Abstracts

Part I: Circadian Disruption as a Cancer Cause

SESSION I: How does Circadian Disruption and/or Light at Night Increase Cancer Risk? Is Melatonin Suppression By Light at Night an Important Potential Cause of Increased Cancer Risk?

The Melatonin Hypothesis (Light-At-Night, Circadian Disruption, And Breast Cancer)

Richard G. Stevens

Breast cancer incidence is increasing worldwide for mostly unknown reasons. Mortality is also increasing rapidly in the developing world. The idea was stated over 20 years ago that increasing use of electric light might be a driver of risk based on light-induced disruption of circadian rhythms, especially of melatonin. The theory has provided a series of predictions including that non-day shift work would increase risk, blind women would be at lower risk, long sleep duration would lower risk, and community nighttime light level would co-distribute with breast cancer incidence on the population level. On the basis of existing epidemiological evidence, the IARC concluded "shift-work that involves circadian disruption is probably carcinogenic to humans (Group 2A)". It is important to determine the biological mechanism for the purposes of mitigation and intervention because increasing numbers of people must do non-day shift work in throughout the world.

Originally, the suggested biological mechanism was a light-induced reduction in nocturnal melatonin production leading to increased estrogen production and consequent increased lifetime risk of breast cancer. The scope of biological possibilities has expanded both with regard to how reduced or altered melatonin could affect risk, and to how alterations in other aspects of the circadian rhythm could influence risk, particularly functioning of circadian genes.
A newly recognized potential mechanism is by promoter methylation of circadian genes. In a case-control study in Connecticut, we found a significant hypo-methylation of CLOCK promoter and hyper-methylation of CRY2 promoter in cases compared to controls; the cases had donated blood before any therapy had begun. We are currently designing a study to determine if non-day shift work also results in promoter alterations in these genes consistent with an increased risk of breast cancer.

Epidemiology of Circadian Disruption and Cancer Risk: The Nurses’ Health Study and Beyond

Eva S. Schernhammer, Harvard Medical School, Boston, MA

Night shift work was recently classified by the WHO as probably carcinogenic.
Today there is growing support, both from experimental as well as from observational studies including the Nurses’ Health Study cohorts, for a positive association between light exposure at night (as encountered by night workers), circulating melatonin, and risk of cancer as well as other chronic diseases. During this presentation, you will learn about underlying mechanisms and current epidemiologic evidence in support of these associations.

Role of Light and Ocular Physiology for Human Melatonin Regulation

George C. Brainard, Neurology Dept., Thomas Jefferson University, Philadelphia, PA

It has been hypothesized that increased incidence of breast cancer in industrialized countries is partially due to increased nighttime exposure to light which reduces melatonin secretion from the pineal gland (Stevens et al., 2007). In support of this, studies demonstrate that exposure to light at night acutely suppresses melatonin and stimulates tumor progression in rats (Blask et al., 2005). To assess this hypothesis, it is important to understand how the human eye transduces light stimuli for melatonin regulation. More light is required to activate the circadian and neuroendocrine systems than to stimulate the visual system. When exposure is carefully controlled, however, illuminances as low as 100 lux of white light can suppress nocturnal melatonin, and 119 lux of white light can phase-shift melatonin rhythms in humans (Brainard et al., 1997; Zeitzer et al., 2000). To understand how such low illuminances can regulate melatonin, it is necessary to examine the relevant ocular physiology that mediates such photic effects: 1) gaze behavior, 2) ocular lens age, 3) pupillary dilation, 4) photoreceptor sensitivity, 5) retinal photoreceptor location, 6) photoreceptor adaptation, and 7) the neural integration photic stimuli spatially and temporally. Recent analytic action spectra in animals and humans show that light in the blue portion of the visible spectrum (446-485 nm) is most potent for circadian, neuroendocrine and neurobehavioral regulation (Brainard and Hanifin, 2005). When exposures to monochromatic 460 nm light are carefully controlled, as little as 1.3 lux can acutely suppress melatonin and 5 lux can phase-shift the melatonin rhythm (Brainard et al., 2001; Lockley et al., 2003). Highly controlled laboratory exposures, however, are not likely to represent relevant exposures in everyday life. Given the increasing exposure of citizens to light during the night in industrialized countries, it is important to elucidate the photosensory physiology in the eye for melatonin regulation. Support: NIH RO1NS36590, Nat. Space Biomedical Res. Inst. under NASA Cooperative Agreement NCC 9-58, NCI RO1CA85408 and NIEHS R21ES11659.

Melatonin Receptors and Their Function and Physiology in Cancer

Margarita L. Dubocovich, Department Pharmacology and Toxicology, School of Medicine and Biomedical Science, University at Buffalo, Buffalo, NY

Melatonin transmits dark signal information and modulates a number of physiological functions including sleep promotion, circadian phase, vascular function, metabolism, and tumor cell growth, through activation of MT1 and/or MT2 melatonin receptors. The discovery and development of novel and receptor type specific ligands, the elucidation of the molecular structure and signaling pathways for the receptors, and the creation of mice with genetic deletion of either the MT1 and/or MT2 melatonin receptors lead to dramatic advances in our understanding of melatonin receptor function and their role in the treatment of circadian rhythms disruptions.
Light at night decreases endogenous melatonin secretion and disrupts circadian rhythmicity leading to decreases in MT1 melatonin receptor activation and in turn cancer cell growth (Blask D. et al., Cancer Res., 2005). Our results suggest that endogenous melatonin through activation of MT1 and MT2 melatonin receptors plays a key role in maintaining circadian homeostasis. Furthermore, we demonstrated that activation of MT1 melatonin receptors by exogenous melatonin entrains disrupted circadian rhythms through actions in the suprachiasmatic nucleus. We conclude that melatonin supplementation, through activation of MT1 melatonin receptors, plays a key role in attenuating circadian disruptions-induced cancer cell growth and in entraining disrupted circadian phase.

Molecular Mechanisms of Melatonin Anticancer Effects

Steven M. Hill, Shulin Xian, Lin Yuan, Tamika Duplessis and Lulu Mao,Department of Structural & Cellular Biology, Tulane Cancer Center and Louisiana Cancer Research Consoritum,Tulane University School of Medicine, New Orleans, LA

Melatonin has been shown by numerous laboratories to suppress the development and growth of breast cancer. We have demonstrated that via activation of its MT1 receptor, melatonin modulates the transcriptional activity of various nuclear receptors (ER, GR, ROR and RAR) and the proliferation of both ER+ and ER- human breast cancer cells. Upon activation by melatonin, the MT1 receptor specifically couples to a number of G proteins including the Gi2, Gi3, Gq and Gll. Employing dominant-negative (DN) and dominant-positive (DP) G proteins we demonstrated that Gi2 proteins mediate the suppression of estrogen-induced ER transcriptional activity by melatonin, while the Gq proteins mediate the enhancement of retinoid-induced RAR transcriptional activity by melatonin. The MT1 receptor is expressed in human breast cancer cell lines and primary human breast tumors and our studies demonstrate an inverse correlation between ER and MT1 expression. Furthermore, our immunofluorescent/confocal microscopic studies demonstrate that the MT1 receptor is localized to the caveoli, and that MT1 expression in breast cancer cells can be repressed by estrogen and melatonin. Multiple mechanisms are utilized by melatonin, via activation of its MT1 receptor, to suppress the development and growth of breast cancer including regulation of growth factors (PKA, PKC, Erk/MAPK, Ca++/CaM, etc.), regulation of gene expression (via modulation of nuclear receptors, ER, RAR, RXR and ROR), regulation of clock genes, suppression of linoleic acid uptake and 13-HODE production, inhibition of tumor cell invasion and metastasis, and even regulation of mammary gland development. We have previously reported that the clock gene, Period 2 (Per2), is not expressed or expressed at very low levels in human breast cancer cells but, that its re-expression in breast cancer cells results in increased expression of p53 and induction of apoptosis. Thus, Per2 acts as a tumor suppressor gene in human breast cancer. We have also demonstrated that melatonin, via repression of ROR transcriptional activity can block the expression of the clock gene, BMAL1, and that this is associated with the decreased expression of the sertuin, SIRT1. SIRT1, a member of the Silencing Information Regulator family, is a well-know histone deacetylase that can block the expression of DNA repair enzymes (p53, BRCA1 & 2 and Ku70) and can suppress the expression of apoptosis associated genes (p53, FOXOA3) while enhancing tumor metabolism via regulation of PGC-1 and PPAR expression. Finally, we have generated an MMTV-MT1-flag mammary Knock-In transgenic mouse to examine the role of melatonin and the MT1 receptor in mammary gland development. Real time PCR and Western blotting analysis demonstrate MT1-flag expression within mammary glands of pubescent virgin MT1 transgenic female mice, and a significant increase of MT1-flag expression in pregnant MT1 transgenic mice. Analysis of mammary gland whole mounts from MT1 transgenic mice show significantly reduced ductal branching, reduced ductal epithelium proliferation and reduced terminal end bud (TEB) formation within the mammary gland of nulliparous (post-pubescent) and parous transgenic mice. Elevated levels of MT1-transgene expression in lactating female MT1-transgenic mice are associated with a dramatic reduction in the expression of -casein and whey acidic milk proteins in lactating mammary epithelium. A significant reduction in body weight was noted in suckling pups from MT1 transgenic dams, however, body weight differences between pups of transgenic and control dams was lost after weaning, supporting the concept that impaired lactation in MT1 transgenic dams resulted in decreased pup weights. Further analyses showed significantly reduced ER expression in mammary glands of MT1 transgenic mice. These results demonstrate that the MT1 receptor is a major transducer of melatonin’s actions in the breast suppressing mammary gland development and mediating the anti-cancer actions of melatonin through multiple pathways.

Circadian Stage-Dependent Metabolic and Anticancer Effects of Melatonin in Rats and Women and Their Disruption by Light at Night

David E. Blask, Ph.D.,M.D1., Robert T. Dauchy, B.A.1, George C. Brainard, Ph.D2., and John Hanifin, B.S.2, 1Tulane University School of Medicine, New Orleans, LA and 2Thomas Jefferson University, Philadelphia, PA

The circadian production of melatonin by the pineal gland during the night provides an inhibitory signal to tissue-isolated steroid receptor negative (SR-) MCF-7 human breast cancer xenografts in female nude rats. A central mechanism for melatonin’s anticancer effects in vivo involves a melatonin receptor-mediated inhibition of linoleic acid (LA) uptake and its metabolism to mitogenically active 13-hydroxyoctadecadienoic acid (13-HODE). These human breast cancer xenografts exhibit robust circadian rhythms of glucose uptake and metabolism to lactic acid, LA uptake and metabolism to 13-HODE, cAMP formation, and proliferative activity. Exposure of xenograft-bearing rats to 0.08 W/cm2 (0.2 lux) of dim, polychromatic light at night suppresses melatonin while the nocturnal circadian rhythm of feeding and drinking behavior is preserved under these conditions. Dim light at night results in the elimination or modification of these circadian rhythms culminating in unfettered tumor glucose, and LA uptake and metabolism, cAMP formation, [3H]thymidine incorporation into DNA and tumor growth. Similar effects occur in xenografts perfused with blood from healthy female subjects during the dark and after exposure to bright (2800 lux) polychromatic light at night.

SESSION II: The cellular molecular clock and cancer risk and biology

Molecular Clock Mechanisms by Which Circadian Disruption Causes Colon and Breast Cancer

Patricia Wood, Xiaoming Yang, William Hrushesky, Dorn VA Medical Center, University of South Carolina, Columbia, SC

Period genes (Per2, Per1) are essential circadian clock genes. Period genes also function as negative growth regulators. Per2 mutation in mice is associated with de novo and radiation-induced epithelial hyperplasias, tumors, and an abnormal DNA damage response. Period gene mutations or decreased expression along with increased promoter methylation are reported in human tumors. Other clock gene mutations in rodents, however, have not been associated with a tumor prone phenotype. Clinical settings associated with circadian clock disruption (e.g. shift work, light at night) are associated with an increased cancer risk. The mechanisms responsible for these connections between the circadian clock and cancer are not well defined. We hypothesize that circadian disruption per se is not uniformly tumor promoting and the mechanisms for tumor promotion by specific circadian clock disturbances will differ dependent upon the gene(s) and pathway(s) involved. We hypothesize specifically that Period clock gene mutations promote tumorigenesis by unique molecular pathways. We find that Per2 modulates β-catenin and cell proliferation in colon and non-colon cancer cell lines. The Per2 mutation is associated with an increase in intestinal β-catenin levels and colon polyp formation. Per2 mutation also increases ApcMin/+-mediated intestinal and colonic polyp formation. Our results support the role of the Per2 clock gene as a tumor suppressor. We propose that tumor promotion by loss of Per2 clock gene is unique to Period genes as a result of altered β-catenin signaling. Altered Per2 expression may have similar effects in the promotion of other epithelial cancers. Period clock genes may offer new targets for cancer prevention and control.

Circadian Time Dependent Tumor Suppressor Function of Period Genes

Xiaoming Yang¹, Patricia Wood ^1,2 and William Hrushesky ^1,2, Dorn VA Medical Center ^1, University of South Carolina ², Columbia, SC

The core clock genes, Periods (Per1 and Per2), have tumor suppressor properties. Altered methylation status in Per1 and Per2 promoters and mutations in their coding sequences have been identified in breast cancers. Per2 deficient mice show premature aging and cancer prone phenotypes. On the other hand, overexpression of Per1 or Per2 inhibits cancer cell growth in culture. Per1 has also been linked to Chk2 mediated DNA damage response pathway. We have showed Per1 and Per2 exert their tumor suppressor functions in a circadian time dependent manner. Tumor growth has a circadian rhythm in animals. Down regulation of Per1 or Per2 increases tumor growth only at certain times of the day. In addition, Per1 and Per2 differentially regulate tumor growth rhythm in vivo. From chronotherapy point of view, tumors with mutant or down regulated Per1 or Per2 may respond to a given anti-proliferation drug differently than tumors with intact Period genes.

Per Gene Studies in Leukemia and Other Cancers

Sigal Gery¹ and H. Phillip Koeffler¹, ¹Cedars-Sinai Medical Center, Division of Hematology/Oncology, UCLA School of Medicine, Los Angeles, CA

Circadian rhythms are endogenous biological clocks that govern fundamental physiological and behavioral functions. Consequently, perturbations of these rhythms have bee associated with pathogenic conditions, such as depression, diabetes, and cancer. CCAAT/enhancer-binding proteins (C/EBPs) are a family of transcription factors that regulate cell growth and differentiation in various tissues, and have also been implicated in many cancer types. Using expression profiling studies, we found that the levels of 2 core components of the circadian network, Per2 and Rev-Erbalpha, are significantly altered by C/EBPs. Further studies showed that levels of Per2 were reduced in diffuse large B-cell lymphoma (DLBCL) and acute myeloid leukemia (AML) patient samples, as well as in lymphoma cell lines. Overexpression of Per2 in a myeloid human leukemia cell line (K562) and a murine pro-B lymphoid cell line (Ba/F3) resulted in growth inhibition, cell cycle arrest, apoptosis and loss of clonogenic ability. Additionally, we and others have shown that Per1 and Per2 are downregulated in solid tumors including breast, endometrial and lung cancers. Furthermore, ectopic expression of Per1 or Per2 in cancer cell lines from these tissues strongly inhibits their growth. These results support the emerging role of circadian genes in tumor suppression. Elucidating the connections between clock genes and cell proliferation could open avenues for new therapeutic strategies.

Circadian Disruption as Preventable Cause for and Relievable Burden of Cancer

William J.M. Hrushesky, MD, WJB Dorn Veterans Affairs Medical Center and Dept. of Epidemiology and Biostatistics, University of South Carolina, Columbia, SC

Life has evolved on this planet with regular daily spans of direct solar energy availability alternating with nocturnal spans of dark. Virtually every earth-borne life form has factored this circadian pattern into its biology in order to assure the temporal coordination with its resonating environment, a task essential for its individual and its species survival. The first whole genome inspections of mutations in human colon and breast cancer have observed specific retained clock gene mutations. Single nucleotide polymorphisms of clock, clock-controlled and melatonin pathways have been found to confer excess and protection from cancer risk. Experimental studies have shown that specific core clock genes (Per2 and Per1) are tumor suppressors, as their genetic absence doubles tumor number and decreasing their expression in cancer cells doubles cancer growth rate, while their over-expression decreases cancer growth rate. Experimental interference with circadian clock function increases cancer growth rate and clinical circadian disruption is associated with higher cancer incidence, faster cancer progression, and shorter cancer patient survival. Patients with advanced lung cancer suffering greater circadian activity/sleep cycle disruption suffer greater interference with function, greater anxiety and depression, poorer nighttime sleep, greater daytime fatigue, and poorer quality of life than comparable patients who maintain good circadian integration. We must now determine whether strategies known to help synchronize the circadian clocks of normal individuals can do so in advanced cancer patients and whether doing so allows cancer patients to feel better and/or live longer. Several academic laboratories and at least two large pharmaceutical firms are screening for small molecules targeting the circadian clock to stabilize its phase and enhance its amplitude and thereby consolidate and coordinate circadian organization which, in turn, is likely to help prevent and control human cancer

PART 2: CANCER AS A CAUSE OF CIRCADIAN DISRUPTION

SESSION III: Strategies for Understanding and Correcting Cancer Associated Circadian Disruption and Relieving Cancer Patient Suffering

Defining the Burdens of Circadian Disruption in Advanced Lung Cancer and How They May B Diminished

William JM Hrushesky, James Grutsch, Patricia Wood, Carol Ferrans, Justin Reynolds, Dinah Quiton, Jovelyn Du-Quiton, Robert Levin, Christopher Lis, Donald Braun. Dorn VA Medical Center, University of South Carolina, Columbia, South Carolina; Cancer Treatment Centers of America, Zion, IL

Lung cancer is the most common and most deadly cancer of the developed and developing world. Once discovered, it is seldom cured, spreads rapidly, and usually kills within a year or two. The diagnosis of advanced lung cancer, defined as cancer extent precluding surgical resection with curative intent, is accompanied by a range of symptoms and subsequent sickness behaviors that severely limit the performance capacities, comfort, and well being of these patients. The most frequent symptoms include nocturnal restlessness and poor sleep accompanied by daytime malaise and fatigue, i.e. subjective circadian sleep activity rhythm disruption; a general loss of energy and vitality, a decrease in appetite and gustatory enjoyment especially in the second half of the daily waking hours with subsequent muscle mass and weight loss and cachexia; as well as anxiety depression and a loss of joi d’vivre with severely diminished quality of life when compared to those without lung cancer. We hypothesized that cancer-caused circadian disruption is a potentially remediable root cause of many of the most frequent symptom burdens of advanced lung cancer. We tested this hypothesis by objectively measuring sleep and activity rhythms, subjectively assessing nocturnal sleep quality, the frequency and severity of daytime fatigue, anxiety, depression, and quality of life among 84 patients suffering from unresectable advanced non-small cell lung cancer (Stage III or IV). We found that many quantitative measures of the robustness of circadian organization were positively associated with nocturnal sleep quality and quantity, daytime activity levels, low daytime fatigue levels, low anxiety and depression scores, better performance of tasks of daily living, higher quality of life (as measured by the ECOG lung cancer QOL scale) and most importantly the Ferrans/Powers QLI scale satisfaction with health functioning domain. The most robust correlations exist between Actigraphic measures of the robustness of daytime activity and quietude of nightly sleep, the amplitude of the daily activity patterns and the day-to-day stability of the peak of the daily activity signature. This work allows us to quantitatively and objectively define the concept of circadian disruption and its key physiologic correlates within patients with advanced lung cancer. It shows us that the most prominent negative symptoms associated with advanced lung cancer are quantitatively reflected in these key objective measures of circadian activity/sleep disruption. These findings will now allow us to test strategies to reverse or improve these specific measures of circadian disruption and to discover whether doing so, in turn, diminishes symptom burden allowing advanced lung cancer patients to feel better longer and, perhaps, to live well longer.

CIRCADIAN RHYTHM IN REST AND ACTIVITY: A BIOLOGICAL CORRELATE OF QUALITY OF LIFE AND A PREDICTOR OF SURVIVAL IN PATIENTS WITH METASTATIC COLORECTAL CANCER

Pasquale F. Innominato ^1,2,3, Christian Focan ⁴, Thierry Gorlia ⁵, Thierry Moreau ⁶, Carlo Garufi ⁷, Jim Waterhouse ⁸, Sylvie Giacchetti ^1,2,3, Bruno Coudert ⁹, Stefano Iacobelli ¹⁰, Dominique Genet ¹¹, Marco Tampellini ¹², Philippe Chollet ¹³, Marie-Ange Lentz ⁵, Marie-Christine Mormont ¹§, Francis Lévi ^1,2,3, Georg A. Bjarnason ¹⁴ for the ARTBC Chronotherapy Group.

1. INSERM, U776 « Biological Rhythms and Cancers », Villejuif, France. 2. Univ Paris-Sud, UMR-S0776, Orsay, France. 3. Assistance Publique-Hôpitaux de Paris, Chronotherapy Unit, Department of Oncology, hôpital Paul Brousse, 14 avenue P.V. Couturier, 94808 Villejuif, Cedex, France. 4. CHC-Clinique Saint Joseph, rue de Hesbaye 75, B-4000-Liège, Belgium. 5. European Organisation for Research and Treatment of Cancer (EORTC) Data Center, AISBL-IVZW, Avenue E. Mounierlaan, 83/11, Bruxelles 1200 Brussel, Belgium. 6. INSERM, U780 “Research in Epidemiology and Biostatistic”, 14 avenue P.V. Couturier, 94808 Villejuif, Cedex, France.7. Istituto Regina Elena, Via Elio Chianesi 53, 00144 Roma, Italy. 8. Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Hatton Garden, Liverpool, L3 2AJ United Kingdom. 9. Centre Georges-François Leclerc, 1 rue du Pr Marion, BP 77980 - 21079 Dijon CEDEX – FRANCE. 10. Department of Oncology & Neurosciences, University «G. d’Annunzio» Medical School, Via dei Vestini, 5 - 66100 Chieti, Italy. 11. Service d'Oncologie Médicale, CHU Dupuytren, 2 Avenue M.L. King, 87042 Limoges Cedex. France. 12. Ospedale San Luigi Gonzaga, Regione Gonzole 10, 10043 Orbassano, Italy. 13. Centre Jean Perrin, 58 Rue Montalembert, BP 392, 63011 Clermont-Ferrand, France. 14. Sunnybrook Odette Cancer Centre, 2075 Bayview Avenue, Toronto, Ontario, M4N 3M5, Canada. § Current address: Pfizer Oncology, Pfizer Inc., Kirkland, QC, Canada

In a single-institution study, the extent of rest/activity rhythm (CircAct) perturbation independently predicted for survival and tumor response in 192 patients receiving chemotherapy for metastatic colorectal cancer (MCRC). Moreover, the main CircAct parameters correlated with several quality of life (HRQoL) scales. In this prospective study we attempted to extend these results to an independent cohort of chemotherapy-naïve MCRC patients participating in an international randomized phase III trial (EORTC 05963) of chronomodulated vs. conventional chemotherapy with 5-fluorouracil, leucovorin and oxaliplatin. Patients from nine institutions completed the EORTC QLQ-C30, and wore a wrist-accelerometer (actigraph) for 3 days before chemotherapy delivery. Two validated actigraphy parameters (I<O and r24) were used to estimate CircAct. Of 130 patients with baseline CircAct assessments, 96 had baseline HRQoL data. I<O correlated with global quality of life, physical functioning, social functioning, fatigue and appetite loss (r>|0.25|, p<0.01). I<O independently predicted for overall survival with a Hazard Ratio of 0.94 (p<0.0001). Unexpected gender differences in survival of patient on this trials and recent data on gender differences in rhythmic gene expression will be discussed. The circadian timing system constitutes a novel therapeutic target. Interventions that normalize circadian timing system dysfunction may impact quality of life and survival in cancer patients.

Symptoms, Quality of Life and Neurocognitive Assessment, 24 Hour Rest/Activity and Cortisol Rhythms, Correlated with Serum Cytokines in Gastrointestinal Cancer Patients Treated with Chemoradiation

Tyvin Rich, Meredyth Evans, Michele Turner, Haidy Lee, Gina Petroni, University of Virginia Health System, Charlottesville, VA

Introduction: Current hypotheses for the cause of de novo symptoms in cancer patients, and for those induced by treatment, center around models of a) sickness behavior and b) disrupted circadian / hypothalamic signaling. We have assessed serum levels of pro-inflammatory cytokines and epidermal growth factor ligands in conjunction with behavioral and circadian rhythms in cancer patients.
Methods: 27 patients with a mean age of 62 and a male/female ratio of 1.2, with diagnoses of pancreatic, esophageal, rectal, and hepatoma, were treated with Tomotherapy plus daily Capecitabine. Prior to and at the end of treatment fatigue and Pain inventories, Anxiety and Depression assessment, FACT-G, Sleep disturbance, 24 hour rest/activity and cortisol rhythms, and serum cytokines were assessed.
Results: These patients were significantly fatigued, slept poorly, and have high levels of anxiety and depression prior to and at the completion of treatment compared to a normal population; damped actigraphy patterns (r 24 was 0.37 and 0.32, prior to and at the end of treatment); the cortisol slope fell from 1.79 to 1.62. There were no alterations in neurocognitive functions. Serum IL-6 and IL-8 and VEGF levels were significantly elevated compared to a large normal population. No elevations in IL-1, INF-gamma, TNF-alpha, or EGF. The mean levels of TGF-alpha were 14 to 17 ng/ml. Western blot for other loco/motor inhibitors showed neuregulin-1(a member of the EGFR-3 family) and cardiotrophin- like cytokine.
Summary: Symptoms are associated with poor rest/activity patterns and damped serum cortisol levels in gastrointestinal cancer patients treated with chemoradiation. There is a significant elevation of the proinflammatory cytokines family and elevated levels of ligands of the EGFR.

Circadian Phase Setting Effects of Melatonin in Free Living People

Steven W. Lockley ¹. Division of Sleep Medicine, Brigham and Women’s Hospital, Boston, Massachusetts; ². Division of Sleep Medicine, Harvard Medical School, Boston, MA

In addition to the potential oncostatic properties of melatonin therapy currently under investigation, melatonin treatment has well-established effects on the timing of the circadian pacemaker and on sleep. Melatonin can phase shift the timing of the circadian clock in humans to an earlier time (phase advance) or later time (phase delay) depending on the timing of treatment: Under normal conditions, melatonin administered in the evening will cause a phase advance whereas melatonin administered in the morning will cause a phase delay. Melatonin treatment also has direct sleep-promoting properties, particularly when taken at a time when endogenous melatonin is not being produced, during the biological day. These properties of melatonin may be useful in alleviating the sleep disturbances reported by cancer patients either directly, or by correcting circadian phase disturbances that may be associated with cancer or its symptoms. Several analogues of melatonin have also been developed which may have similar benefits although there are no studies to date on the effects of these drugs in cancer patients. This talk will review the potential benefits of melatonin and its analogues for alleviating cancer-associated circadian disruption and sleep disturbance.

Meal Timing, Circadian Organization, and Cancer Growth Rate, Health and Longevity

Elizabeth Filipski, PhD^1,2, Francis Lévi, MD, PhD^1,2,3. 1INSERM U776, 2Univ Paris-Sud, UMR-S0776, Orsay, 3AP-HP, Chronotherapy Unit, Department of Oncology, Hôpital Paul Brousse, Villejuif, France

The circadian timing system (CTS) coordinated by the suprachiasmatic nuclei (SCN) of the hypothalamus regulates daily rhythms of behavior and physiology. Altered circadian rhythms predicted for poor survival in cancer patients. An increased incidence of cancers has been reported in flying attendants and in shift workers.To explore the contribution of the CTS to tumor growth, we developed experimental models of disrupted or enhanced coordination of circadian clocks through stereotaxic destruction of the SCN, modifications of photoperiodic or feeding synchronizers and/or the administration of pharmacologic agents. Stereotaxic destruction of the SCN or subjecting the mice to experimental chronic jet-lag (CJL: an 8-hour advance of the light-dark cycle every 2 days) ablated the 24-h rest-activity cycle and markedly altered the rhythms in body temperature, serum corticosterone and lymphocyte count and significantly accelerated malignant growth in two transplantable tumor models. Similar growth rate acceleration of both tumor models was observed in Clockm/m mice with arrhythmic physiology in DD. CJL suppressed or altered the rhythms of clock gene expression in mouse SCN (Per1) and liver (Cry1, Rev-erbα, Per2 and Bmal1). It suppressed p53 and derepressed c-Myc expression in mouse liver, a result in line with the promotion of diethylnitrosamine–initiated hepatocarcinogenesis in jet-lagged mice. The accelerating effect of CJL on tumor growth could be counterbalanced by the timing of food access. Thus, meal timing at usual “eating” times (during subjective darkness) prevented the circadian disruption from irregular light-dark exposures such as CJL and slowed down tumor growth. Furthermore, meal timing during rest in synchronized mice reinforced host circadian coordination, phase-shifted the transcriptional rhythms of clock genes in the liver of tumor-bearing mice and slowed down cancer progression. These results support the role of the CTS in cancer progression and call for the development of therapeutic strategies aimed at preventing or treating circadian clock dysfunctions. The reinforcement of circadian coordination through programmed physical exercise, meal timing or chronobiotics should be envisaged in subjects at increased cancer risk such as elderly or night workers as well as in cancer patients. Supported by the EU (TEMPO LSHG-ct-2006-037543).

Making Circadian Cancer Therapy Practical

Keith I. Block, M.D, Block Center for Integrative Cancer Treatment, 1800 Sherman Ave., Suite 350, Evanston IL

Practical circadian therapy for the cancer patient involves three spheres of intervention – improving lifestyle, optimizing internal biochemical milieu and adjusting treatment times. The potential value of improving overall circadian functioning is shown in the work of Mormont et al in which pronounced rest-activity rhythms were associated with better survival in colorectal cancer patients receiving chronomodulated chemotherapy. Lifestyle interventions that may improve circadian functioning involve diet, physical activity and mind-body therapies. A diet that is anti-inflammatory and has appropriate carbohydrate intake, as well as regular meal timing, encourages normal circadian cycles. Adequate daytime physical activity encourages restful sleep, and morning light exposure during exercise may entrain melatonin rhythms. Meditation and other mind-body therapies can reduce anxiety and depression that may disrupt sleep. Aspects of the biochemical milieu that specifically disrupt circadian functioning are inflammation and stress hormones. Inflammation and cytokine disruption can be addressed with diet, herbs and other natural substances. Chronomodulation of chemotherapy in a U.S. clinical setting will be discussed. A series of 12 cases will be presented of patients who experienced Grade 3-4 toxicities with various chemotherapy regimens for colorectal cancer. When rechallenged with the same regimens administered chronotherapeutically, none of the patients experienced Grade 3-4 toxicity. Integrating all the above treatment modalities has the potential to improve both quality of life and disease outcomes in cancer patients.

Circadian Disruption, Melatonin Suppression And Cancer

Russel J. Reiter, Ph.D., University of Texas Health Science Center, San Antonio, TX

Circadian rhythms are fundamental and pervasive in all living organisms. Given that the regular recurring intervals of light and darkness are a major factor in synchronizing the master oscillator, the suprachiasmatic nuclei (SCN), then it should come as no surprise that the corruption of this very basic environmental signal would negatively impact the master clock and, additionally, all cellular slave oscillators as well. Virtually every function in an organism exhibits a circadian rhythm which is presumably impelled by clock genes within individual cells; moreover, these intrinsic cellular rhythms are under control of the master oscillator in the SCN. As a consequence, the disruption of the rhythmicity of the SCN may predictably alter many physiological events that are cyclic over a 24 hour period. If, in fact, breast cancer is a consequence of central chronodisruption and melatonin suppression due to light at night, then it can reasonably be presumed that perturbations in circadian physiology would affect cancer of many, perhaps all, types. Furthermore, considering the central role of circadian rhythms in determining optimal physiology, chronodisruption due to inappropriate light exposure may contribute to other diseases, e.g., possibly especially those with an oxidative stress component. Finally, chronodisruption could negate the importance of the nascent discipline of chronopharmacology which depends on drug administration at the optimal circadian time. Humans, as well as other organisms, are endowed with a set of rhythmic genes that evolved over eons of time and took advantage of regular fluctuations in the light:dark environment to adjust cellular physiology accordingly. Unfortunately, since the invention of artificial light by Thomas Alva Edison in 1879, the genetic machinery has been confused by light being imposed during the normal dark period. While the basic genetic mechanisms governing rhythms have remained stable, the major controlling factor has changed dramatically. This incongruity would be expected to cause physiological breakdowns and disease. In addition to cancer, diseases that may be influenced by perturbations of circadian rhythms include diabetes, metabolic syndrome, hypertension, obesity and cardiovascular disease. In view of this scenario, to avoid chronodisruption and the associated pathophysiological consequences, the use of proper light hygiene should become progressively more important as light pollution becomes worse.