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Nguyen DH, Martinez-Ruiz H, Barcellos-Hoff MH. Consequences of epithelial or stromal TGFβ1 depletion in the mammary gland. J Mammary Gland Biol Neoplasia 2011; 16:147-55. [PMID: 21590374 DOI: 10.1007/s10911-011-9218-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2011] [Accepted: 03/14/2011] [Indexed: 01/21/2023] Open
Abstract
Transforming growth factor β1 (TGFβ) affects stroma and epithelial composition and interactions that mediate mammary development and determine the course of cancer. The reduction of TGFβ in Tgfβ1 heterozygote mice, which are healthy and long-lived, provides an important model to dissect the contribution of TGFβ in mammary gland biology and cancer. We used both intact mice and mammary chimeras in conjunction with Tgfβ1 genetic depletion and TGFβ neutralizing antibodies to evaluate how stromal or epithelial TGFβ depletion affect mammary development and response to physiological stimuli. Our studies of radiation carcinogenesis have revealed new aspects of TGFβ biology and suggest that the paradoxical TGFβ switch from tumor suppressor to tumor promoter can be resolved by assessing distinct stromal versus epithelial actions.
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Affiliation(s)
- David H Nguyen
- Endocrinology Graduate Group, University of California, Berkeley, CA, USA
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Barcellos-Hoff MH, Akhurst RJ. Transforming growth factor-beta in breast cancer: too much, too late. Breast Cancer Res 2009; 11:202. [PMID: 19291273 PMCID: PMC2687712 DOI: 10.1186/bcr2224] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The contribution of transforming growth factor (TGF)β to breast cancer has been studied from a myriad perspectives since seminal studies more than two decades ago. Although the action of TGFβ as a canonical tumor suppressor in breast is without a doubt, there is compelling evidence that TGFβ is frequently subverted in a malignant plexus that drives breast cancer. New knowledge that TGFβ regulates the DNA damage response, which underlies cancer therapy, reveals another facet of TGFβ biology that impedes cancer control. Too much TGFβ, too late in cancer progression is the fundamental motivation for pharmaceutical inhibition.
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Andarawewa KL, Paupert J, Pal A, Barcellos-Hoff MH. New rationales for using TGFbeta inhibitors in radiotherapy. Int J Radiat Biol 2008; 83:803-11. [PMID: 18058368 DOI: 10.1080/09553000701711063] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
PURPOSE The first reports that ionizing radiation (IR) induces rapid and persistent activation of transforming growth factor beta1 (TGFbeta) were nearly two decades ago. Subsequent studies have shown that TGFbeta is a major mediator of cellular and tissue responses to IR and have revealed novel facets of its complex biology. RESULTS We and others have recently shown that inhibition of production or signaling of TGFbeta in epithelial cells modulates radiosensitivity and impedes activation of the DNA damage response program. The primary transducer of cellular response to DNA damage caused by ionizing radiation is the nuclear protein kinase ataxia telangiectasia mutated, whose activity is severely compromised when TGFbeta is inhibited. Thus, in conjunction, with its well-recognized contribution to normal tissue fibrosis, the role of TGFbeta in the genotoxic stress program provides a previously unsuspected avenue to modulate radiotherapy. CONCLUSIONS We hypothesize that identification of the circumstances and tumors in which TGFbeta manipulation enhances tumor cell radiosensitivity, while protecting normal tissues, could significantly increase therapeutic index.
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Costes SV, Ponomarev A, Chen JL, Nguyen D, Cucinotta FA, Barcellos-Hoff MH. Image-based modeling reveals dynamic redistribution of DNA damage into nuclear sub-domains. PLoS Comput Biol 2007; 3:e155. [PMID: 17676951 PMCID: PMC1937017 DOI: 10.1371/journal.pcbi.0030155] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 06/18/2007] [Indexed: 11/19/2022] Open
Abstract
Several proteins involved in the response to DNA double strand breaks (DSB) form microscopically visible nuclear domains, or foci, after exposure to ionizing radiation. Radiation-induced foci (RIF) are believed to be located where DNA damage occurs. To test this assumption, we analyzed the spatial distribution of 53BP1, phosphorylated ATM, and γH2AX RIF in cells irradiated with high linear energy transfer (LET) radiation and low LET. Since energy is randomly deposited along high-LET particle paths, RIF along these paths should also be randomly distributed. The probability to induce DSB can be derived from DNA fragment data measured experimentally by pulsed-field gel electrophoresis. We used this probability in Monte Carlo simulations to predict DSB locations in synthetic nuclei geometrically described by a complete set of human chromosomes, taking into account microscope optics from real experiments. As expected, simulations produced DNA-weighted random (Poisson) distributions. In contrast, the distributions of RIF obtained as early as 5 min after exposure to high LET (1 GeV/amu Fe) were non-random. This deviation from the expected DNA-weighted random pattern can be further characterized by “relative DNA image measurements.” This novel imaging approach shows that RIF were located preferentially at the interface between high and low DNA density regions, and were more frequent than predicted in regions with lower DNA density. The same preferential nuclear location was also measured for RIF induced by 1 Gy of low-LET radiation. This deviation from random behavior was evident only 5 min after irradiation for phosphorylated ATM RIF, while γH2AX and 53BP1 RIF showed pronounced deviations up to 30 min after exposure. These data suggest that DNA damage–induced foci are restricted to certain regions of the nucleus of human epithelial cells. It is possible that DNA lesions are collected in these nuclear sub-domains for more efficient repair. DNA damages are daily cellular events. If such events are left unchecked in an organism, they can lead to DNA mutations and possibly cancer over a long period of time. Consequently, cells have very efficient DNA repair machinery. Many studies have focused on the different molecular factors involved in the repair machinery, neglecting to consider the spatial context where damage occurs. Therefore, little is known about the role the nuclear architecture might have in the DNA damage response. In this study, we introduce computer modeling and image analysis tools in order to relate the position of DNA damage markers to morphologically distinct regions of the nucleus. Using these tools, we show that radiation-induced damages locate preferentially in non-condensed DNA regions or at the boundary of regions with condensed DNA. These results contradict the current dogma that the molecular response to randomly generated DNA damages is independent of their nuclear locations. Instead, this suggests the existence of repair centers in the nucleus. Overall, our approach shows that nuclear architecture plays a role in the DNA damage response, reminding us that the nucleus is not simply a soup of DNA and proteins.
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Affiliation(s)
- Sylvain V Costes
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, United States of America.
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Kirshner J, Jobling MF, Pajares MJ, Ravani SA, Glick AB, Lavin MJ, Koslov S, Shiloh Y, Barcellos-Hoff MH. Inhibition of transforming growth factor-beta1 signaling attenuates ataxia telangiectasia mutated activity in response to genotoxic stress. Cancer Res 2006; 66:10861-9. [PMID: 17090522 DOI: 10.1158/0008-5472.can-06-2565] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Ionizing radiation causes DNA damage that elicits a cellular program of damage control coordinated by the kinase activity of ataxia telangiectasia mutated protein (ATM). Transforming growth factor beta (TGFbeta)-1, which is activated by radiation, is a potent and pleiotropic mediator of physiologic and pathologic processes. Here we show that TGFbeta inhibition impedes the canonical cellular DNA damage stress response. Irradiated Tgfbeta1 null murine epithelial cells or human epithelial cells treated with a small-molecule inhibitor of TGFbeta type I receptor kinase exhibit decreased phosphorylation of Chk2, Rad17, and p53; reduced gammaH2AX radiation-induced foci; and increased radiosensitivity compared with TGFbeta competent cells. We determined that loss of TGFbeta signaling in epithelial cells truncated ATM autophosphorylation and significantly reduced its kinase activity, without affecting protein abundance. Addition of TGFbeta restored functional ATM and downstream DNA damage responses. These data reveal a heretofore undetected critical link between the microenvironment and ATM, which directs epithelial cell stress responses, cell fate, and tissue integrity. Thus, Tgfbeta1, in addition to its role in homoeostatic growth control, plays a complex role in regulating responses to genotoxic stress, the failure of which would contribute to the development of cancer; conversely, inhibiting TGFbeta may be used to advantage in cancer therapy.
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Affiliation(s)
- Julia Kirshner
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California, USA
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Liu X, Guo Y, Li Y, Jiang Y, Chubb S, Azuma A, Huang P, Matsuda A, Hittelman W, Plunkett W. Molecular Basis for G2Arrest Induced by 2′-C-Cyano-2′-Deoxy-1-β-d-Arabino-Pentofuranosylcytosine and Consequences of Checkpoint Abrogation. Cancer Res 2005; 65:6874-81. [PMID: 16061671 DOI: 10.1158/0008-5472.can-05-0288] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
2'-C-cyano-2'-deoxy-1-beta-D-arabino-pentofuranosylcytosine (CNDAC) is a nucleoside analogue with a novel mechanism of action that is currently being evaluated in clinical trials. Incorporation of CNDAC triphosphate into DNA and extension during replication leads to single-strand breaks directly caused by beta-elimination. These breaks, or the lesions that arise from further processing, cause cells to arrest in G2. The purpose of this investigation was to define the molecular basis for G2 checkpoint activation and to delineate the sequelae of its abrogation. Cell lines derived from diverse human tissues underwent G2 arrest after CNDAC treatment, suggesting a common mechanism of response to the damage created. CNDAC-induced G2 arrest was instituted by activation of the Chk1-Cdc25C-Cdk1/cyclin B checkpoint pathway. Neither Chk2, p38, nor p53 was required for checkpoint activation. Inhibition of Chk1 kinase with 7-hydroxystaurosporine (UCN-01) abrogated the checkpoint pathway as indicated by dephosphorylation of checkpoint proteins and progression of cells through mitosis and into G1. Cell death was first evident in hematologic cell lines after G1 entry. As indicated by histone H2AX phosphorylation, DNA damage initiated by CNDAC incorporation was transformed into double-strand breaks when ML-1 cells arrested in G2. Some breaks were manifested as chromosomal aberrations when the G2 checkpoint of CNDAC-arrested cells was abrogated by UCN-01 but also in a minor population of cells that escaped to mitosis during treatment with CNDAC alone. These findings provide a mechanistic rationale for the design of new strategies, combining CNDAC with inhibitors of cell cycle checkpoint regulation in the therapy of hematologic malignancies.
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Affiliation(s)
- Xiaojun Liu
- Department of Experimental Therapeutics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA
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Greenberg RA, Rudolph KL. Telomere structural dynamics in genome integrity control and carcinogenesis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2005; 570:311-341. [PMID: 18727506 DOI: 10.1007/1-4020-3764-3_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Roger A Greenberg
- Department of Cancer Biology, Dana Farber Cancer Institute, Boston, Massasuchsetts 02115, USA
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Myster SH, Wang F, Cavallo R, Christian W, Bhotika S, Anderson CT, Peifer M. Genetic and bioinformatic analysis of 41C and the 2R heterochromatin of Drosophila melanogaster: a window on the heterochromatin-euchromatin junction. Genetics 2004; 166:807-22. [PMID: 15020470 PMCID: PMC1470754 DOI: 10.1534/genetics.166.2.807] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Genomic sequences provide powerful new tools in genetic analysis, making it possible to combine classical genetics with genomics to characterize the genes in a particular chromosome region. These approaches have been applied successfully to the euchromatin, but analysis of the heterochromatin has lagged somewhat behind. We describe a combined genetic and bioinformatics approach to the base of the right arm of the Drosophila melanogaster second chromosome, at the boundary between pericentric heterochromatin and euchromatin. We used resources provided by the genome project to derive a physical map of the region, examine gene density, and estimate the number of potential genes. We also carried out a large-scale genetic screen for lethal mutations in the region. We identified new alleles of the known essential genes and also identified mutations in 21 novel loci. Fourteen complementation groups map proximal to the assembled sequence. We used PCR to map the endpoints of several deficiencies and used the same set of deficiencies to order the essential genes, correlating the genetic and physical map. This allowed us to assign two of the complementation groups to particular "computed/curated genes" (CGs), one of which is Nipped-A, which our evidence suggests encodes Drosophila Tra1/TRRAP.
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Affiliation(s)
- Steven H Myster
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill 27599-3280, USA
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Myster SH, Wang F, Cavallo R, Christian W, Bhotika S, Anderson CT, Peifer M. Genetic and Bioinformatic Analysis of 41C and the 2R Heterochromatin of Drosophila melanogaster: A Window on the Heterochromatin-Euchromatin Junction. Genetics 2004. [DOI: 10.1093/genetics/166.2.807] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Abstract
Genomic sequences provide powerful new tools in genetic analysis, making it possible to combine classical genetics with genomics to characterize the genes in a particular chromosome region. These approaches have been applied successfully to the euchromatin, but analysis of the heterochromatin has lagged somewhat behind. We describe a combined genetic and bioinformatics approach to the base of the right arm of the Drosophila melanogaster second chromosome, at the boundary between pericentric heterochromatin and euchromatin. We used resources provided by the genome project to derive a physical map of the region, examine gene density, and estimate the number of potential genes. We also carried out a large-scale genetic screen for lethal mutations in the region. We identified new alleles of the known essential genes and also identified mutations in 21 novel loci. Fourteen complementation groups map proximal to the assembled sequence. We used PCR to map the endpoints of several deficiencies and used the same set of deficiencies to order the essential genes, correlating the genetic and physical map. This allowed us to assign two of the complementation groups to particular “computed/curated genes” (CGs), one of which is Nipped-A, which our evidence suggests encodes Drosophila Tra1/TRRAP.
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Affiliation(s)
- Steven H Myster
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599-3280
| | - Fei Wang
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280
| | - Robert Cavallo
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280
| | - Whitney Christian
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280
| | - Seema Bhotika
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280
| | - Charles T Anderson
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280
| | - Mark Peifer
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, North Carolina 27599-3280
- Department of Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, North Carolina 27599-3280
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Shiloh Y. ATM: from phenotype to functional genomics--and back. ERNST SCHERING RESEARCH FOUNDATION WORKSHOP 2002:51-70. [PMID: 11859564 DOI: 10.1007/978-3-662-04667-8_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Andegeko Y, Moyal L, Mittelman L, Tsarfaty I, Shiloh Y, Rotman G. Nuclear retention of ATM at sites of DNA double strand breaks. J Biol Chem 2001; 276:38224-30. [PMID: 11454856 DOI: 10.1074/jbc.m102986200] [Citation(s) in RCA: 191] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The ATM protein kinase mediates a rapid induction of cellular responses to DNA double strand breaks (DSBs). ATM kinase activity is enhanced immediately after exposure of cells to DSB-inducing agents, but no changes in its amount or subcellular location following that activation have been reported. We speculated that some of the ATM molecules associate with sites of DSBs, while the rest of the nuclear ATM pool remains in the nucleoplasm, masking detection of the damage-associated ATM fraction. Using detergent extraction to remove nucleoplasmic proteins, we show here that immediately following induction of DSBs, a fraction of the ATM pool becomes resistant to extraction and is detected in nuclear aggregates. Colocalization of the retained ATM with the phosphorylated form of histone H2AX (gamma-H2AX) and with foci of the Nbs1 protein suggests that ATM associates with sites of DSBs. The striking correlation between the appearance of retained ATM and of gamma-H2AX, and the rapid association of a fraction of ATM with gamma-H2AX foci, are consistent with a major role for ATM in the early detection of DSBs and subsequent induction of cellular responses.
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Affiliation(s)
- Y Andegeko
- David and Inez Myers Laboratory for Genetic Research, Department of Human Genetics and Molecular Medicine, Interdepartmental Core Facility, Sackler School of Medicine, Tel Aviv University, Ramat Aviv 69978, Israel
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Macaulay VM, Salisbury AJ, Bohula EA, Playford MP, Smorodinsky NI, Shiloh Y. Downregulation of the type 1 insulin-like growth factor receptor in mouse melanoma cells is associated with enhanced radiosensitivity and impaired activation of Atm kinase. Oncogene 2001; 20:4029-40. [PMID: 11494131 DOI: 10.1038/sj.onc.1204565] [Citation(s) in RCA: 106] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2001] [Revised: 02/26/2001] [Accepted: 04/19/2001] [Indexed: 01/26/2023]
Abstract
The type 1 insulin-like growth factor receptor (IGF1R) is required for growth, tumorigenicity and protection from apoptosis. IGF1R overexpression is associated with radioresistance in breast cancer. We used antisense (AS) RNA to downregulate IGF1R expression in mouse melanoma cells. Cells expressing AS-IGF1R transcripts were more radiosensitive in vitro and in vivo than controls. Also they showed reduced radiation-induced p53 accumulation and p53 serine 18 phosphorylation, and radioresistant DNA synthesis. These changes were reminiscent of the cellular phenotype of the human genetic disorder ataxia-telangiectasia (A-T), caused by mutations in the ATM gene. Cellular Atm protein levels were lower in AS-IGF1R-transfected cells than in control cells, although there was no difference in Atm expression at the transcriptional level. AS-IGF1R cells had detectable basal Atm kinase activity, but failed to induce kinase activity after irradiation. This suggests that IGF1R signalling can modulate the function of Atm, and supports the concept of targeted IGF1R downregulation as a potential treatment for malignant melanoma and other radioresistant tumours.
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MESH Headings
- Animals
- Apoptosis
- Ataxia Telangiectasia/pathology
- Down-Regulation
- Enzyme Activation
- Female
- Gene Expression Regulation, Neoplastic
- Humans
- Melanoma, Experimental/enzymology
- Melanoma, Experimental/genetics
- Melanoma, Experimental/pathology
- Mice
- Mice, Inbred C57BL
- Neoplasm Proteins/genetics
- Neoplasm Proteins/metabolism
- Neoplasm Transplantation
- Oligodeoxyribonucleotides, Antisense/pharmacology
- Phenotype
- Phosphorylation
- Protein Processing, Post-Translational
- Radiation Tolerance/genetics
- Receptor, IGF Type 1/biosynthesis
- Receptor, IGF Type 1/genetics
- Receptor, IGF Type 1/physiology
- Transfection
- Tumor Cells, Cultured/enzymology
- Tumor Cells, Cultured/radiation effects
- Tumor Cells, Cultured/transplantation
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Affiliation(s)
- V M Macaulay
- IGF Group, Molecular Oncology Laboratories, Weatherall Institute of Molecular Medicine, Oxford, OX3 9DS, UK.
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