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Nagata K, Nishimura M, Daino K, Nishimura Y, Hattori Y, Watanabe R, Iizuka D, Yokoya A, Suzuki K, Kakinuma S, Imaoka T. Luminal progenitor and mature cells are more susceptible than basal cells to radiation-induced DNA double-strand breaks in rat mammary tissue. JOURNAL OF RADIATION RESEARCH 2024; 65:640-650. [PMID: 39238338 PMCID: PMC11420845 DOI: 10.1093/jrr/rrae067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 06/07/2024] [Indexed: 09/07/2024]
Abstract
Ionizing radiation promotes mammary carcinogenesis. Induction of DNA double-strand breaks (DSBs) is the initial event after radiation exposure, which can potentially lead to carcinogenesis, but the dynamics of DSB induction and repair are not well understood at the tissue level. In this study, we used female rats, which have been recognized as a useful experimental model for studying radiation effects on the mammary gland. We focused on differences in DSB kinetics among basal cells, luminal progenitor and mature cells in different parts of the mammary duct. 53BP1 foci were used as surrogate markers of DSBs, and 53BP1 foci in each mammary epithelial cell in immunostained tissue sections were counted 1-24 h after irradiation and fitted to an exponential function of time. Basal cells were identified as cytokeratin (CK) 14+ cells, luminal progenitor cells as CK8 + 18low cells and luminal mature cells as CK8 + 18high cells. The number of DSBs per nucleus tended to be higher in luminal cells than basal cells at 1 h post-irradiation. A model analysis indicated that basal cells in terminal end buds (TEBs), which constitute the leading edge of the mammary duct, had significantly fewer initial DSBs than the two types of luminal cells, and there was no significant difference in initial amount among the cell types in the subtending duct. The repair rate did not differ among mammary epithelial cell types or their locations. Thus, luminal progenitor and mature cells are more susceptible to radiation-induced DSBs than are basal cells in TEBs.
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Affiliation(s)
- Kento Nagata
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4–9–1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Mayumi Nishimura
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4–9–1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Kazuhiro Daino
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4–9–1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yukiko Nishimura
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4–9–1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yuya Hattori
- Department of Electrical Engineering and Information Science, Faculty of Electrical Engineering and Information Science, National Institute of Technology Kure College, 2–2–11 Aga-minami, Kure, Hiroshima 737-8506, Japan
| | - Ritsuko Watanabe
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, 4–9–1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Daisuke Iizuka
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4–9–1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Akinari Yokoya
- Institute for Quantum Life Science, National Institutes for Quantum Science and Technology, 4–9–1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Keiji Suzuki
- Department of Radiation Medical Sciences, Atomic Bomb Disease Institute, Nagasaki University, 1–12–4 Sakamoto, Nagasaki 852-8523, Japan
| | - Shizuko Kakinuma
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4–9–1 Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Tatsuhiko Imaoka
- Department of Radiation Effects Research, Institute for Radiological Science, National Institutes for Quantum Science and Technology, 4–9–1 Anagawa, Inage-ku, Chiba 263-8555, Japan
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2
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Nicotra R, Lutz C, Messal HA, Jonkers J. Rat Models of Hormone Receptor-Positive Breast Cancer. J Mammary Gland Biol Neoplasia 2024; 29:12. [PMID: 38913216 PMCID: PMC11196369 DOI: 10.1007/s10911-024-09566-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Accepted: 06/07/2024] [Indexed: 06/25/2024] Open
Abstract
Hormone receptor-positive (HR+) breast cancer (BC) is the most common type of breast cancer among women worldwide, accounting for 70-80% of all invasive cases. Patients with HR+ BC are commonly treated with endocrine therapy, but intrinsic or acquired resistance is a frequent problem, making HR+ BC a focal point of intense research. Despite this, the malignancy still lacks adequate in vitro and in vivo models for the study of its initiation and progression as well as response and resistance to endocrine therapy. No mouse models that fully mimic the human disease are available, however rat mammary tumor models pose a promising alternative to overcome this limitation. Compared to mice, rats are more similar to humans in terms of mammary gland architecture, ductal origin of neoplastic lesions and hormone dependency status. Moreover, rats can develop spontaneous or induced mammary tumors that resemble human HR+ BC. To date, six different types of rat models of HR+ BC have been established. These include the spontaneous, carcinogen-induced, transplantation, hormone-induced, radiation-induced and genetically engineered rat mammary tumor models. Each model has distinct advantages, disadvantages and utility for studying HR+ BC. This review provides a comprehensive overview of all published models to date.
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Affiliation(s)
- Raquel Nicotra
- Division of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, Netherlands
- Oncode Institute, Amsterdam, Netherlands
| | - Catrin Lutz
- Division of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, Netherlands.
- Oncode Institute, Amsterdam, Netherlands.
| | - Hendrik A Messal
- Division of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, Netherlands.
- Oncode Institute, Amsterdam, Netherlands.
| | - Jos Jonkers
- Division of Molecular Pathology, The Netherlands Cancer Institute, Amsterdam, Netherlands.
- Oncode Institute, Amsterdam, Netherlands.
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Miller JL, Bartlett AP, Harman RM, Majhi PD, Jerry DJ, Van de Walle GR. Induced mammary cancer in rat models: pathogenesis, genetics, and relevance to female breast cancer. J Mammary Gland Biol Neoplasia 2022; 27:185-210. [PMID: 35904679 DOI: 10.1007/s10911-022-09522-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 07/05/2022] [Accepted: 07/06/2022] [Indexed: 10/16/2022] Open
Abstract
Mammary cancer, or breast cancer in women, is a polygenic disease with a complex etiopathogenesis. While much remains elusive regarding its origin, it is well established that chemical carcinogens and endogenous estrogens contribute significantly to the initiation and progression of this disease. Rats have been useful models to study induced mammary cancer. They develop mammary tumors with comparable histopathology to humans and exhibit differences in resistance or susceptibility to mammary cancer depending on strain. While some rat strains (e.g., Sprague-Dawley) readily form mammary tumors following treatment with the chemical carcinogen, 7,12-dimethylbenz[a]-anthracene (DMBA), other strains (e.g., Copenhagen) are resistant to DMBA-induced mammary carcinogenesis. Genetic linkage in inbred strains has identified strain-specific quantitative trait loci (QTLs) affecting mammary tumors, via mechanisms that act together to promote or attenuate, and include 24 QTLs controlling the outcome of chemical induction, 10 QTLs controlling the outcome of estrogen induction, and 4 QTLs controlling the outcome of irradiation induction. Moreover, and based on shared factors affecting mammary cancer etiopathogenesis between rats and humans, including orthologous risk regions between both species, rats have served as useful models for identifying methods for breast cancer prediction and treatment. These studies in rats, combined with alternative animal models that more closely mimic advanced stages of breast cancer and/or human lifestyles, will further improve our understanding of this complex disease.
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Affiliation(s)
- James L Miller
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, 14853, Ithaca, NY, USA
| | - Arianna P Bartlett
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, 14853, Ithaca, NY, USA
| | - Rebecca M Harman
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, 14853, Ithaca, NY, USA
| | - Prabin Dhangada Majhi
- Department of Veterinary & Animal Sciences, University of Massachusetts, 01003, Amherst, MA, USA
| | - D Joseph Jerry
- Department of Veterinary & Animal Sciences, University of Massachusetts, 01003, Amherst, MA, USA
| | - Gerlinde R Van de Walle
- Baker Institute for Animal Health, College of Veterinary Medicine, Cornell University, 14853, Ithaca, NY, USA.
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Hosoki A, Ogawa M, Nishimura Y, Nishimura M, Daino K, Kakinuma S, Shimada Y, Imaoka T. The effect of radiation on the ability of rat mammary cells to form mammospheres. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2020; 59:711-721. [PMID: 32996008 DOI: 10.1007/s00411-020-00869-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 08/29/2020] [Indexed: 06/11/2023]
Abstract
As classical transplantation repopulation assays for studying the radiobiology of rat mammary stem/progenitor cells are extremely time-consuming, this study aimed to characterize the radiobiological properties of mammospheres, spherical clumps of mammary cells formed under non-adherent culture conditions, which are a simple and widely used technique for assessing progenitor cell activity. Rat mammary cells were dissociated and used in transplantation repopulation assays and for the formation of mammospheres. Immunofluorescence for cytokeratin 14 and 18 was used to identify basal and luminal mammary epithelial cells, respectively. Incorporation of 5-bromo-2'-deoxyuridine was used to evaluate cell proliferation. The repopulating activity of the transplanted primary rat mammary cells demonstrated their radiosensitivity, reproducing previous data, with a significant reduction in repopulating activity at ≥ 2 Gy. Cells constituting rat mammospheres were positive for either cytokeratin 14 or 18, with occasional double-positive cells. Both proliferation and aggregation contributed to sphere formation. Cells obtained from the spheres showed lower repopulating activity after transplantation than primary cells. When primary cells were irradiated and then used for sphere formation, the efficiency of sphere formation was significantly decreased at 8 Gy but not at ≤ 6 Gy, indicating radioresistance of the formation process. Irradiation at 8 Gy reduced the proliferation of cells during sphere formation, whereas the cellular composition of the resulting spheres was unaffectes. Thus, mammosphere formation assays may measure a property of putative mammary progenitors that is different from what is measured in the classic transplantation repopulation assay in radiobiology.
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Affiliation(s)
- Ayaka Hosoki
- Fukushima Project Headquarters, National Institute of Radiological Sciences (NIRS), Chiba, Japan
- Healios KK Kobe Research Institute, Kobe, Japan
| | - Mari Ogawa
- Department of Radiation Effects Research, NIRS, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1, Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Yukiko Nishimura
- Department of Radiation Effects Research, NIRS, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1, Anagawa, Inage-ku, Chiba, 263-8555, Japan
- Institute for Environmental Sciences, Aomori, Japan
| | - Mayumi Nishimura
- Department of Radiation Effects Research, NIRS, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1, Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Kazuhiro Daino
- Department of Radiation Effects Research, NIRS, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1, Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Shizuko Kakinuma
- Department of Radiation Effects Research, NIRS, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1, Anagawa, Inage-ku, Chiba, 263-8555, Japan
| | - Yoshiya Shimada
- Executive Board, QST, Chiba, Japan
- Institute for Environmental Sciences, Aomori, Japan
| | - Tatsuhiko Imaoka
- Department of Radiation Effects Research, NIRS, National Institutes for Quantum and Radiological Science and Technology (QST), 4-9-1, Anagawa, Inage-ku, Chiba, 263-8555, Japan.
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Abstract
Breast cancer is one of the most common cancers worldwide, which makes it a very impactful malignancy in the society. Breast cancers can be classified through different systems based on the main tumor features and gene, protein, and cell receptors expression, which will determine the most advisable therapeutic course and expected outcomes. Multiple therapeutic options have already been proposed and implemented for breast cancer treatment. Nonetheless, their use and efficacy still greatly depend on the tumor classification, and treatments are commonly associated with invasiveness, pain, discomfort, severe side effects, and poor specificity. This has demanded an investment in the research of the mechanisms behind the disease progression, evolution, and associated risk factors, and on novel diagnostic and therapeutic techniques. However, advances in the understanding and assessment of breast cancer are dependent on the ability to mimic the properties and microenvironment of tumors in vivo, which can be achieved through experimentation on animal models. This review covers an overview of the main animal models used in breast cancer research, namely in vitro models, in vivo models, in silico models, and other models. For each model, the main characteristics, advantages, and challenges associated to their use are highlighted.
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Helm JS, Rudel RA. Adverse outcome pathways for ionizing radiation and breast cancer involve direct and indirect DNA damage, oxidative stress, inflammation, genomic instability, and interaction with hormonal regulation of the breast. Arch Toxicol 2020; 94:1511-1549. [PMID: 32399610 PMCID: PMC7261741 DOI: 10.1007/s00204-020-02752-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 04/16/2020] [Indexed: 12/15/2022]
Abstract
Knowledge about established breast carcinogens can support improved and modernized toxicological testing methods by identifying key mechanistic events. Ionizing radiation (IR) increases the risk of breast cancer, especially for women and for exposure at younger ages, and evidence overall supports a linear dose-response relationship. We used the Adverse Outcome Pathway (AOP) framework to outline and evaluate the evidence linking ionizing radiation with breast cancer from molecular initiating events to the adverse outcome through intermediate key events, creating a qualitative AOP. We identified key events based on review articles, searched PubMed for recent literature on key events and IR, and identified additional papers using references. We manually curated publications and evaluated data quality. Ionizing radiation directly and indirectly causes DNA damage and increases production of reactive oxygen and nitrogen species (RONS). RONS lead to DNA damage and epigenetic changes leading to mutations and genomic instability (GI). Proliferation amplifies the effects of DNA damage and mutations leading to the AO of breast cancer. Separately, RONS and DNA damage also increase inflammation. Inflammation contributes to direct and indirect effects (effects in cells not directly reached by IR) via positive feedback to RONS and DNA damage, and separately increases proliferation and breast cancer through pro-carcinogenic effects on cells and tissue. For example, gene expression changes alter inflammatory mediators, resulting in improved survival and growth of cancer cells and a more hospitable tissue environment. All of these events overlap at multiple points with events characteristic of "background" induction of breast carcinogenesis, including hormone-responsive proliferation, oxidative activity, and DNA damage. These overlaps make the breast particularly susceptible to ionizing radiation and reinforce that these biological activities are important characteristics of carcinogens. Agents that increase these biological processes should be considered potential breast carcinogens, and predictive methods are needed to identify chemicals that increase these processes. Techniques are available to measure RONS, DNA damage and mutation, cell proliferation, and some inflammatory proteins or processes. Improved assays are needed to measure GI and chronic inflammation, as well as the interaction with hormonally driven development and proliferation. Several methods measure diverse epigenetic changes, but it is not clear which changes are relevant to breast cancer. In addition, most toxicological assays are not conducted in mammary tissue, and so it is a priority to evaluate if results from other tissues are generalizable to breast, or to conduct assays in breast tissue. Developing and applying these assays to identify exposures of concern will facilitate efforts to reduce subsequent breast cancer risk.
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Affiliation(s)
- Jessica S Helm
- Silent Spring Institute, 320 Nevada Street, Suite 302, Newton, MA, 02460, USA
| | - Ruthann A Rudel
- Silent Spring Institute, 320 Nevada Street, Suite 302, Newton, MA, 02460, USA.
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Fiordelisi MF, Cavaliere C, Auletta L, Basso L, Salvatore M. Magnetic Resonance Imaging for Translational Research in Oncology. J Clin Med 2019; 8:jcm8111883. [PMID: 31698697 PMCID: PMC6912299 DOI: 10.3390/jcm8111883] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 12/19/2022] Open
Abstract
The translation of results from the preclinical to the clinical setting is often anything other than straightforward. Indeed, ideas and even very intriguing results obtained at all levels of preclinical research, i.e., in vitro, on animal models, or even in clinical trials, often require much effort to validate, and sometimes, even useful data are lost or are demonstrated to be inapplicable in the clinic. In vivo, small-animal, preclinical imaging uses almost the same technologies in terms of hardware and software settings as for human patients, and hence, might result in a more rapid translation. In this perspective, magnetic resonance imaging might be the most translatable technique, since only in rare cases does it require the use of contrast agents, and when not, sequences developed in the lab can be readily applied to patients, thanks to their non-invasiveness. The wide range of sequences can give much useful information on the anatomy and pathophysiology of oncologic lesions in different body districts. This review aims to underline the versatility of this imaging technique and its various approaches, reporting the latest preclinical studies on thyroid, breast, and prostate cancers, both on small laboratory animals and on human patients, according to our previous and ongoing research lines.
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Bespalov VG, Baranenko DA, Aleksandrov VA, Semenov AL, Kovan’ko EG, Ivanov SD. Chemoprevention of Radiation-Induced Carcinogenesis Using Decoction of Meadowsweet (Filipendula Ulmaria) Flowers. Pharm Chem J 2019. [DOI: 10.1007/s11094-019-1915-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Imaoka T, Nishimura M, Daino K, Hosoki A, Takabatake M, Nishimura Y, Kokubo T, Morioka T, Doi K, Shimada Y, Kakinuma S. Prominent Dose-Rate Effect and Its Age Dependence of Rat Mammary Carcinogenesis Induced by Continuous Gamma-Ray Exposure. Radiat Res 2018; 191:245-254. [PMID: 30543491 DOI: 10.1667/rr15094.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Although the risk of breast cancer after high-dose-rate irradiation has been firmly established, however, the risk incurred for low-dose-rate irradiation is not well understood. Here we provide experimental evidence for dose rate and age dependencies induced by continuous γ-ray irradiation on mammary carcinogenesis. Female rats received continuous whole-body irradiation at one of the following time points: at 7 weeks of age (denoted adults) at a dose rate of 3-60 mGy/h (4 Gy total); or at either 3 weeks (denoted juveniles) or 7 weeks of age at a dose rate of 6 mGy/h (1-8 Gy total). Additional rats were acutely irradiated at 13 weeks of age at a dose rate of 30 Gy/h (0.5-4 Gy total). We observed the incidence of mammary tumors by weekly palpation until they were 90 weeks old and after pathological inspection upon autopsy. The tumor incidence rate for each group was characterized by Cox regression analysis. When adult rats were irradiated at 60 mGy/h for a total of 4 Gy, their hazard ratio for mammary carcinoma significantly increased relative to nonirradiated controls; however, for adult rats irradiated at 3-24 mGy/h, even though they also received a total of 4 Gy, their hazard ratio for carcinoma incidence did not significantly increase. A larger increase in the incidence rate of carcinoma per dose was found for the juveniles than for the adults irradiated at 6 mGy/h, whereas age did not influence the effect of acute irradiation at 30 Gy/h; a threshold-like dose response was observed for irradiation at 6 mGy/h (threshold, ∼2.5 and ∼4 Gy for juveniles and adults, respectively). Regarding benign tumors of the mammary gland, a significant increase in their incidence was observed for irradiation down to 6 mGy/h, but not at 3 mGy/h and there was no evidence of age-dependent induction. Thus, induction of female rat mammary carcinogenesis by continuous γ-ray exposure was age dependent and drastically increased for adult rats that received between 24 and 60 mGy/h irradiation.
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Affiliation(s)
- Tatsuhiko Imaoka
- a Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan.,d QST Advanced Study Laboratory, QST, Chiba, Japan.,e Tokyo Metropolitan University, Tokyo, Japan
| | - Mayumi Nishimura
- a Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
| | - Kazuhiro Daino
- a Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
| | - Ayaka Hosoki
- f Fukushima Project Headquarters, NIRS, Chiba, Japan
| | - Masaru Takabatake
- a Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan.,e Tokyo Metropolitan University, Tokyo, Japan
| | - Yukiko Nishimura
- a Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
| | - Toshiaki Kokubo
- b Department of Engineering and Safety, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
| | - Takamitsu Morioka
- a Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
| | - Kazutaka Doi
- c Center for Radiation Protection Knowledge, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
| | - Yoshiya Shimada
- e Tokyo Metropolitan University, Tokyo, Japan.,g Executive Director, QST, Chiba, Japan
| | - Shizuko Kakinuma
- a Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan
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Gray JM, Rasanayagam S, Engel C, Rizzo J. State of the evidence 2017: an update on the connection between breast cancer and the environment. Environ Health 2017; 16:94. [PMID: 28865460 PMCID: PMC5581466 DOI: 10.1186/s12940-017-0287-4] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 07/17/2017] [Indexed: 05/23/2023]
Abstract
BACKGROUND In this review, we examine the continually expanding and increasingly compelling data linking radiation and various chemicals in our environment to the current high incidence of breast cancer. Singly and in combination, these toxicants may have contributed significantly to the increasing rates of breast cancer observed over the past several decades. Exposures early in development from gestation through adolescence and early adulthood are particularly of concern as they re-shape the program of genetic, epigenetic and physiological processes in the developing mammary system, leading to an increased risk for developing breast cancer. In the 8 years since we last published a comprehensive review of the relevant literature, hundreds of new papers have appeared supporting this link, and in this update, the evidence on this topic is more extensive and of better quality than that previously available. CONCLUSION Increasing evidence from epidemiological studies, as well as a better understanding of mechanisms linking toxicants with development of breast cancer, all reinforce the conclusion that exposures to these substances - many of which are found in common, everyday products and byproducts - may lead to increased risk of developing breast cancer. Moving forward, attention to methodological limitations, especially in relevant epidemiological and animal models, will need to be addressed to allow clearer and more direct connections to be evaluated.
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Affiliation(s)
- Janet M. Gray
- Department of Psychology and Program in Science, Technology, and Society, Vassar College, 124 Raymond Avenue, Poughkeepsie, NY 12604-0246 USA
| | - Sharima Rasanayagam
- Breast Cancer Prevention Partners, 1388 Sutter St., Suite 400, San Francisco, CA 94109-5400 USA
| | - Connie Engel
- Breast Cancer Prevention Partners, 1388 Sutter St., Suite 400, San Francisco, CA 94109-5400 USA
| | - Jeanne Rizzo
- Breast Cancer Prevention Partners, 1388 Sutter St., Suite 400, San Francisco, CA 94109-5400 USA
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Imaoka T, Nishimura M, Daino K, Hosoki A, Takabatake M, Kokubo T, Doi K, Showler K, Nishimura Y, Moriyama H, Morioka T, Shimada Y, Kakinuma S. Age Modifies the Effect of 2-MeV Fast Neutrons on Rat Mammary Carcinogenesis. Radiat Res 2017; 188:419-425. [DOI: 10.1667/rr14829.1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Tatsuhiko Imaoka
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Mayumi Nishimura
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Kazuhiro Daino
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Ayaka Hosoki
- Radiation Effect Accumulation and Prevention Project, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 116-8551, Japan
| | - Masaru Takabatake
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Toshiaki Kokubo
- Department of Engineering and Safety, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Kazutaka Doi
- Center for Radiation Protection Knowledge, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Kaye Showler
- Radiobiology for Children's Health Program, NIRS, Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 116-8551, Japan
| | - Yukiko Nishimura
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Hitomi Moriyama
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | - Takamitsu Morioka
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
| | | | - Shizuko Kakinuma
- Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba 263-8555, Japan
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12
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Stepp MW, Doll MA, Samuelson DJ, Sanders MAG, States JC, Hein DW. Congenic rats with higher arylamine N-acetyltransferase 2 activity exhibit greater carcinogen-induced mammary tumor susceptibility independent of carcinogen metabolism. BMC Cancer 2017; 17:233. [PMID: 28359264 PMCID: PMC5374573 DOI: 10.1186/s12885-017-3221-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 03/22/2017] [Indexed: 11/19/2022] Open
Abstract
Background Recent investigations suggest role(s) of human arylamine N-acetyltransferase 1 (NAT1) in breast cancer. Rat NAT2 is orthologous to human NAT1 and the gene products are functional homologs. We conducted in vivo studies using F344.WKY-Nat2rapid/slow rats, congenic at rat Nat2 for high (rapid) and low (slow) arylamine N-acetyltransferase activity, to assess a possible role for rat NAT2 in mammary tumor susceptibility. Methods Mammary carcinogens, methylnitrosourea (MNU) and 7,12-dimethylbenzanthracene (DMBA) neither of which is metabolized by N-acetyltransferase, were administered to assess mammary tumors. MNU was administered at 3 or 8 weeks of age. DMBA was administered at 8 weeks of age. NAT2 enzymatic activity and endogenous acetyl-coenzyme A (AcCoA) levels were measured in tissue samples and embryonic fibroblasts isolated from the congenic rats. Results Tumor latency was shorter in rapid NAT2 rats compared to slow NAT2 rats, with statistical significance for MNU administered at 3 and 8 weeks of age (p = 0.009 and 0.050, respectively). Tumor multiplicity and incidence were higher in rapid NAT2 rats compared to slow NAT2 rats administered MNU or DMBA at 8 weeks of age (MNU, p = 0.050 and 0.035; DMBA, p = 0.004 and 0.027, respectively). Recombinant rat rapid-NAT2, as well as tissue samples and embryonic fibroblasts derived from rapid NAT2 rats, catalyzed p-aminobenzoic acid N-acetyl transfer and folate-dependent acetyl-coenzyme A (AcCoA) hydrolysis at higher rates than those derived from rat slow-NAT2. Embryonic fibroblasts isolated from rapid NAT2 rats displayed lower levels of cellular AcCoA than slow NAT2 rats (p < 0.01). Conclusions A novel role for rat NAT2 in mammary cancer was discovered unrelated to carcinogen metabolism, suggesting a role for human NAT1 in breast cancer.
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Affiliation(s)
- Marcus W Stepp
- Department of Pharmacology and Toxicology, School of Medicine, University of Louisville, Louisville, KY, 40202, USA.,James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA
| | - Mark A Doll
- Department of Pharmacology and Toxicology, School of Medicine, University of Louisville, Louisville, KY, 40202, USA.,James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA
| | - David J Samuelson
- James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA.,Department of Biochemistry & Molecular Genetics, School of Medicine, University of Louisville, Louisville, KY, 40202, USA
| | - Mary Ann G Sanders
- Department of Pathology, University of Louisville Hospital, Louisville, KY, 40202, USA
| | - J Christopher States
- Department of Pharmacology and Toxicology, School of Medicine, University of Louisville, Louisville, KY, 40202, USA.,James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA
| | - David W Hein
- Department of Pharmacology and Toxicology, School of Medicine, University of Louisville, Louisville, KY, 40202, USA. .,James Graham Brown Cancer Center, University of Louisville, Louisville, KY, 40202, USA.
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13
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Showler K, Nishimura M, Daino K, Imaoka T, Nishimura Y, Morioka T, Blyth BJ, Kokubo T, Takabatake M, Fukuda M, Moriyama H, Kakinuma S, Fukushi M, Shimada Y. Analysis of genes involved in the PI3K/Akt pathway in radiation- and MNU-induced rat mammary carcinomas. JOURNAL OF RADIATION RESEARCH 2017; 58:183-194. [PMID: 27738081 PMCID: PMC5571612 DOI: 10.1093/jrr/rrw097] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 07/11/2016] [Accepted: 08/30/2016] [Indexed: 05/31/2023]
Abstract
The PI3K/AKT pathway is one of the most important signaling networks in human breast cancer, and since it was potentially implicated in our preliminary investigations of radiation-induced rat mammary carcinomas, our aim here was to verify its role. We included mammary carcinomas induced by the chemical carcinogen 1-methyl-1-nitrosourea to determine whether any changes were radiation-specific. Most carcinomas from both groups showed activation of the PI3K/AKT pathway, but phosphorylation of AKT1 was often heterogeneous and only present in a minority of carcinoma cells. The negative pathway regulator Inpp4b was significantly downregulated in both groups, compared with in normal mammary tissue, and radiation-induced carcinomas also showed a significant decrease in Pten expression, while the chemically induced carcinomas showed a decrease in Pik3r1 and Pdk1. Significant upregulation of the positive regulators Erbb2 and Pik3ca was observed only in chemically induced carcinomas. However, no genes showed clear correlations with AKT phosphorylation levels, except in individual carcinomas. Only rare carcinomas showed mutations in PI3K/AKT pathway genes, yet these carcinomas did not exhibit stronger AKT phosphorylation. Thus, while AKT phosphorylation is a common feature of rat mammary carcinomas induced by radiation or a canonical chemical carcinogen, the mutation of key genes in the pathways or permanent changes to gene expression of particular signaling proteins do not explain the pathway activation in the advanced cancers. Although AKT signaling likely facilitates cancer development and growth in rat mammary carcinomas, it is unlikely that permanent disruption of the PI3K/AKT pathway genes is a major causal event in radiation carcinogenesis.
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Affiliation(s)
- Kaye Showler
- Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 116-8551, Japan
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Mayumi Nishimura
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Kazuhiro Daino
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Tatsuhiko Imaoka
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Yukiko Nishimura
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Takamitsu Morioka
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Benjamin J. Blyth
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Toshiaki Kokubo
- Department of Engineering and Safety, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Masaru Takabatake
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Maki Fukuda
- Faculty of Health Sciences, Tokyo Metropolitan University, Tokyo 116-8551, Japan
| | - Hitomi Moriyama
- Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 116-8551, Japan
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Shizuko Kakinuma
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
| | - Masahiro Fukushi
- Graduate School of Human Health Sciences, Tokyo Metropolitan University, Tokyo 116-8551, Japan
- Faculty of Health Sciences, Tokyo Metropolitan University, Tokyo 116-8551, Japan
| | - Yoshiya Shimada
- Department of Radiation Effects Research, National Institute of Radiological Sciences, National Institutes for Quantum and Radiological Science and Technology, 4-9-1, Anagawa, Inage-ku, Chiba 263-8555, Japan
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Abstract
Potential ionising radiation exposure scenarios are varied, but all bring risks beyond the simple issues of short-term survival. Whether accidentally exposed to a single, whole-body dose in an act of terrorism or purposefully exposed to fractionated doses as part of a therapeutic regimen, radiation exposure carries the consequence of elevated cancer risk. The long-term impact of both intentional and unintentional exposure could potentially be mitigated by treatments specifically developed to limit the mutations and precancerous replication that ensue in the wake of irradiation The development of such agents would undoubtedly require a substantial degree of in vitro testing, but in order to accurately recapitulate the complex process of radiation-induced carcinogenesis, well-understood animal models are necessary. Inbred strains of the laboratory mouse, Mus musculus, present the most logical choice due to the high number of molecular and physiological similarities they share with humans. Their small size, high rate of breeding and fully sequenced genome further increase its value for use in cancer research. This chapter will review relevant m. musculus inbred and F1 hybrid animals of radiation-induced myeloid leukemia, thymic lymphoma, breast and lung cancers. Method of cancer induction and associated molecular pathologies will also be described for each model.
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15
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Fu Q, Satterlee A, Wang Y, Wang Y, Wang D, Tang J, He Z, Liu F. Novel murine tumour models depend on strain and route of inoculation. Int J Exp Pathol 2016; 97:351-356. [PMID: 27464477 DOI: 10.1111/iep.12192] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 04/15/2016] [Indexed: 02/06/2023] Open
Abstract
This study describes variations in tumour growth patterns which occur when changes in the routes of inoculation and mouse strain are used to introduce tumours into established murine model systems that are known to vary in location and aggression. Intraperitoneal, subcutaneous, intravenous and hydrodynamic inoculations of B16F10 cells were compared among CD-1, C57BL/6 and Balb/c mice. Most surprisingly, allogeneic tumour growth in Balb/c mice after intravenous and hydrodynamic inoculation of B16F10 cells was faster than tumour growth in the syngeneic C57BL/6 mice. These and other variations in the tumour growth patterns described here can help provide the researcher with more experimental control when planning to use the optimal tumour model for any particular study.
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Affiliation(s)
- Qiang Fu
- School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China.
| | - Andrew Satterlee
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Yongjun Wang
- School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China
| | - Yuhua Wang
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - Dun Wang
- Key Laboratory of Structure-Based Drug Design and Discovery, Ministry of Education, Shenyang Pharmaceutical University, Shenyang, China
| | - Jingling Tang
- School of Pharmacy, Harbin Medical University, Harbin, China
| | - Zhonggui He
- School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, China
| | - Feng Liu
- Division of Molecular Pharmaceutics, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Imaoka T, Nishimura M, Daino K, Morioka T, Nishimura Y, Uemura H, Akimoto K, Furukawa Y, Fukushi M, Wakabayashi K, Mutoh M, Shimada Y. A Rat Model to Study the Effects of Diet-Induced Obesity on Radiation-Induced Mammary Carcinogenesis. Radiat Res 2016; 185:505-15. [PMID: 27135968 DOI: 10.1667/rr14309.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
A detailed understanding of the relationship between radiation-induced breast cancer and obesity is needed for appropriate risk management and to prevent the development of a secondary cancer in patients who have been treated with radiation. Our goal was to develop an animal model to study the relationship by combining two existing Sprague-Dawley rat models of radiation-induced mammary carcinogenesis and diet-induced obesity. Female rats were fed a high-fat diet for 4 weeks and categorized as obesity prone or obesity resistant based on their body weight at 7 weeks of age, at which time the rats were irradiated with 4 Gy. Control rats were fed a standard diet and irradiated at the same time and in the same manner. All rats were maintained on their initial diets and assessed for palpable mammary cancers once a week for the next 30 weeks. The obesity-prone rats were heavier than those in the other groups. The obesity-prone rats were also younger than the other animals at the first detection of mammary carcinomas and their carcinoma weights were greater. A tendency toward higher insulin and leptin blood levels were observed in the obesity-prone rats compared to the other two groups. Blood angiotensin II levels were elevated in the obesity-prone and obesity-resistant rats. Genes related to translation and oxidative phosphorylation were upregulated in the carcinomas of obesity-prone rats. Expression profiles from human breast cancers were used to validate this animal model. As angiotensin is potentially an important factor in obesity-related morbidities and breast cancer, a second set of rats was fed in a similar manner, irradiated and then treated with an angiotensin-receptor blocker, losartan and candesartan. Neither blocker altered mammary carcinogenesis; analyses of losartan-treated animals indicated that expression of renin in the renal cortex and of Agtr1a (angiotensin II receptor, type 1) in cancer tissue was significantly upregulated, suggesting the presence of compensating mechanisms for blocking angiotensin-receptor signaling. Thus, obesity-related elevation of insulin and leptin blood levels and an increase in available energy may facilitate sustained protein synthesis in cancer cells, which is required for rapid cancer development.
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Affiliation(s)
- Tatsuhiko Imaoka
- a Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences (NIRS) Chiba, Japan;,b Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, NIRS, Chiba, Japan
| | - Mayumi Nishimura
- a Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences (NIRS) Chiba, Japan;,b Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, NIRS, Chiba, Japan
| | - Kazuhiro Daino
- a Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences (NIRS) Chiba, Japan;,b Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, NIRS, Chiba, Japan
| | - Takamitsu Morioka
- a Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences (NIRS) Chiba, Japan;,b Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, NIRS, Chiba, Japan
| | - Yukiko Nishimura
- a Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences (NIRS) Chiba, Japan
| | - Hiroji Uemura
- c Department of Urology and Renal Transplantation, Yokohama City University Medical Center, Yokohama, Japan
| | - Kenta Akimoto
- a Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences (NIRS) Chiba, Japan;,d Division of Radiological Sciences, Faculty of Health Sciences, Tokyo Metropolitan University, Tokyo, Japan
| | - Yuki Furukawa
- a Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences (NIRS) Chiba, Japan;,d Division of Radiological Sciences, Faculty of Health Sciences, Tokyo Metropolitan University, Tokyo, Japan
| | - Masahiro Fukushi
- d Division of Radiological Sciences, Faculty of Health Sciences, Tokyo Metropolitan University, Tokyo, Japan
| | - Keiji Wakabayashi
- e Graduate Division of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan; and
| | - Michihiro Mutoh
- f Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo, Japan
| | - Yoshiya Shimada
- a Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences (NIRS) Chiba, Japan;,b Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, NIRS, Chiba, Japan
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17
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Merck LH, Ward LA, Applegate KE, Choo E, Lowery-North DW, Heilpern KL. Written Informed Consent for Computed Tomography of the Abdomen/Pelvis is Associated with Decreased CT Utilization in Low-Risk Emergency Department Patients. West J Emerg Med 2015; 16:1014-24. [PMID: 26759646 PMCID: PMC4703183 DOI: 10.5811/westjem.2015.9.27612] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Revised: 09/21/2015] [Accepted: 09/27/2015] [Indexed: 11/22/2022] Open
Abstract
INTRODUCTION The increasing rate of patient exposure to radiation from computerized tomography (CT) raises questions about appropriateness of utilization. There is no current standard to employ informed consent for CT (ICCT). Our study assessed the relationship between informed consent and CT utilization in emergency department (ED) patients. METHODS An observational multiphase before-after cohort study was completed from 4/2010-5/2011. We assessed CT utilization before and after (Time I/Time II) the implementation of an informed consent protocol. Adult patients were included if they presented with symptoms of abdominal/pelvic pathology or completed ED CT. We excluded patients with pregnancy, trauma, or altered mental status. Data on history, exam, diagnostics, and disposition were collected via standard abstraction tool. We generated a multivariate logistic model via stepwise regression, to assess CT utilization across risk groups. Logistic models, stratified by risk, were generated to include study phase and a propensity score that controlled for potential confounders of CT utilization. RESULTS 7,684 patients met inclusion criteria. In PHASE 2, there was a 24% (95% CI [10-36%]) reduction in CT utilization in the low-risk patient group (p<0.002). ICCT did not affect CT utilization in the high-risk group (p=0.16). In low-risk patients, the propensity score was significant (p<0.001). There were no adverse events reported during the study period. CONCLUSION The implementation of ICCT was associated with reduced CT utilization in low-risk ED patients. ICCT has the potential to increase informed, shared decision making with patients, as well as to reduce the risks and cost associated with CT.
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Affiliation(s)
- Lisa H. Merck
- The Warren Alpert Medical School of Brown University, Department of Emergency Medicine and Diagnostic Imaging, Providence, Rhode Island
| | - Laura A. Ward
- Rollins School of Public Health, Department of Biostatistics, Emory University, Atlanta, Georgia
| | - Kimberly E. Applegate
- Emory University School of Medicine, Department of Radiology and Imaging Sciences, Atlanta, Georgia
| | - Esther Choo
- The Warren Alpert Medical School of Brown University, Department of Emergency Medicine, Providence, Rhode Island
| | - Douglas W. Lowery-North
- Emory University School of Medicine and Grady Memorial Hospital, Department of Emergency Medicine, Atlanta, Georgia
| | - Katherine L. Heilpern
- Emory University School of Medicine and Grady Memorial Hospital, Department of Emergency Medicine, Atlanta, Georgia
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18
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Kovalchuk IP, Golubov A, Koturbash IV, Kutanzi K, Martin OA, Kovalchuk O. Age-dependent changes in DNA repair in radiation-exposed mice. Radiat Res 2015; 182:683-94. [PMID: 25409128 DOI: 10.1667/rr13697.1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Ionizing radiation (IR) is a well-known human carcinogen. Young and adult individuals are known to respond to radiation in a different manner. In this study, we analyzed changes in the spleen of juvenile (two-week-old), adult (two-month-old) and old (18-month-old) C57BL/6 male mice subjected to a whole-body exposure to 1 Gy of X rays. We measured the number of γ-H2AX foci and ATM protein levels as a reflection of the level of DNA double-strand breaks (DSBs), and found that old animals had a high frequency of occurrence of noninduced DSBs. Exposure to X rays resulted in a rapid increase in the number of DSBs in juvenile and adult animals at 6 h postirradiation followed by a return to preirradiated DSB values at 96 h postirradiation. No changes were observed in old animals. The analysis of the levels of proteins involved in DNA damage base excision and mismatch repair pathways, including KU70, RAD51, POL β, POL δ, POL ε, APE1 and MSH2 showed substantial age-dependent radiation-induced differences. Finally, we demonstrated that old animals had a higher background level of cell apoptosis compared to younger animals, but in contrast to younger animals, old animals were not able to commit spleen cells to apoptosis after being irradiated. Thus, spleen cells of old mice have a high level of spontaneous DNA damage, but they are not able to deal with additional radiation-induced damage as efficiently as younger animals, substantiating age-depending differences in radiation-induced DNA damage and repair response and its outcomes.
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Affiliation(s)
- Igor P Kovalchuk
- a Department of Biological Sciences, University of Lethbridge, Lethbridge, Alberta, Canada
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19
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El-Abd EA, Sultan AS, Shalaby EA, Matalkah F. Animal Models of Breast Cancer. OMICS APPROACHES IN BREAST CANCER 2014:297-314. [DOI: 10.1007/978-81-322-0843-3_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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20
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Imaoka T, Nishimura M, Doi K, Tani S, Ishikawa KI, Yamashita S, Ushijima T, Imai T, Shimada Y. Molecular characterization of cancer reveals interactions between ionizing radiation and chemicals on rat mammary carcinogenesis. Int J Cancer 2013; 134:1529-38. [PMID: 24105445 DOI: 10.1002/ijc.28480] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 08/27/2013] [Indexed: 11/06/2022]
Abstract
Although various mechanisms have been inferred for combinatorial actions of multiple carcinogens, these mechanisms have not been well demonstrated in experimental carcinogenesis models. We evaluated mammary carcinogenesis initiated by combined exposure to various doses of radiation and chemical carcinogens. Female rats at 7 weeks of age were γ-irradiated (0.2-2 Gy) and/or exposed to 1-methyl-1-nitrosourea (MNU) (20 or 40 mg/kg, single intraperitoneal injection) or 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) (40 mg/kg/day by gavage for 10 days) and were observed until 50 weeks of age. The incidence of mammary carcinoma increased steadily as a function of radiation dose in the absence of chemicals; mathematical analysis supported an additive increase when radiation was combined with a chemical carcinogen, irrespective of the chemical species and its dose. Hras mutations were characteristic of carcinomas that developed after chemical carcinogen treatments and were overrepresented in carcinomas induced by the combination of radiation and MNU (but not PhIP), indicating an interaction of radiation and MNU at the level of initiation. The expression profiles of seven classifier genes, previously shown to distinguish two classes of rat mammary carcinomas, categorized almost all examined carcinomas that developed after individual or combined treatments with radiation (1 Gy) and chemicals as belonging to a single class; more comprehensive screening using microarrays and a separate test sample set failed to identify differences in gene expression profiles among these carcinomas. These results suggest that a complex, multilevel interaction underlies the combinatorial action of radiation and chemical carcinogens in the experimental model.
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Affiliation(s)
- Tatsuhiko Imaoka
- Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Japan; Radiation Effect Accumulation and Prevention Project, Fukushima Project Headquarters, National Institute of Radiological Sciences, Japan
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21
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Nemes S, Danielsson A, Parris TZ, Jonasson JM, Bülow E, Karlsson P, Steineck G, Helou K. A diagnostic algorithm to identify paired tumors with clonal origin. Genes Chromosomes Cancer 2013; 52:1007-16. [DOI: 10.1002/gcc.22096] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Accepted: 07/02/2013] [Indexed: 11/07/2022] Open
Affiliation(s)
- Szilárd Nemes
- Division of Clinical Cancer Epidemiology; Department of Oncology; Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg; Gothenburg Sweden
- Regional Cancer Centre (West); Western Sweden Health Care Region, Sahlgrenska University Hospital; Gothenburg Sweden
| | - Anna Danielsson
- Department of Oncology; Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg; Gothenburg Sweden
| | - Toshima Z. Parris
- Department of Oncology; Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg; Gothenburg Sweden
| | - Junmei Miao Jonasson
- Division of Clinical Cancer Epidemiology; Department of Oncology; Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg; Gothenburg Sweden
| | - Erik Bülow
- Regional Cancer Centre (West); Western Sweden Health Care Region, Sahlgrenska University Hospital; Gothenburg Sweden
| | - Per Karlsson
- Department of Oncology; Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg; Gothenburg Sweden
| | - Gunnar Steineck
- Division of Clinical Cancer Epidemiology; Department of Oncology; Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg; Gothenburg Sweden
- Division of Clinical Cancer Epidemiology; Department of Oncology and Pathology; Karolinska Institutet; Stockholm Sweden
| | - Khalil Helou
- Department of Oncology; Institute of Clinical Sciences, Sahlgrenska Academy at University of Gothenburg; Gothenburg Sweden
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Markowitz J, Wesolowski R, Papenfuss T, Brooks TR, Carson WE. Myeloid-derived suppressor cells in breast cancer. Breast Cancer Res Treat 2013; 140:13-21. [PMID: 23828498 DOI: 10.1007/s10549-013-2618-7] [Citation(s) in RCA: 122] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 06/20/2013] [Indexed: 12/19/2022]
Abstract
Myeloid-derived suppressor cells (MDSCs) are a population of immature myeloid cells defined by their suppressive actions on immune cells such as T cells, dendritic cells, and natural killer cells. MDSCs typically are positive for the markers CD33 and CD11b but express low levels of HLADR in humans. In mice, MDSCs are typically positive for both CD11b and Gr1. These cells exert their suppressive activity on the immune system via the production of reactive oxygen species, arginase, and cytokines. These factors subsequently inhibit the activity of multiple protein targets such as the T cell receptor, STAT1, and indoleamine-pyrrole 2,3-dioxygenase. The numbers of MDSCs tend to increase with cancer burden while inhibiting MDSCs improves disease outcome in murine models. MDSCs also inhibit immune cancer therapeutics. In light of the poor prognosis of metastatic breast cancer in women and the correlation of increasing levels of MDSCs with increasing disease burden, the purposes of this review are to (1) discuss why MDSCs may be important in breast cancer, (2) describe model systems used to study MDSCs in vitro and in vivo, (3) discuss mechanisms involved in MDSC induction/function in breast cancer, and (4) present pre-clinical and clinical studies that explore modulation of the MDSC-immune system interaction in breast cancer. MDSCs inhibit the host immune response in breast cancer patients and diminishing MDSC actions may improve therapeutic outcomes.
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Affiliation(s)
- Joseph Markowitz
- Division of Medical Oncology, The Ohio State University, 320 W. 10th Ave., Columbus, OH 43210, USA.
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Mouse models for efficacy testing of agents against radiation carcinogenesis—a literature review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2012; 10:107-43. [PMID: 23271302 PMCID: PMC3564133 DOI: 10.3390/ijerph10010107] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 10/06/2012] [Revised: 11/26/2012] [Accepted: 12/11/2012] [Indexed: 12/12/2022]
Abstract
As the number of cancer survivors treated with radiation as a part of their therapy regimen is constantly increasing, so is concern about radiation-induced cancers. This increases the need for therapeutic and mitigating agents against secondary neoplasias. Development and efficacy testing of these agents requires not only extensive in vitro assessment, but also a set of reliable animal models of radiation-induced carcinogenesis. The laboratory mouse (Mus musculus) remains one of the best animal model systems for cancer research due to its molecular and physiological similarities to man, small size, ease of breeding in captivity and a fully sequenced genome. This work reviews relevant M. musculus inbred and F1 hybrid animal models and methodologies of induction of radiation-induced leukemia, thymic lymphoma, breast, and lung cancer in these models. Where available, the associated molecular pathologies are also included.
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Imaoka T, Hisatsune H, Sakanishi Y, Nishimura Y, Nishimura M, Shimada Y. Progesterone stimulates proliferation of a long-lived epithelial cell population in rat mammary gland. J Endocrinol Invest 2012; 35:828-34. [PMID: 22186344 DOI: 10.3275/8189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Long-lived somatic cells such as stem/progenitor cells may progressively accumulate oncogenic mutations and cause cancer. Some evidence suggests that pre-menopausal administration of progesterone confers a long-term increased risk of breast cancer. AIM To clarify the effect of progesterone on long-lived mammary epithelial cells in rats. MATERIALS AND METHODS Female Sprague- Dawley rats (3 and 7 weeks of age) were implanted sc with 14-day slow-release pellets of 5-bromo-2'-deoxyuridine (BrdU) and were sacrificed every 2 weeks between 0 and 10 weeks after the release period. Some rats at 7 weeks of age were also implanted with progesterone and sacrificed 0 or 10 weeks after the release period. Mammary glands were examined by immunohistochemistry and immunofluorescence for BrdU, proliferative cell nuclear antigen (PCNA) and progesterone receptor (PR). RESULTS After BrdU labeling of 3- and 7-week-old rats, the BrdU index decreased gradually over 10 weeks and resulted in small fractions (1-3%) of label-retaining epithelial cells (LREC) 10 weeks after BrdU labeling in both mammary lobules and ducts. Treatment with progesterone during labeling significantly increased the fraction of long-lived LREC in lobules and ducts by 9- and 4-fold, respectively. The long-lived LREC population in the ducts was enriched for PCNA- and PR-positive cells, but the percentage of positive cells was not affected by progesterone in either lobules or ducts. CONCLUSIONS Progesterone stimulates proliferation of a long-lived epithelial cell population in the mammary lobules and ducts of rats. Such cells in the duct are characterized by a high proliferation rate and PR expression.
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Affiliation(s)
- T Imaoka
- Radiobiology for Children's Health Program, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan.
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Radiation-induced carcinogenesis: mechanistically based differences between gamma-rays and neutrons, and interactions with DMBA. PLoS One 2011; 6:e28559. [PMID: 22194850 PMCID: PMC3237439 DOI: 10.1371/journal.pone.0028559] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 11/10/2011] [Indexed: 12/29/2022] Open
Abstract
Different types of ionizing radiation produce different dependences of cancer risk on radiation dose/dose rate. Sparsely ionizing radiation (e.g. γ-rays) generally produces linear or upwardly curving dose responses at low doses, and the risk decreases when the dose rate is reduced (direct dose rate effect). Densely ionizing radiation (e.g. neutrons) often produces downwardly curving dose responses, where the risk initially grows with dose, but eventually stabilizes or decreases. When the dose rate is reduced, the risk increases (inverse dose rate effect). These qualitative differences suggest qualitative differences in carcinogenesis mechanisms. We hypothesize that the dominant mechanism for induction of many solid cancers by sparsely ionizing radiation is initiation of stem cells to a pre-malignant state, but for densely ionizing radiation the dominant mechanism is radiation-bystander-effect mediated promotion of already pre-malignant cell clone growth. Here we present a mathematical model based on these assumptions and test it using data on the incidence of dysplastic growths and tumors in the mammary glands of mice exposed to high or low dose rates of γ-rays and neutrons, either with or without pre-treatment with the chemical carcinogen 7,12-dimethylbenz-alpha-anthracene (DMBA). The model provides a mechanistic and quantitative explanation which is consistent with the data and may provide useful insight into human carcinogenesis.
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Hudson D, Kovalchuk I, Koturbash I, Kolb B, Martin OA, Kovalchuk O. Induction and persistence of radiation-induced DNA damage is more pronounced in young animals than in old animals. Aging (Albany NY) 2011; 3:609-20. [PMID: 21685513 PMCID: PMC3164369 DOI: 10.18632/aging.100340] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Younger individuals are more prone to develop cancer upon ionizing radiation (IR) exposure. Radiation-induced tumors are associated with inefficient repair of IR-induced DNA damage and genome instability. Phosphorylation of histone H2AX (γ-H2AX) is the initial event in repair of IR-induced DNA damage on the chromatin flanking the DNA strand breaks. This step is crucially important for the repair of DNA strand breaks and for the maintenance of genome stability. We studied the molecular underpinnings of the age-related IR effects using an animal model. By assaying for IR-induced γ-H2AX foci we analyzed the induction and repair of the DNA strand breaks in spleen, thymus, liver, lung, kidney, cerebellum, hippocampus, frontal cortex and olfactory bulb of 7, 14, 24, 30 and 45 days old male and female mice as a function of age. We demonstrate that tissues of younger animals are much more susceptible to IR-induced DNA damage. Younger animals exhibited higher levels of γ-H2AX formation which partially correlated with cellular proliferation and expression of DNA repair proteins. Induction and persistence of γ-H2AX foci was the highest in lymphoid organs (thymus and spleen) of 7 and 14 day old mice. The lowest focal induction was seen in lung and brain of young animals. The mechanisms of cell and tissue-specificity of in vivo IR responses need to be further dissected. This study provides a roadmap for the future analyses of DNA damage and repair induction in young individuals.
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Affiliation(s)
- Darryl Hudson
- Department of Biological Sciences, University of Lethbridge, Lethbridge, AB, T1K 3M4 Canada
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Rudel RA, Fenton SE, Ackerman JM, Euling SY, Makris SL. Environmental exposures and mammary gland development: state of the science, public health implications, and research recommendations. ENVIRONMENTAL HEALTH PERSPECTIVES 2011; 119:1053-61. [PMID: 21697028 PMCID: PMC3237346 DOI: 10.1289/ehp.1002864] [Citation(s) in RCA: 153] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2010] [Accepted: 05/17/2011] [Indexed: 05/18/2023]
Abstract
OBJECTIVES Perturbations in mammary gland (MG) development may increase risk for later adverse effects, including lactation impairment, gynecomastia (in males), and breast cancer. Animal studies indicate that exposure to hormonally active agents leads to this type of developmental effect and related later life susceptibilities. In this review we describe current science, public health issues, and research recommendations for evaluating MG development. DATA SOURCES The Mammary Gland Evaluation and Risk Assessment Workshop was convened in Oakland, California, USA, 16-17 November 2009, to integrate the expertise and perspectives of scientists, risk assessors, and public health advocates. Interviews were conducted with 18 experts, and seven laboratories conducted an MG slide evaluation exercise. Workshop participants discussed effects of gestational and early life exposures to hormonally active agents on MG development, the relationship of these developmental effects to lactation and cancer, the relative sensitivity of MG and other developmental end points, the relevance of animal models to humans, and methods for evaluating MG effects. SYNTHESIS Normal MG development and MG carcinogenesis demonstrate temporal, morphological, and mechanistic similarities among test animal species and humans. Diverse chemicals, including many not considered primarily estrogenic, alter MG development in rodents. Inconsistent reporting methods hinder comparison across studies, and relationships between altered development and effects on lactation or carcinogenesis are still being defined. In some studies, altered MG development is the most sensitive endocrine end point. CONCLUSIONS Early life environmental exposures can alter MG development, disrupt lactation, and increase susceptibility to breast cancer. Assessment of MG development should be incorporated in chemical test guidelines and risk assessment.
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Hattori N, Okochi-Takada E, Kikuyama M, Wakabayashi M, Yamashita S, Ushijima T. Methylation silencing of angiopoietin-like 4 in rat and human mammary carcinomas. Cancer Sci 2011; 102:1337-43. [PMID: 21489049 DOI: 10.1111/j.1349-7006.2011.01955.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Aberrant DNA methylation is deeply involved in the development and progression of human breast cancers, but its inducers and molecular mechanisms are still unclear. To reveal such inducers and clarify the molecular mechanisms, animal models are indispensable. Here, to identify genes silenced by promoter DNA methylation in rat mammary carcinomas, we took a combined approach of methylated DNA immunoprecipitation (MeDIP)-CpG island (CGI) microarray analysis and expression microarray analysis after treatment with epigenetic drugs. MeDIP-CGI microarray revealed that among 5031 genes with promoter CGI, 465 were methylated in a carcinoma cell line induced by 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), but not in normal mammary epithelial cells. By treatment of the cell line with 5-aza-2'-deoxycytidine and trichostatin A, 29 of the 465 genes were shown to be re-expressed. In primary mammary carcinomas, five (Angptl4, Coro1a, RGD1304982, Tmem37 and Ndn) of the 29 genes were methylated in one or more of 25 samples. Quantitative expression analysis revealed that Angptl4 had high expression in normal mammary glands, but low expression in primary carcinomas. Also in humans, ANGPTL4 was unmethylated and expressed in normal mammary epithelial cells, but was methylated in 11 of 91 (12%) primary breast cancers. This is the first study to identify genes aberrantly methylated in rat mammary carcinomas, and Angptl4 is a novel methylation-silenced gene both in rat and human mammary carcinomas. The combination of the MeDIP-CGI microarray analysis and expression microarray analysis after treatment with epigenetic drugs was effective in reducing the number of methylated genes that are not methylation silenced.
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Affiliation(s)
- Naoko Hattori
- Division of Epigenomics, National Cancer Center Research Institute, Tokyo, Japan
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An exposure driven functional model of carcinogenesis. Med Hypotheses 2011; 77:195-8. [PMID: 21550177 DOI: 10.1016/j.mehy.2011.04.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2010] [Revised: 04/07/2011] [Accepted: 04/08/2011] [Indexed: 12/26/2022]
Abstract
The understanding of general models of carcinogenesis have not advanced substantially over the last years despite a rapidly increasing amount of detailed knowledge in molecular biology, genetics and epidemiology, and it has been difficult to come up with specific hypotheses in order to test existing models. Current multistage models consider mutations per se as the driving forces of carcinogenesis. In contrast, novel knowledge in epidemiology and basic research combined with upcoming large scale technologies of transcriptomics and epigenetics offers a new model--the exposure driven functional model. In this model exposures to carcinogenic substances are the determinants of the carcinogenesis leading to functional changes in gene regulation and to mutations. The diversity of exposures and functional changes could give not one, but many different cancer phenotypes. Under this novel model, cessation of exposure could arrest or reverse the carcinogenic process. To test hypotheses based on this novel model, studies with valid exposures measurements, biological material suitable for all "-omics" analyses, and a design that takes into account the time order principle of causality are a prerequisite. In epidemiology, such designs have been proposed, while in basic genetic research most designs only comply with some, but not all of these conditions. The strength of the exposure driven functional model is the potential for testing specific hypothesis of the effect of many exposures on different stages or mutations. An example of such design would be the testing of the effect of continuing or stopping exposures in relation to the last stage of carcinogenesis in a prospective or globolomic design. If successful the exposure driven carcinogenic model and the use of functional genomics could improve the understanding of carcinogenesis and concomitantly the assessment of causality as part of systems epidemiology.
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Imaoka T, Nishimura M, Iizuka D, Nishimura Y, Ohmachi Y, Shimada Y. Pre- and postpubertal irradiation induces mammary cancers with distinct expression of hormone receptors, ErbB ligands, and developmental genes in rats. Mol Carcinog 2011; 50:539-52. [PMID: 21374731 DOI: 10.1002/mc.20746] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 11/05/2010] [Accepted: 01/14/2011] [Indexed: 11/08/2022]
Abstract
Childhood exposure to carcinogens renders a higher risk of breast cancer. The molecular mechanisms underlying cancer development after such exposure are not, however, well understood. Here we examined how the mechanism of cancer development relates to the age at exposure to ionizing radiation (IR) or the carcinogen 1-methyl-1-nitrosourea (MNU). Pre- and postpubertal (3- and 7-wk-old, respectively) female Sprague-Dawley rats were whole-body γ-irradiated (2 Gy), injected intraperitoneally with MNU (20 mg/kg) or left untreated and were autopsied at 50 wk of age. Mammary carcinomas were examined for estrogen receptor (ER) α, progesterone receptor (PR) and ErbB ligand expression and for expression microarrays. Early histological changes of the ovaries were also evaluated. The incidence of mammary cancer was higher after postpubertal, rather than prepubertal, IR exposure; the inverse was true for MNU. Most cancers were positive for both ERα and PR except for the prepubertal IR group. Cancers of the prepubertal IR group expressed a different set of ErbB ligands from those of the other groups and did not overexpress Areg, which encodes an estrogen-regulated ErbB ligand, or other developmentally related genes including those for hormonally regulated mammary gland development. Prepubertal IR exposure resulted in ovarian dysfunction as revealed by a reduced follicular pool. Evidence thus suggests that mammary carcinogenesis induced by prepubertal IR exposure is independent of ovarian hormones but requires certain ErbB ligands; induction by postpubertal exposure depends on ovarian hormones and different ErbB ligands. In contrast, the mechanism of MNU-induced carcinogenesis was less influenced by the age at exposure.
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Affiliation(s)
- Tatsuhiko Imaoka
- Experimental Radiobiology for Children's Health Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, Japan
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Iizuka D, Imaoka T, Takabatake T, Nishimura M, Kakinuma S, Nishimura Y, Shimada Y. DNA copy number aberrations and disruption of the p16Ink4a/Rb pathway in radiation-induced and spontaneous rat mammary carcinomas. Radiat Res 2010; 174:206-15. [PMID: 20681787 DOI: 10.1667/rr2006.1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Chromosomal amplifications and deletions are thought to be important events in spontaneous and radiation-induced carcinogenesis. To clarify how ionizing radiation induces mammary carcinogenesis, we characterized genomic copy number aberrations for gamma-ray-induced rat mammary carcinomas using microarray-based comparative genomic hybridization. We examined 14 carcinomas induced by gamma radiation (2 Gy) and found 26 aberrations, including trisomies of chromosomes 4 and 10 for three and one carcinomas, respectively, an amplification of the chromosomal region 1q12 in two carcinomas, and deletions of the chromosomal regions 3q35q36, 5q32 and 7q11 in two, two and four carcinomas, respectively. These aberrations were not observed in seven spontaneous mammary carcinomas. The expression of p16Ink4a and p19Arf, which are located in the chromosomal region 5q32, was always up-regulated except for a carcinoma with a homozygous deletion of region 5q32. The up-regulation was not accounted for by gene mutations or promoter hypomethylation. However, the amounts of Rb and its mRNA were down-regulated in these carcinomas, indicating a disruption of the p16Ink4a/Rb pathway. This is the first report of array CGH analysis for radiation-induced mammary tumors, which reveals that they show distinct DNA copy number aberration patterns that are different from those of spontaneous tumors and those reported previously for chemically induced tumors.
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Affiliation(s)
- Daisuke Iizuka
- Experimental Radiobiology for Children's Health Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba, 263-8555, Japan
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Bugelski PJ, Volk A, Walker MR, Krayer JH, Martin P, Descotes J. Critical Review of Preclinical Approaches to Evaluate the Potential of Immunosuppressive Drugs to Influence Human Neoplasia. Int J Toxicol 2010; 29:435-66. [DOI: 10.1177/1091581810374654] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Many immunosuppressive drugs are associated with an increased risk of B-cell lymphoma, squamous cell carcinoma, and Kaposi sarcoma. Thirteen immunosuppressive drugs have been tested in 2-year carcinogenicity studies (abatacept; azathioprine; busulfan; cyclophosphamide; cyclosporine; dexamethasone; everolimus; leflunomide; methotrexate; mycophenolate mofetil; prednisone; sirolimus; and tacrolimus) and in additional models including neonatal and genetically modified mice; chemical, viral, ultraviolet, and ionizing radiation co-carcinogenesis, and in models with transplanted tumor cells. The purpose of this review is to outline the mechanisms by which immunosuppressive drugs can influence neoplasia, to summarize the available preclinical data on the 13 drugs, and to critically review the performance of the models. A combination of primary tumor and metastasis assays conducted with transplanted cells may provide the highest value for hazard identification and can be applied on a case-by-case basis. However, for both small molecules and therapeutic proteins, determining the relative risk to patients from preclinical data remains problematic. Classifying immunosuppressive drugs based on their mechanism of action and hazard identification from preclinical studies and a prospective pharmacovigilance program to monitor carcinogenic risk may be a feasible way to manage patient safety during the clinical development program and postmarketing.
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Affiliation(s)
| | - Amy Volk
- Biologics Toxicology, Centocor R&D, Radnor, PA, USA
| | | | | | | | - Jacques Descotes
- Centre Antipoison–Centre de Pharmacovigilance, Hôpital Edouard Herriot, Lyon, France
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Hamada N, Imaoka T, Masunaga SI, Ogata T, Okayasu R, Takahashi A, Kato TA, Kobayashi Y, Ohnishi T, Ono K, Shimada Y, Teshima T. Recent advances in the biology of heavy-ion cancer therapy. JOURNAL OF RADIATION RESEARCH 2010; 51:365-383. [PMID: 20679739 DOI: 10.1269/jrr.09137] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Superb biological effectiveness and dose conformity represent a rationale for heavy-ion therapy, which has thus far achieved good cancer controllability while sparing critical normal organs. Immediately after irradiation, heavy ions produce dense ionization along their trajectories, cause irreparable clustered DNA damage, and alter cellular ultrastructure. These ions, as a consequence, inactivate cells more effectively with less cell-cycle and oxygen dependence than conventional photons. The modes of heavy ion-induced cell death/inactivation include apoptosis, necrosis, autophagy, premature senescence, accelerated differentiation, delayed reproductive death of progeny cells, and bystander cell death. This paper briefly reviews the current knowledge of the biological aspects of heavy-ion therapy, with emphasis on the authors' recent findings. The topics include (i) repair mechanisms of heavy ion-induced DNA damage, (ii) superior effects of heavy ions on radioresistant tumor cells (intratumor quiescent cell population, TP53-mutated and BCL2-overexpressing tumors), (iii) novel capacity of heavy ions in suppressing cancer metastasis and neoangiogenesis, and (iv) potential of heavy ions to induce secondary (especially breast) cancer.
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Affiliation(s)
- Nobuyuki Hamada
- Radiation Safety Research Center, Nuclear Technology Research Laboratory, Central Research Institute of Electric Power Industry, Komae, Tokyo, Japan.
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