Molecular Marker Of Aging Research Articles

Nonlinear dynamics of multi-omics profiles during human aging.

Aging is a complex process associated with nearly all diseases. Understanding the molecular changes underlying aging and identifying therapeutic targets for aging-related diseases are crucial for increasing healthspan. Although many studies have explored linear changes during aging, the prevalence of aging-related diseases and mortality risk accelerates after specific time points, indicating the importance of studying nonlinear molecular changes. In this study, we performed comprehensive multi-omics profiling on a longitudinal human cohort of 108 participants, aged between 25 years and 75 years. The participants resided in California, United States, and were tracked for a median period of 1.7 years, with a maximum follow-up duration of 6.8 years. The analysis revealed consistent nonlinear patterns in molecular markers of aging, with substantial dysregulation occurring at two major periods occurring at approximately 44 years and 60 years of chronological age. Distinct molecules and functional pathways associated with these periods were also identified, such as immune regulation and carbohydrate metabolism that shifted during the 60-year transition and cardiovascular disease, lipid and alcohol metabolism changes at the 40-year transition. Overall, this research demonstrates that functions and risks of aging-related diseases change nonlinearly across the human lifespan and provides insights into the molecular and biological pathways involved in these changes.

Dysregulation of Lipid Metabolism in Aging Meibomian Glands and Its Molecular Markers.

The main function of exocrine Meibomian glands (MGs) is to produce a lipid-rich secretion called meibum which plays a critical role in maintaining the ocular surface homeostasis of humans and most mammals. The chemical composition of meibum, and its quantity produced by MGs, largely determine whether it can fulfill its role successfully. Aging was frequently associated with the onset of various MG-related pathologies. The goal of this study was to determine how aging affects the chemical composition and quantity of meibum in mice, and identify possible molecular markers of aging. Unbiased, untargeted and targeted lipidomic evaluation of mouse MG lipids was conducted using liquid chromatography-high-resolution mass spectrometry, and the results were analyzed using Principal Component, Orthogonal Projections to Latent Structures Discriminant, and Partial Least Square Discriminant Analyses. We found that aging leads to dysregulation of lipid metabolism in MGs, changing the ratios of major classes of MG lipids (such as wax esters, triacylglycerols, and phospholipids) in a progressive manner. Several lipid species that belong to these groups of MG lipids are proposed as clear markers of aging in a mouse model.

Abstract B013: Epigenetic clocks and breast cancer outcomes: A scoping review. [R

Abstract Introduction: Age is a strong predictor for breast cancer (BCa) risk. The median age at diagnosis varies by race/ethnicity. In the United States (U.S.), non-White women are more likely to be diagnosed at a younger age than non-Hispanic White (NHW) women. Epigenetic age, measured as changes to DNA via methylation (DNAm) using epigentic clocks, is highly accurate at estimating cellular age using several tissues and cell types may differ from chronological age. Epigenetic age is more robust than other molecular markers of aging, such as telomere length. Differences between epigenetic age and chronological age, termed epigenetic age acceleration, may be the driver of age and race/ethnicity discrepancies when estimating BCa risk. Age-related methylation between disease-free and tumor breast tissue is significantly differentially methylated. For example, aberrant methylation of promoter regions of polycomb group protein target genes and CpG islands associated with BCa risk and progression. Therefore, the purpose of this scoping review is to gather data on epigenetic clocks as a predictor for BCa incidence. Study objective: Synthesize the existing evidence on epigenetic accelerated aging measured with epigenetic clocks and breast cancer risk in the U.S. Methods: The PROSPERO Scoping Review Protocol was used for this project. We performed multiple PubMed searches utilizing search language developed by an experienced search librarian. The searches were conducted from January 2022 to April 2022. The searches yielded a total of 2,908 studies in the search process. The eligibility for inclusion applied during article review was: 1) the study must have used an epigenetic clock to assess epigenetic accelerated age in their sample, 2) the study’s primary outcome needed to be breast cancer risk, 3) the study needed to use a U.S. based study sample 3) the study needed to be published in a peer-reviewed PubMed indexed journal, 4) the study must have been published by April 30, 2022. Results: A total of seven articles from the 2,908 were determined eligible for inclusion. Data extraction from these seven articles demonstrated epigenetic accelerated age measured with epigenetic clocks does have an associative relationship with the development of breast cancer. Discussion: BCa risk is also known to drastically increase after menopause, although there are significant differences of menopausal transition in race/ethnicity. On average, African American, Asian, and Latina women begin menopause earlier than non-Hispanic White women. Emerging evidence suggests that earlier menopause in these populations may be a result of structural factors experienced by historically disadvantaged communities. The studies included in this review focused primarily on NHW women. More research is needed to better understand the role of DNAm and accelerated epigenetic age in diverse populations. Citation Format: Jennifer Daw, Devin Saunders, Adria Vasquez, Celina Valencia. Epigenetic clocks and breast cancer outcomes: A scoping review. [R] [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr B013.

Biological age and diet: Measuring the impact of lifestyle on a 6CpG-epigenetic clock

BACKGROUND: Changes in DNA methylation along the life have been documented, and environmental exposures (including diet, physical activity and smoking) can accelerate or decelerate this process. The epigenetic clock estimates the biological age of an individual measuring methylation patterns in specific areas of its genome. Recently, a new epigenetic clock based on 6 CpGs has been proposed, with high potential to become an easy accessible tool able to measure the epigenetic age (EA) of an individual. OBJECTIVES: This study aims to validate the 6 CpG epigenetic clock comparing it with other biomarkers of aging such as telomere length (TL) and methylation in the long interspersed nuclear element-1 (LINE-1). The impact of lifestyle associated factors on these molecular marks has been evaluated. METHODS: 200 healthy participants having extreme dietary patterns (healthy vs western diet) were selected. Dietary intakes, body composition, physical activity level and smoking has been assessed. DNA extracted from whole blood was used to measure the 6CpG-EA, TL and LINE-1 methylation levels. RESULTS: 6CpG-EA was positively correlated with chronological age (r = 0.591; p = 7.2*10-20) and negatively with TL (r = –0.150; p = 0.040) and LINE-1 methylation (r = –0.240; p = 0.001). Despite the fact that no significant associations were detected with the overall diet quality (HEI), 6CpG-EA was correlated with dietary intakes of nutrients involved in the one-carbon (1 C) metabolism, especially in the western diet group. CONCLUSION: These results support the 6CpG epigenetic clock as an easy accessible tool to estimate biological age, in accordance with other molecular markers of aging, and suggest that EA can be modulated by micronutrients involved in the 1 C metabolism.

PPARδ Inhibits Hyperglycemia-Triggered Senescence of Retinal Pigment Epithelial Cells by Upregulating SIRT1.

Emerging evidence shows that peroxisome proliferator-activated receptor delta (PPARδ) plays a pivotal role in cellular aging. However, its function in retinal disease processes such as hyperglycemia-associated diabetic retinopathy is unclear. Here, we demonstrate that PPARδ inhibits premature senescence of retinal pigment epithelial (RPE) cells induced by high glucose (HG) through SIRT1 upregulation. A specific ligand GW501516-activation of PPARδ suppressed premature senescence and production of reactive oxygen species induced by HG in ARPE-19 cells, a spontaneously arising human RPE cell line. These effects were accompanied by the regulation of the premature senescence-associated genes p53, p21, and SMP-30. Furthermore, GW501516-activated PPARδ almost completely abolished the effects of HG treatment on the formation of phosphorylated H2A histone family member X (γ-H2A.X) foci, a molecular marker of aging. These inhibitory effects of GW501516 were significantly reversed in ARPE-19 cells stably expressing small hairpin RNA targeting PPARδ. Notably, GW501516 significantly increased the mRNA and protein levels of SIRT1, indicating that GW501516-activated PPARδ exerted its beneficial effects through SIRT1. In addition, GW501516 restored HG-suppressed SIRT1 expression, corroborating the role of SIRT1 in the anti-senescence function of PPARδ. The effects of PPARδ on HG-induced premature senescence and the expression of the senescence-associated genes p53, p21, and SMP-30 were mimicked by the SIRT1 activator resveratrol, but blocked by the SIRT1 inhibitor sirtinol. Collectively, these results indicate that GW501516-activated PPARδ inhibits HG-triggered premature senescence of RPE cells by modulating SIRT1 signaling.

Sex-specific aging in animals: Perspective and future directions.

Sex differences in aging occur in many animal species, and they include sex differences in lifespan, in the onset and progression of age‐associated decline, and in physiological and molecular markers of aging. Sex differences in aging vary greatly across the animal kingdom. For example, there are species with longer‐lived females, species where males live longer, and species lacking sex differences in lifespan. The underlying causes of sex differences in aging remain mostly unknown. Currently, we do not understand the molecular drivers of sex differences in aging, or whether they are related to the accepted hallmarks or pillars of aging or linked to other well‐characterized processes. In particular, understanding the role of sex‐determination mechanisms and sex differences in aging is relatively understudied. Here, we take a comparative, interdisciplinary approach to explore various hypotheses about how sex differences in aging arise. We discuss genomic, morphological, and environmental differences between the sexes and how these relate to sex differences in aging. Finally, we present some suggestions for future research in this area and provide recommendations for promising experimental designs.

Molecular markers of aging, exercise capacity, & physical activity in COPD

BackgroundExercise capacity (EC) and physical activity (PA) are independent, potentially modifiable predictors of clinical outcomes in COPD. Molecular measures of biological age may help characterize variability in EC and PA observed among COPD patients. MethodsVeterans with COPD (FEV1/FVC<0.7 or emphysema on chest computed tomography) enrolled in 2 cohorts at VA Boston completed questionnaires, a 6-min walk distance (6MWD) for EC, and blood collection at enrollment. PA data (average daily step count) was collected using an HJ-720 ITC pedometer over ≥5 days. A subset of subjects returned for repeat assessment after 12 weeks. DNA methylation data was generated using the HumanMethylationEPIC platform; epigenetic estimates of biological age and age acceleration were generated using established algorithms. Multivariable models examined the associations between biological age, 6MWD, PA and future acute exacerbations (AEs), adjusting for chronological age, sex, race, smoking status, pack-years, body mass index, cohort, and estimated cell counts. ResultsSubjects (n = 269) were predominantly male (98.5%), white (92.9%), and elderly (70.6 ± 8.5 years) with average FEV1% of 57.7 ± 21.1, 6MWD of 374.3 ± 93.5 m, and daily steps of 3043.4 ± 2374 at baseline. In adjusted models, multiple measures of baseline epigenetic age and age acceleration were inversely associated with 6MWD; only GrimAge was inversely associated with PA. Longitudinal change in Hannum-Age was inversely associated with change in EC at 12 weeks (n = 94). No measures of biological age were significantly associated with prospective AEs over 1.3 ± 0.3 years. ConclusionsEpigenetic measures of biological age are independent predictors of EC and PA, but not AEs, among individuals with COPD.

Abstract 774: Methylation-derived biologic age, telomere length, and lung cancer mortality in heavy smokers from CARET

Abstract Epigenetic alterations, including changes in DNA methylation, and telomere length (TL) are established molecular markers of aging, morbidity, and mortality. We hypothesized that older methylation-derived biologic age (meAge) measured prior to lung cancer diagnoses would be associated with increased post-diagnosis mortality in high risk heavy smokers. Our study included 372 lung cancer cases from the β-Carotene and Retinol Efficacy Trial (CARET), a unique population of heavy smokers at high risk for lung cancer. Genome-wide DNA methylation data (Illumina MethylationEPIC) and TL were assayed in blood collected on average 4.9 years prior to diagnosis. We estimated meAge using scores developed by Hannum (leukocytes; 65/71 CpGs), Horvath (pan tissue; 335/353 CpGs), and Levine (DNAm PhenoAge, whole blood; 513 CpGs). We assessed Pearson correlations between meAge, age at blood draw, and log2-transformed TL, and we defined meAge acceleration (ΔmeAge) as the difference between each meAge and age. We examined associations between ΔmeAge, with and without TL adjustment, and all-cause mortality after lung cancer diagnoses using Cox proportional hazards models adjusted for age, sex, smoking status, pack years, time between blood draw and diagnosis, and methylation-estimated blood cell counts, including a strata variable for early (I/II), late (III/IV), or unknown stage. We assessed mortality in those with both old meAge and short TL (dichotomized at the medians) compared to those with both young meAge and long TL. We modeled all cases and by histotype (adenocarcinoma N=148, squamous cell N=115, small cell N=81). In our study population, mean age (64.3) was underestimated by Hannum and Levine meAges (52.4 and 57.0, respectively) and overestimated by Horvath meAge (70.3). Age was positively correlated with meAges (Hannum r=0.55, P=1E-30; Horvath r=0.49, P=2E-24; Levine r=0.41, P=2E-16), as were meAges with each other (all r≥0.66, P≤3E-48). TL was negatively correlated with age (r=-0.13, P=0.01) and meAges (Hannum r=-0.20, P=0.0001; Horvath r=-0.17, P=0.001; Levine r=-0.15, P=0.003). While each year of age was associated with 3% higher mortality in all cases (95% confidence interval (CI): 1.01-1.06), we did not observe an independent association with ΔmeAge (Hannum 0.99, 0.97-1.01; Horvath 1.00, 0.99-1.02; Levine 1.00, 0.99-1.01) regardless of TL adjustment or histotype. Shorter TL was associated with increased mortality in those who developed small cell lung cancer, as we reported previously; here, we observed that this association was independent of ΔmeAge. Combined old meAge and short TL was not associated with mortality. Though prospectively collected ΔmeAge has been reported to predict all-cause mortality in population-based studies, we did not observe that pre-diagnosis ΔmeAge, nor combined meAge-TL, were associated with mortality in a group of heavy smokers who went on to develop lung cancer. Citation Format: Laurie Grieshober, Stefan Graw, Matt J. Barnett, Mark D. Thornquist, Gary E. Goodman, Chu Chen, Devin C. Koestler, Carmen J. Marsit, Jennifer A. Doherty. Methylation-derived biologic age, telomere length, and lung cancer mortality in heavy smokers from CARET [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 774.

Spatiotemporal dynamics of γH2AX in the mouse brain after acute irradiation at different postnatal days with special reference to the dentate gyrus of the hippocampus.

Gamma H2A histone family member X (γH2AX) is a molecular marker of aging and disease. However, radiosensitivity of the different brain cells, including neurons, glial cells, cells in cerebrovascular system, epithelial cells in pia mater, ependymal cells lining the ventricles of the brain in immature animals at different postnatal days remains unknown. Whether radiation-induced γH2AX foci in immature brain persist in adult animals still needs to be investigated. Hence, using a mouse model, we showed an extensive postnatal age-dependent induction of γH2AX foci in different brain regions at 1 day after whole body gamma irradiation with 5Gy at postnatal day 3 (P3), P10 and P21. P3 mouse brain epithelial cells in pia mater, glial cells in white matter and cells in cerebrovascular system were more radiosensitive at one day after radiation exposure than those from P10 and P21 mice. Persistent DNA damage foci (PDDF) were consistently demonstrated in the brain at 120 days and 15 months after irradiation at P3, P10 and P21, and these mice had shortened lifespan compared to the age-matched control. Our results suggest that early life irradiation-induced PDDF at later stages of animal life may be related to the brain aging and shortened life expectancy of irradiated animals.

Telomere shortening in late-life depression: A potential marker of depression severity.

ObjectivesTelomeres are structures at the extremity of chromosomes that prevents genomic instability, and its shortening seems to be a hallmark of cellular aging. Past studies have shown contradictory results of telomere length (TL) in major depression, and are a few studies in late‐life depression (LLD). This explores the association between TL as a molecular marker of aging and diagnosis of LLD, the severity of depressive symptoms, and cognitive performance in older adults.Methods/designWe included 78 older adults (45 with LLD and 33 nondepressed controls, according to DSM‐V criteria), aged 60–90 years. TL was measured in leukocytes by a quantitative polymerase chain reaction, determining the relative ratio (T/S) between the telomere region copy number (T) and a single copy gene (S), using a relative standard curve.ResultsTL was significantly shorter in the LLD compared with control participants (p = .039). Comparing groups through the severity of depressive symptoms, we found a negative correlation with the severity of depressive symptoms (Hamilton Depression Rating Scale‐21, r = −0.325, p = .004) and medical burden (r = −0.271, p = .038). There was no significant correlation between TL and cognitive performance (Mattis Dementia Rating Scale, r = 0.152, p = .21).ConclusionsWe found that older adults with LLD have shorter telomere than healthy controls, especially those with a more severe depressive episode. Our findings suggest that shorter TL can be a marker of the severity of depressive episodes in older adults and indicate that these individuals may be at higher risk of age‐associated adverse outcomes linked to depression.

Correlation between Telomere Length and Chronic Obstructive Pulmonary Disease-Related Phenotypes: Results from the Chronic Obstructive Pulmonary Disease in Dusty Areas (CODA) Cohort.

BackgroundChronic obstructive pulmonary disease (COPD) is a common chronic respiratory disease with increased prevalence in the elderly. Telomeres are repetitive DNA sequences found at the end of the chromosome, which progressively shorten as cells divide. Telomere length is known to be a molecular marker of aging. This study aimed to assess the relationship between telomere length and the risk of COPD, lung function, respiratory symptoms, and emphysema index in Chronic Obstructive Pulmonary Disease in Dusty Areas (CODA) cohort.MethodsWe extracted DNA from the peripheral blood samples of 446 participants, including 285 COPD patients and 161 control participants. We measured absolute telomere length using quantitative real-time polymerase chain reaction. All participants underwent spirometry and quantitative computed tomography scan. Questionnaires assessing respiratory symptoms and the COPD Assessment Test was filled by all the participants.ResultsThe mean age of participants at the baseline visit was 72.5±7.1 years. Males accounted for 72% (321 participants) of the all participants. The mean telomere length was lower in the COPD group compared to the non-COPD group (COPD, 16.81±13.90 kb; non-COPD, 21.97±14.43 kb). In COPD patients, 112 (75.7%) were distributed as tertile 1 (shortest), 91 (61.1%) as tertile 2 and 82 (55%) as tertile 3 (longest). We did not find significant associations between telomere length and lung function, exacerbation, airway wall thickness, and emphysema index after adjusting for sex, age, and smoking status.ConclusionIn this study, the relationship between various COPD phenotypes and telomere length was analyzed, but no significant statistical associations were shown.

From the Literature

From the Literature

Alternate Day Fasting Improves Physiological and Molecular Markers of Aging in Healthy, Non-obese Humans

Caloric restriction and intermittent fasting are known to prolong life- and healthspan in model organisms, while their effects on humans are less well studied. In a randomized controlled trial study (ClinicalTrials.gov identifier: NCT02673515), we show that 4weeks of strict alternate day fasting (ADF) improved markers of general health in healthy, middle-aged humans while causing a 37% calorie reduction on average. No adverse effects occurred even after >6months. ADF improved cardiovascular markers, reduced fat mass (particularly the trunk fat), improving the fat-to-lean ratio, and increased β-hydroxybutyrate, even on non-fasting days. On fasting days, the pro-aging amino-acid methionine, among others, was periodically depleted, while polyunsaturated fatty acids were elevated. We found reduced levels sICAM-1 (anage-associated inflammatory marker), low-density lipoprotein, and the metabolic regulator triiodothyronine after long-term ADF. These results shed light on the physiological impact of ADF and supports its safety. ADF could eventually become a clinically relevant intervention.

Quality of life for men of different ages in the European Russian North and its relationship with self-rated health and hormonal status

Assessment of the quality of life in male inhabitants of the European Russian North revealed decreased indices of the physical health component (the scale of role functioning determined by physical condition) and mental health component (the scales of social-role functioning and role functioning determined by emotional state and mental health) as compared to the inhabitants of Siberia as a control (comparison) group. Men aged under 29 had the highest scores at all scales. The scores decreased with age. The greatest reduction was observed for the scales of general well-being and bodily pain. There was a moderate decrease for the scales of physical functioning, role functioning determined by emotional state, and role functioning determined by physical condition. Quality of life was closely related to the northerners’ self-rated health, pathology index, molecular marker of aging, and biological age. A negative correlation between these values implies deterioration in the physical and mental health with biological age. The quality of life for the northerners also correlated with their hormonal status. There was a relationship between testosterone and three scales of physical health components, i.e., between cortisol and one scale of physical component and between both dehydroepiandrosterone sulfate and insulin and the scales of physical and mental components of health. The effect of various hormones on different age groups of northerners was demonstrated.

Peptides and CCL11 and HMGB1 as molecular markers of aging: Literature review and own data

Cytokines CCL11 (eotaxin) and HMGB1 (alarmin 1) are molecular markers of ageing and neurological, cardiovascular, and immune diseases. Created at the St. Petersburg Institute of Bioregulation and Gerontology, these short peptides are known to regulate gene expression and protein synthesis. They promote decreased mortality and deceleration of pathology in the elderly. The review suggests that the dipeptide vilon (Lys-Glu) and tetrapeptide epitalon (Ala-Glu-Asp-Gly) are involved in regulation of the CCL11 and HMGB1 genes as activators of their expression. The geroprotective effect of vilon and epitalon is probably due to the suppression of these genes.

Quantitative analysis of isomeric (l-α-, l-β-, d-α-, d-β-) aspartyl residues in proteins from elderly donors

Homochirality is essential for life. For a long time, it was considered that d-amino acids were excluded from living systems. In the past 30 years, however, d-amino acids have been found in living organisms in the form of free amino acids, peptides and proteins, owing to advances in the analysis of optical isomers of amino acids. Free d-amino acids and d-amino-acid-containing peptides have been shown to have important physiological functions. The amount of d-aspartate (Asp) residues in protein spontaneously increases in metabolically inert tissues such as the eye and brain during aging, and may be related to cataract formation and the development of Alzheimer disease, suggesting that d-Asp might be a molecular marker of aging and age-related disorders. The presence of d-Asp in living organisms is thought to result from the isomerization of l-Asp residues in some proteins. Furthermore, the isomerization of Asp does not occur uniformly but only at specific sites. Therefore, it is necessary to determine the sites of isomeric Asp in these proteins in order to elucidate the mechanism of spontaneous Asp isomerization during aging. Herein, we summarize the localization and mechanism of d-amino acids in proteins of living tissues, and the effects of d-amino acid formation in proteins. Furthermore, we describe methods for the analysis of protein-bound d-amino acids including a conventional enantioseparation method based on HPLC and a new convenient method based on LC–MS that can identify the specific sites of d-Asp in proteins.

Abstract P6-08-34: p16INK4a expression and chemotherapy toxicity in women with early stage breast cancer

Abstract Background: Increased expression of p16INK4a, a molecular marker of aging, is a hallmark of increased cellular senescence in most mammalian tissues. In human peripheral blood T-lymphocytes, expression of p16INK4a increases 10-fold between 20 and 80 years of age (Liu et al, Aging Cell, 2009). We hypothesized that higher "molecular age," as evidenced by increased T-cell expression of p16INK4a at the time of initiation of breast cancer (BC) chemotherapy (CRx), predicts increased treatment-related toxicity. Methods: Patients (pts) with early breast cancer scheduled to receive neoadjuvant (NA) or adjuvant (Adj) chemotherapy (CRx) had p16INK4a evaluation performed prior to treatment. Expression of p16INK4a mRNA in CD3+ T-lymphocytes was determined using TaqMan real time quantitative reverse transcription polymerase chain reaction. Grade 3 and 4 (G3/4) hematologic (H) and non-hematologic (NH) toxicities (NCI CTCAE version 4) were assessed during and within 4 weeks of completion of CRx. Wilcoxon Rank Sum tests compared p16INK4a between groups. Results: 93 pts with Stage I-III BC and complete toxicity data during and within 4 weeks after completion of CRx have been accrued. Median age (range) was 52 (25-76). 48 (52%) of pts were hormone receptor (HR) positive, 21 (23%) HER-2 positive, and 24 (26%) triple-negative. 39 (42%) received NA and 54 (58%) received Adj CRx. 57 pts (61%) received an anthracycline containing combination and 21 (23%) cyclophosphamide/docetaxel (TC). 85 pts (91%) received pegfilgrastim. Overall, 69 pts (74%) had a G3/4 toxicity during or ≤4 wks of CRx, 54% NH and 40% H. 22 pts (24%) were hospitalized for CRx related toxicity and 11 (12%) of these admissions were for neutropenic fever (NF). 23 (25%) reported G3/4 fatigue during CRx and had significantly higher p16INK4a values at baseline than those without fatigue (p=0.03). There was no significant association of baseline p16INK4a and other NH or H toxicity or hospitalization in this cohort. Conclusion: In this small sample of pts treated with anthracycline and non-anthracycline containing NA and Adj CRx regimens, there was a significant association of baseline p16INK4a and G3/4 fatigue. The heterogeneity of treatment and use of pegfilgrastim in almost all pts limits the power of this study to find significant relationships between p16INK4a and other toxicities. The cohort for this study is being expanded to further explore p16INK4a as a predictor for G3/4 toxicity. Support: Breast Cancer Treatment Foundation, New York, NY; University Cancer Research Fund, University of North Carolina, Chapel Hill. Citation Format: Hyman Muss, Allison Deal, Arti Hurria, Natalia Mitin, Chad Torrice, Krishnamurthy Janakiraman, Trevor Jolly, Grant Williams, Shani Alston, Jerard West, Laura Zavala, Vani Katheria, Norman Sharpless. p16INK4a expression and chemotherapy toxicity in women with early stage breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-08-34.

P16INK4aexpression after chemotherapy in older women with early-stage breast cancer.

9002 Background: Breast cancer (BC) is a disease of aging. In healthy humans, p16INK4a expression increases markedly in peripheral blood T-lymphocytes with chronologic age and exposure to mutagens such as tobacco. The expression of p16INK4a increases exponentially with age, with an average 10-fold increase between ages 20 and 80 years old (Liu et al, Aging Cell, 2010). To determine the effects of BC therapy on a molecular marker of aging, we measured T-cell expression of p16INK4a in older women undergoing therapy for early stage BC. Methods: Pts ≥65 yrs with Stage I-III BC had p16INK4a expression measured in peripheral blood T-cells isolated by magnetic bead sorting on the same day as phlebotomy. Expression of p16INK4a was determined at least 3 months after the completion of BC therapy by TaqMan qRT-PCR. Expression of p16INK4a was measured in replicate and normalized to a housekeeping control gene (18S ribosomal RNA). Expression analysis was determined by investigators blinded to clinical data. Results: 73 of 200 planned patients have had T-cell expression of p16INK4a assessed. Mean/median age range (years) for all pts was 73/71 and (65-93). All pts had surgery, 42 (58%, mean age 74), had no chemotherapy (CRx) and 31 (42%, mean age 71) had CRx. Of the 31 with CRx 19 (61%) had anthracyclines, 24 (77%) cyclophosphamide, and 20 (65%) breast irradiation. Expression of p16INK4a was not correlated with endocrine therapy use or radiotherapy. Expression was increased in patients treated with CRx (Table). Conclusions: In the oldest patients, CRx use was associated with increased expression of p16INK4a, a molecular marker of aging. In patients over the age of 65, CRx use is associated with a more than one decade increase in a marker of molecular age. Accrual continues and expanded data will include toxicity assessment based on pre-treatment p16INK4a. Supported by the Breast Cancer Research Foundation, New York, NY; the Burroughs Wellcome Fund; and the National Institute of Aging (AG024379). Age group No. of pts. No CRx vs. CRx Log2 [p16INK4a] (SEM) No CRx vs. CRx P value All (age adjusted) 42 / 31 7.52 (0.15) / 8.12 (0.14) 0.009 Age 65-74 25 / 23 7.89 (0.18) / 8.23 (0.17) 0.23 Age ≥ 75 17 / 8 8.23 (0.23) / 9.22 (0.30) 0.03

Gene activities that mediate increased life span of C. elegans insulin-like signaling mutants

Genetic and RNA interference (RNAi) screens for life span regulatory genes have revealed that the daf-2 insulin-like signaling pathway plays a major role in Caenorhabditis elegans longevity. This pathway converges on the DAF-16 transcription factor and may regulate life span by controlling the expression of a large number of genes, including free-radical detoxifying genes, stress resistance genes, and pathogen resistance genes. We conducted a genome-wide RNAi screen to identify genes necessary for the extended life span of daf-2 mutants and identified approximately 200 gene inactivations that shorten daf-2 life span. Some of these gene inactivations dramatically shorten daf-2 mutant life span but less dramatically shorten daf-2; daf-16 mutant or wild-type life span. Molecular and behavioral markers for normal aging and for extended life span in low insulin/IGF1 (insulin-like growth factor 1) signaling were assayed to distinguish accelerated aging from general sickness and to examine age-related phenotypes. Detailed demographic analysis, molecular markers of aging, and insulin signaling mutant test strains were used to filter progeric gene inactivations for specific acceleration of aging. Highly represented in the genes that mediate life span extension in the daf-2 mutant are components of endocytotic trafficking of membrane proteins to lysosomes. These gene inactivations disrupt the increased expression of the DAF-16 downstream gene superoxide dismutase sod-3 in a daf-2 mutant, suggesting trafficking between the insulin-like receptor and DAF-16. The activities of these genes may normally decline during aging.