Chronotherapeutics: the relevance of timing in cancer therapy

Covalent conjugates based on nanodiamonds with doxorubicin and a cytostatic drug from the group of 1,3,5-triazines: Synthesis, biocompatibility and biological activity

We report the synthesis of covalent conjugates of nanodiamonds with doxorubicin and a cytostatic drug from the class of 1,3,5-triazines. The obtained conjugates were identified using a number of physicochemical methods (IR-spectroscopy, NMR-spectroscopy, XRD, XPS, TEM). As a result of our study, it was found that ND-СONH-Dox and ND-COO-Diox showed good hemocompatibility, since they did not affect plasma coagulation hemostasis, platelet functional activity, and erythrocyte membrane. The ND-COO-Diox conjugates are also capable of binding to human serum albumin due to the presence of ND in their composition. In the study of the cytotoxic properties of ND-СONH-Dox and ND-COO-Diox in the T98G glioblastoma cell line, indicating that ND-СONH-Dox and ND-COO-Diox demonstrate greater cytotoxicity at lower concentrations of Dox and Diox in the composition of the conjugates compared to individual drugs; the cytotoxic effect of ND-COO-Diox was statistically significantly higher than that of ND-СONH-Dox at all concentrations studied. Greater cytotoxicity at lower concentrations of Dox and Diox in the composition of conjugates compared to individual cytostatics makes it promising to further study the specific antitumor activity and acute toxicity of these conjugates in models of glioblastoma in vivo. Our results demonstrated that ND-СONH-Dox and ND-COO-Diox enter HeLa cells predominantly via a nonspecific actin-dependent mechanism, while for ND-СONH-Dox a clathrin-dependent endocytosis pathway. All data obtained provide that the synthesized nanomaterials show a potential application as the agents for intertumoral administration.

Time dependent cisplatin dosing differences on hypoalgesia focusing on oxidative stress

Although cisplatin is a key drug in cancer chemotherapy, it often causes sensory peripheral neuropathy, presenting as allodynia in the early stage and hypoalgesia in the serious stage. Chronotherapy has previously been shown to ameliorate cisplatin-induced peripheral neuropathy that was severe enough to cause hypoalgesia in rats. It also has adverse effects such as renal dysfunction and ototoxicity, which are induced by oxidative stress. Here, we show that oxidative stress causes severe cisplatin-induced peripheral neuropathy, and that differences in oxidative stress occur depending on the dosing time of cisplatin. Cisplatin was administered to rats at 5:00 or 17:00 every seven days for four weeks. The antioxidant agent, 1,3-Dimethylthiourea (DMTU), was administered before and after the administration of cisplatin. The hot plate test was used to assess hypoalgesia. Oxidative stress in the sciatic nerve was assessed from thiobarbituric acid reactive substances (TBARs) and superoxide dismutase (SOD) activity. Nerve apoptosis was analysed with qRT-PCR. We observed an increase in TBARs and a decrease in SOD activity with the development of cisplatin-induced hypoalgesia, which was ameliorated by DMTU treatment. Furthermore, differences in the dosing time of cisplatin caused differences in oxidative stress which were correlated with cisplatin-induced hypoalgesia. Severe oxidative stress caused cisplatin-induced hypoalgesia, and chronotherapy with cisplatin ameliorated hypoalgesia by reducing oxidative stress. In the future, chronotherapy with cisplatin may contribute to the treatment of cancer in humans.

Chemotherapy delivery time affects treatment outcomes of female patients with diffuse large B cell lymphoma

BACKGROUNDChronotherapy is a drug intervention at specific times of the day to optimize efficacy and minimize adverse effects. Its value in hematologic malignancy remains to be explored, in particular in adult patients.METHODSWe performed chronotherapeutic analysis using 2 cohorts of patients with diffuse large B cell lymphoma (DLBCL) undergoing chemotherapy with a dichotomized schedule (morning or afternoon). The effect of a morning or afternoon schedule of rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) on survival and drug tolerability was evaluated in a survival cohort (n = 210) and an adverse event cohort (n = 129), respectively. Analysis of about 14,000 healthy individuals followed to identify the circadian variation in hematologic parameters.RESULTSBoth progression-free survival (PFS) and overall survival (OS) of female, but not male, patients were significantly shorter when patients received chemotherapy mostly in the morning (PFS HR 0.357, P = 0.033; and OS HR 0.141, P = 0.032). The dose intensity was reduced in female patients treated in the morning (cyclophosphamide 10%, P = 0.002; doxorubicin 8%, P = 0.002; and rituximab 7%, P = 0.003). This was mainly attributable to infection and neutropenic fever: female patients treated in the morning had a higher incidence of infections (16.7% vs. 2.4%) and febrile neutropenia (20.8% vs. 9.8%) as compared with those treated in the afternoon. The sex-specific chronotherapeutic effects can be explained by the larger daily fluctuation of circulating leukocytes and neutrophils in female than in male patients.CONCLUSIONIn female DLBCL patients, R-CHOP treatment in the afternoon can reduce toxicity while it improves efficacy and survival outcome.FUNDINGNational Research Foundation of Korea (NRF) grant funded by the Korean government (grant number NRF-2021R1A4A2001553), Institute for Basic Science IBS-R029-C3, and Human Frontiers Science Program Organization Grant RGY0063/2017.

Developments on tumour site-specific chrono-oncology towards personalised treatment

Research into chronotherapy has seen notable developments over the past decades, with a clear focus on the identification of circadian clock genes as potential treatment targets. Moreover, new factors are investigated, such as gender and the role of cancer stem cells in influencing the outcome of chronomodulated treatments. These factors could add to the arsenal of parameters that assist with patient stratification and treatment personalisation. Literature analysis showed that certain anatomical sites received more attention and the associated studies reported clinically significant results, even though some findings are contradictory. The aim of this work was to review the existing studies on chrono-oncology using a tumour site-specific approach and to highlight the status of research in various cancers. Inconsistencies in data reporting, the nature of the studies and the highly heterogeneous patient characteristics, highlight the need for well-designed randomised controlled trials to elucidate the real potential of chronotherapy in oncology.

A guideline proposal for mice preparation and care in 18F-FDG PET imaging

The experimental outcomes of small-animal positron emission tomography (PET) imaging with ¹⁸F-labelled fluorodeoxyglucose (¹⁸F-FDG) can be particularly compromised by animal preparation and care. Several works intend to improve research reporting and amplify the quality and reliability of published research. Though these works provide valuable information to plan and conduct animal studies, manuscripts describe different methodologies—standardization does not exist. Consequently, the variation in details reported can explain the difference in the experimental results found in the literature. Additionally, the resources and guidelines defining protocols for small-animal imaging are scarce, making it difficult for researchers to obtain and compare accurate and reproducible data. Considering the selection of suitable procedures key to ensure animal welfare and research improvement, this paper aims to prepare the way for a future guideline on mice preparation and care for PET imaging with ¹⁸F-FDG. For this purpose, a global standard protocol was created based on recommendations and good practices described in relevant literature.

Predicting circadian phase across populations: a comparison of mathematical models and wearable devices

From smart work scheduling to optimal drug timing, there is enormous potential in translating circadian rhythms research results for precision medicine in the real world. However, the pursuit of such effort requires the ability to accurately estimate circadian phase outside of the laboratory. One approach is to predict circadian phase non-invasively using light and activity measurements and mathematical models of the human circadian clock. Most mathematical models take light as an input and predict the effect of light on the human circadian system. However, consumer-grade wearables that are already owned by millions of individuals record activity instead of light, which prompts an evaluation of the accuracy of predicting circadian phase using motion alone. Here, we evaluate the ability of four different models of the human circadian clock to estimate circadian phase from data acquired by wrist-worn wearable devices. Multiple datasets across populations with varying degrees of circadian disruption were used for generalizability. Though the models we test yield similar predictions, analysis of data from 27 shift workers with high levels of circadian disruption shows that activity, which is recorded in almost every wearable device, is better at predicting circadian phase than measured light levels from wrist-worn devices when processed by mathematical models. In those living under normal living conditions, circadian phase can typically be predicted to within 1 hour, even with data from a widely available commercial device (the Apple Watch). These results show that circadian phase can be predicted using existing data passively collected by millions of individuals with comparable accuracy to much more invasive and expensive methods.

Circadian Effects of Drug Responses

Circadian rhythms describe physiological systems that repeat themselves with a cycle of approximately 24 h. Our understanding of the cellular and molecular origins of these oscillations has improved dramatically, allowing us to appreciate the significant role these oscillations play in maintaining physiological homeostasis. Circadian rhythms allow living organisms to predict and efficiently respond to a dynamically changing environment, set by repetitive day/night cycles. Since circadian rhythms underlie almost every aspect of human physiology, it is unsurprising that they also influence the response of a living organism to disease, stress, and therapeutics. Therefore, not only do the mechanisms that maintain health and disrupt homeostasis depend on our internal circadian clock, but also the way drugs are perceived and function depends on these physiological rhythms. We present a holistic view of the therapeutic process, discussing components such as disease state, pharmacokinetics, and pharmacodynamics, as well as adverse reactions that are critically affected by circadian rhythms. We outline challenges and opportunities in moving toward personalized medicine approaches that explore and capitalize on circadian rhythms for the benefit of the patient.

Synchronized oscillations in growing cell populations are explained by demographic noise

Understanding synchrony in growing populations is important for applications as diverse as epidemiology and cancer treatment. Recent experiments employing fluorescent reporters in melanoma cell lines have uncovered growing subpopulations exhibiting sustained oscillations, with nearby cells appearing to synchronize their cycles. In this study, we demonstrate that the behavior observed is consistent with long-lasting transient phenomenon initiated and amplified by the finite-sample effects and demographic noise. We present a novel mathematical analysis of a multistage model of cell growth, which accurately reproduces the synchronized oscillations. As part of the analysis, we elucidate the transient and asymptotic phases of the dynamics and derive an analytical formula to quantify the effect of demographic noise in the appearance of the oscillations. The implications of these findings are broad, such as providing insight into experimental protocols that are used to study the growth of asynchronous populations and, in particular, those investigations relating to anticancer drug discovery.

Effectiveness of preventive onabotulinumtoxin A injections for migraine headaches is dependent on the circadian time of administration

We have previously shown that quarterly preventive onabotulinumtoxin A (BTA) injections administered to diurnally active patients for chronic migraines (CM) associate with increased discomfort when performed in the morning. The purpose of this study was to further examine if the effectiveness of preventive BTA injections depends on the procedure's circadian timing. A total of 90 diurnally active patients with a medical history of CM and undergoing BTA injection therapy were enrolled in the study. One hundred and fifty-five units of BTA were administered according to the standardized PREEMPT protocol, either during the course of morning (AM) or afternoon (PM) clinic hours. Patients were asked to keep headache diaries, which were reviewed at the time of their follow-up BTA injections 3 months later. The number of headache days experienced during the first, second, and third month following BTA injection, and the number of headache days during the last 7 days prior to follow-up was collected, as was the self-rating of the effectiveness of BTA treatment. Fifty-five (61%) patients were injected during the AM clinic and 35 (39%) during the PM clinic. There was no difference in gender, race, and age variables between the AM and PM patients. The average total number of headache days during 3 months following injection was significantly higher for the AM-treated compared to the PM-treated patients (22.37 ± 18.85 vs. 10.54 ± 7.5, p =.0007). AM patients also reported a higher number of headache days during each of the 3 months following BTA injection. In contrast, PM patients reported higher effectiveness of preventive BTA treatment. The average number of headache days during the week prior to the follow up, as well as the presence of headache on the day of the follow-up was not significantly different between the AM and PM groups. Scheduling diurnally active CM patients with stable circadian sleep/wake routine for afternoon BTA injections appear to improve the effectiveness of BTA therapy as well as patients' satisfaction with the treatment.

Comparing Conventional Chemotherapy to Chronomodulated Chemotherapy for Cancer Treatment: Protocol for a Systematic Review

BACKGROUND

Chronomodulated chemotherapy aims to achieve maximum drug safety and efficacy by adjusting the time of treatment to an optimal biological time as determined by the circadian clock. Although it is a promising alternative to conventional (non-time-stipulated) chemotherapy in several instances, the lack of scientific consensus and the increased logistical burden of timed administration limit the use of a chronomodulated administration protocol.

OBJECTIVE

With the goal to increase scientific consensus on this subject, we plan to conduct a systematic review of the current literature to compare the drug safety and efficacy of chronomodulated chemotherapy with those of conventional chemotherapy.

METHODS

This systematic review will comply with the PRISMA (Preferred Reporting Items for the Systematic Reviews and Meta-Analysis) guidelines. In order to identify relevant studies, we conducted a comprehensive search in PubMed and Embase on May 18, 2020. We included clinical studies that compare either the safety or efficacy of chronomodulated chemotherapy with that of conventional chemotherapy. Potential studies will be reviewed and screened by 2 independent reviewers. Quality assessment will be performed using the National Institutes of Health's Study Quality Assessment Tool (Quality Assessment of Controlled Intervention Studies). Disagreements will be resolved by consulting a third independent reviewer.

RESULTS

This protocol has received funding, and the search for studies from databases commenced on May 18, 2020. The systematic review is planned to be completed by October 31, 2020.

CONCLUSIONS

In this systematic review, we will compare drug safety and drug efficacy for cancer patients who were administered either chronomodulated chemotherapy or conventional chemotherapy. Moreover, we will highlight the outcomes and quality of the selected trials for this review.

TRIAL REGISTRATION

PROSPERO International Prospective Register of Systematic Reviews CRD42020177878; https://tinyurl.com/y53w9nq6.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/18023.

Circadian rhythm impacts preclinical FDG-PET quantification in the brain, but not in xenograft tumors

The inner clock of biological organisms plays a pivotal role and has strong effects on metabolic processes such as glucose consumption. Since the commonly used positron emission tomography (PET) tracer ¹⁸F-flourodeoxygucose (FDG) is a glucose analogue, it is not surprising that the FDG distribution in mice and humans has been shown to succumb to daily rhythms. In preclinical studies, the circadian rhythm of animals is often not considered, and studies are performed at different times of day. Only a few studies have analyzed the effect of the circadian rhythm on FDG uptake in mice, and none of these studies included human tumor xenografts. Therefore, it is not known how strongly a preclinical tumor study is influenced by the time of day. In this work, the effect of the circadian rhythm on FDG uptake in human tumor xenografts and other organs was analyzed. CD1 nu/nu mice were kept for three weeks under a 12 h light/12 h dark rhythm and then injected s.c. with PC3 or A431 tumor cells. When the tumors had reached an appropriate volume, FDG-PET scans were performed on different animal groups (n = 4–5) every 4 h over a time period from 8 A.M. to 8 P.M. Tracer uptake in the tumors and in other organs was determined based on the PET scans and biodistribution studies. The standardized uptake value and %injected dose/cc of the tumors remained constant over the whole observed time period, and no statistically significant differences were determined according to the PET analysis. In the brain, we found a small but statistically significant increase from noon to 4 P.M., which led to a decrease in the tumor-to-brain ratio. No evidence for an effect of the circadian rhythm on FDG uptake could be found in subcutaneous tumors, however, in brain studies the circadian rhythm needs to be considered.

The Effects of Melatonin on the Descending Pain Inhibitory System and Neural Plasticity Markers in Breast Cancer Patients Receiving Chemotherapy: Randomized, Double-Blinded, Placebo-Controlled Trial

Background: Adjuvant chemotherapy for breast cancer (ACBC) has been associated with fatigue, pain, depressive symptoms, and disturbed sleep. And, previous studies in non-cancer patients showed that melatonin could improve the descending pain modulatory system (DPMS). We tested the hypothesis that melatonin use before and during the first cycle of ACBC is better than placebo at improving the DPMS function assessed by changes in the 0–10 Numerical Pain Scale (NPS) during the conditioned pain modulating task (CPM-task) (primary outcome). The effects of melatonin were evaluated in the following secondary endpoints: heat pain threshold (HPT), heat pain tolerance (HPTo), and neuroplasticity state assessed by serum brain-derived neurotrophic factor (BDNF), tropomyosin kinase receptor B, and S100B-protein and whether melatonin’s effects on pain and neuroplasticity state are due more so to its impact on sleep quality.

Methods: Thirty-six women, ages 18 to 75 years old, scheduled for their first cycle of ACBC were randomized to receive 20mg of oral melatonin (n = 18) or placebo (n = 18). The effect of treatment on the outcomes was analyzed by delta (Δ)-values (from pre to treatment end).

Results: Multivariate analyses of covariance revealed that melatonin improved the function of the DPMS. The Δ-mean (SD) on the NPS (0–10) during the CPM-task in the placebo group was −1.91 [−1.81 (1.67) vs. −0.1 (1.61)], and in the melatonin group was −3.5 [−0.94 (1.61) vs. −2.29 (1.61)], and the mean difference (md) between treatment groups was 1.59 [(95% CI, 0.50 to 2.68). Melatonin’s effect increased the HPTo and HPT while reducing the (Δ)-means of the serum neuroplasticity marker in placebo vs. melatonin. The Δ-BDNF is 1.87 (7.17) vs. −20.44 (17.17), respectively, and the md = 22.31 [(95% CI = 13.40 to 31.22)]; TrKB md = 0.61 [0.46 (0.17) vs. −0.15 (0.18); 95% CI = 0.49 to 0.73)] and S00B-protein md = −8.27[(2.89 (11.18) vs. −11.16 (9.75); 95% CI = −15.38 to −1.16)]. However, melatonin’s effect on pain and the neuroplastic state are not due to its effect on sleep quality.

Conclusions: These results suggest that oral melatonin, together with the first ACBC counteracts the dysfunction in the inhibitory DPMS and improves pain perception measures. Also, it shows that changes in the neuroplasticity state mediate the impact of melatonin on pain.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier NCT03205033.

Macroscopic Models for Human Circadian Rhythms

Mathematical models have a long and influential history in the study of human circadian rhythms. Accurate predictive models for the human circadian light response have been used to study the impact of a host of light exposures on the circadian system. However, generally, these models do not account for the physiological basis of these rhythms. We illustrate a new paradigm for deriving models of the human circadian light response. Beginning from a high-dimensional model of the circadian neural network, we systematically derive low-dimensional models using an approach motivated by experimental measurements of circadian neurons. This systematic reduction allows for the variables and parameters of the derived model to be interpreted in a physiological context. We fit and validate the resulting models to a library of experimental measurements. Finally, we compare model predictions for experimental measurements of light levels and discuss the differences between our model’s predictions and previous models. Our modeling paradigm allows for the integration of experimental measurements across the single-cell, tissue, and behavioral scales, thereby enabling the development of accurate low-dimensional models for human circadian rhythms.

Circadian Regulation of the Brain and Behavior: A Neuroendocrine Perspective

Neuroendocrine systems are key regulators of brain and body functions, providing an important nexus between internal states and the external world, which then modulates appropriate behavioral outputs. Circadian (daily) rhythms are endogenously generated rhythms of approximately 24 h that help to synchronize internal physiological processes and behavioral states to the external environmental light-dark cycle. Given the importance of timing (hours, days, annual) in many different neuroendocrine axes, understanding how the circadian timing system regulates neuroendocrine function is particularly critical. Similarly, neuroendocrine signals can significantly affect circadian timing, and understanding these mechanisms can provide insights into general concepts of neuroendocrine regulation of brain circuits and behavior. This chapter will review the circadian timing system and its control of two key neuroendocrine systems: the hypothalamic-pituitary-gonadal (HPG) axis and the hypothalamic-pituitary-adrenal (HPA) axis. It will also discuss how outputs from these axes feedback to affect the circadian clock. Given that disruption of circadian timing is a central component of many mental and physical health conditions and that neuroendocrine function is similarly implicated in many of the same conditions, understanding these links will help illuminate potentially shared causality and perhaps lead to a better understanding of how to manipulate these systems when they begin to malfunction.

Clinical chronobiology: a timely consideration in critical care medicine

A fundamental aspect of human physiology is its cyclical nature over a 24-h period, a feature conserved across most life on Earth. Organisms compartmentalise processes with respect to time in order to promote survival, in a manner that mirrors the rotation of the planet and accompanying diurnal cycles of light and darkness. The influence of circadian rhythms can no longer be overlooked in clinical settings; this review provides intensivists with an up-to-date understanding of the burgeoning field of chronobiology, and suggests ways to incorporate these concepts into daily practice to improve patient outcomes. We outline the function of molecular clocks in remote tissues, which adjust cellular and global physiological function according to the time of day, and the potential clinical advantages to keeping in time with them. We highlight the consequences of "chronopathology", when this harmony is lost, and the risk factors for this condition in critically ill patients. We introduce the concept of "chronofitness" as a new target in the treatment of critical illness: preserving the internal synchronisation of clocks in different tissues, as well as external synchronisation with the environment. We describe methods for monitoring circadian rhythms in a clinical setting, and how this technology may be used for identifying optimal time windows for interventions, or to alert the physician to a critical deterioration of circadian rhythmicity. We suggest a chronobiological approach to critical illness, involving multicomponent strategies to promote chronofitness (chronobundles), and further investment in the development of personalised, time-based treatment for critically ill patients.

Advances in bacterial cancer therapies using synthetic biology

Synthetic biology aims to apply engineering principles to biology by modulating the behavior of living organisms. An emerging application of this field is the engineering of bacteria as a cancer therapy by the programming of therapeutic, safety, and specificity features through genetic modification. Here, we review progress in this engineering including the targeting of bacteria to tumors, specific sensing and response to tumor microenvironments, remote induction methods, and controllable release of therapeutics. We discuss the most prominent bacteria strains used and their specific properties and the types of therapeutics tested thus far. Finally, we note current challenges, such as genetic stability, that researchers must address for successful clinical implementation of this novel therapy in humans.

Does chronomodulated radiotherapy improve pathological response in locally advanced rectal cancer?

The predominant mode of radiation-induced cell death for solid tumours is mitotic catastrophe, which is in part dependent on sublethal damage repair being complete at around 6 h. Circadian variation appears to play a role in normal cellular division, and this could influence tumour response of radiation treatment depending on the time of treatment delivery. We tested the hypothesis that radiation treatment later in the day may improve tumour response and nodal downstaging in rectal cancer patients treated neoadjuvantly with radiation therapy. Recruitment was by retrospective review of 267 rectal cancer patients treated neoadjuvantly in the Department of Radiation Oncology at the Canberra Hospital between January 2010 and November 2015. One hundred and fifty-five patients met the inclusion criteria for which demographic, pathological and imaging data were collected, as well as the time of day patients received treatment with each fraction of radiotherapy. Data analysis was performed using the Statistical Package R with nonparametric methods of significance for all tests set at p < 0.05. Of the 45 female and 110 male patients, the median age was 64. Seventy-three percent had cT3 disease and there was a mean tumour distance from the anal verge of 7 cm. Time to surgical resection following radiotherapy ranged from 4 to 162 days with a median of 50 days, with a complete pathological response seen in 21% of patients. Patients exhibiting a favourable pathological response had smaller median pre- and postradiotherapy tumour size and had a greater change in tumour size following treatment (p < 0.01). Patients who received the majority of their radiotherapy fractions after 12:00 pm were more likely to show a complete or moderate pathological response (p = 0.035) and improved nodal downstaging. There were also more favourable responses amongst patients with longer time to surgical resection postradiotherapy (p < 0.004), although no relationship was seen between response and tumour distance from the anal verge. Females were less likely to exhibit several of the above responses. Neoadjuvant radiotherapy for locally advanced rectal cancer performed later in the day coupled with a longer time period to surgical resection may improve pathological tumour response rates and nodal downstaging. A prospective study in chronomodulated radiotherapy in this disease is warranted.

Personalized Drug Dosage - Closing the Loop

A brief account is given of various approaches to the individualization of drug dosage, including the use of pharmacodynamic markers, therapeutic monitoring of plasma drug concentrations, genotyping, computer-guided dosage using ‘dashboards’, and automatic closed-loop control of pharmacological action. The potential for linking the real patient to his or her ‘virtual twin’ through the application of physiologically-based pharmacokinetic modeling is also discussed.

Disruption of clock gene expression in human colorectal liver metastases

The circadian timing system controls about 40 % of the transcriptome and is important in the regulation of a wide variety of biological processes including metabolic and proliferative functions. Disruption of the circadian clock could have significant effect on human health and has an important role in the development of cancer. Here, we compared the expression levels of core clock genes in primary colorectal cancer (CRC), colorectal liver metastases (CRLM), and liver tissue within the same patient. Surgical specimens of 15 untreated patients with primary CRC and metachronous CRLM were studied. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to measure the expression of 10 clock genes: CLOCK, BMAL1, PER1, PER2, PER3, CRY1, CRY2, CSNK1E, TIM, TIPIN, and 2 clock-controlled genes: Cyclin-D1, and WEE1. Expression levels of 7 core clock genes were downregulated in CRLM: CLOCK (p = 0.006), BMAL1 (p = 0.003), PER1 (p = 0.003), PER2 (p = 0.002), PER3 (p < 0.001), CRY1 (p = 0.002), and CRY2 (p < 0.001). In CRC, 5 genes were downregulated: BMAL1 (p = 0.02), PER1 (p = 0.004), PER2 (p = 0.008), PER3 (p < 0.001), and CRY2 (p < 0.001). CSNK1E was upregulated in CRC (p = 0.02). Cyclin-D1 and WEE1 were both downregulated in CRLM and CRC. Related to clinicopathological factors, a significant correlation was found between low expression of CRY1 and female gender, and low PER3 expression and the number of CRLM. Our data demonstrate that the core clock is disrupted in CRLM and CRC tissue from the same patient. This disruption may be linked to altered cell-cycle dynamics and carcinogenesis.

Circadian disruption and breast cancer: an epigenetic link?

Breast cancer is already the most common malignancy affecting women worldwide, and evidence is mounting that breast cancer induced by circadian disruption (CD) is a warranted concern. Numerous studies have investigated various aspects of the circadian clock in relation to breast cancer, and evidence from these studies indicates that melatonin and the core clock genes can play a crucial role in breast cancer development. Even though epigenetics has been increasingly recognized as a key player in the etiology of breast cancer and linked to circadian rhythms, and there is evidence of overlap between epigenetic deregulation and breast cancer induced by circadian disruption, only a handful of studies have directly investigated the role of epigenetics in CD-induced breast cancer. This review explores the circadian clock and breast cancer, and the growing role of epigenetics in breast cancer development and circadian rhythms. We also summarize the current knowledge and next steps for the investigation of the epigenetic link in CD-induced breast cancer.

Carcinogenic effects of circadian disruption: an epigenetic viewpoint

Circadian rhythms refer to the endogenous rhythms that are generated to synchronize physiology and behavior with 24-h environmental cues. These rhythms are regulated by both external cues and molecular clock mechanisms in almost all cells. Disruption of circadian rhythms, which is called circadian disruption, affects many biological processes within the body and results in different long-term diseases, including cancer. Circadian regulatory pathways result in rhythmic epigenetic modifications and the formation of circadian epigenomes. Aberrant epigenetic modifications, such as hypermethylation, due to circadian disruption may be involved in the transformation of normal cells into cancer cells. Several studies have indicated an epigenetic basis for the carcinogenic effects of circadian disruption. In this review, I first discuss some of the circadian genes and regulatory proteins. Then, I summarize the current evidence related to the epigenetic modifications that result in circadian disruption. In addition, I explain the carcinogenic effects of circadian disruption and highlight its potential role in different human cancers using an epigenetic viewpoint. Finally, the importance of chronotherapy in cancer treatment is highlighted.

Circadian systems biology: When time matters

The circadian clock is a powerful endogenous timing system, which allows organisms to fine-tune their physiology and behaviour to the geophysical time. The interplay of a distinct set of core-clock genes and proteins generates oscillations in expression of output target genes which temporally regulate numerous molecular and cellular processes. The study of the circadian timing at the organismal as well as at the cellular level outlines the field of chronobiology, which has been highly interdisciplinary ever since its origins. The development of high-throughput approaches enables the study of the clock at a systems level. In addition to experimental approaches, computational clock models exist which allow the analysis of rhythmic properties of the clock network. Such mathematical models aid mechanistic understanding and can be used to predict outcomes of distinct perturbations in clock components, thereby generating new hypotheses regarding the putative function of particular clock genes. Perturbations in the circadian timing system are linked to numerous molecular dysfunctions and may result in severe pathologies including cancer. A comprehensive knowledge regarding the mechanistic of the circadian system is crucial to develop new procedures to investigate pathologies associated with a deregulated clock.

In this manuscript we review the combination of experimental methodologies, bioinformatics and theoretical models that have been essential to explore this remarkable timing-system. Such an integrative and interdisciplinary approach may provide new strategies with regard to chronotherapeutic treatment and new insights concerning the restoration of the circadian timing in clock-associated diseases.

Resistance to cancer chemotherapy: failure in drug response from ADME to P-gp

Cancer chemotherapy resistance (MDR) is the innate and/or acquired ability of cancer cells to evade the effects of chemotherapeutics and is one of the most pressing major dilemmas in cancer therapy. Chemotherapy resistance can arise due to several host or tumor-related factors. However, most current research is focused on tumor-specific factors and specifically genes that handle expression of pumps that efflux accumulated drugs inside malignantly transformed types of cells. In this work, we suggest a wider and alternative perspective that sets the stage for a future platform in modifying drug resistance with respect to the treatment of cancer.

Report of clinical studies on chronochemotherapy for advanced non-small cell lung cancer in China

Chronochemotherapy has been proposed as a promising modality to provide timely optimized medication to achieve maximum efficacy with minimum side effect for patients with non-small cell lung cancer for years. We collected the data of 11 clinical studies performed in China with the purpose to compare the difference between chronochemotherapy and traditional chemotherapy. Results showed that chronochemotherapy has a more favorable efficacy and safety than traditional chemotherapy.

Quantification of interactions among circadian clock proteins via surface plasmon resonance

Circadian clock is an internal time keeping system recurring 24 h daily rhythm in physiology and behavior of organisms. Circadian clock contains transcription and translation feedback loop involving CLOCK/NPAS2, BMAL1, Cry1/2, and Per1/2. In common, heterodimer of CLOCK/NPAS2 and BMAL1 binds to EBOX element in the promoter of Per and Cry genes in order to activate their transcription. CRY and PER making heterodimeric complexes enter the nucleus in order to inhibit their own BMAL1-CLOCK-activated transcription. The aim of this study was to investigate and quantify real-time binding affinities of clock proteins among each other on and off DNA modes using surface plasmon resonance. The pairwise interaction coefficients among clock proteins, as well as interaction of PER2, CRY2, and PER2 : CRY2 proteins with BMAL1 : CLOCK complex in the presence and absence of EBOX motif have been investigated via analysis of surface plasmon resonance data with pseudo first-order reaction kinetics approximation and via nonlinear regression curve fitting. The results indicated that CRY2 and PER2, BMAL1, and CLOCK proteins form complexes in vitro and that PER2, CRY2 and PER2 : CRY2 complex have similar affinities toward BMAL1 : CLOCK complex. CRY2 protein had the highest affinity toward EBOX complex, whereas PER2 and CRY2 : PER2 complexes displayed low affinity toward EBOX complex. The quantification of the interaction between clock proteins is critical to understand the operation mechanism of the biological clock and to address the behavioral and physiological disorders, and it will be useful for the design of new drugs toward clock-related diseases.

Circadian clock gene expression regulates cancer cell growth through glutaminase

Glutamine is an essential amino acid for malignant tumor cells. Glutaminase that metabolizes glutamine reaches a maximum expression in tumors immediately before the maximum proliferation rate. Tumor cells grow at different rates during the day. We postulated that the activity of glutaminase in tumor cells is subject to the regulation of circadian clock gene. We measured glutaminase by western blot analysis and circadian clock gene expression by real-time polymerase chain reaction in the liver and tumor cells at six equispaced time points of the day in individual mice of a 12/12 h light/dark schedule. The results showed that the tumor-bearing mice, under normal diurnal conditions, are circadianly entrained, as reflected by the normal host locomotor activity rhythms and rhythmic liver clock gene expression. The tumors within these mice are also circadianly organized, as reflected by circadian clock gene (Bmal1) expression. What is most remarkable is that kidney-type glutaminase also showed circadian rhythms in the same pattern with tumor circadian clock gene expression in liver cancer xenograft model, indicating that conditionally inhibiting glutaminase activity may provide a new target for cancer therapy.

Improving therapeutic ratio in head and neck cancer with adjuvant and cisplatin-based treatments

Advanced head and neck cancers are difficult to manage despite the large treatment arsenal currently available. The multidisciplinary effort to increase disease-free survival and diminish normal tissue toxicity was rewarded with better locoregional control and sometimes fewer side effects. Nevertheless, locoregional recurrence is still one of the main reasons for treatment failure. Today, the standard of care in head and neck cancer management is represented by altered fractionation radiotherapy combined with platinum-based chemotherapy. Targeted therapies as well as chronotherapy were trialled with more or less success. The aim of the current work is to review the available techniques, which could contribute towards a higher therapeutic ratio in the treatment of advanced head and neck cancer patients.

Human circadian phase estimation from signals collected in ambulatory conditions using an autoregressive model

Phase estimation of the human circadian rhythm is a topic that has been explored using various modeling approaches. The current models range from physiological to mathematical, all attempting to estimate the circadian phase from different physiological or behavioral signals. Here, we have focused on estimation of the circadian phase from unobtrusively collected signals in ambulatory conditions using a statistically trained autoregressive moving average with exogenous inputs (ARMAX) model. Special attention has been given to the evaluation of heart rate interbeat intervals (RR intervals) as a potential circadian phase predictor. Prediction models were trained using all possible combinations of RR intervals, activity levels, and light exposures, each collected over a period of 24 hours. The signals were measured without any behavioral constraints, aside from the collection of saliva in the evening to determine melatonin concentration, which was measured in dim-light conditions. The model was trained and evaluated using 2 completely independent datasets, with 11 and 19 participants, respectively. The output was compared to the gold standard of circadian phase: dim-light melatonin onset (DLMO). The most accurate model that we found made use of RR intervals and light and was able to yield phase estimates with a prediction error of 2 ± 39 minutes (mean ± SD) from the DLMO reference value.

Retrospective analysis of chronomodulated chemotherapy versus conventional chemotherapy with paclitaxel, carboplatin, and 5-fluorouracil in patients with recurrent and/or metastatic head and neck squamous cell carcinoma

BACKGROUND

Chronomodulated chemotherapy has emerged as a new therapy as a result of recent studies focusing on the biological clock. It has been demonstrated that combination chronomodulated chemotherapy of platinum-based drugs and 5-fluorouracil (5-Fu) can significantly improve efficacy and reduce the incidence of adverse events in patients with metastatic colorectal cancer, as compared with conventional chemotherapy. However, the results may be different in different tumors. Recurrent and metastatic head and neck squamous cell carcinoma (HNSCC) is very difficult to treat, with an extremely unfavorable prognosis. So far, no report is available on chronomodulated chemotherapy for HNSCC.

METHODS

Retrospective analyses were made on 49 patients with local recurrent and/or metastatic HNSCC who underwent palliative treatments with paclitaxel, carboplatin, and 5-Fu. The patients were divided into a chronomodulated chemotherapy group (28 patients) and a conventional chemotherapy group (21 patients) according to their administration times. The two groups were compared for tumor objective response rate, overall survival (OS), progression-free survival (PFS), and the incidence of adverse events.

RESULTS

The tumor objective response rate and patients' OS were significantly higher and longer in the chronomodulated chemotherapy group than in the conventional chemotherapy group (71.43% versus 42.86%, respectively, P<0.05; and median OS 15.3 months versus 10.6 months, respectively, P<0.05). However, PFS was similar statistically (median PFS 11.6 months versus 7.2 months, P>0.05). The global incidence of adverse events in the chronomodulated chemotherapy group was significantly lower than that in the conventional chemotherapy group (46.43% versus 76.19%, P<0.05), with significantly lower incidence of grade 3-4 adverse events (7.14% versus 33.33%, P<0.05).

CONCLUSION

Chronomodulated chemotherapy with paclitaxel, carboplatin, and 5-Fu may be a new and effective therapy for patients with recurrent and/or metastatic HNSCC as compared with conventional chemotherapy.

The drug efficacy and adverse reactions in a mouse model of oral squamous cell carcinoma treated with oxaliplatin at different time points during a day

Background

Recent studies have shown that the growth and proliferation of cancer cells in vivo exhibit circadian rhythm, and the efficacy and adverse reactions of platinum-based anticancer drugs administered at different times of the day vary significantly on colon cancer. However, since the circadian rhythms of growth and proliferation of various cancer cells often differ, the question of whether the administration of platinum anticancer drugs at different times of the day exerts significantly different efficacy and adverse effects on oral cancers remains to be elucidated. This study has compared the efficacy and adverse effects of oxaliplatin (L-OHP) administration at different times during a day on oral squamous cell carcinoma in mice and has analyzed cellular circadian rhythms.

Methods

The mouse model for oral squamous cell carcinoma was established in 75 nude mice, housed in a 12 hour light/12 hour dark cycle environment. The mice were randomly divided into five groups; four experimental groups were intravenously injected with L-OHP at four time points within a 24-hour period (4, 10, 16, and 22 hours after lights on [HALO]). The control group was intravenously injected with the same volume of saline. Treatment efficacy and adverse reactions were compared on the seventh day after the injection, at 22 HALO. The existence of circadian rhythms was determined by cosine analysis.

Results

Only injections of L-OHP at 16 and 22 HALO significantly prolonged animal survival time. The adverse reactions in mice injected with L-OHP at 16 and 22 HALO were significantly less than those observed in mice administered L-OHP at 4 and 10 HALO. The cosine fitting curve showed that the survival time and adverse reactions exhibited circadian rhythm.

Conclusion

The time factor should be considered when treating patients with oral squamous cell carcinoma with L-OHP in order to achieve better efficacy, reduce the adverse reactions, and improve the patients’ survival time and quality of life.

Circadian rhythm characteristics of oral squamous cell carcinoma growth in an orthotopic xenograft model

Background

Recent studies show that circadian rhythm changes are closely related to the occurrence and development of various tumors, such as breast, liver, and prostate. However, there are significant differences in circadian rhythm between different tumors. At present, the circadian rhythm characteristics of oral cancer remain unknown. The purpose of this study is to investigate the circadian rhythm characteristics of the in vivo growth of oral squamous cell carcinoma (OSCC).

Materials and methods

Thirty-two nude mice were placed under 12-hour light/12-hour dark cycles. The human OSCC cell line BcaCD885 was inoculated in the cheek of nude mice. After 3 weeks, eight mice were sacrificed at four time points, including 4 hours after light onset (HALO), 10 HALO, 16 HALO, and 22 HALO, during a period of 24 hours. The volume of excised tumors was measured and the proliferative index (PI) and apoptotic index (AI) of tumor cells were determined by flow cytometry. A cosine analysis method was used to determine whether the tumor volume, PI, and AI obeyed a circadian rhythm.

Results

There was a significant circadian rhythm in the tumor volume and PI of OSCC cells. For the tumor volume, there were significant differences between the four time points. The peak and trough values of the tumor volume appeared at 3.23 HALO and 15.23 HALO, whereas the peak and trough values of PI appeared at 6.60 HALO and 18.16 HALO, respectively. However, there was no circadian rhythm in the AI of tumor cells, despite significant differences between the four time points.

Conclusion

This study demonstrates, for the first time, that the tumor volume and PI of in vivo growing OSCC undergo circadian rhythms. These results support the assertion that time factor should be considered in the occurrence, development, treatment, efficacy evaluation and pathophysiology of OSCC.

Phase ii trial of a metronomic schedule of docetaxel and capecitabine with concurrent celecoxib in patients with prior anthracycline exposure for metastatic breast cancer

BACKGROUND

This phase ii clinical trial examined the activity of a metronomic dosing schedule of docetaxel and capecitabine chemotherapy in patients with advanced breast cancer. Patients also received daily oral celecoxib in an effort to improve outcome measures and to ameliorate some of the common side effects of chemotherapy.

METHODS

Patients received docetaxel at a starting dose of 15 mg/m² weekly, oral capecitabine 1250 mg/m² once daily, and oral celecoxib 200 mg twice daily. The primary endpoint was clinical benefit: percentage of patients experiencing either an objective response or stable disease (sd) for more than 6 months. In the absence of significant neutropenia, the dose of docetaxel was escalated after 4 and 8 weeks of treatment. Therapy was given until disease progression or development of unacceptable toxicity. The level of thymidine phosphorylase expression in peripheral white blood cells of patients was measured before and during treatment to determine the effect on this capecitabine-activating enzyme.

RESULTS

Of 47 patients enrolled, 38 (81%) completed treatment to a disease endpoint. No complete responses were achieved, but 13 of the 38 patients (34%) experienced a partial response, and another 3 patients (8%) experienced sd for more than 6 months. The clinical benefit rate was therefore 42% (95% confidence interval: 27% to 57%). The median time to disease progression for all evaluable patients was 3.6 months (range: 0.9-21.7 months). The most common nonhematologic toxicities were diarrhea, plantar- palmar erythrodysesthesia, fatigue, mucositis, and vomiting. Most patients (89%) received combination chemotherapy until disease progression.

CONCLUSIONS

The present study demonstrates that metronomic docetaxel-capecitabine chemotherapy with daily celecoxib can produce significant anticancer activity, with predictable toxicity. Efficacy fell short of expectations, with outcome measures being similar to those obtained when the study agents are given in conventional dosing. Furthermore, there is mounting evidence to indicate that a low dose of taxanes fails to induce thymidine phosphorylase expression, an effect believed to be important in achieving therapeutic synergism when taxanes are given concurrently with capecitabine.

Role of circadian clocks in the development and therapeutics of cancer

Circadian clocks are endogenous molecular time-keeping systems that underlie daily fluctuations in multiple physiological and biochemical processes. It is now well recognized that dysfunction of the circadian system may be associated with a heightened incidence of cancer. This brief review presents evidence supporting the important role played by circadian clocks in the development of cancer and the therapeutic efficacy of anticancer agents. A number of circadian clock genes have been identified, which include transcription factors that regulate gene expression. Continued research in this area should increase understanding of the role of circadian clocks which could, ultimately, reduce the incidence of cancer in people with disrupted sleep-wake cycles, such as 24-h shift workers and flight attendants, and provide optimal chronopharmacology for cancer treatment.

Prospective influences of circadian clocks in adipose tissue and metabolism

Circadian rhythms make a critical contribution to endocrine functions that involve adipose tissue. These contributions are made at the systemic, organ and stem cell levels. The transcription factors and enzymes responsible for the maintenance of circadian rhythms in adipose depots and other peripheral tissues that are metabolically active have now been identified. Furthermore, the circadian regulation of glucose and lipid metabolism is well-established. Animal and human models provide strong evidence that disturbances in circadian pathways are associated with an increased risk of type 2 diabetes mellitus, obesity and their comorbidities. Thus, circadian mechanisms represent a novel putative target for therapy in patients with metabolic diseases.

Imatinib targets PDGF signaling in melanoma and host smooth muscle neighboring cells

In previous in vitro studies, we showed that imatinib abrogated platelet-derived growth factor receptor α (PDGFRα) signaling, disrupting both breast cancer and smooth muscle cells (SMC). PDGF is also a powerful mitogen for neural crest origin cells like melanocytes. The purpose of the present study was to evaluate the effect of imatinib on melanoma growth and in angiogenesis, with emphasis to the involvement in PDGF signaling. B16 melanoma cells incubation with 5 µM (IC50) imatinib resulted in a significant reduction in cell proliferation and migration. Apoptosis, however, was not significantly affected. Phosphorylated-PDGFRα expression was decreased in B16 lysates. In a mouse model of B16 melanoma, intraperitoneal administration of imatinib at early day light significantly decreased tumor growth. These findings were corroborated by a highly significant reduction in cell proliferation and increase in apoptosis in melanoma tumors. This was accompanied by a decrease in microvessel density and in the number of SMC-presenting vessels. Imatinib further inhibited PDGFRα expression and activity, as confirmed by the down-regulation of downstream Erk signaling pathway. Altogether, this study demonstrates that besides targeting tumor cells, imatinib also prevents vascular integrity. The current study provides evidence that the paracrine crosstalk between tumor cells and host neighboring cells is crucial for the elucidation of imatinib effects. In addition, the fact that this molecule targets vascular support cells further enlarges its therapeutic purpose to a wide range of vasculoproliferative pathologies.

Circadian disruption accelerates tumor growth and angio/stromagenesis through a Wnt signaling pathway

Epidemiologic studies show a high incidence of cancer in shift workers, suggesting a possible relationship between circadian rhythms and tumorigenesis. However, the precise molecular mechanism played by circadian rhythms in tumor progression is not known. To identify the possible mechanisms underlying tumor progression related to circadian rhythms, we set up nude mouse xenograft models. HeLa cells were injected in nude mice and nude mice were moved to two different cases, one case is exposed to a 24-hour light cycle (L/L), the other is a more "normal" 12-hour light/dark cycle (L/D). We found a significant increase in tumor volume in the L/L group compared with the L/D group. In addition, tumor microvessels and stroma were strongly increased in L/L mice. Although there was a hypervascularization in L/L tumors, there was no associated increase in the production of vascular endothelial cell growth factor (VEGF). DNA microarray analysis showed enhanced expression of WNT10A, and our subsequent study revealed that WNT10A stimulates the growth of both microvascular endothelial cells and fibroblasts in tumors from light-stressed mice, along with marked increases in angio/stromagenesis. Only the tumor stroma stained positive for WNT10A and WNT10A is also highly expressed in keloid dermal fibroblasts but not in normal dermal fibroblasts indicated that WNT10A may be a novel angio/stromagenic growth factor. These findings suggest that circadian disruption induces the progression of malignant tumors via a Wnt signaling pathway.

Deletion of the PER3 gene on chromosome 1p36 in recurrent ER-positive breast cancer

PURPOSE

To investigate the role of the PER3 circadian rhythm gene, located within the commonly deleted region of chromosome 1p36, in human breast cancer development.

PATIENTS AND METHODS

The frequency of genetic alterations at 1p36 and PER3 gene copy number status were analyzed in 180 lymph node-negative breast cancers from patients who had received treatment with chemotherapy and/or tamoxifen. The expression levels of PER3 were also analyzed using published microarray profiles from > 400 breast cancer samples. Finally, the effect of loss of Per3 on tumor susceptibility was tested using two mouse models of breast cancer.

RESULTS

Deletion of PER3 is directly related to tumor recurrence in patients with estrogen receptor (ER) - positive breast cancers treated with tamoxifen. Low expression of PER3 mRNA is associated with poor prognosis, particularly in a subset of tumors that are ER positive, and either luminal A or ERBB2-positive tumors. Mice deficient in Per3 showed increased susceptibility to breast cancer induced by carcinogen treatment or by overexpression of Erbb2.

CONCLUSION

Disruption of PER3 function may serve as an indicator of probability of tumor recurrence in patients with ER-positive tumors. Further investigations of this pathway may reveal links between deregulation of sleep homeostasis and breast tumorigenesis.