HDA August 2010 NUTRITIONAL PROTECTION OF DNA & TELOMERES Michael Fenech CSIRO Food and Nutritional Sciences GENOME HEALTH NUTRIGENOMICS LABORATORY michael.fenech@csiro.au
DNA DAMAGE BIOMARKERS FOR STUDYING NUTRITIONAL PREVENTION OF DNA DAMAGE Dietary Reference Values for DNA Damage Prevention Fenech M (2010) Am. J. Clin. Nutr. LYMPHOCYTE CBMN ASSAY BUCCAL MN ASSAY RBC MN ASSAY COMET ASSAY TELOMERE LENGTH MITOCHONDRIAL DNA DELETION DNA OXIDATION DNA METHYLATION
Genome damage Micronuclei CYTOKINESIS-BLOCK MICRONUCLEUS (CBMN) ASSAY Oxidative stress Nutrient deficiency Excess calories Strand breaks in DNA Chromosome malsegregation DNA hypomethylation Telomere shortening Human cells with damaged & unstable genomes
Genome damage increases with age 50 40 30 20 10 0 18-25 26-35 36-45 46-55 56-65 66-75 76-90 MN per 1000 BN cells Fenech et al. 2000 NEONATES AGE (years)
Chromosome loss TELOMERE & CENTROMERE PROBES Acentric Fragment & Mis-repair TELOMERE & CENTROMERE PROBES Telomere end fusion
NUCLEOPLASMIC BRIDGES ARE IMPORTANT BIOMARKERS OF DNA BREAK MIS-REPAIR, TELOMERE DYSFUNCTION & CHROMOSOMAL INSTABILITY Lymphocytes exposed to X-rays (Fenech et al. Mutagenesis 1999, 2003) Ch 4 Ch 4 Ch 4 Ch 4 Oral squamous cell carcinoma (Saunders et al PNAS 2000) Ch 11
FOLATE DEFICIENCY CAUSES CHROMOSOMAL INSTABILITY [A] MICRONUCLEATED CELLS [B] NUCLEAR BUDS MNed BNs/1000 BNs 40 30 20 10 * ANOVA P < 0.0001 ** Buds/1000 BNs 15 10 5 * ANOVA P<0.0001 ** 0 12 24 60 120 folic acid in medium (nm) 0 12 24 60 120 folic acid in medium (nm) [C] NUCLEOPLASMIC BRIDGES [D] URACIL NPB/1000 BNs 10.0 7.5 5.0 2.5 * ANOVA P<0.0001 ** pg uracil / µg DNA 50 40 30 20 10 * * ANOVA P < 0.0001 0.0 12 24 60 120 Crott et al. Carcinogenesis 2001 [folic acid] in medium (nm) 0 12 24 60 120 [folic acid] in medium (nm)
MICRONUTRIENTS AND GENOME DAMAGE RESULTS OF ANALYSIS OF FOOD FREQUENCY QUESTIONNAIRE AND GENOME DAMAGE DATABASE % variation in genome damage with increased intake relative to lowest tertile of intake % variation in MN freq 70 60 50 40 30 20 10 0-10 -20-30 -40-50 Vitamin E * P < 0.006 * * * * * * Calcium Folate Retinol Nicotinic acid * β-carotene * Riboflavin * * Pantothenic acid * Biotin mid-tertile highest tertile Fenech et al. Carcinogenesis (2005)
Q. Which dietary pattern will best protect the genome? AMOUNTS IN 100g EXPRESSED AS % OF MIMIMUM REQUIREMENT FOR OPTIMUM GENOME HEALTH A. It depends on the nutriome of the foods you prefer to eat 300 200 100 CALCIUM FOLATE NIACIN VITAMIN E BETA-CAROTENE RETINOL 0 ALMONDS WHEATBRAN CHEDDAR CHEESE BROCCOLI (BOILED) TUNA (CANNED) BEEF (COOKED) BANANA Would a FBNERC POLYPILL do the trick?? Fenech, Food Chem Tox 2008
TELOMERES TELOMERES (TTAGGG repeats) ARE ESSENTIAL FOR CHROMOSOME STABILITY TELOMERE SHORTENING OR DYSFUNCTION INCREASES RISK FOR CANCER AND ACCELERATED SENESCENCE
Wong & Collins Lancet 2003
Thomas et al, Mech Aging Dev, 2008 Shorter telomeres in WBCs and Buccal cells of Alzheimer s disease (AD) cases compared to controls Absolute telomere length (Kb per diploid genome) 175 150 125 100 75 50 25 0 a Young controls b Old controls c Younger AD bc Older AD WBC TL <115 Kb per diploid genome OR of being diagnosed with AD is 10.8 specificity 46% sensitivity 92.9%. Absolute telomere length (Kb per diploid genome) 50 40 30 20 10 0 a Young controls a Old controls ab Younger AD b Older AD Buccal TL <40 kb per diploid genome OR of being identified with AD is 4.6 specificity 63% sensitivity 72.7%. young controls (N=30), old controls (N=26), younger AD (N=14), older AD (N=18).
High protein (TWD) or high carbohydrate (HC) weight-loss diets reverse telomere shortening in rectum in over-weight men Telomere length (kb) 18.2 15.6 13.0 10.4 7.8 5.2 2.6 TWD HC 2 way ANOVA P<0.0001 0.0 O Callaghan, Clifton, Noakes, Fenech. Rejuvenation Res. 2009 0 12 52 0 12 52 weeks on diet
O Callaghan, Clifton, Noakes, Fenech. Rejuvenation Res. 2009 REDUCTION IN FAT CORRELATES WITH INCREASE IN TELOMERE LENGTH
Telomere length in older men is significantly associated with plasma folate and homocysteine Telomere length is negatively correlated with plasma homocysteine in older men. Telomere length is positively correlated with plasma folate in males but not in females. Males; r = -0.57, p = 0.004 (n = 24). Females; r = 0.092, p = 0.68 (n = 23) Males; r = 0.42, p = 0.04 (n = 24). Females; r = -0.11, p = 0.61 (n = 23) Bull, O Callaghan, Mayrhofer & Fenech Rejuvenation Res (2009)
ANTIOXIDANT DEFICIENCY OR OXIDATIVE STRESS 8-OHdG BREAKS IN TELOMERE Bull & Fenech Proc. Br Nutr Soc 2008 FOLATE DEFICIENCY? NIACIN OR NICOTINIC ACID DEFICIENCY? URACIL HYPO- METHYLATED SUBTELOMERE REDUCED TANK1 ACTIVITY? REDUCED TRF1, TRF2 BINDING LOSS OF TELOMERE LENGTH CONTROL DYSFUNCTIONAL AND/OR SHORT TELOMERES; TELOMERE END FUSIONS; AND CIN MALNUTRITION & TELOMERE DAMAGE CASCADE
LONGER FOLATE VITAMIN E VITAMIN D Ω3-FATTY ACIDS CEREAL FIBRE MULTIVITAMIN USE TELOMERES CURRENT KNOWLEDGE SHORTER PUFA OXIDATIVE STRESS OBESITY PSYCHOLOGICAL STRESS PROCESSED MEAT HOMOCYSTEINE
Acknowledgements CSIRO C. Salisbury P. Thomas J. Crott V. Dhillon M. Hor T. Almond Jing Wu C. Bull N. O Callaghan W. Leifert G. Patten B. Benassi S. Beetstra NATHAN O CALLAGHAN CAROLINE BULL PHIL THOMAS FUNDING Kellogs Pty Ltd, MLA Blackmore s, Nutrilite/Amway NHMRC, CancerCouncil SA, NIH EUCancerRiskBiomarkers Program DPI-Victoria THE GENOME HEALTH NUTRIGENOMICS DREAM TEAM