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Klappenbach CM, Wang Q, Jensen AL, Glodosky NC, Delevich K. Sex and timing of gonadectomy relative to puberty interact to influence weight, body composition, and feeding behaviors in mice. Horm Behav 2023; 151:105350. [PMID: 36996734 DOI: 10.1016/j.yhbeh.2023.105350] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 03/14/2023] [Accepted: 03/17/2023] [Indexed: 04/01/2023]
Abstract
Gonadal sex steroids are important regulators of energy balance in adult rodents, and gonadectomy (GDX) has opposing effects on weight gain in sexually mature males and females. Puberty is associated with the emergence of sex differences in weight, body composition, and feeding behaviors, yet the role of gonadal hormones at puberty remains unclear. To address this, we performed GDX or sham surgery in male and female C57Bl/6 mice at postnatal day (P)25 (prepubertal) or P60 (postpubertal) timepoints and measured weight and body composition for 35 days, after which ad libitum and operant food intake was measured using Feeding Experimentation Device 3 (FED3s) in the home cage. Consistent with previous studies, postpubertal GDX caused weight gain in females and weight loss in males and increased adiposity in both sexes. However, prepubertal GDX decreased weight gain and altered body composition across the adolescent transition (P25 to P60) in males but had no effect in females. Despite the varied effects on weight, GDX decreased food intake and motivation for food as assessed in operant tasks regardless of sex or timing of surgery relative to puberty. Our findings indicate that GDX interacts with both sex and age at surgery to influence weight, body composition, and feeding behavior.
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Affiliation(s)
- Courtney M Klappenbach
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA
| | - Qing Wang
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA
| | - Allison L Jensen
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA
| | - Nicholas C Glodosky
- Department of Psychology Washington State University, Pullman, WA 99164, USA
| | - Kristen Delevich
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA 99164, USA.
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2
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Wellberg EA, Corleto KA, Checkley LA, Jindal S, Johnson G, Higgins JA, Obeid S, Anderson SM, Thor AD, Schedin PJ, MacLean PS, Giles ED. Preventing ovariectomy-induced weight gain decreases tumor burden in rodent models of obesity and postmenopausal breast cancer. Breast Cancer Res 2022; 24:42. [PMID: 35725493 PMCID: PMC9208221 DOI: 10.1186/s13058-022-01535-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 06/01/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND Obesity and adult weight gain are linked to increased breast cancer risk and poorer clinical outcomes in postmenopausal women, particularly for hormone-dependent tumors. Menopause is a time when significant weight gain occurs in many women, and clinical and preclinical studies have identified menopause (or ovariectomy) as a period of vulnerability for breast cancer development and promotion. METHODS We hypothesized that preventing weight gain after ovariectomy (OVX) may be sufficient to prevent the formation of new tumors and decrease growth of existing mammary tumors. We tested this hypothesis in a rat model of obesity and carcinogen-induced postmenopausal mammary cancer and validated our findings in a murine xenograft model with implanted human tumors. RESULTS In both models, preventing weight gain after OVX significantly decreased obesity-associated tumor development and growth. Importantly, we did not induce weight loss in these animals, but simply prevented weight gain. In both lean and obese rats, preventing weight gain reduced visceral fat accumulation and associated insulin resistance. Similarly, the intervention decreased circulating tumor-promoting growth factors and inflammatory cytokines (i.e., BDNF, TNFα, FGF-2), with greater effects in obese compared to lean rats. In obese rats, preventing weight gain decreased adipocyte size, adipose tissue macrophage infiltration, reduced expression of the tumor-promoting growth factor FGF-1 in mammary adipose, and reduced phosphorylated FGFR indicating reduced FGF signaling in tumors. CONCLUSIONS Together, these findings suggest that the underlying mechanisms associated with the anti-tumor effects of weight maintenance are multi-factorial, and that weight maintenance during the peri-/postmenopausal period may be a viable strategy for reducing obesity-associated breast cancer risk and progression in women.
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Affiliation(s)
- Elizabeth A. Wellberg
- grid.266902.90000 0001 2179 3618Department of Pathology, Harold Hamm Diabetes Center, and Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA
| | - Karen A. Corleto
- grid.264756.40000 0004 4687 2082Department of Nutrition, Texas A&M University, College Station, TX USA
| | - L. Allyson Checkley
- grid.430503.10000 0001 0703 675XDivisions of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO USA
| | - Sonali Jindal
- grid.5288.70000 0000 9758 5690Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Knight Cancer Institute, Oregon Health & Science University, Portland, OR USA
| | - Ginger Johnson
- grid.430503.10000 0001 0703 675XDivisions of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO USA ,grid.430503.10000 0001 0703 675XAnschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, CO USA
| | - Janine A. Higgins
- grid.430503.10000 0001 0703 675XDepartment of Pediatrics, Endocrinology Section, University of Colorado Anschutz Medical Campus, Aurora, CO USA
| | - Sarina Obeid
- grid.264756.40000 0004 4687 2082Department of Nutrition, Texas A&M University, College Station, TX USA
| | - Steven M. Anderson
- grid.430503.10000 0001 0703 675XDepartment of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO USA ,grid.499234.10000 0004 0433 9255University of Colorado Cancer Center, Aurora, CO USA
| | - Ann D. Thor
- grid.430503.10000 0001 0703 675XDepartment of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO USA ,grid.499234.10000 0004 0433 9255University of Colorado Cancer Center, Aurora, CO USA
| | - Pepper J. Schedin
- grid.5288.70000 0000 9758 5690Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Knight Cancer Institute, Oregon Health & Science University, Portland, OR USA
| | - Paul S. MacLean
- grid.430503.10000 0001 0703 675XDivisions of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO USA ,grid.430503.10000 0001 0703 675XAnschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, CO USA ,grid.499234.10000 0004 0433 9255University of Colorado Cancer Center, Aurora, CO USA
| | - Erin D. Giles
- grid.214458.e0000000086837370School of Kinesiology, University of Michigan, Ann Arbor, MI USA
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3
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Glenny EM, Coleman MF, Giles ED, Wellberg EA, Hursting SD. Designing Relevant Preclinical Rodent Models for Studying Links Between Nutrition, Obesity, Metabolism, and Cancer. Annu Rev Nutr 2021; 41:253-282. [PMID: 34357792 DOI: 10.1146/annurev-nutr-120420-032437] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Diet and nutrition are intricately related to cancer prevention, growth, and treatment response. Preclinical rodent models are a cornerstone to biomedical research and remain instrumental in our understanding of the relationship between cancer and diet and in the development of effective therapeutics. However, the success rate of translating promising findings from the bench to the bedside is suboptimal. Well-designed rodent models will be crucial to improving the impact basic science has on clinical treatment options. This review discusses essential experimental factors to consider when designing a preclinical cancer model with an emphasis on incorporating these models into studies interrogating diet, nutrition, and metabolism. The aims of this review are to (a) provide insight into relevant considerations when designing cancer models for obesity, nutrition, and metabolism research; (b) identify common pitfalls when selecting a rodent model; and (c) discuss strengths and limitations of available preclinical models. Expected final online publication date for the Annual Review of Nutrition, Volume 41 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Elaine M Glenny
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA;
| | - Michael F Coleman
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA;
| | - Erin D Giles
- Department of Nutrition, Texas A&M University, College Station, Texas 77843, USA
| | - Elizabeth A Wellberg
- Department of Pathology, University of Oklahoma Health Science Center, Oklahoma City, Oklahoma 73104, USA
| | - Stephen D Hursting
- Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA; .,Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599, USA.,Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, North Carolina 28081, USA
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4
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Giles ED, Wellberg EA. Preclinical Models to Study Obesity and Breast Cancer in Females: Considerations, Caveats, and Tools. J Mammary Gland Biol Neoplasia 2020; 25:237-253. [PMID: 33146844 PMCID: PMC8197449 DOI: 10.1007/s10911-020-09463-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 10/09/2020] [Indexed: 12/28/2022] Open
Abstract
Obesity increases the risk for breast cancer and is associated with poor outcomes for cancer patients. A variety of rodent models have been used to investigate these relationships; however, key differences in experimental approaches, as well as unique aspects of rodent physiology lead to variability in how these valuable models are implemented. We combine expertise in the development and implementation of preclinical models of obesity and breast cancer to disseminate effective practices for studies that integrate these fields. In this review, we share, based on our experience, key considerations for model selection, highlighting important technical nuances and tips for use of preclinical models in studies that integrate obesity with breast cancer risk and progression. We describe relevant mouse and rat paradigms, specifically highlighting differences in breast tumor subtypes, estrogen production, and strategies to manipulate hormone levels. We also outline options for diet composition and housing environments to promote obesity in female rodents. While we have applied our experience to understanding obesity-associated breast cancer, the experimental variables we incorporate have relevance to multiple fields that investigate women's health.
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Affiliation(s)
- Erin D Giles
- Department of Nutrition, Texas A&M University, College Station, TX, USA.
| | - Elizabeth A Wellberg
- Department of Pathology, University of Oklahoma Health Science Center, Stephenson Cancer Center, Harold Hamm Diabetes Center, Oklahoma City, OK, USA
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5
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Ecker BL, Lee JY, Sterner CJ, Solomon AC, Pant DK, Shen F, Peraza J, Vaught L, Mahendra S, Belka GK, Pan TC, Schmitz KH, Chodosh LA. Impact of obesity on breast cancer recurrence and minimal residual disease. Breast Cancer Res 2019; 21:41. [PMID: 30867005 PMCID: PMC6416940 DOI: 10.1186/s13058-018-1087-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2017] [Accepted: 03/13/2018] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Obesity is associated with an increased risk of breast cancer recurrence and cancer death. Recurrent cancers arise from the pool of residual tumor cells, or minimal residual disease (MRD), that survives primary treatment and persists in the host. Whether the association of obesity with recurrence risk is causal is unknown, and the impact of obesity on MRD and breast cancer recurrence has not been reported in humans or in animal models. METHODS Doxycycline-inducible primary mammary tumors were generated in intact MMTV-rtTA;TetO-HER2/neu (MTB/TAN) mice or orthotopic recipients fed a high-fat diet (HFD; 60% kcal from fat) or a control low-fat diet (LFD; 10% kcal from fat). Following oncogene downregulation and tumor regression, mice were followed for clinical recurrence. Body weight was measured twice weekly and used to segregate HFD mice into obese (i.e., responders) and lean (i.e., nonresponders) study arms, and obesity was correlated with body fat percentage, glucose tolerance (measured using intraperitoneal glucose tolerance tests), serum biomarkers (measured by enzyme-linked immunosorbent assay), and tissue transcriptomics (assessed by RNA sequencing). MRD was quantified by droplet digital PCR. RESULTS HFD-Obese mice weighed significantly more than HFD-Lean and LFD control mice (p < 0.001) and had increased body fat percentage (p < 0.001). Obese mice exhibited fasting hyperglycemia, hyperinsulinemia, and impaired glucose tolerance, as well as decreased serum levels of adiponectin and increased levels of leptin, resistin, and insulin-like growth factor 1. Tumor recurrence was accelerated in HFD-Obese mice compared with HFD-Lean and LFD control mice (median relapse-free survival 53.0 days vs. 87.0 days vs. 80.0 days, log-rank p < 0.001; HFD-Obese compared with HFD-Lean HR 2.52, 95% CI 1.52-4.16; HFD-Obese compared with LFD HR 2.27, 95% CI 1.42-3.63). HFD-Obese mice harbored a significantly greater number of residual tumor cells than HFD-Lean and LFD mice (12,550 ± 991 vs. 7339 ± 2182 vs. 4793 ± 1618 cells, p < 0.001). CONCLUSION These studies provide a genetically engineered mouse model for study of the association of diet-induced obesity with breast cancer recurrence. They demonstrate that this model recapitulates physiological changes characteristic of obese patients, establish that the association between obesity and recurrence risk is causal in nature, and suggest that obesity is associated with the increased survival and persistence of residual tumor cells.
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MESH Headings
- Animals
- Body Mass Index
- Body Weight
- Breast Neoplasms/mortality
- Breast Neoplasms/pathology
- Cell Line, Tumor/transplantation
- Datasets as Topic
- Diet, High-Fat/adverse effects
- Disease-Free Survival
- Female
- Humans
- Mammary Neoplasms, Experimental/genetics
- Mammary Neoplasms, Experimental/mortality
- Mammary Neoplasms, Experimental/pathology
- Mice, Obese
- Mice, Transgenic
- Neoplasm Recurrence, Local/mortality
- Neoplasm Recurrence, Local/pathology
- Neoplasm, Residual
- Obesity/etiology
- Obesity/pathology
- Receptor, ErbB-2/genetics
- Survival Analysis
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Affiliation(s)
- Brett L. Ecker
- Department of Surgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
| | - Jun Y. Lee
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
| | - Christopher J. Sterner
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
| | - Aaron C. Solomon
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
| | - Dhruv K. Pant
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
| | - Fei Shen
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
| | - Javier Peraza
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
| | - Lauren Vaught
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
| | - Samyukta Mahendra
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
| | - George K. Belka
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
| | - Tien-chi Pan
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
| | - Kathryn H. Schmitz
- Penn State Cancer Institute, Penn State College of Medicine, Hershey, PA 17033 USA
| | - Lewis A. Chodosh
- Department of Cancer Biology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA USA
- 2-PREVENT Translational Center of Excellence, Abramson Cancer Center, University of Pennsylvania, Philadelphia, PA USA
- The Abramson Family Cancer Research Institute, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104-6160 USA
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Giles ED, Jindal S, Wellberg EA, Schedin T, Anderson SM, Thor AD, Edwards DP, MacLean PS, Schedin P. Metformin inhibits stromal aromatase expression and tumor progression in a rodent model of postmenopausal breast cancer. Breast Cancer Res 2018; 20:50. [PMID: 29898754 PMCID: PMC6000949 DOI: 10.1186/s13058-018-0974-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2017] [Accepted: 04/30/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Obesity and type II diabetes are linked to increased breast cancer risk in postmenopausal women. Patients treated with the antidiabetic drug metformin for diabetes or metabolic syndrome have reduced breast cancer risk, a greater pathologic complete response to neoadjuvant therapy, and improved breast cancer survival. We hypothesized that metformin may be especially effective when targeted to the menopausal transition, as this is a lifecycle window when weight gain and metabolic syndrome increase, and is also when the risk for obesity-related breast cancer increases. METHODS Here, we used an 1-methyl-1-nitrosourea (MNU)-induced mammary tumor rat model of estrogen receptor (ER)-positive postmenopausal breast cancer to evaluate the long-term effects of metformin administration on metabolic and tumor endpoints. In this model, ovariectomy (OVX) induces rapid weight gain, and an impaired whole-body response to excess calories contributes to increased tumor glucose uptake and increased tumor proliferation. Metformin treatment was initiated in tumor-bearing animals immediately prior to OVX and maintained for the duration of the study. RESULTS Metformin decreased the size of existing mammary tumors and inhibited new tumor formation without changing body weight or adiposity. Decreased lipid accumulation in the livers of metformin-treated animals supports the ability of metformin to improve overall metabolic health. We also found a decrease in the number of aromatase-positive, CD68-positive macrophages within the tumor microenvironment, suggesting that metformin targets the immune microenvironment in addition to improving whole-body metabolism. CONCLUSIONS These findings suggest that peri-menopause/menopause represents a unique window of time during which metformin may be highly effective in women with established, or at high risk for developing, breast cancer.
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Affiliation(s)
- Erin D Giles
- Department of Nutrition & Food Science, Texas A&M University, 373 Olsen Blvd; 2253 TAMU, College Station, TX, 77843, USA.
| | - Sonali Jindal
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Rd, Mailing Code: L215, Portland, OR, 97239, USA
| | - Elizabeth A Wellberg
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Troy Schedin
- Department of Medical Oncology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Steven M Anderson
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Ann D Thor
- Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Dean P Edwards
- Departments of Molecular & Cellular Biology and Pathology Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Paul S MacLean
- Anschutz Health & Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.,Department of Medicine, Divisions of Endocrinology, Metabolism, and Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.,Department of Pathology, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Pepper Schedin
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Rd, Mailing Code: L215, Portland, OR, 97239, USA.,Knight Cancer Institute, Oregon Health & Science University, 1130 NW 22nd Ave #100, Portland, OR, 97239, USA
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7
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Sherk VD, Jackman MR, Giles ED, Higgins JA, Foright RM, Presby DM, Johnson GC, Houck JA, Houser JL, Oljira R, MacLean PS. Prior weight loss exacerbates the biological drive to gain weight after the loss of ovarian function. Physiol Rep 2018; 5:e13272. [PMID: 28533263 PMCID: PMC5449558 DOI: 10.14814/phy2.13272] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 02/01/2023] Open
Abstract
Both the history of obesity and weight loss may change how menopause affects metabolic health. The purpose was to determine whether obesity and/or weight loss status alters energy balance (EB) and subsequent weight gain after the loss of ovarian function. Female lean and obese Wistar rats were randomized to 15% weight loss (WL) or ad libitum fed controls (CON). After the weight loss period, WL rats were kept in EB at the reduced weight for 8 weeks prior to ovariectomy (OVX). After OVX, all rats were allowed to eat ad libitum until weight plateaued. Energy intake (EI), spontaneous physical activity, and total energy expenditure (TEE) were measured with indirect calorimetry before OVX, immediately after OVX, and after weight plateau. Changes in energy intake (EI), TEE, and weight gain immediately after OVX were similar between lean and obese rats. However, obese rats gained more total weight and fat mass than lean rats over the full regain period. Post-OVX, EI increased more (P ≤ 0.03) in WL rats (58.9 ± 3.5 kcal/d) than CON rats (8.5 ± 5.2 kcal/d), and EI partially normalized (change from preOVX: 20.5 ± 4.2 vs. 1.5 ± 4.9 kcal/day) by the end of the study. As a result, WL rats gained weight (week 1:44 ± 20 vs. 7 ± 25 g) more rapidly (mean = 44 ± 20 vs. 7 ± 25 g/week; P < 0.001) than CON Prior obesity did not affect changes in EB or weight regain following OVX, whereas a history of weight loss prior to OVX augmented disruptions in EB after OVX, resulting in more rapid weight regain.
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Affiliation(s)
- Vanessa D Sherk
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Matthew R Jackman
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Erin D Giles
- Department of Nutrition & Food Science, Texas A&M University, College Station, Texas
| | - Janine A Higgins
- Section of Endocrinology, Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Rebecca M Foright
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - David M Presby
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Ginger C Johnson
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Julie A Houck
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Jordan L Houser
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Robera Oljira
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
| | - Paul S MacLean
- Division of Endocrinology, Metabolism, and Diabetes, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado
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8
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Banin RM, de Andrade IS, Cerutti SM, Oyama LM, Telles MM, Ribeiro EB. Ginkgo biloba Extract (GbE) Stimulates the Hypothalamic Serotonergic System and Attenuates Obesity in Ovariectomized Rats. Front Pharmacol 2017; 8:605. [PMID: 28928661 PMCID: PMC5591947 DOI: 10.3389/fphar.2017.00605] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 08/21/2017] [Indexed: 11/13/2022] Open
Abstract
Menopause is associated with increased risk to develop obesity but the mechanisms involved are not fully understood. We have shown that Ginkgo biloba extract (GbE) improved diet-induced obesity. Since GbE might be effective in the treatment of obesity related to menopause, avoiding the side effects of hormone replacement therapy, we investigated the effect of GbE on hypothalamic systems controlling energy homeostasis. Wistar rats were either ovariectomized (OVX) or Sham-operated. After 2 months, either 500 mg.kg-1 of GbE or vehicle were administered daily by gavage for 14 days. A subset of animals received an intracerebroventricular (i.c.v.) injection of serotonin (300 μg) or vehicle and food intake was measured after 12 and 24 h. Another subset was submitted to in vivo microdialysis and 5-HT levels of the medial hypothalamus were measured by high performance liquid chromatography, before and up to 2 h after the administration of 500 mg.kg-1 of GbE. Additional animals were used for quantification of 5-HT1A, 5-HT1B, 5-HT2C, 5-HTT, and pro-opiomelanocortin hypothalamic protein levels by Western blotting. OVX increased food intake and body weight and adiposity while GbE attenuated these alterations. i.c.v. serotonin significantly reduced food intake in Sham, Sham + GbE, and OVX + GbE groups while it failed to do so in the OVX group. In the OVX rats, GbE stimulated 5-HT microdialysate levels while it reduced hypothalamic 5-HTT protein levels. The results indicate that GbE improved the ovariectomy-induced resistance to serotonin hypophagia, at least in part through stimulation of the hypothalamic serotonergic activity. Since body weight gain is one of the most important consequences of menopause, the stimulation of the serotonergic transmission by GbE may represent a potential alternative therapy for menopause-related obesity.
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Affiliation(s)
- Renata M Banin
- Disciplina de Fisiologia da Nutrição, Departamento de Fisiologia, Universidade Federal de São PauloSão Paulo, Brazil.,Setor de Morfofisiologia e Patologia, Departamento de Ciências Biológicas, Universidade Federal de São PauloDiadema, Brazil
| | - Iracema S de Andrade
- Disciplina de Fisiologia da Nutrição, Departamento de Fisiologia, Universidade Federal de São PauloSão Paulo, Brazil
| | - Suzete M Cerutti
- Setor de Morfofisiologia e Patologia, Departamento de Ciências Biológicas, Universidade Federal de São PauloDiadema, Brazil
| | - Lila M Oyama
- Disciplina de Fisiologia da Nutrição, Departamento de Fisiologia, Universidade Federal de São PauloSão Paulo, Brazil
| | - Mônica M Telles
- Disciplina de Fisiologia da Nutrição, Departamento de Fisiologia, Universidade Federal de São PauloSão Paulo, Brazil.,Setor de Morfofisiologia e Patologia, Departamento de Ciências Biológicas, Universidade Federal de São PauloDiadema, Brazil
| | - Eliane B Ribeiro
- Disciplina de Fisiologia da Nutrição, Departamento de Fisiologia, Universidade Federal de São PauloSão Paulo, Brazil
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9
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The Androgen Receptor Supports Tumor Progression After the Loss of Ovarian Function in a Preclinical Model of Obesity and Breast Cancer. Discov Oncol 2017; 8:269-285. [PMID: 28741260 DOI: 10.1007/s12672-017-0302-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/26/2017] [Accepted: 07/06/2017] [Indexed: 12/13/2022] Open
Abstract
The androgen receptor (AR) has context-dependent roles in breast cancer growth and progression. Overall, high tumor AR levels predict a favorable patient outcome, but several studies have established a tumor promotional role for AR, particularly in supporting the growth of estrogen receptor positive (ER-positive) breast cancers after endocrine therapy. Our previous studies have demonstrated that obesity promotes mammary tumor progression after ovariectomy (OVX) in a rat model of postmenopausal breast cancer. Here, we investigated a potential role for AR in obesity-associated post-OVX mammary tumor progression following ovarian estrogen loss. In this model, we found that obese but not lean rats had nuclear localized AR in tumors that progressed 3 weeks after OVX, compared to those that regressed. AR nuclear localization is consistent with activation of AR-dependent transcription. Longer-term studies (8 weeks post-OVX) showed that AR nuclear localization and expression were maintained in tumors that had progressed, but AR expression was nearly lost in tumors that were regressing. The anti-androgen enzalutamide effectively blocked tumor progression in obese rats by promoting tumor necrosis and also prevented the formation of new tumors after OVX. Neither circulating nor mammary adipose tissue levels of the AR ligand testosterone were elevated in obese compared to lean rats; however, IL-6, which we previously reported to be higher in plasma from obese versus lean rats, sensitized breast cancer cells to low levels of testosterone. Our study demonstrates that, in the context of obesity, AR plays a role in driving ER-positive mammary tumor progression in an environment of low estrogen availability, and that circulating factors unique to the obese host, including IL-6, may influence how cancer cells respond to steroid hormones.
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10
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Checkley LA, Rudolph MC, Wellberg EA, Giles ED, Wahdan-Alaswad RS, Houck JA, Edgerton SM, Thor AD, Schedin P, Anderson SM, MacLean PS. Metformin Accumulation Correlates with Organic Cation Transporter 2 Protein Expression and Predicts Mammary Tumor Regression In Vivo. Cancer Prev Res (Phila) 2017; 10:198-207. [PMID: 28154203 DOI: 10.1158/1940-6207.capr-16-0211-t] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 01/19/2017] [Accepted: 01/20/2017] [Indexed: 02/07/2023]
Abstract
Several epidemiologic studies have associated metformin treatment with a reduction in breast cancer incidence in prediabetic and type II diabetic populations. Uncertainty exists regarding which patient populations and/or tumor subtypes will benefit from metformin treatment, and most preclinical in vivo studies have given little attention to the cellular pharmacology of intratumoral metformin uptake. Epidemiologic reports consistently link western-style high fat diets (HFD), which drive overweight and obesity, with increased risk of breast cancer. We used a rat model of HFD-induced overweight and mammary carcinogenesis to define intratumoral factors that confer metformin sensitivity. Mammary tumors were initiated with 1-methyl-1-nitrosourea, and rats were randomized into metformin-treated (2 mg/mL drinking water) or control groups (water only) for 8 weeks. Two-thirds of existing mammary tumors responded to metformin treatment with decreased tumor volumes (P < 0.05), reduced proliferative index (P < 0.01), and activated AMPK (P < 0.05). Highly responsive tumors accumulated 3-fold greater metformin amounts (P < 0.05) that were positively correlated with organic cation transporter-2 (OCT2) protein expression (r = 0.57; P = 0.038). Importantly, intratumoral metformin concentration negatively associated with tumor volume (P = 0.03), and each 10 pmol increase in intratumoral metformin predicted >0.11 cm3 reduction in tumor volume. Metformin treatment also decreased proinflammatory arachidonic acid >1.5-fold in responsive tumors (P = 0.023). Collectively, these preclinical data provide evidence for a direct effect of metformin in vivo and suggest that OCT2 expression may predict metformin uptake and tumor response. Cancer Prev Res; 10(3); 198-207. ©2017 AACR.
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Affiliation(s)
- L Allyson Checkley
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Michael C Rudolph
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Elizabeth A Wellberg
- Department of Pathology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Erin D Giles
- Department of Nutrition and Food Science, Texas A&M University, College Station, Texas
| | - Reema S Wahdan-Alaswad
- Department of Pathology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Julie A Houck
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Susan M Edgerton
- Department of Pathology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Ann D Thor
- Department of Pathology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Pepper Schedin
- Department of Cell, Developmental and Cancer Biology, Oregon Health & Science University, Portland, Oregon.,Knight Cancer Institute, Oregon Health & Science University, Portland, Oregon
| | - Steven M Anderson
- Department of Pathology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
| | - Paul S MacLean
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado. .,Department of Pathology, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado.,Center for Human Nutrition, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado
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11
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Giles ED, Jackman MR, MacLean PS. Modeling Diet-Induced Obesity with Obesity-Prone Rats: Implications for Studies in Females. Front Nutr 2016; 3:50. [PMID: 27933296 PMCID: PMC5121240 DOI: 10.3389/fnut.2016.00050] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 10/28/2016] [Indexed: 12/03/2022] Open
Abstract
Obesity is a worldwide epidemic, and the comorbidities associated with obesity are numerous. Over the last two decades, we and others have employed an outbred rat model to study the development and persistence of obesity, as well as the metabolic complications that accompany excess weight. In this review, we summarize the strengths and limitations of this model and how it has been applied to further our understanding of human physiology in the context of weight loss and weight regain. We also discuss how the approach has been adapted over time for studies in females and female-specific physiological conditions, such as menopause and breast cancer. As excess weight and the accompanying metabolic complications have become common place in our society, we expect that this model will continue to provide a valuable translational tool to establish physiologically relevant connections to the basic science studies of obesity and body weight regulation.
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Affiliation(s)
- Erin D Giles
- Department of Nutrition and Food Science, Texas A&M University , College Station, TX , USA
| | - Matthew R Jackman
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Paul S MacLean
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, CO, USA; Division of Endocrinology, Diabetes and Metabolism, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
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12
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The Obesity-Breast Cancer Conundrum: An Analysis of the Issues. Int J Mol Sci 2016; 17:ijms17060989. [PMID: 27338371 PMCID: PMC4926517 DOI: 10.3390/ijms17060989] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 06/09/2016] [Accepted: 06/15/2016] [Indexed: 02/07/2023] Open
Abstract
Breast cancer develops over a timeframe of 2-3 decades prior to clinical detection. Given this prolonged latency, it is somewhat unexpected from a biological perspective that obesity has no effect or reduces the risk for breast cancer in premenopausal women yet increases the risk for breast cancer in postmenopausal women. This conundrum is particularly striking in light of the generally negative effects of obesity on breast cancer outcomes, including larger tumor size at diagnosis and poorer prognosis in both pre- and postmenopausal women. This review and analysis identifies factors that may contribute to this apparent conundrum, issues that merit further investigation, and characteristics of preclinical models for breast cancer and obesity that should be considered if animal models are used to deconstruct the conundrum.
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13
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Mattheis L, Jung JS, Hiebl B, Garrels W, Kielstein H, Spielmann J. Perioperative support reduces mortality of obese BALB/c mice after ovariectomy. Lab Anim (NY) 2016; 45:262-7. [PMID: 27327014 DOI: 10.1038/laban.1042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 11/24/2015] [Indexed: 01/22/2023]
Abstract
The incidence of obesity is on the rise in most western countries and represents major risks to health. Obesity causes complex metabolic dysfunctions and can be associated with a large number of secondary diseases. To investigate causal mechanisms of obesity and develop better options for treatment, researchers study the condition in animal models. In addition to genetically engineered animal models, diet-induced obesity is often used because it occurs similarly in animals as it does in humans. For several types of investigations that use obesity models, investigators must carry out surgical interventions and they frequently encounter severe perioperative complications induced by anesthesia. In an example of this problem, we observed 100% mortality in obese BALB/c mice after ovariectomy, despite no obvious surgical complications. We supposed that a failure to recover from surgery was the primary cause of this increased mortality. Therefore, to support their recovery from surgery we administered atropine to obese mice in order to facilitate blood circulation, and we also increased the oxygen content of the ambient air. With this specific support before and after surgery, we increased the survival rate of obese ovariectomized mice up to 83%. These results confirm the assumption that obesity is a risk factor for the recovery of obese animal models after ovariectomy, and they highlight the need to provide additional interventions for such experimental animals.
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Affiliation(s)
- Laura Mattheis
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Juliane-Susanne Jung
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Bernhard Hiebl
- Center for Medical Basic Research, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Wiebke Garrels
- Laboratory Animal Science, Hannover Medical School, Hannover, Germany
| | - Heike Kielstein
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Julia Spielmann
- Department of Anatomy and Cell Biology, Martin Luther University Halle-Wittenberg, Halle, Germany
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14
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The role of ovarian sex steroids in metabolic homeostasis, obesity, and postmenopausal breast cancer: molecular mechanisms and therapeutic implications. BIOMED RESEARCH INTERNATIONAL 2015; 2015:140196. [PMID: 25866757 PMCID: PMC4383469 DOI: 10.1155/2015/140196] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/06/2014] [Indexed: 12/20/2022]
Abstract
Obese postmenopausal women have an increased risk of breast cancer and are likely to have a worse prognosis than nonobese postmenopausal women. The cessation of ovarian function after menopause results in withdrawal of ovarian sex steroid hormones, estrogen, and progesterone. Accumulating evidence suggests that the withdrawal of estrogen and progesterone causes homeostasis imbalances, including decreases in insulin sensitivity and leptin secretion and changes in glucose and lipid metabolism, resulting in a total reduction in energy expenditure. Together with a decrease in physical activity and consumption of a high fat diet, these factors significantly contribute to obesity in postmenopausal women. Obesity may contribute to breast cancer development through several mechanisms. Obesity causes localized inflammation, an increase in local estrogen production, and changes in cellular metabolism. In addition, obese women have a higher risk of insulin insensitivity, and an increase in insulin and other growth factor secretion. In this review, we describe our current understanding of the molecular actions of estrogen and progesterone and their contributions to cellular metabolism, obesity, inflammation, and postmenopausal breast cancer. We also discuss how modifications of estrogen and progesterone actions might be used as a therapeutic approach for obesity and postmenopausal breast cancer.
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15
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Matthews SB, Zhu Z, Jiang W, McGinley JN, Neil ES, Thompson HJ. Excess weight gain accelerates 1-methyl-1-nitrosourea-induced mammary carcinogenesis in a rat model of premenopausal breast cancer. Cancer Prev Res (Phila) 2014; 7:310-8. [PMID: 24441676 DOI: 10.1158/1940-6207.capr-13-0297] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In contrast to the null effects generally reported, high-risk premenopausal women (Gail score ≥1.66) enrolled in the Breast Cancer Prevention P-1 Trial were recently reported to be at increased risk for breast cancer when overweight (HR = 1.59) or obese (HR = 1.70). To investigate this clinical observation in a preclinical setting, ovary-intact female rats were intraperitoneally injected with 50 mg/kg 1-methyl-1-nitrosourea at 21 days of age to simulate premenopausal women with increased risk. Two commercially available strains of Sprague-Dawley rat (Taconic Farms) were used, which are dietary resistant (DR) or dietary susceptible (DS) to excess weight gain when fed a purified diet containing 32% kcal from fat, similar to levels consumed by the typical American woman. DS rats were approximately 15.5% heavier than DR rats at study termination and plasma leptin indicated a marked difference in adiposity. DS rats had higher incidence (26% increase), multiplicity (2.5-fold increase), and burden (5.4-fold increase) of mammary carcinomas with a concomitant reduction in cancer latency (16% earlier detection) compared with DR rats (P < 0.001 for all analyses), and displayed a higher proportion of hormone receptor negative tumors compared with DR rats [OR = 1.78; 95% confidence interval (CI), 0.83-3.81]. Circulating levels of several breast cancer-risk factors, including leptin, adiponectin:leptin ratio, insulin, insulin-like growth factor (IGF)-1, IGF-1:IGF-1 binding protein-3 ratio, and calculated insulin resistance (HOMA-IR) were negatively impacted in DS rats (P < 0.05 for all analyses). These findings support further investigation of the effects of excess weight in high-risk premenopausal women and demonstrate a useful preclinical model for rapid evaluation of mechanistic hypotheses.
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Affiliation(s)
- Shawna B Matthews
- 111 Shepardson Building, 1173 Campus Delivery, Colorado State University, Fort Collins, CO 80523-1173.
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16
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Cleary MP. Impact of obesity on development and progression of mammary tumors in preclinical models of breast cancer. J Mammary Gland Biol Neoplasia 2013; 18:333-43. [PMID: 24122258 PMCID: PMC4296516 DOI: 10.1007/s10911-013-9300-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 09/24/2013] [Indexed: 12/29/2022] Open
Abstract
Overweight and/or obesity are known risk factors for postmenopausal breast cancer. More recently increased body weight has also been associated with poor prognosis for premenopausal breast cancer. This relationship has primarily been identified through epidemiological studies. Additional information from in vitro studies has also been produced in attempts to delineate mechanisms of action for the association of obesity and body weight and breast cancer. This approach has identified potential growth factors such as insulin, leptin, estrogen and IGF-I which are reported to be modulated by body weight changes. However, in vitro studies are limited in scope and frequently use non-physiological concentrations of growth factors, while long follow-up is needed for human studies. Preclinical animal models provide an intermediary approach to investigate the impact of body weight and potential growth factors on mammary/breast tumor development and progression. Here results of a number of studies addressing this issue are presented. In the majority of the studies either genetically-obese or diet-induced obese rodent models have been used to investigate spontaneous, transgenic and carcinogen-induced mammary tumor development. To study tumor progression the major focus has been allograft studies in mice with either genetic or dietary-induced obesity. In general, obesity has been demonstrated to shorten mammary tumor latency and to impact tumor pathology. However, in rodents with defects in leptin and other growth factors the impact of obesity is not as straightforward. Future studies using more physiologically relevant obesity models and clearly distinguishing diet composition from body weight effects will be important in continuing to understand the factors associated with body weight's impact on mammary/breast cancer development and progression.
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Affiliation(s)
- Margot P. Cleary
- The Hormel Institute University of Minnesota 801 16th Avenue NE Austin, MN 55912 507-434-6952,
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17
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Martinson HA, Lyons TR, Giles ED, Borges VF, Schedin P. Developmental windows of breast cancer risk provide opportunities for targeted chemoprevention. Exp Cell Res 2013; 319:1671-8. [PMID: 23664839 PMCID: PMC3980135 DOI: 10.1016/j.yexcr.2013.04.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 04/26/2013] [Accepted: 04/28/2013] [Indexed: 12/12/2022]
Abstract
The magnitude of the breast cancer problem implores researchers to aggressively investigate prevention strategies. However, several barriers currently reduce the feasibility of breast cancer prevention. These barriers include the inability to accurately predict future breast cancer diagnosis at the individual level, the need for improved understanding of when to implement interventions, uncertainty with respect to optimal duration of treatment, and negative side effects associated with currently approved chemoprevention therapies. None-the-less, the unique biology of the mammary gland, with its postnatal development and conditional terminal differentiation, may permit the resolution of many of these barriers. Specifically, lifecycle-specific windows of breast cancer risk have been identified that may be amenable to risk-reducing strategies. Here, we argue for prevention research focused on two of these lifecycle windows of risk: postpartum mammary gland involution and peri-menopause. We provide evidence that these windows are highly amenable to targeted, limited duration treatments. Such approaches could result in the prevention of postpartum and postmenopausal breast cancers, correspondingly.
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Affiliation(s)
- Holly A Martinson
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, MS8117, RC1S, 8401K, 12801 East 17th Avenue, Aurora, CO 80045, USA; Program in Cancer Biology, University of Colorado Anschutz Medical Campus, MS8104, RC1S, 5117, 12801 East 17th Avenue, Aurora, CO 80045, USA
| | - Traci R Lyons
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, MS8117, RC1S, 8401K, 12801 East 17th Avenue, Aurora, CO 80045, USA
| | - Erin D Giles
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Anschutz Medical Campus School of Medicine, RC1S, Room 7103, 12801 East 17th Avenue, Mail Stop 8106, Aurora, CO 80045, USA; Anschutz Health and Wellness Center, 12348 East Montview Boulevard, Campus Box C263, Aurora, CO 80045, USA
| | - Virginia F Borges
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, MS8117, RC1S, 8401K, 12801 East 17th Avenue, Aurora, CO 80045, USA; University of Colorado Cancer Center, Building 500, Suite 6004C, 13001 East 17th Place, Aurora, CO 80045, USA; Young Women's Breast Cancer Translational Program, University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, 1665 Aurora Court, Aurora, CO 80045, USA
| | - Pepper Schedin
- Department of Medicine, Division of Medical Oncology, University of Colorado Anschutz Medical Campus, MS8117, RC1S, 8401K, 12801 East 17th Avenue, Aurora, CO 80045, USA; Program in Cancer Biology, University of Colorado Anschutz Medical Campus, MS8104, RC1S, 5117, 12801 East 17th Avenue, Aurora, CO 80045, USA; University of Colorado Cancer Center, Building 500, Suite 6004C, 13001 East 17th Place, Aurora, CO 80045, USA; Young Women's Breast Cancer Translational Program, University of Colorado Cancer Center, University of Colorado Anschutz Medical Campus, 1665 Aurora Court, Aurora, CO 80045, USA.
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18
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Giles ED, Wellberg EA, Astling DP, Anderson SM, Thor AD, Jindal S, Tan AC, Schedin PS, Maclean PS. Obesity and overfeeding affecting both tumor and systemic metabolism activates the progesterone receptor to contribute to postmenopausal breast cancer. Cancer Res 2012; 72:6490-501. [PMID: 23222299 DOI: 10.1158/0008-5472.can-12-1653] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Obese postmenopausal women have increased risk of breast cancers with poorer clinical outcomes than their lean counterparts. However, the mechanisms underlying these associations are poorly understood. Rodent model studies have recently identified a period of vulnerability for mammary cancer promotion, which emerges during weight gain after the loss of ovarian function (surgical ovariectomy; OVX). Thus, a period of transient weight gain may provide a life cycle-specific opportunity to prevent or treat postmenopausal breast cancer. We hypothesized that a combination of impaired metabolic regulation in obese animals prior to OVX plus an OVX-induced positive energy imbalance might cooperate to drive tumor growth and progression. To determine if lean and obese rodents differ in their metabolic response to OVX-induced weight gain, and whether this difference affects later mammary tumor metabolism, we performed a nutrient tracer study during the menopausal window of vulnerability. Lean animals preferentially deposited excess nutrients to mammary and peripheral tissues rather than to the adjacent tumors. Conversely, obese animals deposited excess nutrients into the tumors themselves. Notably, tumors from obese animals also displayed increased expression of the progesterone receptor (PR). Elevated PR expression positively correlated with tumor expression of glycolytic and lipogenic enzymes, glucose uptake, and proliferation markers. Treatment with the antidiabetic drug metformin during ovariectomy-induced weight gain caused tumor regression and downregulation of PR expression in tumors. Clinically, expression array analysis of breast tumors from postmenopausal women revealed that PR expression correlated with a similar pattern of metabolic upregulation, supporting the notion that PR+ tumors have enhanced metabolic capacity after menopause. Our findings have potential explanative power in understanding why obese, postmenopausal women display an increased risk of breast cancer.
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Affiliation(s)
- Erin D Giles
- Anschutz Health and Wellness Center, University of Colorado Anschutz Medical Campus, Aurora, Colorado 80045, USA
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19
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Inagaki T, Kaneko N, Zukin RS, Castillo PE, Etgen AM. Estradiol attenuates ischemia-induced death of hippocampal neurons and enhances synaptic transmission in aged, long-term hormone-deprived female rats. PLoS One 2012; 7:e38018. [PMID: 22675505 PMCID: PMC3366987 DOI: 10.1371/journal.pone.0038018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2012] [Accepted: 05/02/2012] [Indexed: 11/18/2022] Open
Abstract
Background Transient global forebrain ischemia causes selective, delayed death of hippocampal CA1 pyramidal neurons, and the ovarian hormone 17β-estradiol (E2) reduces neuronal loss in young and middle-aged females. The neuroprotective efficacy of E2 after a prolonged period of hormone deprivation is controversial, and few studies examine this issue in aged animals given E2 treatment after induction of ischemia. Methodology/Principal Findings The present study investigated the neuroprotective effects of E2 administered immediately after global ischemia in aged female rats (15–18 months) after 6 months of hormone deprivation. We also used electrophysiological methods to assess whether CA1 synapses in the aging hippocampus remain responsive to E2 after prolonged hormone withdrawal. Animals were ovariohysterectomized and underwent 10 min global ischemia 6 months later. A single dose of E2 (2.25 µg) infused intraventricularly after reperfusion significantly increased cell survival, with 45% of CA1 neurons surviving vs 15% in controls. Ischemia also induced moderate loss of CA3/CA4 pyramidal cells. Bath application of 1 nM E2 onto brain slices derived from non-ischemic aged females after 6 months of hormone withdrawal significantly enhanced excitatory transmission at CA1 synapses evoked by Schaffer collateral stimulation, and normal long-term potentiation (LTP) was induced. The magnitude of LTP and of E2 enhancement of field excitatory postsynaptic potentials was indistinguishable from that recorded in slices from young rats. Conclusions/Significance The data demonstrate that 1) acute post-ischemic infusion of E2 into the brain ventricles is neuroprotective in aged rats after 6 months of hormone deprivation; and 2) E2 enhances synaptic transmission in CA1 pyramidal neurons of aged long-term hormone deprived females. These findings provide evidence that the aging hippocampus remains responsive to E2 administered either in vivo or in vitro even after prolonged periods of hormone withdrawal.
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Affiliation(s)
- Tomoko Inagaki
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Naoki Kaneko
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - R. Suzanne Zukin
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Pablo E. Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Anne M. Etgen
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
- * E-mail:
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20
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Giles ED, Jackman MR, Johnson GC, Schedin PJ, Houser JL, MacLean PS. Effect of the estrous cycle and surgical ovariectomy on energy balance, fuel utilization, and physical activity in lean and obese female rats. Am J Physiol Regul Integr Comp Physiol 2010; 299:R1634-42. [PMID: 20926768 DOI: 10.1152/ajpregu.00219.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This study presents an in-depth analysis of the effects of obesity on energy balance (EB) and fuel utilization in adult female rats, over the estrous cycle and immediately after surgical ovariectomy (OVX), to model pre- and postmenopausal states, respectively. Female Wistar rats were fed a high-fat (46%) diet for 16 wk to produce mature lean and obese animals. Stage of estrous was identified by daily vaginal lavage, while energy intake (EI), total energy expenditure (TEE), and fuel utilization were monitored in a multichamber indirect calorimeter and activity was monitored by infrared beam breaks. Metabolic monitoring studies were repeated during the 3-wk period of rapid OVX-induced weight gain. Component analysis of TEE was performed to determine the nonresting and resting portions of energy expenditure. Obesity was associated with a greater fluctuation in EB across the estrous cycle. Cycling obese rats were less active, expended more energy per movement, and oxidized more carbohydrate than lean rats. The changes in EB over the cycle in lean and obese rats were driven by changes in EI. Finally, OVX induced a large positive energy imbalance in obese and lean rats. This resulted primarily from an increase in EI in both groups, with little change in TEE following OVX. These observations reveal a dominant effect of obesity on EB, fuel utilization, and activity levels in cycling rats, which has implications for studies focused on obesity and EB in female rodents.
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Affiliation(s)
- Erin D Giles
- Center for Human Nutrition, Univ. of Colorado Denver, 12800 East 19 Ave., Aurora, CO 80045, USA
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