1. Diet, Epigenetics and Breast Cancer
Shuk-Mei Ho Ph.D.
Jacob G. Schmidlapp Professor and
Chair of Department of Environmental Health
Director, Center for Environmental Genetics
Director, Microarray and Genomic Core
Associate Director, Cincinnati Cancer Center University of Cincinnati College of Medicine

3. Lamarckian Evolution
Jean-Baptiste Lamarck (1744–1829), a French naturalist, was among the first group of scholars advancing the idea that evolution occurred and proceeded in accordance with natural laws.
Wikipedia ( 11/16/2010)

4. Major thesis of Lamarckian Evolution:
The environment brings up new needs, resulting in adaptive changes in animals
Lamarck proposed the theory of "inheritance of acquired characters.” He believed animals including the human lose unused traits and develop useful characteristics that are inherited by their offspring
He cited examples such as blindness in moles, the absence of teeth in birds,
Wikipedia ( 11/16/2010)

5. and the elongated necks of giraffes as evidence in support of his theory His ideas were well accepted by most naturalists until Charles Darwin published his “Origin of Species”

6. Darwinian Evolution- Natural Selection
Charles Robert Darwin (1809 –1882), an English naturalist, proposed and published his highly popular evolution theory known as natural selection as a book entitled “On the Origin of Species.” It explains how all species of life have evolved over time from common ancestors.
Slowly but surely…..Darwin wrote, "…Natural selection acts only by taking advantage of slight successive variations; she can never take a great and sudden leap, but must advance by short and sure, though slow steps."
Wikipedia ( 11/16/2010)

7. Darwinian Evolution- Natural Selection
Population speciation: Evolution is a process that occurs in the heritable characteristics of a population over time.
However, the Darwian evolution fails to explain the transmission of acquired characters such as a significant increase in breast cancer risk among Asian-American women within one generation after immigration.
Wikipedia ( 11/16/2010)

8. Genetic Basis of Disease Variability
In the past, susceptibility of disease was believed to be determined solely by inheritable information carried on the primary sequence of the DNA
Aberrant changes in linear DNA sequence result in mutations, deletions, gene fusion, tandem duplications, or gene amplifications causing disregulation of gene expression that underlies the genesis of disease
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007

9. Genetic charges give rise to alternative traits that are better fits for a new environment : e.g.. Skin color (I)
10,000 yr
10,000 yr
30,000 yr
35,000 yr
45,000 yr
50,000 yr

10. Genetic charges give rise to alternative traits that are better fits for a new environment : e.g.. Skin color (I)
10,000 yr
10,000 yr
30,000 yr
35,000 yr
45,000 yr
50,000 yr

11. Conrad H. Waddington (1905-1975) – a developmental biologist
The term epigenetics means outside
conventional genetics
Waddington exposed Drosophila pupae to heat and observed altered wing-vein patterns (1940) when the flies emerged. The altered phenotype persisted in the population long after the stimulus was removed, suggesting that exposure to an environmental factor during a critical developmental window could produce a lifetime phenotype-change
He argued that this phenomenon represented an acquired character had been assimilated into the genetic code of the flies and referred to this as “genetic assimilation,” or “epigenetics” in modern terminology
Nature Reviews Genetics
(1977 The Royal Society)
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007

12. Unique features of epigenetics
Epigenetics regulates when and which sets of genes are turned on and turned off in a specific cell type or organ
It refers to features such as chromatin and DNA modifications that are stable over rounds of cell proliferation. The acquired characters can be transmitted to daughter cells or perhaps to the next generation
It does not involve changes in the primary DNA sequence of the cell/organism and therefore is potentially reversible
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007
Ho SM J. Allergies Clinical Immulogy 2010

13. Epigenetics- an emerging theory to explain individual variations in cancer risk
Epigenetics is the process by which the genotype of an organism interacts with the environment to produce its phenotype. It provides a framework to explain the source of variations in individual organisms and among populations
Epigenetics explains why cells, tissues, and organs in an individual are different when every cell in the body are carrying identical genetic information. The differences are caused by the expression of different sets of genes in different cells in a distinct temporal sequence
It also explains why members of a population or identical twins are different albeit the members/twins have very similar or identical genetic materials
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007
Ho SM J. Allergies Clinical Immulogy 2010

14. Epigenetic mediation of normal differentiation - genes are compartmentalized into active (filled circles) and inactive (open circles) domains v
morphogens

15. Epigenetic mediation of normal differentiation - genes are compartmentalized into active (filled circles) and inactive (open circles) domains v v v v v v v v v X X
morphogens

16. Genetic polymorphisms
The epigenetics serves as an interface between the environment and the inherited genome
Environmental factors ?
Genetic polymorphisms ?
Epigenetics

17. Relationship between genetics and epigenetics
Epigenetics are markings etched in the "margins" of one's genetic make-up
Genome: static
Epigenome: dynamic; subjected to changes including those brought on by environmental factors
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007
Ho SM J. Allergies Clinical Immulogy 2010

18. Epigenetic affects gene expression leading to altered disease risk
There are at least three ways epigenetics work to affect gene expression :
Non-coding RNAs, DNA methylation, and Histone modification
These processes put genes in active and inactive compartments.
Singularly or conjointly, they determine whether and when a gene or a set of genes is silenced or activated >> alter cell/organ functions
A disruption of gene and protein expression by endogenous and exogenous
factors are the bases of disease development
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007
Ho SM J. Allergies Clinical Immulogy 2010

19. How does epigenetic work? - I
I. DNA Methylation
Methylation is the attachment of methyl groups to regulatory regions of the DNA.
Methyl groups
Methyl groups

20. How does epigenetic work? - II
II. Histone Modification
The double stranded DNA wraps around a group of proteins called the histones
N-terminal tails of histones are often undergo covalent modifications : acetylation, methylation, phosphorylation and ubiquitination.
These modified histone tails acts like “tags” marking regions of DNA as active (transcribale) or inactive (silenced or cannot be transcribed) into mRNA
K= lysine; R= Arginine; S= Serine
Histone methylation (Arginine): associate w/ HAT to form co-activator which mediates TF binding.
Histone methylation (Lysine): Depend on which residue. K4H3: transcription activation; K9H3: transcription repression. Also, it often associates heterochromatin formation/ chromosome loss
Histone phosphorylation: transcription activation by promoting acetylation of K14H3 and/or chromosome condensation.
Histone ubiquitination (Lysine): is generally associated with increased gene expression. Exact mechanism is not fully understood.
Daryl C. Drummond et al, 2004

21. Histone deacetylation
Active and inactive chromatin and gene regulation
Active chromatin
DNA
Inactive chromatin
Transcription H3 M TF A
Silenced K9 K4
K27
Pol II
Histone acetylation
DNA demethylation
Histone deacetylation
DNA methylation
HMTs
HDACs
DNMTs
MBPs
HATs
DMEs
HDMs
Zhang X & Ho SM J. Mol Endocrinol 2010

22. Which factors affect epigenetics ?
Environmental factors, such as types and quantities of dietary fats, smoking, stress, and toxins may alter DNA methylation at sites important in health.
Gene expression effects can be seen for at least three generations.
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007
Ho SM J. Allergies Clinical Immulogy 2010; Zhang X & Ho SM J. Mol Endocrinol 2010

23. Can high fat diets promote breast cancer through epigenetics in adult life?

24. Published data from UC on the continuous high fat exposure model
Part I:
Animal studies on Continuous high fat diets
Samples collected at Day Day Day 100
DMBA*
(In utero exposure)(pups with mothers)
Tumor
AIN, HFO,HFB, HFS
AIN, HFO,HFB, HFS
Breeding
Birth
Weaning
High olive oil (HFO; primarily n-9 monounsaturated fatty acids)
High butter (HFB; primarily saturated fatty acids)
High safflower oil (HFS; primarily n-6 polyunsaturated fatty acids)
DMBA induced DCIS and invasive adenocarcinoma

25. Continuous exposure to high fats diets stimulate mammary epithelial cell proliferation
AIN
HFO
Medvedovic et al 2009

26. Continuous exposure to high fat diets induces a unique cell proliferation gene signature in mammary epithelial cells
Medvedovic et al 2009

27. Early origins of human diseases
Epidemiologic studies now support an early origin of adult human diseases. Classic examples include association between low birth weight and a greater risk of coronary heart disease, hypertension, stroke, depression, type 2 diabetes, and osteoporosis in later life
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007
Ho SM J. Allergies Clinical Immulogy 2010; Zhang X & Ho SM J. Mol Endocrinol 2010

28. Developmental Plasticity- Windows of Susceptibility
Most human organ systems begin to develop early in gestation and do not become fully mature until weeks, months, or years after birth. A relatively long gestation and a period of postnatal and perhaps prepubertal maturation allow for prolonged interactions with the environment
These include episodes of hypoxia; hypo- or hypernourishment; infection; and hormonal, drug, or toxin exposures. Developmental plasticity occurs when such exposures, during critical periods of maturation, result in permanent alterations in the structure or function of specific organ systems
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007
Ho SM J. Allergies Clinical Immulogy 2010; Zhang X & Ho SM J. Mol Endocrinol 2010

29. Developmental reprogramming
It is a so-called adaptive trait since it is an attempt to establish phenotypes that meet the demands of later-life environment
When the resulting phenotypes match the predicted later-life demands, the individual will remain healthy
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007
Ho SM J. Allergies Clinical Immulogy 2010; Zhang X & Ho SM J. Mol Endocrinol 2010

30. Increased odds of a mismatch between early developmental programming and later-life demands
When there is a high degree of mismatch, however, one’s adaptability to adult life challenges will be impeded and disease risk will be elevated
The latter scenario is more frequent today than in past decades since contemporary human life is greatly influenced by lifestyle choices, which often are in conflict with the programmed adaptive changes made during early development.
Synthetic chemicals that mimic internal cues and artificial reproductive technologies are introduced into daily life at alarming rates. These can induce developmental reprogramming with no apparent late-life adaptive values.
Tang WY and Ho SM Reviews in Endocrine & Metabolic Disorders 2007
Ho SM J. Allergies Clinical Immulogy 2010; Zhang X & Ho SM J. Mol Endocrinol 2010

31. Q; When? A: Early-life exposure
Q: What? A: High fat diets & pollutants
Modified from Foley et al., 2008
Germline
epimutation
Genome-wide
Demethylation
Developmental epigenetic reprogramming
Somatic epimutation
Dysregulation of epigenetic process-> Disease development
Environmental exposure
Maternal Factors
Diet and Lifestyle

32. Which factors affect epigenetics during early life through transplacental exposure ?
Next to smoking, diet is the most critical way to affect your offspring’s epigenomes are dietary fats.

33. In utero high fat diet exposure model
Part II:
Animal studies on in utero exposure of high fat diets
Samples collected at Day Day Day 100
DMBA*
(In utero exposure) (pups with mothers)
Tumor
AIN, HFO,HFB, HFS AIN
AIN
Breeding
Birth
Weaning
High olive oil (HFO; primarily n-9 monounsaturated fatty acids)
High butter (HFB; primarily saturated fatty acids)
High safflower oil (HFS; primarily n-6 polyunsaturated fatty acids)
DMBA induced DCIS and invasive adenocarcinoma
Ho SM et at unpublished 2010

34. In utero high fat exposure increases BCa tumor burden and volume in adult life
Ho SM et al unpublished 2010
* Different (p<.05) by Individual T-Test from HFO

35. Altered epigenome, gene expression
A new question to be addressed in our new grant -
Combinational Effects between Diet and Toxicants ?
Diet
Genetics
Environment
Bisphenol A
Dietary
Fatty acids
Leads to changes in cell behavior and morphology => Increased BCa risk
Altered epigenome, gene expression
and hormones
In utero exposure
Leptin
Steroid
hormones
Adiponectin
Adipokines

36. Which dietary components have protective effects?
For example, a young man who overeats gluttony likely has shorten the live of his sons and his grandsons through epigenetic effects.

37. Opportunities
Identification of epigenetic biomarkers associated with early reprogramming of breast cancer risk
Use these epigenetic biomarkers for the prediction of higher susceptibility and establish early surveillance (early detection) and intervention measures (diet and lifestyle modifications)
Outreach and education; researcher and advocates working together

38. Looking Forward
Diet is the second most important effector of our epigenetic modification known at this time. Its not just what we eat, but also how much.
Epigenetic markers are long-lasting and hence are good warning signs. It is a new frontiers for us to control some aspects of our health.
We can take charge of some aspects of our health but also affecting the health of our unborn children, growing children and their children.

39. RESEARCH PARTNERS COMMUNITY PARTNERS Presentations Publications
Shuk-mei
Tracie
Presentations
Publications
Conferences
Education
Liz
Ricky
Banita
Mario
Events
Education
Support
Presentations
Social media
Newsletter
Karen
Linda
Pattie
Scott
Marian
Wendy
S M Ho 2010

40. S M Ho 2010

41. S M Ho 2010

42. Acknowledgement UC Outreach Liaison Dr. Marian Miller Outreach Partner
Pink Ribbon Girls
Ms. Tracie Metzger
Ms. Benita Bailey
Ms. Liz Kelly
All members in Pink Ribbon Girls
UC Science Team
Dr. Shuk-mei Ho
Dr. Scott Belcher
Dr. Mario Medvedovic
Dr. Ricky Leung
Dr. Linda Levin
Former UC members
Dr. Bob Bornschein
Dr. Marshall Anderson
Ms .Robin Gear
NIEHS 1U01ES
S M Ho 2010