Diet and Cancer

ReportOpenSource Diets-Creating a Clean Backgroundfor Oncology Research

100by Matthew R. Ricci, Ph.D. VP, Science Director, Research Diets, Inc. andMichael A. Pellizzon, Ph. D., Senior Scientist, Research Diets, Inc.

80

90Repeat

RevisePMI # 5002 Mill Dates
7/23/1997

D & G 223 ug/g

11/7/2003
8/20/200370

Low Phyto. Diets

D & G 98 ug/g

Laboratory animal models are important tools in oncology
research, as they allow scientists to test their in vitro-generated
hypotheses in a mammalian, whole-animal system. Since many
types of cancer can be affected by environmental factors, having
control over these factors is key to generating reproducible,
meaningful data.
Research Diets products are routinely used for oncology research.
OpenSource diets contain purified ingredients, which provide aclean background (i.e. phytoestrogen and cholorphyll-free) toreduce ‘noise’ during in vivo imaging and control over factorsthat may impact gene expression.

Effects of Phytoestrogens in Grain-based Dietson Cancer and Related Endpoints
Grain-based chow diets contain ingredients possessing biologically
active compounds that can alter the cancer phenotype. One classof compounds called phytoestrogens, which are found in soybean
meal and alfalfa, have all been shown to impact cancer endpoints(1, 2) and the concentration of these compounds in chow can havemeaningful biological effects on cancer and other phenotypes (3,4).
Since the level of these compounds can vary from one lot to thenext by as much as 3 – 6 fold (4) (Fig1), it is possible that they canmask the influence of experimental compounds.
Genistein is a soy-based phytoestrogen that is commonly found in
grain-based chow diets, and its influence on cancer is thought tobe mediated by its ability to bind estrogen receptors (5, 6). Its
potential impact on cancer (i.e. carcinogenic or anticarcinogenic)
is related to factors including the dose, age, mode of cancer
induction, and rodent model being studied (6). For example,
exposure to genistein early in life (i.e. gestational and lactational
phases) dose-dependently reduced tumor formation of a
carcinogen-induced mammary cancer rat model (7). In contrast,
dietary genistein dose-dependently increased mammary tumor
area in the context of an estrogen-sensitive ovariectomized mousemodel (8).

Effects on Gene Expression
In addition, effects of varying levels of phytoestrogens and othercompounds in chow (i.e. arsenic), can impact the phenotype atthe gene level, (9-11), which can compromise the process ofdetermining the mechanism by which various treatments or genetic
mutations influence gene expression. Furthermore, the potential
for unknown compounds in grains used in chows mayhave further
impact on phenotype, which may translate to the gene level.

% VO

605040

D & G 7 ug/g

30
D & G 431 ug/g

20
10030

32

343638

Post Natal Days
FIGURE 1. Batch-to-batch variation in total daidzein (D) and genistein (G) contentversus vaginal opening (VO) data in F344 rats fed different mill dates of Purina Mills,Inc. (PMI) # 5002 diet. The total D & G content can vary 3-fold in different milldates producing significant (p < 0.05) differences in the time of VO between different
mill dates at postnatal days 34 and 36. The low phytoestrogen diet in the chart is PMI#5K96, but similar results were seen with Harlan Sprague Dawley (HSD) 2014S andHSD 2016S. Graphic representation - for details see reference (10).

Effects on In Vivo Imaging
Finally, the presence of chlorophyll in ingredients of chows such asalfalfa can create background noise in studies where imaging
technology is used. Therefore, it is essential to use chlorophyll-freediets when such technology is used.

Mice fed a grain-based chow diet as seen
through the CRi in vivo imaging system.

Mice fed OpenSource Diet # D10001
as seen through the CRi in vivoimaging system.

OpenSource Diets
Aside offering a clean background, the purified nature of OpenSource
diets allows for easy customizations, which provide researchers anadditional advantage in the cancer field. While certain genetic
manipulations and carcinogen exposure are commonly used forcancer development in rodents, making select changes to various
nutrients such as the level of fat, fiber, and certain vitamins andminerals are capable of influencing tumor incidence in wild-type mice
without carcinogen exposure given a long enough timeframe (12, 13).

Diet and Cancer
OpenSource purified ingredient diets are a solution to these issues,
as they do not contain phytoestrogens or chlorophyll and can be
modified with ease. While the lack of these compounds makes
purified diets important tools for oncology research, the very natureof OpenSource purified diets argues for their use in all lab animalresearch.

Contact our Resource Center for valuable insight from morethan 25 years of product experience in the field of cancer.
Let us formulate the diets to meet your specific study needs.
Custom OpenSource Diets
Research Diets, Inc has pioneered the formulation andproduction of phytoestrogen-free/chlorophyll-free diets inlaboratory animals. Our scientists specialize in providing
custom purified OpenSource diets. By carefully designing
the diet formula to fit your protocol, you have complete
control over small or large changes in diet composition.
Plus you are able to report what your animals werefed, repeat the formula and revise diet composition
as necessary.

Incorporate Test Compounds
Research Diets, Inc. will incorporate your test compound
into pelleted diets for simple, safe dosing. Feeding test
compounds eliminates dosing related stress to theanimal, eliminates vehicle effects, and saves time andlabor. Consult with one of our scientists on the formula,determine the dosage required and the diet will be
produced and shipped in 5 to 7 business days.

Value Added Resource
The value of our products is in the scientific support weprovide. Our Resource Center is staffed with Masters andPh.D. level scientists with access to over 14,000 original
formulas and a database of more than 3,800 journal
articles. We welcome the opportunity to talk science withresearchers throughout the world as we maintain ourleadership role as the knowledge base for OpenSource
Diet formulation.

References
1. Zhou, JR, Gugger, ET, Tanaka, T, Guo, Y, Blackburn, GL and Clinton, SK. Soybean
phytochemicals inhibit the growth of transplantable human prostate carcinoma andtumor angiogenesis in mice. J Nutr 129:1628–1635, 1999.
2. Javid, SH, Moran, AE, Carothers, AM, Redston, M and Bertagnolli, MM.
Modulation of tumor formation and intestinal cell migration by estrogens in theApcMin/+ mouse model of colorectal cancer. Carcinogenesis. 26 (3):587--595, 2005.
3. Brown, NM and Setchell, KDR. Animal models impacted by phytoestrogens incommercial chow: Implications for pathways influenced by hormones. Laboratory
Investigation; 81(5):735-747, 2001.
4. Thigpen, JE, Setchell, KDR, Saunders,HE, Haseman,JK, Grant, MG and Forsythe,
DB. Selecting the appropriate rodent diet for endocrine disruptor research andtesting studies. ILAR Journal; 45(4):401-416, 2004.
5. Nikov GN, Hopkins NE, Boue S, Alworth WL. Interactions of dietary estrogens withhuman estrogen receptors and the effect on estrogen receptor-estrogen response
element complex formation. Environ Health Perspect 108:867-872, 2000.
6. Bouker, KB, Hilakivi-Clarke, L. Genistein: Does it prevent or promote breast
cancer? Environ Health Perspect 108:701-708, 2000.
7. Fritz, WA, Coward, L, Wang, J, and Lamartiniere, CA. Dietary genistein: Perinatal
mammary cancer prevention, bioavailability and toxicity testing in the rat.
Carcinogenesis 19:2151–2158, 1998.
8. Allred, CD, Allred, KF, Ju, YH, Virant, SM, Helferich, WG. Soy diets containing
varying amounts of genistein stimulate growth of estrogen-dependent (MCF-7)
tumors in a dose-dependent manner. Cancer Res 61:5045-5050, 2001.
9. Tovar-Palacio, C, Potter, SM, Hafermann, JC, and Shay, NF. Intake of soy protein
and soy protein extracts influences lipid metabolism and hepatic gene expression ingerbils. J Nutr 128:839–842. 1997.
10. Si, H and Liu, D. Genistein, a soy phytoestrogen, upregulates the expression ofhuman endothelial nitric oxide synthase and lowers blood pressure in
spontaneously hypertensive rats. J Nutr 138: 297–304, 2008.
11. Kozul, CD, Nomikos, AP, Hampton TD, Warnke, LA, Gosse, JA, Davey, JC,Thorpe, JE, Jackson, BP, Ihnat, MA, Hamilton, JW. Laboratory diet profoundly alters
gene expression and confounds genomic analysis in mouse liver and lung.
Chemico-Biological Interactions, 173:129-140, 2008.
12. Newmark, HL, Yang, K, Lipkin, M, Kopelovich, L, Liu, Y, Fan, K, Shinozaki, H. A
Western-style diet induces benign and malignant neoplasms in the colon of normal
C57BL/6 mice. Carcinogenesis 22(11): 1871-1875, 2001.
13. Yang, K, Kurihara, N, Fan, K, Newmark, H, Rigas, B, Bancroft, L, Corner, G, Livote,E, Lesser, M, Edlemann, W, Velcich, A, Lipkin, M, Augenlicht, L. Dietary inductionof colonic tumors in a mouse model of sporadic colon cancer.
Cancer Res 68(19):7803-10, 2008.

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BioDAQ E2 Episodic monitoring system measures thead libitum food and water intake behavior of singly
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Where NutriPhenomics Begins

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