Dysregulation, functional implications, and prognostic ability of the circadian clock across cancers

A review for the impacts of circadian disturbance on urological cancers

Circadian rhythm is an internal timing system and harmonizes a variety of cellular, behavioral, and physiological processes to daily environment. Circadian disturbance caused by altered life style or disrupted sleep patterns inevitably contributes to various disorders. As the rapidly increased cancer occurrences and subsequent tremendous financial burdens, more researches focus on reducing the morbidity rather than treating it. Recently, many epidemiologic studies demonstrated that circadian disturbance was tightly related to the occurrence and development of cancers. For urinary system, numerous clinical researches observed the incidence and progress of prostate cancer were influenced by nightshift work, sleep duration, chronotypes, light exposure, and meal timing, this was also proved by many genetic and fundamental findings. Although the epidemiological studies regarding the relationship between circadian disturbance and kidney/bladder cancers were relative limited, some basic researches still claimed circadian disruption was closely correlated to these two cancers. The role of circadian chemotherapy on cancers of prostate, kidney, and bladder were also explored, however, it has not been regularly recommended considering the limited evidence and poor standard protocols. Finally, the researches for the impacts of circadian disturbance on cancers of adrenal gland, penis, testis were not found at present. In general, a better understanding the relationship between circadian disturbance and urological cancers might help to provide more scientific work schedules and rational lifestyles which finally saving health resource by reducing urological tumorigenesis, however, the underlying mechanisms are complex which need further exploration.

Insight into immune checkpoint inhibitor therapy for colorectal cancer from the perspective of circadian clocks

Colorectal cancer (CRC) is one of the most common malignant tumours and the third most common cause of cancer deaths worldwide, with high morbidity and mortality. Circadian clocks are widespread in humans and temporally regulate physiologic functions to maintain homeostasis. Recent studies showed that circadian components were strong regulators of the tumour immune microenvironment (TIME) and the immunogenicity of CRC cells. Therefore, insight into immunotherapy from the perspective of circadian clocks can be promising. Although immunotherapy, especially immune checkpoint inhibitor (ICI) treatment, has been a milestone in cancer treatment, greater accuracy is still needed for selecting patients who will respond positively to immunotherapy with minimal side effects. In addition, there were few reviews focusing on the role of the circadian components in the TIME and the immunogenicity of CRC cells. Therefore, this review highlights the crosstalk between the TIME in CRC and the immunogenicity of CRC cells based on the circadian clocks. With the goal to achieve the possibility that patients with CRC can benefit most from the ICI treatment, we provide potential evidence and a novel idea for building a predictive framework combined with circadian factors, searching for enhancers of ICIs targeting circadian components and clinically implementing the timing of ICI treatment for patients with CRC.

A positive association between the prevalence of circadian syndrome and overactive bladder in United States adults

Objective

To explore the association between the prevalence of circadian syndrome (CircS) and overactive bladder (OAB).

Materials and methods

Cross-section analysis was based on the National Health and Nutrition Examination Survey 2005-2018. Data regarding OAB was collected from questionnaires. The association between the prevalence of CircS and OAB was elucidated using three multivariable logistic regression models. Stratified and interaction analyses were performed to find whether some factors can modify the association.

Results

Totally 8,033 males and 8,065 females were included. People with CircS had a significantly higher prevalence of OAB compared to the non-CircS group in the fully-adjusted model (OR = 1.238, 95%CI 1.080-1.419). A significant positive correlation between the number of CircS components and the prevalence of OAB was observed when the components were ≥ 6 (OR = 1.975, 95%CI 1.463-2.665). No significant interaction was seen in the three models.

Conclusion

There is a positive association between the prevalence of CircS and OAB. When the number of components is ≥6, the prevalence of OAB shows a strongly positive correlation with the number of CircS components.

Identification and validation of a novel prognostic circadian rhythm-related gene signature for stomach adenocarcinoma

Circadian rhythm genes were reported to be strongly associated with the development and prognosis of circadian rhythm disorders related to stomach adenocarcinoma (STAD), which is one of the most prevalent cancers. This study aimed to identify a circadian rhythm-related gene signature that could help predict STAD outcome. Using bioinformatics analysis approaches, 105 genes were examined in 350 patients with STAD. Overall, six hub-type circadian rhythm-associated genes (GNA11, PER1, SOX14, EZH2, MAGED1, and NR1D1) were identified using univariate and multivariate Cox regression analyses. These genes were then used to build a genetic predictive model, which was further validated using a publicly available dataset (GSE26899). Overall, genes associated with the circadian rhythm were found to be substantially correlated with the characteristics of the STAD patients (grade, sex, and M stage). In addition, the circadian rhythm-related gene signature was significantly associated with the MAPK and Notch signaling pathways, which are known risk factors for poorer STAD outcome. Taken together, these findings suggest that the herein proposed prognostic model based on six circadian rhythm-associated genes may have predictive value and potential application for clinical decision-making and for personalized treatment of STAD.

The interplay between circadian clock and viral infections: A molecular perspective

The circadian clock influences almost every aspect of mammalian behavioral, physiological and metabolic processes. Being a hierarchical network, the circadian clock is driven by the central clock in the brain and is composed of several peripheral tissue-specific clocks. It orchestrates and synchronizes the daily oscillations of biological processes to the environment. Several pathological events are influenced by time and seasonal variations and as such implicate the clock in pathogenesis mechanisms. In context with viral infections, circadian rhythmicity is closely associated with host susceptibility, disease severity, and pharmacokinetics and efficacies of antivirals and vaccines. Leveraging the circadian molecular mechanism insights has increased our understanding of clock infection biology and proposes new avenues for viral diagnostics and therapeutics. In this chapter, we address the molecular interplay between the circadian clock and viral infections and discuss the importance of chronotherapy as a complementary approach to conventional medicines, emphasizing the significance of virus-clock studies.

In Silico and In Vivo Evaluation of microRNA-181c-5p's Role in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a fatal disease, accounting for 75-85% of primary liver cancers. The conclusive research on miR-181c-5p's role in hepatocarcinogenesis, whether it has oncogenic effects or acts as a tumor repressor, is limited and fluctuating. Therefore, the current study aimed to elucidate the role of miR-181c-5p in HCC in silico and in vivo. The bioinformatics analysis of miR-181c-5p expression data in HCC using several databases strongly shed light on its involvement in HCC development, but also confirmed the fluctuating data around its role. miR-181c-5p was proven here to have an oncogenic role by increasing HepG2 cells' viability as confirmed by MTT analysis. In addition, miR-181c-5p was upregulated in the HCC positive control group and progressed the HCC development and malignant features by its forced expression in an HCC mouse model by targeted delivery using a LA-PAMAM polyplex. This is indicated by the cancerous gross and histological features, and the significant increase in liver function biomarkers. The functional enrichment bioinformatics analyses of miR-181c-5p-downregulated targets in HCC indicated that miR-181c-5p targets were significantly enriched in multiple pathways and biological processes involved in HCC development. Fbxl3, an example for miR-181c-5p potential targets, downregulation and its correlation with miR-181c-5p were validated by qPCR. In conclusion, miR-181c-5p is upregulated in HCC and has an oncogenic role enhancing HCC progression.

Circadian clock-based therapeutics in chronic pulmonary diseases

The circadian clock is the biochemical oscillator that orchestrates the observable circadian rhythms in physiology and behavior. Disruption of the circadian clock in the lungs during chronic pulmonary diseases is considered one of the key etiological risk factors that drive pathobiology. Preclinical studies support that pharmacological manipulation of the circadian clock is a conceivable approach for the development of novel clock-based therapeutics. Despite recent advances, no effort has been undertaken to integrate novel findings for the treatment and management of chronic lung diseases. We, therefore, recognize the need to discuss the candidate clock genes that can be potentially targeted for therapeutic intervention. Here, we aim to create the first roadmap that will advance the development of circadian- clock-based therapeutics that may provide better outcomes in treating chronic pulmonary diseases.

Review of Under-Recognized Adjunctive Therapies for Cancer

Patients and providers may not be aware that several adjunctive measures can significantly improve the quality of life, response to treatment, and possibly outcomes for cancer patients. This manuscript presents a review of practical under-recognized adjunctive therapies that are effective including exercise; stress-reduction techniques such as mindfulness, massage, yoga, Tai Chi, breathing exercises; importance of sleep quality; diet modifications such as calorie restriction at the time of chemotherapy and avoidance of high carbohydrate foods; supplements such as aspirin, green tea, turmeric, and melatonin; and repurposed prescription medications such as metformin and statins. Each recommendation should be tailored to the individual patient to assure no contraindications.

The circadian rhythm of viruses and its implications on susceptibility to infection

INTRODUCTION

Circadian genes have an impact on multiple hormonal, metabolic, and immunological pathways and have recently been implicated in some infectious diseases.

AREAS COVERED

We review aspects related to the current knowledge about circadian rhythm and viral infections, their consequences, and the potential therapeutic options.

EXPERT OPINION

Expert opinion: In order to address a problem, it is necessary to know the topic in depth. Although in recent years there has been a growing interest in the role of circadian rhythms, many relevant questions remain to be resolved. Thus, the mechanisms linking the circadian machinery against viral infections are poorly understood. In a clear approach to personalized precision medicine, in order to treat a disease in the most appropriate phase of the circadian rhythm, and in order to achieve the optimal efficacy, it is highly recommended to carry out studies that improve the knowledge about the circadian rhythm.

Concurrent Disruption of the Ras/MAPK and NF-κB Pathways Induces Circadian Deregulation and Hepatocarcinogenesis

The Ras/Erk and NF-κB pathways play critical roles in cell proliferation and are known to drive oncogenesis when overactivated. Herein we report a gatekeeper function of the two pathways by working in synergy to suppress liver tumorigenesis. Hepatocyte-specific deletion of both Shp2/Ptpn11 and Ikkβ in mice, which promote Ras/Erk and NF-κB signaling, respectively, exacerbated chemical carcinogenesis and even triggered spontaneous development of hepatocellular carcinoma (HCC). We show that the unanticipated severe tumor phenotype was contributed collectively by severe cholestasis, metabolic changes, upregulated cell-cycle progression, and disruption of circadian rhythm in mutant hepatocytes. Remarkably, human HCCs with dysregulated circadian gene expression displayed downregulation of Ras/Erk and NF-κB signaling and poor prognosis. Together, these data indicate that at the ground state, the two central pathways, previously known as oncogenic, cooperate to sustain tumor-suppressive physiologic homeostasis and to prevent hepatic damage. Disruption of this intricate signaling network is carcinogenic in the liver.

IMPLICATIONS

We demonstrate here that basal levels of the Ras/MAPK and NF-κB pathways, while promoting tumorigenesis if overactivated, are required to maintain physiologic homeostasis and regulate circadian rhythm in the liver, which are antitumorigenic.

Circadian Clock Genes Modulate Immune, Cell Cycle and Apoptosis in the Diagnosis and Prognosis of Pan-Renal Cell Carcinoma

Background: Pan-renal cell carcinoma (pan-RCC) is mainly divided into renal clear cell carcinoma (KIRC), renal papillary cell carcinoma (KIRP), and chromophobe cell carcinoma (KICH). Pan-RCC is a common malignant neoplasm with a high incidence and poor prognosis. Several studies have demonstrated a close association between cancer development and circadian rhythms; however, the clinical significance and molecular mechanism of the clock gene remain unclear in pan-RCC.

Methods: In this study, we systematically characterized the alterations of 15 well-known clock genes of three types of kidney cancer. Bioinformatics methods, including differential expression analysis, survival analysis, signing pathway analysis, co-expression network analysis, and drug sensitivity analysis were used to study the diagnosis, prognostic role, and mechanism of clock genes.

Results: Thirteen rhythmic genes fluctuated in circadian rhythm in the kidney tissue of mice, and the opposite trend of these rhythm phases was also found in baboons. There are twelve clock genes that were differentially expressed in at least two types of RCC, of which NR1D1, DBP, BHLHE40, CRY1, and CLOCK had the same trend in RCC. Changes in clock control genes may be regulated through methylation, copy number, and mutations. Five rhythmic genes, including PER2, DBP, PER3, CRY2, and RORA, have significant prognostic role in patient survival in at least two types of kidney cancer. Immune infiltration analysis showed that the expression of these rhythmic genes related to prognosis was positively correlated with the infiltration levels of CD4 and CD8 T cells. Pathway analysis suggests that the clock genes is widely related to cancer-related signaling pathways, such as apoptosis, cell cycle, and other pathways. The PPI network showed that circadian genes are closely linked to cancer-related genes such as HIF-1A, TP53, and ERBB2. Moreover, clock gene expression is correlated with the sensitivity of anticancer drugs such as bleomycin and methotrexate in pan-RCC.

Conclusion: Taken together, the abnormal expression of biological clock genes plays an important role in the clinical prognosis of RCC through immunity, cell cycle, and apoptosis. These findings provide a reliable basis for the diagnosis, prognosis, and drug guidance for RCC.

Prognostic values of the core components of the mammalian circadian clock in prostate cancer

Background

Prostate cancer (PC) is one of the most common malignancies in males. Extensive and complex connections between circadian rhythm and cancer were found. Nonetheless, in PC, the potential role of the core components of the mammalian circadian clock (CCMCCs) in prognosis prediction has not been fully clarified.

Methods

We firstly collected 605 patients with PC from The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) databases. Survival analysis was carried out for each CCMCC. Then, we investigated the prognostic ability of CCMCCs by Cox regression analysis. Independent prognostic signatures were extracted for the establishment of the circadian clock-based risk score model. We explored the predictive performance of the risk score model in the TCGA training cohort and the independent GEO dataset. Finally, the relationships between risk score and clinicopathological parameters, biological processes, and signaling pathways were evaluated.

Results

The expression levels of CCMCCs were widely correlated with age, tumor status, lymph node status, disease-free survival (DFS), progression-free survival (PFS), and overall survival (OS). Nine circadian clock genes, including CSNK1D, BTRC, CLOCK, CSNK1E, FBXL3, PRKAA2, DBP, NR1D2, and RORB, were identified as vital prognostic factors in PC and were used to construct the circadian clock-based risk score model. For DFS, the area under the 3-year or 5-year receiver operating characteristic curves ranged from 0.728 to 0.821, suggesting better predictive performance. When compared with T3-4N1 stage, PC patients at T2N0 stage might be benefited more from the circadian clock-based risk score model. Furthermore, a high circadian clock-based risk score indicated shorter DFS (p < 0.0001), early progression (p < 0.0001), and higher 5-year death rate (p = 0.007) in PC. The risk score was related to tumor status (p < 0.001), lymph node status (p < 0.001), and ribosome-related biogenesis and pathways.

Conclusions

The vital roles of circadian clock genes in clinical outcomes were fully depicted. The circadian clock-based risk score model could reflect and predict the prognosis of patients with PC.

Circadian Rhythms, Disease and Chronotherapy

Circadian clocks are biological timing mechanisms that generate 24-h rhythms of physiology and behavior, exemplified by cycles of sleep/wake, hormone release, and metabolism. The adaptive value of clocks is evident when internal body clocks and daily environmental cycles are mismatched, such as in the case of shift work and jet lag or even mistimed eating, all of which are associated with physiological disruption and disease. Studies with animal and human models have also unraveled an important role of functional circadian clocks in modulating cellular and organismal responses to physiological cues (ex., food intake, exercise), pathological insults (e.g. virus and parasite infections), and medical interventions (e.g. medication). With growing knowledge of the molecular and cellular mechanisms underlying circadian physiology and pathophysiology, it is becoming possible to target circadian rhythms for disease prevention and treatment. In this review, we discuss recent advances in circadian research and the potential for therapeutic applications that take patient circadian rhythms into account in treating disease.

The Expression and Function of Circadian Rhythm Genes in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is among the most common and lethal form of cancer worldwide. However, its diagnosis and treatment are still dissatisfactory, due to limitations in the understanding of its pathogenic mechanism. Therefore, it is important to elucidate the molecular mechanisms and identify novel therapeutic targets for HCC. Circadian rhythm-related genes control a variety of biological processes. These genes play pivotal roles in the initiation and progression of HCC and are potential diagnostic markers and therapeutic targets. This review gives an update on the research progress of circadian rhythms, their effects on the initiation, progression, and prognosis of HCC, in a bid to provide new insights for the research and treatment of HCC.

The role of the circadian clock in cancer hallmark acquisition and immune-based cancer therapeutics

The circadian system temporally regulates physiology to maintain homeostasis. Co-opting and disrupting circadian signals appear to be distinct attributes that are functionally important for the development of a tumor and can enable or give rise to the hallmarks that tumors use to facilitate their initiation, growth and progression. Because circadian signals are also strong regulators of immune cell proliferation, trafficking and exhaustion states, they play a role in how tumors respond to immune-based cancer therapeutics. While immuno-oncology has heralded a paradigm shift in cancer therapeutics, greater accuracy is needed to increase our capability of predicting who will respond favorably to, or who is likely to experience the troubling adverse effects of, immunotherapy. Insights into circadian signals may further refine our understanding of biological determinants of response and help answer the fundamental question of whether certain perturbations in circadian signals interfere with the activity of immune checkpoint inhibitors. Here we review the body of literature highlighting circadian disruption as a cancer promoter and synthesize the burgeoning evidence suggesting circadian signals play a role in how tumors respond to immune-based anti-cancer therapeutics. The goal is to develop a framework to advance our understanding of the relationships between circadian markers, cancer biology, and immunotherapeutics. Bolstered by this new understanding, these relationships may then be pursued in future clinical studies to improve our ability to predict which patients will respond favorably to, and avoid the adverse effects of, traditional and immune-based cancer therapeutics.

Melatonin and Cancer: A Polyhedral Network Where the Source Matters

Melatonin is one of the most phylogenetically conserved signals in biology. Although its original function was probably related to its antioxidant capacity, this indoleamine has been “adopted” by multicellular organisms as the “darkness signal” when secreted in a circadian manner and is acutely suppressed by light at night by the pineal gland. However, melatonin is also produced by other tissues, which constitute its extrapineal sources. Apart from its undisputed chronobiotic function, melatonin exerts antioxidant, immunomodulatory, pro-apoptotic, antiproliferative, and anti-angiogenic effects, with all these properties making it a powerful antitumor agent. Indeed, this activity has been demonstrated to be mediated by interfering with various cancer hallmarks, and different epidemiological studies have also linked light at night (melatonin suppression) with a higher incidence of different types of cancer. In 2007, the World Health Organization classified night shift work as a probable carcinogen due to circadian disruption, where melatonin plays a central role. Our aim is to review, from a global perspective, the role of melatonin both from pineal and extrapineal origin, as well as their possible interplay, as an intrinsic factor in the incidence, development, and progression of cancer. Particular emphasis will be placed not only on those mechanisms related to melatonin’s antioxidant nature but also on the recently described novel roles of melatonin in microbiota and epigenetic regulation.

Melatonin, an ubiquitous metabolic regulator: functions, mechanisms and effects on circadian disruption and degenerative diseases

The last four decades, we assist to an increasing scientific interest on melatonin, a circadian hormone, a metabolic regulator which influences not only plants' metabolism and their defense against pathogens but mostly the animals and humans' metabolic pathways, their response to circadian disruption, stress and burnout syndrome. In humans, as a hormonal regulator, produced in the pineal grand as well in mitochondria, melatonin is involved in different, complex intracellular signaling pathways, with antioxidant and immune stimulating effects, proving to act as a circadian synchronizer, as a preventive and therapeutic agent in many degenerative diseases, and especially in hormone-dependent cancers. Preclinical or clinical studies showed recently the mechanisms involved in regulating the cellular activity, its role in aging and circadian disturbances and impact on degenerative diseases. Melatonin proved to have an anti-inflammatory, antiapoptotic and powerful antioxidant effect by subtle mechanisms in mitochondrial metabolic pathways. This overview includes recent and relevant literature data related to the impact of endogenous and exogeneous melatonin on the prevention of cancer progression and treatment of various degenerative diseases. Metabolomics, an emerging new omics' technology, based on high performance liquid chromatography coupled with mass spectrometry is presented as an encouraging technique to fingerprint and realize a precise evaluation and monitoring of the turnover of melatonin and its metabolites in different pathological circumstances.

Cancer stem cell generation during epithelial-mesenchymal transition is temporally gated by intrinsic circadian clocks

Epithelial-mesenchymal transition (EMT) is a key event preceding tumor cell metastasis that increases cell invasiveness and cancer stem cell (CSC) populations. Studies suggest that genes used in generating circadian rhythms also serve in regulating EMT. To test the role of circadian clocks in cellular EMT events two cancer cell lines were compared, one that has a well-established circadian clock, C6 from rat glioma, and one that does not, MCF-7 from human breast tumor. MCF-7 tumorsphere cultures were tested for evidence of circadian rhythms because of previously reported circadian rhythm enhancement in C6 tumorspheres shown by elevated rhythm amplitude and increased expression of circadian clock gene Per2. Bioluminescence imaging of Per2 gene expression in MCF-7 tumorspheres revealed a previously unconfirmed circadian clock in this important cancer research model. Inducing CSC generation through EMT in C6 and MCF-7 monolayer cultures revealed circadian oscillations in the size of the post-EMT CSC population, confirming that circadian rhythms are additional processes controlling this stage of cancer progression. EMT was verified by distinct cellular morphological changes and expression of stem cell proteins OCT4, nestin, MSI1, and CD133 along with EMT-related proteins ZEB1, vimentin, and TWIST. Quantifying single-cell events and behaviors through time-lapse imaging indicated the post-EMT population size was determined largely by circadian rhythms in epithelial-like cancer cells undergoing EMT. We then identified a specific phase of the circadian rhythm in Per2 gene activation as a potential target for therapeutic treatments that may suppress EMT, minimize CSCs, and limit metastasis.

Dysregulation, functional implications, and prognostic ability of the circadian clock across cancers

It has been proposed that the circadian rhythm generally plays important roles in tumor suppression, but there is also evidence that disruption of the canonical circadian pathway has anticancer effects. In this study, we systematically analyzed the aberrances of circadian clock genes across cancers based on data from The Cancer Genome Atlas (TCGA). These data showed that the frequencies of mutations and copy number alterations in core clock genes (PER1/2/3, CLOCK, CRY1/2, and ARNTL) were low, but that the expression levels of core clock genes were downregulated by the higher levels of DNA methylation in most tumors. The circadian clock index (CCI) was established through a principal component analysis, and this measure well represents the overall expression of the core clock genes. In fact, the CCI was significantly lower in hepatocellular carcinoma with HBV infection than in other cancers. Furthermore, pathways such as the MAPK, JAK-STAT, and immune-related signaling pathways were enriched in tumors with high CCI values. Interestingly, the CCI was generally positively related to the immunophenoscores and immunophenotypes of tumors. Additionally, the expression levels of core clock genes and the CCI were also generally positively related to survival across cancers. Taken together, the results of this study provide a comprehensive analysis of circadian clock aberrances in cancer, and the results should aid further investigations of the molecular mechanisms of cancer and the development of therapeutic strategies.