Dietary Epigenetics in Aging and Cancer Prevention Epigenetics in Aging and Cancer Prevention....

Trygve Tollefsbol, Ph.D., D.O.Professor of Biology

Senior Scientist, Center for Aging, Comprehensive Cancer Center, Nutrition Obesity Research Center and

Comprehensive Diabetes CenterDirector, Cell Senescence Culture Facility

University of Alabama at Birmingham (UAB)

Dietary Epigenetics in Aging and Cancer Prevention

Epigenetics—Time MagazineJanuary 18, 2010.

Epigenetics—Time MagazineJanuary 18, 2010.

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DNA METHYLATION

Epigenetic Modifications of the Genome

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phosphorylation methylation

HISTONE MODIFICATIONS

Environmentally-sensitive heritable and reversible gene regulation without changes in the primary DNA sequence.

Aging &Cancer

•Plant products•Nutrients Epigenetics

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Sulforaphane

Glucose Telomerase (hTERT) gene

Telomerase activity is proposed to be regulated through epigenetic control of the hTERT gene.

TERT

hTERT

hTER

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Telomere Shortening in the Absence of Telomerase

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Number of cell divisions

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HSulforaphane

Sulforaphane Inhibits hTERT and Telomerase Activity

PLoS One, 5(7): e11457, 2010

21% Methylation

Promoter Methylation Inhibition by Sulforaphane in Breast Cancer Cells

hTERT promoter region

Chromatin Modifications of hTERT Induced by Sulforaphane

0 2.5 5 10 0 2.5 5 10Acetyl-H3

Trimethyl-H3K27

Acetyl-H4

Trimethyl- H3K9

Acetyl-H3K9

MAD1

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c-MYC

SFN (µM)MCF-7 MDA-MB-231

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Meeran, S.M., Patel, S.N., and Tollefsbol, T.O. Sulforaphane causes epigenetic repression of hTERT expression in human breast cancer cells. PLoS One, Jul 6;5(7):e11457, 2010.

Sulforaphane of Cruciferous Vegetables Changes DNA Methyltransferase and Histone Demethylase Activity

MDA-MB-231 MCF10AMCF-7

Epigenetic processes such as DNA methylation and chromatin modifications are important in aging and cancer.

hTERT, the regulatory gene for telomerase, is under epigenetic control which is altered in cancer cells. Epigenetic-modifying drugs may have potential in controlling telomerase in cancer.

Dietary components of cruciferous vegetables impact epigenetic processes that control telomerase regulation. This may prevent telomerase activation and cancer.

CAN CONTROLLED FASTING SLOW THE AGING PROCESS?

Calorie restriction (CR) is by far the most established environmental manipulation to extend longevity and reduce the onset of age-related chronic diseases.

CR is typically a diet with reduced calories by about 25-40% less than normal but including all needed nutrients.

Investigations in animals (yeast, mice and non-human primates) have shown CR to have an impressive effect on delaying aging.

Science, 2009, 325, 201-204

Aging is the accumulation of changes in an organism or object over time.

Cellular senescence is a phenomenon where isolated cells demonstrate a limited ability (the Hayflick Limit) to divide in culture.

Leonard Hayflick

“IF AT FIRST AN IDEA DOES NOT SEEM ABSURD, THEN THERE IS NO HOPE FOR IT.”

ALBERT EINSTEIN

Yuanyuan Li, M.D., Ph.D.

Liang Liu, Ph.D.

Could In Vitro Sugar Reduction Help Answer Questions About Human Caloric Restriction, Aging and Cancer Prevention?

Glucose

Li, Y., Liu, L., and Tollefsbol, T.O. (2010) Glucose restriction can extend normal cell lifespan and impair cancer cell growth through epigenetic control of hTERT and p16 expression. FASEB Journal, 24:1442-53.

WI-38 /Glucose WI-38 /Glucose restriction WI-38 /S Glucose WI-38 /S Glucose restriction

Glucose Restriction Extends the Lifespan of Human Normal WI-38 Cells and Reduces Survival of Precancerous WI-38/S Cells

1.77%

17.70%

Glucose

Glucose restriction

WI-38/S (precancerous)WI-38 (normal)

0.39%

1.27%

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Glucose Restriction-induced Apoptosis in WI-38/S Cells

Glucose Restriction has Opposite Effects on the hTERT and p16 Genes in Normal and Precancerous Cells

DNA Methylation of the p16 Promoter in Glucose Restricted WI-38 Normal Cells

However, no changes in DNA methylation of the hTERT promoter with glucose restriction of either cell type.

Also, no changes in DNA methylation of the p16 promoter in WI-38/S cells with glucose restriction.

Glucose Restriction Results in Chromatin Remodeling of the Promoters of the hTERT and p16 Genes

FASEB J. 24, 1442-53, 2010

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DNMTs activity HDAC activity

Changes in Activity of Epigenetic Enzymesin Response to Glucose Restriction

Cellular Lifespan Extended in Glucose-restricted Normal Human Cells

WI-38 cells MRC-5 cells

IMR-90 cells

Glucose restriction

Normal cell

Precancerous cell

Epigenetic regulation

p16 repressionhTERT activation

p16 up-regulationhTERT inhibition

Longevity

Apoptosis,cellular

senescence,cancer inhibition

Effects of glucose restriction on longevity and cancer inhibition through epigenetic regulation

HIGHLIGHTSIn vitro system

Our studies show for the first time that reduced sugar provided to human cells makes them live longer. This cell culture system is much easier and more accurate to control and measure the calories than in a whole organism, consisting of complex metabolic processes.

Epigenetic alteration

This study reveals epigenetic mechanisms by which glucose restriction may cause gene expression alterations in both normal and precancerous cells.

Clinical implications

Our results strongly suggest that a reduction in calories in the human diet may increase the lifespan and reduce the risk of cancer because of effects of this calorie reduction on the individual cells of humans.

Clinical strategies aimed toward the genes that influence this process and the enzymes that modify the activity of these genes could apply to aging and cancer interventions.

Funding Support