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Mansouri W, Fordyce SB, Wu M, Jones D, Cohn D, Lin Q, Feustel P, Sharma T, Bennett JA, Andersen TT. Efficacy and tolerability of AFPep, a cyclic peptide with anti-breast cancer properties. Toxicol Appl Pharmacol 2018. [PMID: 29518411 DOI: 10.1016/j.taap.2018.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
PURPOSE The purpose of this study is to assess the efficacy and safety profile of AFPep, a 9-amino acid cyclic peptide prior to its entry into pre-clinical toxicology analyses en route to clinical trials. METHODS AFPep was assessed for anti-estrogenic activity in a mouse uterine growth assay and for breast cancer therapeutic efficacy in a human tumor xenograft model in mice. AFPep was assessed for tolerability in a variety of in vivo models, notably including assessment for effects on rat liver and human hepatocellular carcinoma cell lines and xenografts. RESULTS AFPep arrests the growth of human MCF-7 breast cancer xenografts, inhibits the estrogen-induced growth of mouse uteri, and does not affect liver growth nor stimulate growth of human hepatocellular carcinoma cell lines when growing in vitro or as xenografts in vivo. AFPep is well tolerated in mice, rats, dogs, and primates. CONCLUSIONS AFPep is effective for the treatment of ER-positive breast cancer and exhibits a therapeutic index that is substantially wider than that for drugs currently in clinical use. The data emphasize the importance of pursuing pre-clinical toxicology studies with the intent to enter clinical trials.
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Affiliation(s)
- Wasila Mansouri
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, United States
| | - Samuel B Fordyce
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, United States; Rensselaer Polytechnic Institute, Rensselaer, NY, United States
| | - Matthew Wu
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, United States; Union College, Schenectady, NY, United States
| | - David Jones
- Department of Pathology, Albany Medical Center Hospital, Albany, NY, United States
| | - Douglas Cohn
- Animal Resource Facility, Albany Medical College, Albany, NY, United States
| | - Qishan Lin
- Center for Functional Genomics, University at Albany, Rensselaer, NY, United States
| | - Paul Feustel
- Deparment of Neuroscience and Experimental Therapeutics, Albany Medical College, United States
| | - Tanuj Sharma
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, United States; Rensselaer Polytechnic Institute, Rensselaer, NY, United States
| | - James A Bennett
- Department of Immunology and Microbial Disease, Albany Medical College, Albany, NY, United States
| | - Thomas T Andersen
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, NY, United States.
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2
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Dennison KL, Samanas NB, Harenda QE, Hickman MP, Seiler NL, Ding L, Shull JD. Development and characterization of a novel rat model of estrogen-induced mammary cancer. Endocr Relat Cancer 2015; 22:239-48. [PMID: 25800038 PMCID: PMC4372900 DOI: 10.1530/erc-14-0539] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The ACI rat model of 17β-estradiol (E2)-induced mammary cancer is highly relevant for use in establishing the endocrine, genetic, and environmental bases of breast cancer etiology and identifying novel agents and strategies for preventing breast cancer. E2 treatment rapidly induces mammary cancer in female ACI rats and simultaneously induces pituitary lactotroph hyperplasia and adenoma. The pituitary tumors can result in undesired morbidity, which compromises long-term studies focused on mammary cancer etiology and prevention. We have defined the genetic bases of susceptibility to E2-induced mammary cancers and pituitary tumors and have utilized the knowledge gained in these studies to develop a novel inbred rat strain, designated ACWi, that retains the high degree of susceptibility to E2-induced mammary cancer exhibited by ACI rats, but lacks the treatment-related morbidity associated with pituitary lactotroph hyperplasia/adenoma. When treated with E2, female ACWi rats developed palpable mammary cancer at a median latency of 116 days, an incidence of 100% by 161 days and exhibited an average of 15.6 mammary tumors per rat following 196 days of treatment. These parameters did not differ from those observed for contemporaneously treated ACI rats. None of the E2-treated ACWi rats were killed before the intended experimental end point due to any treatment-related morbidity other than mammary cancer burden, whereas 20% of contemporaneously treated ACI rats exhibited treatment-related morbidity that necessitated premature killing. The ACWi rat strain is well suited for use by those in the research community, focusing on breast cancer etiology and prevention.
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Affiliation(s)
- Kirsten L Dennison
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, School of Medicine and Public HealthSchool of Medicine and Public HealthMolecular and Environmental Toxicology CenterSchool of Medicine and Public HealthUniversity of Wisconsin Carbone Cancer Center, University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Nyssa Becker Samanas
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, School of Medicine and Public HealthSchool of Medicine and Public HealthMolecular and Environmental Toxicology CenterSchool of Medicine and Public HealthUniversity of Wisconsin Carbone Cancer Center, University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Quincy Eckert Harenda
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, School of Medicine and Public HealthSchool of Medicine and Public HealthMolecular and Environmental Toxicology CenterSchool of Medicine and Public HealthUniversity of Wisconsin Carbone Cancer Center, University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Maureen Peters Hickman
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, School of Medicine and Public HealthSchool of Medicine and Public HealthMolecular and Environmental Toxicology CenterSchool of Medicine and Public HealthUniversity of Wisconsin Carbone Cancer Center, University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Nicole L Seiler
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, School of Medicine and Public HealthSchool of Medicine and Public HealthMolecular and Environmental Toxicology CenterSchool of Medicine and Public HealthUniversity of Wisconsin Carbone Cancer Center, University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
| | - Lina Ding
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, School of Medicine and Public HealthSchool of Medicine and Public HealthMolecular and Environmental Toxicology CenterSchool of Medicine and Public HealthUniversity of Wisconsin Carbone Cancer Center, University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705, USA McArdle Laboratory for Cancer ResearchDepartment of Oncology, School of Medicine and Public HealthSchool of Medicine and Public HealthMolecular and Environmental Toxicology CenterSchool of Medicine and Public HealthUniversity of Wisconsin Carbone Cancer Center, University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
| | - James D Shull
- McArdle Laboratory for Cancer ResearchDepartment of Oncology, School of Medicine and Public HealthSchool of Medicine and Public HealthMolecular and Environmental Toxicology CenterSchool of Medicine and Public HealthUniversity of Wisconsin Carbone Cancer Center, University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705, USA McArdle Laboratory for Cancer ResearchDepartment of Oncology, School of Medicine and Public HealthSchool of Medicine and Public HealthMolecular and Environmental Toxicology CenterSchool of Medicine and Public HealthUniversity of Wisconsin Carbone Cancer Center, University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705, USA McArdle Laboratory for Cancer ResearchDepartment of Oncology, School of Medicine and Public HealthSchool of Medicine and Public HealthMolecular and Environmental Toxicology CenterSchool of Medicine and Public HealthUniversity of Wisconsin Carbone Cancer Center, University of Wisconsin, 1111 Highland Avenue, Madison, Wisconsin 53705, USA
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3
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Cunha FS, Domenice S, Câmara VL, Sircili MHP, Gooren LJG, Mendonça BB, Costa EMF. Diagnosis of prolactinoma in two male-to-female transsexual subjects following high-dose cross-sex hormone therapy. Andrologia 2014; 47:680-4. [DOI: 10.1111/and.12317] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/02/2014] [Indexed: 02/06/2023] Open
Affiliation(s)
- F. S. Cunha
- Unidade de Endocrinologia do Desenvolvimento; Laboratório de Hormônios e Genética Molecular LIM42; Disciplina de Endocrinologia; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; São Paulo SP Brazil
| | - S. Domenice
- Unidade de Endocrinologia do Desenvolvimento; Laboratório de Hormônios e Genética Molecular LIM42; Disciplina de Endocrinologia; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; São Paulo SP Brazil
| | - V. L. Câmara
- Unidade de Endocrinologia do Desenvolvimento; Laboratório de Hormônios e Genética Molecular LIM42; Disciplina de Endocrinologia; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; São Paulo SP Brazil
| | - M. H. P. Sircili
- Unidade de Endocrinologia do Desenvolvimento; Laboratório de Hormônios e Genética Molecular LIM42; Disciplina de Endocrinologia; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; São Paulo SP Brazil
| | - L. J. G. Gooren
- Emeritus VU Medical Center; Amsterdam The Netherlands
- Androconsult; Chiang Mai Thailand
| | - B. B. Mendonça
- Unidade de Endocrinologia do Desenvolvimento; Laboratório de Hormônios e Genética Molecular LIM42; Disciplina de Endocrinologia; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; São Paulo SP Brazil
| | - E. M. F. Costa
- Unidade de Endocrinologia do Desenvolvimento; Laboratório de Hormônios e Genética Molecular LIM42; Disciplina de Endocrinologia; Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; São Paulo SP Brazil
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4
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Kurz SG, Dennison KL, Samanas NB, Hickman MP, Eckert QA, Walker TL, Cupp AS, Shull JD. Ept7 influences estrogen action in the pituitary gland and body weight of rats. Mamm Genome 2014; 25:244-52. [PMID: 24448715 DOI: 10.1007/s00335-014-9504-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2013] [Accepted: 12/30/2013] [Indexed: 11/29/2022]
Abstract
Estrogens control many aspects of pituitary gland biology, including regulation of lactotroph homeostasis and synthesis and secretion of prolactin. In rat models, these actions are strain specific and heritable, and multiple quantitative trait loci (QTL) have been mapped that impact the responsiveness of the lactotroph to estrogens. One such QTL, Ept7, was mapped to RNO7 in female progeny generated in an intercross between BN rats, in which the lactotroph population is insensitive to estrogens, and ACI rats, which develop lactotroph hyperplasia/adenoma and associated hyperprolactinemia in response to estrogen treatment. The primary objective of this study was to confirm the existence of Ept7 and to quantify the impact of this QTL on responsiveness of the pituitary gland of female and male rats to 17β-estradiol (E2) and diethylstilbestrol (DES), respectively. Secondary objectives were to determine if Ept7 influences the responsiveness of the male reproductive tract to DES and to identify other discernible phenotypes influenced by Ept7. To achieve these objectives, a congenic rat strain that harbors BN alleles across the Ept7 interval on the genetic background of the ACI strain was generated and characterized to define the effect of administered estrogens on the anterior pituitary gland and male reproductive tissues. Data presented herein indicate Ept7 exerts a marked effect on development of lactotroph hyperplasia in response to estrogen treatment, but does not affect atrophy of the male reproductive tissues in response to hormone treatment. Ept7 was also observed to exert gender specific effects on body weight in young adult rats.
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Affiliation(s)
- Scott G Kurz
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, 68198, USA
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5
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Ruhlen RL, Willbrand DM, Besch-Williford CL, Ma L, Shull JD, Sauter ER. Tamoxifen induces regression of estradiol-induced mammary cancer in the ACI.COP-Ept2 rat model. Breast Cancer Res Treat 2008; 117:517-24. [PMID: 18830694 DOI: 10.1007/s10549-008-0169-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Accepted: 08/21/2008] [Indexed: 12/21/2022]
Abstract
The ACI rat is a unique model of human breast cancer in that mammary cancers are induced by estrogen without carcinogens, irradiation, xenografts or transgenic manipulations. We sought to characterize mammary cancers in a congenic variant of the ACI rat, the ACI.COP-Ept2. All rats with estradiol implants developed mammary cancers in 5-7 months. Rats bearing estradiol-induced mammary cancers were treated with tamoxifen for three weeks. Tamoxifen reduced tumor mass, measured by magnetic resonance imaging, by 89%. Tumors expressed estrogen receptors (ER), progesterone receptor (PR), and Erbb2. ERalpha and PR were overexpressed in tumor compared to adjacent non-tumor mammary gland. Thus, this model is highly relevant to hormone responsive human breast cancers.
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Affiliation(s)
- Rachel L Ruhlen
- Department of Surgery, University of Missouri-Columbia, One Hospital Drive, Rm N510, Columbia, MO 65212, USA
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6
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Shull JD, Lachel CM, Murrin CR, Pennington KL, Schaffer BS, Strecker TE, Gould KA. Genetic control of estrogen action in the rat: mapping of QTLs that impact pituitary lactotroph hyperplasia in a BN x ACI intercross. Mamm Genome 2007; 18:657-69. [PMID: 17876666 DOI: 10.1007/s00335-007-9052-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2007] [Accepted: 07/11/2007] [Indexed: 10/22/2022]
Abstract
Estrogens are important regulators of growth and development and contribute to the etiology of several types of cancer. Different inbred rat strains exhibit marked, cell-type-specific differences in responsiveness to estrogens as well as differences in susceptibility to estrogen-induced tumorigenesis. Regulation of pituitary lactotroph homeostasis is one estrogen-regulated response that differs dramatically between different inbred rat strains. In this article we demonstrate that the growth response of the anterior pituitary gland of female ACI rats to 17beta-estradiol (E2) markedly exceeds that of identically treated female Brown Norway (BN) rats. We further demonstrate that pituitary mass, a surrogate indicator of absolute lactotroph number, behaves as a quantitative trait in E2-treated F(2) progeny generated in a genetic cross originating with BN females and ACI males. Composite interval mapping analyses of the (BNxACI)F(2) population revealed quantitative trait loci (QTLs) that exert significant effects on E2-induced pituitary growth on rat chromosome 4 (RNO4) (Ept5) and RNO7 (Ept7). Continuous treatment with E2 rapidly induces mammary cancer in female ACI rats but not BN rats, and QTLs that impact susceptibility to E2-induced mammary cancer in the (BNxACI)F(2) population described here have been mapped to RNO3 (Emca5), RNO4 (Emca6), RNO5 (Emca8), RNO6 (Emca7), and RNO7 (Emca4). Ept5 and Emca6 map to distinct regions of RNO4. However, Ept7 and Emca4 map to the same region of RNO7. No correlation between pituitary mass and mammary cancer number at necropsy was observed within the (BNxACI)F(2) population. This observation, together with the QTL mapping data, indicate that with the exception of the Ept7/Emca4 locus on RNO7, the genetic determinants of E2-induced pituitary growth differ from the genetic determinants of susceptibility to E2-induced mammary cancer.
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Affiliation(s)
- James D Shull
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE 68198-5805, USA.
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7
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McCormick DL, Johnson WD, Haryu TM, Bosland MC, Lubet RA, Steele VE. Null effect of dietary restriction on prostate carcinogenesis in the Wistar-Unilever rat. Nutr Cancer 2007; 57:194-200. [PMID: 17571953 DOI: 10.1080/01635580701277494] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Chronic dietary restriction inhibits carcinogenesis in several sites in laboratory animals. To determine the effects of dietary restriction on prostate carcinogenesis, prostate cancers were induced in male Wistar-Unilever rats by a sequential regimen of cyproterone acetate (50 mg/day; 21 days); testosterone propionate (100 mg/kg/day; 3 days); N-methyl-N-nitrosourea [MNU; 30 mg/kg; single dose]; and testosterone (subcutaneous implants of 2 pellets containing 40 mg each). Dietary restriction (0% [ad libitum control], 15%, or 30%) was initiated 2 wk post-MNU, and continued until study termination at 12 mo. Dietary restriction induced a rapid suppression of body weight gain but conferred no protection against prostate carcinogenesis. 74% of carcinogen-treated ad libitum controls developed accessory sex gland cancers, versus cancer incidences of 64% and 72% in groups restricted by 15% and 30%, respectively. Similarly, 44% of dietary controls developed cancers limited to the dorsolateral/prostate, versus incidences of 45% and 53% in groups restricted by 15% and 30%. The results of the present study do not support the hypothesis that prostate carcinogenesis can be prevented by reducing caloric intake. Reducing mean body weight by up to 25% through chronic dietary restriction has no effect on the induction of prostate cancers in the Wistar-Unilever rat model.
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Affiliation(s)
- David L McCormick
- Life Sciences Group, IIT Research Institute, Chicago, IL 60616, USA.
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8
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Gould KA, Strecker TE, Hansen KK, Bynoté KK, Peterson KA, Shull JD. Genetic mapping of loci controlling diethylstilbestrol-induced thymic atrophy in the Brown Norway rat. Mamm Genome 2006; 17:451-64. [PMID: 16688534 DOI: 10.1007/s00335-005-0183-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2005] [Accepted: 02/01/2006] [Indexed: 11/28/2022]
Abstract
Chronic estrogen administration can lead to thymic atrophy in rodents. In this article we report that the Brown Norway (BN) rat is sensitive to thymic atrophy induced by the estrogen diethylstilbestrol (DES). By contrast, DES does not induce significant thymic atrophy in the August x Copenhagen-Irish (ACI) strain. The sensitivity of the BN rat to DES-induced thymic atrophy appears to segregate as an incompletely dominant trait in crosses between the BN and ACI strains. In a (BN x ACI)F(2) population, we find strong evidence for three major genetic determinants of sensitivity to DES-induced thymic atrophy on rat Chromosome (RNO) 10 and RNO2. Genotypes at these loci, termed Esta1, 2, and 3, do not have a significant impact on the ability of DES to induce pituitary tumorigenesis or inhibit growth of these F(2) rats. These data indicate that the genetic factors that control DES-induced thymic atrophy are distinct from those that control the effects of DES on pituitary mass and body mass. The Esta intervals on RNO10 and RNO2 overlap with loci that control sensitivity to radiation-induced thymocyte apoptosis, as well as susceptibility to a variety of allergic and autoimmune pathologies, including allergic encephalitis, arthritis, and glomerulonephritis in rodents. These observations suggest that common genetic determinants may control sensitivity to estrogen-induced thymic atrophy, maintenance of thymocyte homeostasis, and immune function.
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Affiliation(s)
- Karen A Gould
- Department of Genetics, Cell Biology and Anatomy, 985805, University of Nebraska Medical Center, Omaha, Nebraska 68198-5805, USA.
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9
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Gould KA, Pandey J, Lachel CM, Murrin CR, Flood LA, Pennington KL, Schaffer BS, Tochacek M, McComb RD, Meza JL, Wendell DL, Shull JD. Genetic mapping of Eutr1, a locus controlling E2-induced pyometritis in the Brown Norway rat, to RNO5. Mamm Genome 2005; 16:854-64. [PMID: 16284801 DOI: 10.1007/s00335-005-0070-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Accepted: 08/10/2005] [Indexed: 10/25/2022]
Abstract
In certain rat strains, chronic estrogen administration can lead to pyometritis, an inflammation of the uterus accompanied by infection and the accumulation of intraluminal pus. In this article, we report that the Brown Norway (BN) rat is highly susceptible to pyometritis induced by 17beta-estradiol (E2). The susceptibility of the BN rat to E2-induced pyometritis appears to segregate as a recessive trait in crosses to the resistant August x Copenhagen Irish (ACI) strain. In a (BN x ACI)F(2) population, we find strong evidence for a major genetic determinant of susceptibility to E2-induced pyometritis on rat chromosome 5 (RNO5). Our data are most consistent with a model in which the BN allele of this locus, designated Eutr1 (Estrogen-induced uterine response 1), acts in an incompletely dominant manner to control E2-induced pyometritis. Furthermore, we have confirmed the contribution of Eutr1 to E2-induced uterine pyometritis using an RNO5 congenic rat strain. In addition to Eutr1, we obtained evidence suggestive of linkage for five additional loci on RNO2, 4, 11, 17, and X that control susceptibility to E2-induced pyometritis in the (BN x ACI)F(2) population.
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Affiliation(s)
- Karen A Gould
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA.
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10
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Strecker TE, Spady TJ, Schaffer BS, Gould KA, Kaufman AE, Shen F, McLaughlin MT, Pennington KL, Meza JL, Shull JD. Genetic bases of estrogen-induced pituitary tumorigenesis: identification of genetic loci determining estrogen-induced pituitary growth in reciprocal crosses between the ACI and Copenhagen rat strains. Genetics 2005; 169:2189-97. [PMID: 15687265 PMCID: PMC1449615 DOI: 10.1534/genetics.104.039370] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Estrogens stimulate proliferation and enhance survival of the prolactin (PRL)-producing lactotroph of the anterior pituitary gland and induce development of PRL-producing pituitary tumors in certain inbred rat strains but not others. The goal of this study was to elucidate the genetic bases of estrogen-induced pituitary tumorigenesis in reciprocal intercrosses between the genetically related ACI and Copenhagen (COP) rat strains. Following 12 weeks of treatment with the synthetic estrogen diethylstilbestrol (DES), pituitary mass, an accurate surrogate marker of absolute lactotroph number, was increased 10.6-fold in ACI rats and 4.5-fold in COP rats. Composite interval mapping analyses of the phenotypically defined F(2) progeny from the reciprocal crosses identified six quantitative trait loci (QTL) that determine the pituitary growth response to DES. These loci reside on chromosome 6 [Estrogen-induced pituitary tumor (Ept)1], chromosome 3 (Ept2 and Ept6), chromosome 10 (Ept9), and chromosome 1 (Ept10 and Ept13). Together, these six Ept loci and one additional suggestive locus on chromosome 4 account for an estimated 40% of the phenotypic variance exhibited by the combined F(2) population, while 34% of the phenotypic variance was estimated to result from environmental factors. These data indicate that DES-induced pituitary mass behaves as a quantitative trait and provide information that will facilitate identification of genes that determine the tumorigenic response of the pituitary gland to estrogens.
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Affiliation(s)
- Tracy E Strecker
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, 68198, USA
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11
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Harvell DM, Strecker TE, Xie B, Buckles LK, Tochacek M, McComb RD, Shull JD. Diet-gene interactions in estrogen-induced mammary carcinogenesis in the ACI rat. J Nutr 2001; 131:3087S-91S. [PMID: 11694653 DOI: 10.1093/jn/131.11.3087s] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
It is well accepted that hormonal, dietary and genetic factors each influence breast cancer risk. However, the underlying mechanisms and the extent to which these factors interact are largely unknown. We have demonstrated that the female ACI rat exhibits a unique genetically conferred propensity to develop mammary cancers when treated with physiological levels of 17beta-estradiol (E2). More recently, we have mapped to rat chromosome 5 a strong genetic modifier of susceptibility to E2-induced mammary cancers, termed estrogen-induced mammary cancer 1 (Emca1), and have identified potential Emca1 candidate genes. Because estrogens have been inextricably linked to the genesis of breast cancer in humans, the ACI rat model has the potential to reveal novel physiologically relevant insights into how the contributory actions of E2 are modified by specific dietary factors. In the present study, we have examined the ability of a 40% restriction of dietary energy consumption to inhibit E2-induced mammary carcinogenesis. The hypothesis tested was that energy restriction will inhibit mammary carcinogenesis even when circulating E2 remains elevated through administration of exogenous hormone. The data presented herein strongly suggest that energy restriction inhibits E2-induced mammary carcinogenesis in the ACI rat at least partly by retarding progression of atypical hyperplastic foci to carcinoma.
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MESH Headings
- Animals
- Body Weight
- Breast Neoplasms/etiology
- Breast Neoplasms/genetics
- Breast Neoplasms/pathology
- Breast Neoplasms/prevention & control
- Cell Division/drug effects
- Cell Division/physiology
- Diet, Reducing
- Disease Models, Animal
- Energy Intake
- Estradiol/adverse effects
- Female
- Humans
- Mammary Neoplasms, Experimental/etiology
- Mammary Neoplasms, Experimental/pathology
- Mammary Neoplasms, Experimental/prevention & control
- Neoplasms, Hormone-Dependent/etiology
- Neoplasms, Hormone-Dependent/genetics
- Neoplasms, Hormone-Dependent/pathology
- Neoplasms, Hormone-Dependent/prevention & control
- Rats
- Rats, Inbred ACI
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Affiliation(s)
- D M Harvell
- Eppley Institute for Research in Cancer, University of Nebraska Medical Center, Omaha, NE, USA
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