Abstract
Findings in BRCA1 mutation carriers suggest that physical activity, particularly during childhood, may be linked to a reduced risk of developing breast cancer. We investigated whether physical activity at puberty alters the expression of BRCA1 and two other tumor suppressor genes—p53 and estrogen receptor (ER)-β—in rats. In addition, the effects on ER-α expression, mammary proliferation and functional epithelial differentiation were investigated as markers of altered mammary cancer risk in rats exposed to regular physical activity at puberty. Female Sprague Dawley rat pups were randomized to voluntary exercise, sham-exercise control and non-manipulated control groups. Treadmill training (20–25 m/min, 15% grade, 30 min/day, 5 days/week) started on postnatal day 14 and continued through day 32. Third thoracic mammary glands (n = 5 per group and age) were obtained at days 32, 48 and 100 and assessed for changes in morphology through wholemounts, and at 100 days cell proliferation by using Ki67 staining, protein levels of ER-α and ER-β by immunohistochemistry, and mRNA expression levels of BRCA1, p53, ER-α and ER-β by real-time PCR. Mammary glands of rats exposed to exercise during puberty contained fewer terminal end buds (TEBs) and a higher number of differentiated alveolar buds and lobules than the sham controls. However, cell proliferation was not significantly altered among the groups. ER-α protein levels were significantly reduced, while ER-β levels were increased in the mammary ducts and lobular epithelial structures of 100-day old rays which were voluntarily exercised at puberty, compared to sham controls. ER-β, BRCA1 and p53 mRNA levels were significantly higher in the mammary glands of 100-day-old exercised versus sham control rats. Pubertal physical activity reduced mammary epithelial targets for neoplastic transformation through epithelial differentiation and it also up-regulated tumor suppressor genes BRCA1, p53 and ER-β, and reduced ER-α/ER-β ratio in the mammary gland. It remains to be determined whether the up-regulation of BRCA1, and perhaps p53, explains the protective effect of childhood physical activity against breast cancer in women who carry a germline mutation in one of the BRCA1 alleles.
References
Friedenreich CM, Courneya KS, Bryant HE (2001) Influence of physical activity in different age and life periods on the risk of breast cancer. Epidemiology 12:604–612. doi:10.1097/00001648-200111000-00005
Lagerros YT, Hsieh SF, Hsieh CC (2004) Physical activity in adolescence and young adulthood and breast cancer risk: a quantitative review. Eur J Cancer Prev 13:5–12. doi:10.1097/00008469-200402000-00002
King MC, Marks JH, Mandell JB (2003) Breast and ovarian cancer risks due to inherited mutations in BRCA1 and BRCA2. Science 302:643–646. doi:10.1126/science.1088759
Hulver MW, Houmard JA (2003) Plasma leptin and exercise: recent findings. Sports Med 33:473–482. doi:10.2165/00007256-200333070-00001
McTiernan A, Wu L, Chen C, Chlebowski R, Mossavar-Rahmani Y, Modugno F et al (2006) Relation of BMI and physical activity to sex hormones in postmenopausal women. Obesity (Silver Spring) 14:1662–1677. doi:10.1038/oby.2006.191
Tworoger SS, Missmer SA, Eliassen AH, Barbieri RL, Dowsett M, Hankinson SE (2007) Physical activity and inactivity in relation to sex hormone, prolactin, and insulin-like growth factor concentrations in premenopausal women : Exercise and premenopausal hormones. Cancer Causes Control 18:743–752. doi:10.1007/s10552-007-9017-5
Margolis KL, Mucci L, Braaten T, Kumle M, Trolle LY, Adami HO et al (2005) Physical activity in different periods of life and the risk of breast cancer: the Norwegian-Swedish Women’s Lifestyle and Health cohort study. Cancer Epidemiol Biomarkers Prev 14:27–32
Monninkhof EM, Elias SG, Vlems FA, van der Tweel I, Schuit AJ, Voskuil DW, van Leeuwen FE (2007) Physical activity and breast cancer: a systematic review. Epidemiology 18:137–157. doi:10.1097/01.ede.0000251167.75581.98
Steindorf K, Schmidt M, Kropp S, Chang-Claude J (2003) Case-control study of physical activity and breast cancer risk among premenopausal women in Germany. Am J Epidemiol 157:121–130. doi:10.1093/aje/kwf181
Antoniou AC, Easton DF (2006) Models of genetic susceptibility to breast cancer. Oncogene 25:5898–5905. doi:10.1038/sj.onc.1209879
Dobrovic A, Simpfendorfer D (1997) Methylation of the BRCA1 gene in sporadic breast cancer. Cancer Res 57:3347–3350
Matros E, Wang ZC, Lodeiro G, Miron A, Iglehart JD, Richardson AL (2005) BRCA1 promoter methylation in sporadic breast tumors: relationship to gene expression profiles. Breast Cancer Res Treat 91:179–186. doi:10.1007/s10549-004-7603-8
Hoshino A, Yee CJ, Campbell M, Woltjer RL, Townsend RL, van der MR, Shyr Y, Holt JT, Moses HL, Jensen RA (2007) Effects of BRCA1 transgene expression on murine mammary gland development and mutagen-induced mammary neoplasia. Int J Biol Sci 3:281–291
Marquis ST, Rajan JV, Wynshaw-Boris A, Xu J, Yin GY, Abel KJ et al (1995) The developmental pattern of BRCA1 expression implies a role in differentiation of the breast and other tissues. Nat Genet 11:17–26. doi:10.1038/ng0995-17
Russo J, Mailo D, Hu YF, Balogh G, Sheriff F, Russo IH (2005) Breast differentiation and its implication in cancer prevention. Clin Cancer Res 11:931s–936s
Mullan PB, Quinn JE, Harkin DP (2006) The role of BRCA1 in transcriptional regulation and cell cycle control. Oncogene 25:5854–5863. doi:10.1038/sj.onc.1209872
Narod SA, Foulkes WD (2004) BRCA1 and BRCA2: 1994 and beyond. Nat Rev Cancer 4:665–676. doi:10.1038/nrc1431
Fan S, Wang J-A, Yuan R, Ma Y, Meng Q, Erdos MR et al (1999) BRCA1 inhibition of estrogen receptor signalling in transfected cells. Science 284:1354–1356. doi:10.1126/science.284.5418.1354
Fan S, Xian Ma Y, Wang C, Yuan R, Meng Q, Wang J-A et al (2001) Role of direct interaction in BRCA1 inhibition of estrogen receptor activity. Oncogene 20:77–87. doi:10.1038/sj.onc.1204073
Lacroix M, Toillon RA, Leclercq G (2006) p53 and breast cancer, an update. Endocr Relat Cancer 13:293–325. doi:10.1677/erc.1.01172
Varley JM, McGown G, Thorncroft M, Santibanez-Koref MF, Kelsey AM, Tricker KJ et al (1997) Germ-line mutations of TP53 in Li-Fraumeni families: an extended study of 39 families. Cancer Res 57:3245–3252
Kleihues P, Schauble B, Zur HA, Esteve J, Ohgaki H (1997) Tumors associated with p53 germline mutations: a synopsis of 91 families. Am J Pathol 150:1–13
Arizti P, Fang L, Park I, Yin Y, Solomon E, Ouchi T et al (2000) Tumor suppressor p53 is required to modulate BRCA1 expression. Mol Cell Biol 20:7450–7459. doi:10.1128/MCB.20.20.7450-7459.2000
Schuyer M, Berns EM (1999) Is TP53 dysfunction required for BRCA1-associated carcinogenesis? Mol Cell Endocrinol 155:143–152. doi:10.1016/S0303-7207(99) 00117-3
Sengupta S, Wasylyk B (2004) Physiological and pathological consequences of the interactions of the p53 tumor suppressor with the glucocorticoid, androgen, and estrogen receptors. Ann N Y Acad Sci 1024:54–71. doi:10.1196/annals.1321.005
Russo J, Gusterson BA, Rogers AE, Russo IH, Wellings SR, van Zwieten MJ (1990) Comparative study of human and rat mammary tumorigenesis. Lab Invest 62:244–278
Russo J, Russo IH (1987) Biological and molecular bases of mammary carcinogenesis. Lab Invest 57:112–137
Cardiff RD (1998) Are the TDLU of the human the same as the LA of mice? J Mammary Gland Biol Neoplasia 3:3–5. doi:10.1023/A:1018714016205
Clarke RB, Howell A, Potten CS, Anderson E (1997) Dissociation between steroid receptor expression and cell proliferation in the human breast. Cancer Res 57:4987–4991
Paech K, Webb P, Kuiper GG, Gustafsson JA, Kushner PJ, Scanlan TS (1997) Differential ligand activation of estrogen receptors Er alpha and ER beta at AP1 sites. Science 277:1508–1510. doi:10.1126/science.277.5331.1508
Cheng G, Weihua Z, Warner M, Gustafsson JA (2004) Estrogen receptors ER alpha and ER beta in proliferation in the rodent mammary gland. Proc Natl Acad Sci USA 101:3739–3746. doi:10.1073/pnas.0307864100
Chang EC, Frasor J, Komm B, Katzenellenbogen BS (2006) Impact of estrogen receptor beta on gene networks regulated by estrogen receptor alpha in breast cancer cells. Endocrinology 147:4831–4842. doi:10.1210/en.2006-0563
Lin CY, Strom A, Li KS, Kietz S, Thomsen JS, Tee JB et al (2007) Inhibitory effects of estrogen receptor beta on specific hormone-responsive gene expression and association with disease outcome in primary breast cancer. Breast Cancer Res 9:R25. doi:10.1186/bcr1667
Gustafsson JA, Warner M (2000) Estrogen receptor beta in the breast: role in estrogen responsiveness and development of breast cancer. J Steroid Biochem Mol Biol 74:245–248. doi:10.1016/S0960-0760(00) 00130-8
Hilakivi-Clarke L, Clarke R, Onojafe I, Raygada M, Cho E, Lippman ME (1997) A maternal diet high in n-6 polyunsaturated fats alters mammary gland development, puberty onset, and breast cancer risk among female rat offspring. Proc Natl Acad Sci USA 94:9372–9377. doi:10.1073/pnas.94.17.9372
Bocchinfuso WP, Korach KS (1997) Mammary gland development and tumorigenesis in estrogen receptor knockout mice. J Mammary Gland Biol Neoplasia 2:323–334. doi:10.1023/A:1026339111278
Jones LP, Tilli MT, Assefnia S, Torre K, Halama ED, Parrish A et al (2007) Activation of estrogen signaling pathways collaborates with loss of Brca1 to promote development of ERalpha-negative and ERalpha-positive mammary preneoplasia and cancer. Oncogene
Xu X, Wagner KU, Larson D, Weaver Z, Li C, Ried T et al (1999) Conditional mutation of Brca1 in mammary epithelial cells results in blunted ductal morphogenesis and tumour formation. Nat Genet 22:37–43. doi:10.1038/8743
Jerry DJ, Kuperwasser C, Downing SR, Pinkas J, He C, Dickinson E et al (1998) Delayed involution of the mammary epithelium in BALB/c-p53null mice. Oncogene 17:2305–2312. doi:10.1038/sj.onc.1202157
Locke I, Kote-Jarai Z, Fackler MJ, Bancroft E, Osin P, Nerurkar A et al (2007) Gene promoter hypermethylation in ductal lavage fluid from healthy BRCA gene mutation carriers and mutation-negative controls. Breast Cancer Res 9:R20. doi:10.1186/bcr1657
Strathdee G, Sim A, Soutar R, Holyoake TL, Brown R (2007) HOXA5 is targeted by cell-type-specific CpG island methylation in normal cells and during the development of acute myeloid leukaemia. Carcinogenesis 28:299–309. doi:10.1093/carcin/bgl133
Meng ZH, Ben Y, Li Z, Chew K, Ljung BM, Lagios MD et al (2004) Aberrations of breast cancer susceptibility genes occur early in sporadic breast tumors and in acquisition of breast epithelial immortalization. Genes Chromosomes Cancer 41:214–222. doi:10.1002/gcc.20089
Acknowledgments
We thank Dr. Elizabeth Cho-Fertick who provided medical writing services, funded by National Cancer Institute (U54 CA00100971 for L.H.-C.). The study was funded by grants from Prevent Cancer Foundation (K·W.) and National Cancer Institute (U54 CA00100971, L.H.-C.).
Authors’ contributions
The work described in the manuscript was designed to test a hypothesis proposed by Dr. Leena Hilakivi-Clarke who provided overall direction for the study. Drs. Kim Westerlind and Robert Strange performed the animal study and provided tissues for the analysis, Dr. Mingyue Wang did most of the gene and protein expression experiments, together with Drs. Bin Yu, Galam Khan and Dipti Patil. Graduate student Kelly Boeneman processed the mammary glands and performed morphological assessment.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Wang, M., Yu, B., Westerlind, K. et al. Prepubertal physical activity up-regulates estrogen receptor β, BRCA1 and p53 mRNA expression in the rat mammary gland. Breast Cancer Res Treat 115, 213–220 (2009). https://doi.org/10.1007/s10549-008-0062-x
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10549-008-0062-x