rP1-transfectants over that in control cells. Western blot confirmed down-regulation of phosphorylated retinoblastoma protein (pRB) and up-regulation of p53 in IGFBP-rP1-transfectants as compared with control cells. Thus, IGFBP-rP1 might be a key molecule in the cellular senescence pathway. Our results uncovered a novel molecular mechanism involving the altered expression of pRB and p53 for tumor suppressor gene IGFBP-rP1 in colorectal cancer. Restoration of IGFBP-rP1 function might have potential therapeutic significance in colorectal cancer.
Collapse
Affiliation(s)
- Yu Ma
- Department of Pathology, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, 310058, China
| | | | | | | | | | | | | | | | | |
Collapse
|
575
|
Majid S, Kikuno N, Nelles J, Noonan E, Tanaka Y, Kawamoto K, Hirata H, Li LC, Zhao H, Okino ST, Place RF, Pookot D, Dahiya R. Genistein induces the p21WAF1/CIP1 and p16INK4a tumor suppressor genes in prostate cancer cells by epigenetic mechanisms involving active chromatin modification. Cancer Res 2008; 68:2736-44. [PMID: 18413741 DOI: 10.1158/0008-5472.can-07-2290] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Genistein (4',5,7-trihydroxyisoflavone) is the most abundant isoflavone found in the soybean. The effects of genistein on various cancer cell lines have been extensively studied but the precise molecular mechanisms are not known. We report here the epigenetic mechanism of the action of genistein on androgen-sensitive (LNCaP) and androgen-insensitive (DuPro) human prostate cancer cell lines. Genistein induced the expression of tumor suppressor genes p21 (WAF1/CIP1/KIP1) and p16 (INK4a) with a concomitant decrease in cyclins. There was a G(0)-G(1) cell cycle arrest in LNCaP cells and a G(2)-M arrest in DuPro cells after genistein treatment. Genistein also induced apoptosis in DuPro cells. DNA methylation analysis revealed the absence of p21 promoter methylation in both cell lines. The effect of genistein on chromatin remodeling has not been previously reported. We found that genistein increased acetylated histones 3, 4, and H3/K4 at the p21 and p16 transcription start sites. Furthermore, we found that genistein treatment also increased the expression of histone acetyl transferases that function in transcriptional activation. This is the first report on epigenetic regulation of various genes by genistein through chromatin remodeling in prostate cancer. Altogether, our data provide new insights into the epigenetic mechanism of the action of genistein that may contribute to the chemopreventive activity of this dietary isoflavone and have important implications for epigenetic therapy.
Collapse
Affiliation(s)
- Shahana Majid
- Department of Urology, Veterans Affairs Medical Center, University of California, San Francisco, California 94121, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
576
|
Jeyapalan JC, Sedivy JM. Cellular senescence and organismal aging. Mech Ageing Dev 2008; 129:467-74. [PMID: 18502472 DOI: 10.1016/j.mad.2008.04.001] [Citation(s) in RCA: 256] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2007] [Revised: 03/27/2008] [Accepted: 04/06/2008] [Indexed: 01/22/2023]
Abstract
Cellular senescence, first observed and defined using in vitro cell culture studies, is an irreversible cell cycle arrest which can be triggered by a variety of factors. Emerging evidence suggests that cellular senescence acts as an in vivo tumor suppression mechanism by limiting aberrant proliferation. It has also been postulated that cellular senescence can occur independently of cancer and contribute to the physiological processes of normal organismal aging. Recent data have demonstrated the in vivo accumulation of senescent cells with advancing age. Some characteristics of senescent cells, such as the ability to modify their extracellular environment, could play a role in aging and age-related pathology. In this review, we examine current evidence that links cellular senescence and organismal aging.
Collapse
Affiliation(s)
- Jessie C Jeyapalan
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | | |
Collapse
|
577
|
Liu Y, El-Naggar S, Darling DS, Higashi Y, Dean DC. Zeb1 links epithelial-mesenchymal transition and cellular senescence. Development 2008; 135:579-88. [PMID: 18192284 DOI: 10.1242/dev.007047] [Citation(s) in RCA: 236] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Overexpression of zinc finger E-box binding homeobox transcription factor 1 (Zeb1) in cancer leads to epithelial-to-mesenchymal transition (EMT) and increased metastasis. As opposed to overexpression, we show that mutation of Zeb1 in mice causes a mesenchymal-epithelial transition in gene expression characterized by ectopic expression of epithelial genes such as E-cadherin and loss of expression of mesenchymal genes such as vimentin. In contrast to rapid proliferation in cancer cells where Zeb1 is overexpressed, this mesenchymal-epithelial transition in mutant mice is associated with diminished proliferation of progenitor cells at sites of developmental defects, including the forming palate, skeleton and CNS. Zeb1 dosage-dependent deregulation of epithelial and mesenchymal genes extends to mouse embryonic fibroblasts (MEFs), and mutant MEFs also display diminished replicative capacity in culture, leading to premature senescence. Replicative senescence in MEFs is classically triggered by products of the Ink4a (Cdkn2a) gene. However, this Ink4a pathway is not activated during senescence of Zeb1 mutant MEFs. Instead, there is ectopic expression of two other cell cycle inhibitory cyclin-dependent kinase inhibitors, p15Ink4b (Cdkn2b) and p21Cdkn1a (Cdkn1a). We demonstrate that this ectopic expression of p15Ink4b extends in vivo to sites of diminished progenitor cell proliferation and developmental defects in Zeb1-null mice.
Collapse
Affiliation(s)
- Yongqing Liu
- James Graham Brown Cancer Center, Department of Ophthalmology and Visual Sciences, University of Louisville Health Sciences Center, Louisville, KY 40202, USA
| | | | | | | | | |
Collapse
|
578
|
Miyazaki M, Miyazaki K, Itoi M, Katoh Y, Guo Y, Kanno R, Katoh-Fukui Y, Honda H, Amagai T, van Lohuizen M, Kawamoto H, Kanno M. Thymocyte proliferation induced by pre-T cell receptor signaling is maintained through polycomb gene product Bmi-1-mediated Cdkn2a repression. Immunity 2008; 28:231-45. [PMID: 18275833 DOI: 10.1016/j.immuni.2007.12.013] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2007] [Revised: 11/15/2007] [Accepted: 12/07/2007] [Indexed: 11/16/2022]
Abstract
Thymocytes undergo massive proliferation before T cell receptor (TCR) gene rearrangement, ensuring the diversification of the TCR repertoire. Because activated cells are more susceptible to damage, cell-death restraint as well as promotion of cell-cycle progression is considered important for adequate cell growth. Although the molecular mechanism of pre-TCR-induced proliferation has been examined, the mechanisms of protection against cell death during the proliferation phase remain unknown. Here we show that the survival of activated pre-T cells induced by pre-TCR signaling required the Polycomb group (PcG) gene product Bmi-1-mediated repression of Cdkn2A, and that p19Arf expression resulted in thymocyte cell death and inhibited the transition from CD4(-)CD8(-) (DN) to CD4(+)CD8(+) (DP) stage upstream of the transcriptional factor p53 pathway. The expression of Cdkn2A (the gene encoding p19Arf) in immature thymocytes was directly regulated by PcG complex containing Bmi-1 and M33 through the maintenance of local trimethylated histone H3K27. Our results indicate that this epigenetic regulation critically contributes to the survival of the activated pre-T cells, thereby supporting their proliferation during the DN-DP transition.
Collapse
Affiliation(s)
- Masaki Miyazaki
- Department of Immunology, Graduate School of Biomedical Science, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
579
|
Wiedemeyer R, Brennan C, Heffernan TP, Xiao Y, Mahoney J, Protopopov A, Zheng H, Bignell G, Furnari F, Cavenee WK, Hahn WC, Ichimura K, Collins VP, Chu GC, Stratton MR, Ligon KL, Futreal PA, Chin L. Feedback circuit among INK4 tumor suppressors constrains human glioblastoma development. Cancer Cell 2008; 13:355-64. [PMID: 18394558 PMCID: PMC2292238 DOI: 10.1016/j.ccr.2008.02.010] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2007] [Revised: 12/18/2007] [Accepted: 02/12/2008] [Indexed: 11/11/2022]
Abstract
We have developed a nonheuristic genome topography scan (GTS) algorithm to characterize the patterns of genomic alterations in human glioblastoma (GBM), identifying frequent p18(INK4C) and p16(INK4A) codeletion. Functional reconstitution of p18(INK4C) in GBM cells null for both p16(INK4A) and p18(INK4C) resulted in impaired cell-cycle progression and tumorigenic potential. Conversely, RNAi-mediated depletion of p18(INK4C) in p16(INK4A)-deficient primary astrocytes or established GBM cells enhanced tumorigenicity in vitro and in vivo. Furthermore, acute suppression of p16(INK4A) in primary astrocytes induced a concomitant increase in p18(INK4C). Together, these findings uncover a feedback regulatory circuit in the astrocytic lineage and demonstrate a bona fide tumor suppressor role for p18(INK4C) in human GBM wherein it functions cooperatively with other INK4 family members to constrain inappropriate proliferation.
Collapse
Affiliation(s)
- Ruprecht Wiedemeyer
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
| | - Cameron Brennan
- Department of Neurosurgery, Memorial Sloan-Kettering Cancer Center, New York, NY 10065, USA
- Department of Neurosurgery, Weill-Cornell Medical College, New York, NY 10065, USA
- Corresponding author
| | - Timothy P. Heffernan
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
| | - Yonghong Xiao
- Center for Applied Cancer Science, Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - John Mahoney
- Center for Applied Cancer Science, Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Alexei Protopopov
- Center for Applied Cancer Science, Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Hongwu Zheng
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
| | - Graham Bignell
- Cancer Genome Project, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Frank Furnari
- Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA
| | - Webster K. Cavenee
- Ludwig Institute for Cancer Research, University of California, San Diego, La Jolla, CA 92093, USA
| | - William C. Hahn
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
- Center for Cancer Genome Discovery, Dana-Farber Cancer Institute, Boston, MA 02115, USA
- Broad Institute of Harvard and MIT, Cambridge, MA 02142, USA
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Koichi Ichimura
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK
| | - V. Peter Collins
- Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK
| | - Gerald C. Chu
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
- Center for Applied Cancer Science, Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Boston, MA 02115, USA
| | - Michael R. Stratton
- Cancer Genome Project, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
- Institute of Cancer Research, Sutton, Surrey SM2 5NG, UK
| | - Keith L. Ligon
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
- Center for Molecular Oncologic Pathology, Dana-Farber Cancer Institute, Boston, MA 02115, USA
- Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - P. Andrew Futreal
- Cancer Genome Project, Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Lynda Chin
- Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
- Center for Applied Cancer Science, Belfer Institute for Innovative Cancer Science, Dana-Farber Cancer Institute, Boston, MA 02115, USA
- Department of Dermatology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
- Corresponding author
| |
Collapse
|
580
|
SWI/SNF mediates polycomb eviction and epigenetic reprogramming of the INK4b-ARF-INK4a locus. Mol Cell Biol 2008; 28:3457-64. [PMID: 18332116 DOI: 10.1128/mcb.02019-07] [Citation(s) in RCA: 205] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Stable silencing of the INK4b-ARF-INK4a tumor suppressor locus occurs in a variety of human cancers, including malignant rhabdoid tumors (MRTs). MRTs are extremely aggressive cancers caused by the loss of the hSNF5 subunit of the SWI/SNF chromatin-remodeling complex. We found previously that, in MRT cells, hSNF5 is required for p16(INK4a) induction, mitotic checkpoint activation, and cellular senescence. Here, we investigated how the balance between Polycomb group (PcG) silencing and SWI/SNF activation affects epigenetic control of the INK4b-ARF-INK4a locus in MRT cells. hSNF5 reexpression in MRT cells caused SWI/SNF recruitment and activation of p15(INK4b) and p16(INK4a), but not of p14(ARF). Gene activation by hSNF5 is strictly dependent on the SWI/SNF motor subunit BRG1. SWI/SNF mediates eviction of the PRC1 and PRC2 PcG silencers and extensive chromatin reprogramming. Concomitant with PcG complex removal, the mixed lineage leukemia 1 (MLL1) protein is recruited and active histone marks supplant repressive ones. Strikingly, loss of PcG complexes is accompanied by DNA methyltransferase DNMT3B dissociation and reduced DNA methylation. Thus, various chromatin states can be modulated by SWI/SNF action. Collectively, these findings emphasize the close interconnectivity and dynamics of diverse chromatin modifications in cancer and gene control.
Collapse
|
581
|
Talmud PJ, Cooper JA, Palmen J, Lovering R, Drenos F, Hingorani AD, Humphries SE. Chromosome 9p21.3 coronary heart disease locus genotype and prospective risk of CHD in healthy middle-aged men. Clin Chem 2008; 54:467-74. [PMID: 18250146 DOI: 10.1373/clinchem.2007.095489] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
BACKGROUND We investigated whether chromosome 9p21.3 single-nucleotide polymorphisms (SNPs), identified in coronary heart disease (CHD) genome-wide association scans, added significantly to the predictive utility for CHD of conventional risk factors (CRF) in the Framingham risk score (FRS) algorithm. METHODS In the Northwick Park Heart Study II of 2742 men (270 CHD events occurring during a 15-year prospective study), rs10757274 A>G [mean frequency G = 0.48 (95% CI 0.47-0.50)] was genotyped. Using the area under the ROC curve (A(ROC)) and the likelihood ratio (LR) statistic, we assessed the discriminatory performance of the FRS based on CRFs with and without genotype. RESULTS rs10757274 A>G was associated with incident CHD, with an effect size as reported previously [hazard ratio in GG vs AA men of 1.60 (95% CI 1.12-2.28)], independent of CRFs and family history of CHD. Although the A(ROC) for CRFs alone [0.62 (95% CI 0.58-0.66)] did not increase significantly (P = 0.14) when rs10757274 A>G genotype was added [0.64 (95% CI 0.60-0.68)], including genotype gave better fit (LR P = 0.01) and including rs10757274 moved 369 men (13.5% of the total) into more accurate risk categories. To model polygenic effects, 10 hypothetical, randomly assigned gene variants, with similar effect size and frequencies were added. Two variants made significant A(ROC) improvements to the FRS prediction (P = 0.01), whereas further variants had smaller incremental effects (final A(ROC) = 0.71, P <0.001 vs CRFs; LR vs CRFs P <0.0001). CONCLUSIONS Although overall, rs10757274 did not add substantially to the usefulness of the FRS for predicting future events, it did improve reclassification of CHD risk, and thus may have clinical utility.
Collapse
Affiliation(s)
- Philippa J Talmud
- Centre for Cardiovascular Genetics, Department of Medicine, University College London, London, UK
| | | | | | | | | | | | | |
Collapse
|
582
|
Takeshima M, Saitoh M, Kusano K, Nagayasu H, Kurashige Y, Malsantha M, Arakawa T, Takuma T, Chiba I, Kaku T, Shibata T, Abiko Y. High frequency of hypermethylation of p14, p15 and p16 in oral pre-cancerous lesions associated with betel-quid chewing in Sri Lanka. J Oral Pathol Med 2008; 37:475-9. [DOI: 10.1111/j.1600-0714.2008.00644.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
583
|
Orford KW, Scadden DT. Deconstructing stem cell self-renewal: genetic insights into cell-cycle regulation. Nat Rev Genet 2008; 9:115-28. [DOI: 10.1038/nrg2269] [Citation(s) in RCA: 670] [Impact Index Per Article: 41.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
|
584
|
Discovery of genes implicated in whirling disease infection and resistance in rainbow trout using genome-wide expression profiling. BMC Genomics 2008; 9:37. [PMID: 18218127 PMCID: PMC2257940 DOI: 10.1186/1471-2164-9-37] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2007] [Accepted: 01/24/2008] [Indexed: 12/03/2022] Open
Abstract
Background Whirling disease, caused by the pathogen Myxobolus cerebralis, afflicts several salmonid species. Rainbow trout are particularly susceptible and may suffer high mortality rates. The disease is persistent and spreading in hatcheries and natural waters of several countries, including the U.S.A., and the economic losses attributed to whirling disease are substantial. In this study, genome-wide expression profiling using cDNA microarrays was conducted for resistant Hofer and susceptible Trout Lodge rainbow trout strains following pathogen exposure with the primary objective of identifying specific genes implicated in whirling disease resistance. Results Several genes were significantly up-regulated in skin following pathogen exposure for both the resistant and susceptible rainbow trout strains. For both strains, response to infection appears to be linked with the interferon system. Expression profiles for three genes identified with microarrays were confirmed with qRT-PCR. Ubiquitin-like protein 1 was up-regulated over 100 fold and interferon regulating factor 1 was up-regulated over 15 fold following pathogen exposure for both strains. Expression of metallothionein B, which has known roles in inflammation and immune response, was up-regulated over 5 fold in the resistant Hofer strain but was unchanged in the susceptible Trout Lodge strain following pathogen exposure. Conclusion The present study has provided an initial view into the genetic basis underlying immune response and resistance of rainbow trout to the whirling disease parasite. The identified genes have allowed us to gain insight into the molecular mechanisms implicated in salmonid immune response and resistance to whirling disease infection.
Collapse
|
585
|
Bouchard C, Lee S, Paulus-Hock V, Loddenkemper C, Eilers M, Schmitt CA. FoxO transcription factors suppress Myc-driven lymphomagenesis via direct activation of Arf. Genes Dev 2008; 21:2775-87. [PMID: 17974917 DOI: 10.1101/gad.453107] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
FoxO transcription factors play critical roles in cell cycle control and cellular stress responses, and abrogation of FoxO function promotes focus formation by Myc in vitro. Here we show that stable introduction of a dominant-negative FoxO moiety (dnFoxO) into Emu-myc transgenic hematopoietic stem cells accelerates lymphoma development in recipient mice by attenuating Myc-induced apoptosis. When expressed in Emu-myc; p53(+/-) progenitor cells, dnFoxO alleviates the pressure to inactivate the remaining p53 allele in upcoming lymphomas. Expression of the p53 upstream regulator p19(Arf) is virtually undetectable in most dnFoxO-positive Myc-driven lymphomas. We find that FoxO proteins bind to a distinct site within the Ink4a/Arf locus and activate Arf expression. Moreover, constitutive Myc signaling induces a marked increase in nuclear FoxO levels and stimulates binding of FoxO proteins to the Arf locus. These data demonstrate that FoxO factors mediate Myc-induced Arf expression and provide direct genetic evidence for their tumor-suppressive capacity.
Collapse
Affiliation(s)
- Caroline Bouchard
- Institute of Molecular Biology and Tumor Research, 35033 Marburg, Germany
| | | | | | | | | | | |
Collapse
|
586
|
Chen ML, Chang JHM, Yeh KT, Chang YS, Chang JG. Epigenetic changes in tumor suppressor genes, P15, P16, APC-3 and E-cadherin in body fluid. Kaohsiung J Med Sci 2008; 23:498-503. [PMID: 18055295 DOI: 10.1016/s1607-551x(08)70007-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The inactivation of tumor suppressor genes by promoter methylation plays an important role in the development of cancers; it can also be used as a marker to distinguish cancerous cells from non-cancer cells. In this study, we investigated the aberrant methylation profile of the tumor suppressor genes P15, P16, APC and E-cadherin in the cells of body fluid. A methylation-specific polymerase chain reaction was performed in 31 cases of malignant effusion and 39 cases of non-malignant effusion. Aberrant promoter methylation of P15, P16, APC and E-cadherin genes was seen in 0%, 25.8%, 35.5% and 6.5% of malignant effusion cases, respectively, whereas the frequencies were 0%, 2.6%, 2.6% and 0%, respectively, for negative control effusion. There were statistically significant differences in the aberrant methylation of P16 (p = 0.008) and APC (p = 0.018) genes between cases of malignant effusion and controls. Methylation of one of three genes (P16, E-cadherin, APC) was found in 14 out of 31 (45.2%) cases of malignant effusion, and in two out of 39 (5.1%) cases of non-malignant effusion (p = 0.000004). Concurrent methylation was found in nine out of 31 (29%) cases of malignant effusion, but in no non-malignant effusion sample. From these results, we suggest that methylation-specific polymerase chain reaction to analyze the promoters of tumor suppressor genes can distinguish between malignant effusion and benign effusion, and may help cytologists to make more accurate diagnoses.
Collapse
Affiliation(s)
- Mei-Ling Chen
- Department of Pathology, Changhua Christian Hospital, Changhua, Taiwan
| | | | | | | | | |
Collapse
|
587
|
Muscarella P, Bloomston M, Brewer AR, Mahajan A, Frankel WL, Ellison EC, Farrar WB, Weghorst CM, Li J. Expression of the p16INK4A/Cdkn2a gene is prevalently downregulated in human pheochromocytoma tumor specimens. Gene Expr 2008; 14:207-16. [PMID: 19110720 PMCID: PMC6042001 DOI: 10.3727/105221608786883825] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A number of hereditary syndromes have been found to be associated with pheochromocytoma development, but there is a paucity of data regarding secondary molecular events, such as downregulation of the p16INK4A/Cdkn2a gene (hereafter p16), contributing to pheochromocytoma tumorigenesis. Using tissue microarray and immunohistochemistry, we evaluated the expression of p16 in 31 pheochromocytoma tumor specimens. Our results showed that the p16 gene was expressed at low level or even not expressed in all but one specimens [30/31 (96.8%)], indicative of the prevalence of p16 downregulation in pheochromocytomas. In contrast, high expression of pl6 was observed in the majority of control "normal" specimens [5/7 (71.6%)]. To further investigate the molecular mechanisms underlying pl6 downregulation in pheochromocytomas, we used quantitative real-time PCR, methylation-specific PCR, and direct DNA sequencing to analyze these specimens for potential genetic alterations of the p16 gene. Deletions and aberrant CpG methylation of pl6 were identified in 9 (29.0%) and 11 (35.5%) specimens, respectively, while one specimen harbored a point mutation, Ala --> Pro at residue 20 of P16, and this mutation led to an eightfold decrease in the CDK4-inhibitory activity of P16. The overall frequency of pl6 genetic alterations is 67.7%. Taken together, our results demonstrate that reduced expression of pl6 is a common event in human pheochromocytomas, and the primary cause for such downregulation is inactivating genetic abnormalities in the p16 gene.
Collapse
Affiliation(s)
- Peter Muscarella
- *Department of Surgery, College of Medicine, The Ohio State University, Columbus, OH, USA
- §Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Mark Bloomston
- *Department of Surgery, College of Medicine, The Ohio State University, Columbus, OH, USA
- §Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Alexander R. Brewer
- *Department of Surgery, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Anjali Mahajan
- †Department of Chemistry, The Ohio State University, Columbus, OH, USA
| | - Wendy L. Frankel
- ‡Department of Pathology, College of Medicine, The Ohio State University, Columbus, OH, USA
- §Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - E. Christopher Ellison
- *Department of Surgery, College of Medicine, The Ohio State University, Columbus, OH, USA
- §Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - William B. Farrar
- *Department of Surgery, College of Medicine, The Ohio State University, Columbus, OH, USA
- §Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, OH, USA
| | - Christopher M. Weghorst
- §Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, OH, USA
- ¶Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, OH, USA
| | - Junan Li
- §Comprehensive Cancer Center, College of Medicine, The Ohio State University, Columbus, OH, USA
- ¶Division of Environmental Health Sciences, College of Public Health, The Ohio State University, Columbus, OH, USA
| |
Collapse
|
588
|
Hallor KH, Staaf J, Jönsson G, Heidenblad M, Vult von Steyern F, Bauer HCF, Ijszenga M, Hogendoorn PCW, Mandahl N, Szuhai K, Mertens F. Frequent deletion of the CDKN2A locus in chordoma: analysis of chromosomal imbalances using array comparative genomic hybridisation. Br J Cancer 2007; 98:434-42. [PMID: 18071362 PMCID: PMC2361468 DOI: 10.1038/sj.bjc.6604130] [Citation(s) in RCA: 91] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The initiating somatic genetic events in chordoma development have not yet been identified. Most cytogenetically investigated chordomas have displayed near-diploid or moderately hypodiploid karyotypes, with several numerical and structural rearrangements. However, no consistent structural chromosome aberration has been reported. This is the first array-based study characterising DNA copy number changes in chordoma. Array comparative genomic hybridisation (aCGH) identified copy number alterations in all samples and imbalances affecting 5 or more out of the 21 investigated tumours were seen on all chromosomes. In general, deletions were more common than gains and no high-level amplification was found, supporting previous findings of primarily losses of large chromosomal regions as an important mechanism in chordoma development. Although small imbalances were commonly found, the vast majority of these were detected in single cases; no small deletion affecting all tumours could be discerned. However, the CDKN2A and CDKN2B loci in 9p21 were homo- or heterozygously lost in 70% of the tumours, a finding corroborated by fluorescence in situ hybridisation, suggesting that inactivation of these genes constitute an important step in chordoma development.
Collapse
Affiliation(s)
- K H Hallor
- Department of Clinical Genetics, Lund University Hospital, Lund SE-221 85, Sweden.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
589
|
A non-tumor suppressor role for basal p19ARF in maintaining nucleolar structure and function. Mol Cell Biol 2007; 28:1068-80. [PMID: 18070929 DOI: 10.1128/mcb.00484-07] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The nucleolus is the center of ribosome synthesis, with the nucleophosmin (NPM) and p19(ARF) proteins antagonizing one another to either promote or inhibit growth. However, basal NPM and ARF proteins form nucleolar complexes whose functions remain unknown. Nucleoli from Arf(-/)(-) cells displayed increased nucleolar area, suggesting that basal ARF might regulate key nucleolar functions. Concordantly, ribosome biogenesis and protein synthesis were dramatically elevated in the absence of Arf, causing these cells to exhibit tremendous gains in protein amounts and increases in cell volume. The transcription of ribosomal DNA (rDNA), the processing of nascent rRNA molecules, and the nuclear export of ribosomes were all increased in the absence of ARF. Similar results were obtained using targeted lentiviral RNA interference of ARF in wild-type MEFs. Postmitotic osteoclasts from Arf-null mice exhibited hyperactivity in vitro and in vivo, demonstrating a physiological function for basal ARF. Moreover, the knockdown of NPM blocked the increases in Arf(-/-) ribosome output and osteoclast activity, demonstrating that these gains require NPM. Thus, basal ARF proteins act as a monitor of steady-state ribosome biogenesis and growth independent of their ability to prevent unwarranted hyperproliferation.
Collapse
|
590
|
Runx2 deficiency and defective subnuclear targeting bypass senescence to promote immortalization and tumorigenic potential. Proc Natl Acad Sci U S A 2007; 104:19861-6. [PMID: 18077419 DOI: 10.1073/pnas.0709650104] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The osteogenic Runt-related (Runx2) transcription factor negatively regulates proliferation and ribosomal gene expression in normal diploid osteoblasts, but is up-regulated in metastatic breast and prostate cancer cells. Thus, Runx2 may function as a tumor suppressor or an oncogene depending on the cellular context. Here we show that Runx2-deficient primary osteoblasts fail to undergo senescence as indicated by the absence of beta-gal activity and p16(INK4a) tumor suppressor expression. Primary Runx2-null osteoblasts have a growth advantage and exhibit loss of p21(WAF1/CIP1) and p19(ARF) expression. Reintroduction of WT Runx2, but not a subnuclear targeting-defective mutant, induces both p21(WAF/CIP1) and p19(ARF) mRNA and protein resulting in cell-cycle inhibition. Accumulation of spontaneous phospho-H2A.X foci, loss of telomere integrity and the Mre11/Rad50/Nbs1 DNA repair complex, and a delayed DNA repair response all indicate that Runx2 deficiency leads to genomic instability. We propose that Runx2 functions as a tumor suppressor in primary diploid osteoblasts and that subnuclear targeting contributes to Runx2-mediated tumor suppression.
Collapse
|
591
|
Grinstein E, Wernet P. Cellular signaling in normal and cancerous stem cells. Cell Signal 2007; 19:2428-33. [PMID: 17651940 DOI: 10.1016/j.cellsig.2007.06.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2007] [Accepted: 06/21/2007] [Indexed: 12/30/2022]
Abstract
Self-renewing divisions of normal and cancerous stem cells are responsible for the initiation and maintenance of normal and certain cancerous tissues, respectively. Recent findings suggest that tumor surveillance mechanisms can reduce regenerative capacity and frequency of normal stem cells, thereby contributing to tissue aging. Signaling pathways promoting self-renewal of stem cells can also drive proliferation in cancer. The BMI-1 proto-oncogene is required for the maintenance of tissue-specific stem cells and is involved in carcinogenesis within the same tissues. BMI-1 promotes self-renewal of stem cells largely by interfering with two central cellular tumor suppressor pathways, p16(Ink4a)/retinoblastoma protein (Rb) and ARF/p53, whose disruption is a hallmark of cancer. Nucleolin, an Rb-associated protein, is abundant in proliferating cancerous cells and likely contributes to the maintenance of human CD34-positive stem/progenitor cells of hematopoiesis. Elucidation of the involvement of proto-oncogenes and tumor suppressors in the maintenance of stem cells might have therapeutic implications.
Collapse
Affiliation(s)
- Edgar Grinstein
- Institute of Transplantation Diagnostics and Cellular Therapeutics, Heinrich Heine University Medical Center, 40225 Düsseldorf, Germany.
| | | |
Collapse
|
592
|
Inactivation of the polycomb group protein Ring1B unveils an antiproliferative role in hematopoietic cell expansion and cooperation with tumorigenesis associated with Ink4a deletion. Mol Cell Biol 2007; 28:1018-28. [PMID: 18039844 DOI: 10.1128/mcb.01136-07] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Polycomb group (PcG) proteins act as positive regulators of cell proliferation. Ring1B is a PcG gene essential for embryonic development, but its contribution to cell turnover in regenerating tissues in not known. Here, we have generated a conditional mouse mutant line to study the Ring1B role in adult hematopoiesis. Mutant mice developed a hypocellular bone marrow that paradoxically contained an enlarged, hyperproliferating compartment of immature cells, with an intact differentiation potential. These alterations were associated with differential upregulation of cyclin D2, which occurred in all mutant bone marrow cells, and of p16(Ink4a), observed only in the differentiated compartment. Concurrent inactivation of Ink4a rescued the defective proliferation of maturing cells but did not affect the hyperproliferative activity of progenitors and resulted in a shortening of the onset of lymphomas induced by Ink4a inactivation. These data show that Ring1B restricts the progenitors' proliferation and promotes the proliferation of their maturing progeny by selectively altering the expression pattern of cell cycle regulators along hematopoietic differentiation. The novel antiproliferative role of Ring1B's downregulation of a cell cycle activator may play an important role in the tight control of hematopoietic cell turnover.
Collapse
|
593
|
Abstract
Adult stem cells have become the focus of intense research in recent years as a result of their role in the maintenance and repair of tissues. They exert this function through their extensive expansion (self-renewal) and multipotent differentiation capacity. Understanding whether adult stem cells retain this capacity throughout the lifespan of the individual, or undergo a process of ageing resulting in a decreased stem cell pool, is an important area of investigation. Progress in this area has been hampered by lack of suitable models and of appropriate markers and assays to identify stem cells. However, recent data suggest that an understanding of the mechanisms governing stem cell ageing can give insight into the mechanism of tissue ageing and, most importantly, advance our ability to use stem cells in cell and gene therapy strategies.
Collapse
|
594
|
Moulin S, Llanos S, Kim SH, Peters G. Binding to nucleophosmin determines the localization of human and chicken ARF but not its impact on p53. Oncogene 2007; 27:2382-9. [PMID: 17968318 DOI: 10.1038/sj.onc.1210887] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The ARF tumour suppressor gene encodes a small highly basic protein whose known functions are largely determined by the amino acids encoded within the first exon. In mammals, the protein incorporates additional residues specified by an alternative reading frame in the second exon of INK4a, but this arrangement does not apply to the chicken homologue. In exploring the intracellular localization of chicken p7(ARF), we found that while the FLAG- and HA-tagged versions localize in the nucleolus, in line with mammalian ARF, the GFP-tagged version is excluded from the nucleolus. Here we show that irrespective of the source or composition of the ARF fusion proteins, versions that accumulate in the nucleolus share the ability to bind to nucleophosmin (NPM). Depletion of NPM with siRNA results in the re-location and destabilization of nucleolar forms of ARF but has little effect on the location or stability of a nucleoplasmic form of ARF. Importantly, knockdown of endogenous NPM does not impair the ability of ARF to bind to MDM2 and stabilize p53. These findings support the view that nucleolar localization determines the stability of ARF but not its primary function.
Collapse
Affiliation(s)
- S Moulin
- Cancer Research UK, London Research Institute, London, UK
| | | | | | | |
Collapse
|
595
|
Leder A, McMenamin J, Zhou F, Moran JL, Beier DR, Leder P. Genome-wide SNP analysis of Tg.AC transgenic mice reveals an oncogenic collaboration between v-Ha-ras and Ink4a, which is absent in p53 deficiency. Oncogene 2007; 27:2456-65. [DOI: 10.1038/sj.onc.1210866] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
596
|
Campisi J, d'Adda di Fagagna F. Cellular senescence: when bad things happen to good cells. Nat Rev Mol Cell Biol 2007; 8:729-40. [PMID: 17667954 DOI: 10.1038/nrm2233] [Citation(s) in RCA: 2988] [Impact Index Per Article: 175.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cells continually experience stress and damage from exogenous and endogenous sources, and their responses range from complete recovery to cell death. Proliferating cells can initiate an additional response by adopting a state of permanent cell-cycle arrest that is termed cellular senescence. Understanding the causes and consequences of cellular senescence has provided novel insights into how cells react to stress, especially genotoxic stress, and how this cellular response can affect complex organismal processes such as the development of cancer and ageing.
Collapse
Affiliation(s)
- Judith Campisi
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA.
| | | |
Collapse
|
597
|
Oguro H, Iwama A. Life and death in hematopoietic stem cells. Curr Opin Immunol 2007; 19:503-9. [PMID: 17618101 DOI: 10.1016/j.coi.2007.05.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 05/02/2007] [Indexed: 01/15/2023]
Abstract
Hematopoietic stem cells (HSCs) are defined as primitive cells that are capable of both self-renewal and differentiation into any of the hematopoietic cell lineages. HSC numbers need to be precisely regulated to maintain hematopoietic homeostasis. HSCs undergo several cell fate decisions, including decisions on life and death and self-renewal and differentiation, which have crucial roles in the regulation of their numbers and lifespan. Defects in these processes have been found to contribute to hematopoietic insufficiencies and the development of hematopoietic malignancies. Recent studies have begun to elucidate how HSCs make life and death decisions and the underlying molecular mechanisms involved, highlighting the importance of a balance between survival and death in the regulation of HSCs.
Collapse
Affiliation(s)
- Hideyuki Oguro
- Department of Cellular and Molecular Biology, Graduate School of Medicine, Chiba University, Chiba 260-8670, Japan
| | | |
Collapse
|
598
|
Krimpenfort P, Ijpenberg A, Song JY, van der Valk M, Nawijn M, Zevenhoven J, Berns A. p15Ink4b is a critical tumour suppressor in the absence of p16Ink4a. Nature 2007; 448:943-6. [PMID: 17713536 DOI: 10.1038/nature06084] [Citation(s) in RCA: 208] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2007] [Accepted: 07/09/2007] [Indexed: 01/09/2023]
Abstract
The CDKN2b-CDKN2a locus on chromosome 9p21 in human (chromosome 4 in mouse) is frequently lost in cancer. The locus encodes three cell cycle inhibitory proteins: p15INK4b encoded by CDKN2b, p16INK4a encoded by CDKN2a and p14ARF (p19Arf in mice) encoded by an alternative reading frame of CDKN2a (ref. 1). Whereas the tumour suppressor functions for p16INK4a and p14ARF have been firmly established, the role of p15INK4b remains ambiguous. However, many 9p21 deletions also remove CDKN2b, so we hypothesized a synergistic effect of the combined deficiency for p15INK4b, p14ARF and p16INK4a. Here we report that mice deficient for all three open reading frames (Cdkn2ab-/-) are more tumour-prone and develop a wider spectrum of tumours than Cdkn2a mutant mice, with a preponderance of skin tumours and soft tissue sarcomas (for example, mesothelioma) frequently composed of mixed cell types and often showing biphasic differentiation. Cdkn2ab-/- mouse embryonic fibroblasts (MEFs) are substantially more sensitive to oncogenic transformation than Cdkn2a mutant MEFs. Under conditions of stress, p15Ink4b protein levels are significantly elevated in MEFs deficient for p16Ink4a. Our data indicate that p15Ink4b can fulfil a critical backup function for p16Ink4a and provide an explanation for the frequent loss of the complete CDKN2b-CDKN2a locus in human tumours.
Collapse
Affiliation(s)
- Paul Krimpenfort
- Division of Molecular Genetics and Centre for Biomedical Genetics, The Netherlands Cancer Institute, 1066 CX Amsterdam, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
599
|
Abstract
Cellular senescence, a state of irreversible growth arrest, can be triggered by multiple mechanisms including telomere shortening, the epigenetic derepression of the INK4a/ARF locus, and DNA damage. Together these mechanisms limit excessive or aberrant cellular proliferation, and so the state of senescence protects against the development of cancer. Recent evidence suggests that cellular senescence also may be involved in aging.
Collapse
Affiliation(s)
- Manuel Collado
- Spanish National Cancer Research Center (CNIO), Madrid, Spain
| | | | | |
Collapse
|
600
|
Ohtani N, Imamura Y, Yamakoshi K, Hirota F, Nakayama R, Kubo Y, Ishimaru N, Takahashi A, Hirao A, Shimizu T, Mann DJ, Saya H, Hayashi Y, Arase S, Matsumoto M, Kazuki N, Hara E. Visualizing the dynamics of p21(Waf1/Cip1) cyclin-dependent kinase inhibitor expression in living animals. Proc Natl Acad Sci U S A 2007; 104:15034-9. [PMID: 17848507 PMCID: PMC1975854 DOI: 10.1073/pnas.0706949104] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Although the role of p21(Waf1/Cip1) gene expression is well documented in various cell culture studies, its in vivo roles are poorly understood. To gain further insight into the role of p21(Waf1/Cip1) gene expression in vivo, we attempted to visualize the dynamics of p21(Waf1/Cip1) gene expression in living animals. In this study, we established a transgenic mice line (p21-p-luc) expressing the firefly luciferase under the control of the p21(Waf1/Cip1) gene promoter. In conjunction with a noninvasive bioluminescent imaging technique, p21-p-luc mice enabled us to monitor the endogenous p21(Waf1/Cip1) gene expression in vivo. By monitoring and quantifying the p21(Waf1/Cip1) gene expression repeatedly in the same mouse throughout its entire lifespan, we were able to unveil the dynamics of p21(Waf1/Cip1) gene expression in the aging process. We also applied this system to chemically induced skin carcinogenesis and found that the levels of p21(Waf1/Cip1) gene expression rise dramatically in benign skin papillomas, suggesting that p21(Waf1/Cip1) plays a preventative role(s) in skin tumor formation. Surprisingly, moreover, we found that the level of p21(Waf1/Cip1) expression strikingly increased in the hair bulb and oscillated with a 3-week period correlating with hair follicle cycle progression. Notably, this was accompanied by the expression of p63 but not p53. This approach, together with the analysis of p21(Waf1/Cip1) knockout mice, has uncovered a novel role for the p21(Waf1/Cip1) gene in hair development. These data illustrate the unique utility of bioluminescence imaging in advancing our understanding of the timing and, hence, likely roles of specific gene expression in higher eukaryotes.
Collapse
Affiliation(s)
- Naoko Ohtani
- *Institute for Genome Research
- To whom correspondence may be addressed. E-mail:
or
| | | | | | | | - Rika Nakayama
- Center for Developmental Biology, RIKEN, Kobe 650-0047, Japan
| | - Yoshiaki Kubo
- Institute of Health Biosciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Naozumi Ishimaru
- Institute of Health Biosciences, University of Tokushima, Tokushima 770-8503, Japan
| | | | - Atsushi Hirao
- Cancer Research Institute, Kanazawa University, Kanazawa 920-0934, Japan
- **CREST, Japan Science and Technology Agency, Tokyo 102-0075, Japan
| | - Takatsune Shimizu
- Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo 160-8582, Japan; and
| | - David J. Mann
- Division of Cell and Molecular Biology, Imperial College London, London SW7 2AZ, United Kingdom
| | - Hideyuki Saya
- Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo 160-8582, Japan; and
| | - Yoshio Hayashi
- Institute of Health Biosciences, University of Tokushima, Tokushima 770-8503, Japan
| | - Seiji Arase
- Institute of Health Biosciences, University of Tokushima, Tokushima 770-8503, Japan
| | | | - Nakao Kazuki
- Center for Developmental Biology, RIKEN, Kobe 650-0047, Japan
| | - Eiji Hara
- *Institute for Genome Research
- To whom correspondence may be addressed. E-mail:
or
| |
Collapse
|