Non-Metastatic Cutaneous Melanoma Induces Chronodisruption in Central and Peripheral Circadian Clocks

G Protein-Coupled Receptors in Skin Aging

Skin aging is a complex biological process affected by a plethora of intrinsic and extrinsic factors that alter cutaneous functions through the modulations of signaling pathways and responses. Expressed in various cell types and skin tissue layers, G protein-coupled receptors (GPCRs) play a vital role in regulating skin aging. We have cataloged 156 GPCRs expressed in the skin and reviewed their roles in skin aging, such as pigmentation, loss of elasticity, wrinkles, rough texture, and aging-associated skin disorders. By exploring the GPCRs found in the skin, it may be possible to develop new treatment regimens for aging-associated skin conditions using GPCR ligands.

Circadian disruption of feeding-fasting rhythm and its consequences for metabolic, immune, cancer, and cognitive processes

The circadian system is composed by a central hypothalamic clock at the suprachiasmatic nuclei (SCN) that communicates with peripheral circadian oscillators for daily coordination of behavior and physiology. The SCN entrain to the environmental 24-h light-dark (LD) cycle and drive daily rhythms of internal synchronizers such as core body temperature, hypothalamic-hypophysary hormones, sympathetic/parasympathetic activity, as well as behavioral and feeding-fasting rhythms, which supply signals setting core molecular clocks at central and peripheral tissues. Steady phase relationships between the SCN and peripheral oscillators keep homeostatic processes such as microbiota/microbiome composition/activity, metabolic supply/demand, energy balance, immunoinflammatory process, sleep amount and quality, psychophysiological stress, etc. Indeed, the risk of health alterations increase when these phase relationships are chronically changed prompting circadian disruption (CD), as occurring after sudden LD cycle changes (so-called jet-lag), or due to changes of activity/feeding-rest/fasting rhythm with respect to LD cycles (as humans subjected to nightwork, or restricting food access at rest in mice). Typical pathologies observed in animal models of CD and epidemiological studies include metabolic syndrome, type-2 diabetes, obesity, chronic inflammation, cancer, sleep disruption, decrease in physical and cognitive performance, and mood, among others. The present review discusses different aspects of such physiological dysregulations observed in animal models of CD having altered feeding-fasting rhythms, with potential translation to human health.

Circadian rhythm disruption and endocrine-related tumors

This review delved into the intricate relationship between circadian clocks and physiological processes, emphasizing their critical role in maintaining homeostasis. Orchestrated by interlocked clock genes, the circadian timekeeping system regulates fundamental processes like the sleep-wake cycle, energy metabolism, immune function, and cell proliferation. The central oscillator in the hypothalamic suprachiasmatic nucleus synchronizes with light-dark cycles, while peripheral tissue clocks are influenced by cues such as feeding times. Circadian disruption, linked to modern lifestyle factors like night shift work, correlates with adverse health outcomes, including metabolic syndrome, cardiovascular diseases, infections, and cancer. We explored the molecular mechanisms of circadian clock genes and their impact on metabolic disorders and cancer pathogenesis. Specific associations between circadian disruption and endocrine tumors, spanning breast, ovarian, testicular, prostate, thyroid, pituitary, and adrenal gland cancers, are highlighted. Shift work is associated with increased breast cancer risk, with PER genes influencing tumor progression and drug resistance. CLOCK gene expression correlates with cisplatin resistance in ovarian cancer, while factors like aging and intermittent fasting affect prostate cancer. Our review underscored the intricate interplay between circadian rhythms and cancer, involving the regulation of the cell cycle, DNA repair, metabolism, immune function, and the tumor microenvironment. We advocated for integrating biological timing into clinical considerations for personalized healthcare, proposing that understanding these connections could lead to novel therapeutic approaches. Evidence supports circadian rhythm-focused therapies, particularly chronotherapy, for treating endocrine tumors. Our review called for further research to uncover detailed connections between circadian clocks and cancer, providing essential insights for targeted treatments. We emphasized the importance of public health interventions to mitigate lifestyle-related circadian disruptions and underscored the critical role of circadian rhythms in disease mechanisms and therapeutic interventions.

Exercise training induces alteration of clock genes and myokines expression in tumor-bearing mice

To investigate the impact of different exercise training schedules (following a fixed schedule or at random times of the day) on clock genes and myokine expression patterns in the skeletal muscle of tumor-bearing mice. Mice were divided into three groups: tumor (LLC), tumor + exercise training (LLC + T) always performed at the same time of the day (ZT2) and exercise training at random times of the day (ZTAlt). Mice were inoculated subcutaneously with Lewis lung carcinoma cells. The gastrocnemius muscle was dissected and the clock gene expression (Clock/Per1/Per2/Per3/Rev-Erbα/GAPDH) was investigated by quantitative reverse transcription polymerase chain reaction with SYBR® Green. Myokine content in muscle (tumour necrosis factor alpha/IL-10/IL-4) was assessed by enzyme-linked immunosorbent assay. At the end of the protocol, the trained groups showed a reduction in total weight, when compared to Lewis lung carcinoma. Tumor weight was lower in the LLC + T (ZTAlt), when compared to LLC. Clock gene mRNA expression showed a significant increase for ZT20 in the groups that performed physical exercise at LLC + T (ZTAlt), when compared with LLC. The Per family showed increased mRNA expression in ZT4 in both trained mice groups, when compared with LLC. LLC + T (ZTAlt) presented reduction of the expression of anti-inflammatory myokines (Il-10/IL-4) during the night, compared with LLC + T(ZT2). Exercise training is able to induce marked modification of clock gene expression and of the production of myokines, in a way that is dependent on schedule exercise training strategy. Taken together, the results show that exercise is a potent Zeitgeber and may thus contribute to change clock genes expression and myokines that are able to reduce the tumor weight.

Disruptions of Circadian Genes in Cutaneous Melanoma-An In Silico Analysis of Transcriptome Databases

Circadian genes are a set of genes that regulate the body's internal clock and influence various physiological processes, including sleep-wake cycles, metabolism and immune function. Skin cutaneous melanoma (SKCM) is a type of skin cancer that arises from the pigment-producing cells in the skin and is the most deadly form of skin cancer. This study has investigated the relevance of circadian gene expression and immune infiltrations in the outcomes of cutaneous melanoma patients. In the present study, in silico methods based on the GEPIa, TIMER 2.0 and cBioPortal databases were performed, so as to investigate the transcript level and prognostic value of 24 circadian genes in SKCM and their relationship with the immune infiltration level. The in silico analysis showed that significantly more than half of the investigated circadian genes have an altered transcript pattern in cutaneous melanoma compared to normal skin. The mRNA levels of TIMELES and BHLHE41 were upregulated, whereas those of NFIL3, BMAL1, HLF, TEF, RORA, RORC, NR1D1, PER1, PER2, PER3, CRY2 and BHLHE40 were downregulated. The presented research shows that SKCM patients with at least one alteration of their circadian genes have decreased overall survival. Additionally, majority of the circadian genes are significantly corelated with the immune cells' infiltration level. The strongest correlation was found for neutrophils and was followed by circadian genes: NR1D2 r = 0.52 p < 0.0001, BMAL1 r = 0.509 p < 0.0001; CLOCK r = 0.45 p < 0.0001; CSNKA1A1 r = 0.45 p < 0.0001; RORA r = 0.44 p < 0.0001. The infiltration level of immune cells in skin tumors has been associated with patient prognosis and treatment response. Circadian regulation of immune cell infiltration may further contribute to these prognostic and predictive markers. Examining the correlation between circadian rhythm and immune cell infiltration can provide valuable insights into disease progression and guide personalized treatment decisions.

Lack of TRPV1 Channel Modulates Mouse Gene Expression and Liver Proteome with Glucose Metabolism Changes

To investigate the role of the transient receptor potential channel vanilloid type 1 (TRPV1) in hepatic glucose metabolism, we analyzed genes related to the clock system and glucose/lipid metabolism and performed glycogen measurements at ZT8 and ZT20 in the liver of C57Bl/6J (WT) and Trpv1 KO mice. To identify molecular clues associated with metabolic changes, we performed proteomics analysis at ZT8. Liver from Trpv1 KO mice exhibited reduced Per1 expression and increased Pparα, Pparγ, Glut2, G6pc1 (G6pase), Pck1 (Pepck), Akt, and Gsk3b expression at ZT8. Liver from Trpv1 KO mice also showed reduced glycogen storage at ZT8 but not at ZT20 and significant proteomics changes consistent with enhanced glycogenolysis, as well as increased gluconeogenesis and inflammatory features. The network propagation approach evidenced that the TRPV1 channel is an intrinsic component of the glucagon signaling pathway, and its loss seems to be associated with increased gluconeogenesis through PKA signaling. In this sense, the differentially identified kinases and phosphatases in WT and Trpv1 KO liver proteomes show that the PP2A phosphatase complex and PKA may be major players in glycogenolysis in Trpv1 KO mice.

Aggravation of hepatic lipidosis in red-footed tortoise Chelonoidis carbonaria with age is associated with alterations in liver mitochondria

The occurrence of hepatic lipidosis is commonly reported in different reptilian species, especially in animals under captivity. Liver accumulation of fat is associated with disorders, better described in mammals as non-alcoholic fatty liver diseases (NAFLD), ranging from simple steatosis, to non-alcoholic steatohepatitis (NASH), and to more severe lesions of cirrhosis and hepatocellular carcinoma. Mitochondria play a central role in NAFLD pathogenesis, therefore in this study we characterized livers of ad libitum fed captive red-footed tortoise Chelonoidis carbonaria through histological and mitochondrial function evaluations of juvenile and adult individuals. Livers from adult tortoises exhibited higher levels of lipids, melanomacrophages centers and melanin than juveniles. The observed high score levels of histopathological alterations in adult tortoises, such as microvesicular steatosis, inflammation and fibrosis, indicated the progression to a NASH condition. Mitochondrial oxygen consumption at different respiratory states and with different substrates was 30 to 58% lower in adult when compared to juvenile tortoises. Despite citrate synthase activity was also lower in adults, cardiolipin content was similar to juveniles, indicating that mitochondrial mass was unaffected by age. Mitochondrial Ca²⁺ retention capacity was reduced by 70% in adult tortoises. Overall, we found that aggravation of NAFLD in ad libitum fed captive tortoises is associated with compromised mitochondrial function, indicating a critical role of the organelle in liver disease progression in reptiles.

Melanopsin (Opn4) is an oncogene in cutaneous melanoma

The search for new therapeutical targets for cutaneous melanoma and other cancers is an ongoing task. We expanded this knowledge by evaluating whether opsins, light- and thermo-sensing proteins, could display tumor-modulatory effects on melanoma cancer. Using different experimental approaches, we show that melanoma cell proliferation is slower in the absence of Opn4, compared to Opn4WT due to an impaired cell cycle progression and reduced melanocyte inducing transcription factor (Mitf) expression. In vivo tumor progression of Opn4KO cells is remarkably reduced due to slower proliferation, and higher immune system response in Opn4KO tumors. Using pharmacological assays, we demonstrate that guanylyl cyclase activity is impaired in Opn4KO cells. Evaluation of Tumor Cancer Genome Atlas (TCGA) database confirms our experimental data as reduced MITF and OPN4 expression in human melanoma correlates with slower cell cycle progression and presence of immune cells in the tumor microenvironment (TME). Proteomic analyses of tumor bulk show that the reduced growth of Opn4KO tumors is associated with reduced Mitf signaling, higher translation of G2/M proteins, and impaired guanylyl cyclase activity. Conversely, in Opn4WT tumors increased small GTPase and an immune-suppressive TME are found. Such evidence points to OPN4 as an oncogene in melanoma, which could be pharmacologically targeted.

Presence of human breast cancer xenograft changes the diurnal profile of amino acids in mice

Human xenografts are extremely useful models to study the biology of human cancers and the effects of novel potential therapies. Deregulation of metabolism, including changes in amino acids (AAs), is a common characteristic of many human neoplasms. Plasma AAs undergo daily variations, driven by circadian endogenous and exogenous factors. We compared AAs concentration in triple negative breast cancer MDA-MB-231 cells and MCF10A non-tumorigenic immortalized breast epithelial cells. We also measured plasma AAs in mice bearing xenograft MDA-MB-231 and compared their levels with non-tumor-bearing control animals over 24 h. In vitro studies revealed that most of AAs were significantly different in MDA-MB-231 cells when compared with MCF10A. Plasma concentrations of 15 AAs were higher in cancer cells, two were lower and four were observed to shift across 24 h. In the in vivo setting, analysis showed that 12 out of 20 AAs varied significantly between tumor-bearing and non-tumor bearing mice. Noticeably, these metabolites peaked in the dark phase in non-tumor bearing mice, which corresponds to the active time of these animals. Conversely, in tumor-bearing mice, the peak time occurred during the light phase. In the early period of the light phase, these AAs were significantly higher in tumor-bearing animals, yet significantly lower in the middle of the light phase when compared with controls. This pilot study highlights the importance of well controlled experiments in studies involving plasma AAs in human breast cancer xenografts, in addition to emphasizing the need for more precise examination of exometabolomic changes using multiple time points.

Loss of Melanopsin (OPN4) Leads to a Faster Cell Cycle Progression and Growth in Murine Melanocytes

Skin melanocytes harbor a complex photosensitive system comprised of opsins, which were shown, in recent years, to display light- and thermo-independent functions. Based on this premise, we investigated whether melanopsin, OPN4, displays such a role in normal melanocytes. In this study, we found that murine Opn4^KO melanocytes displayed a faster proliferation rate compared to Opn4^WT melanocytes. Cell cycle population analysis demonstrated that OPN4^KO melanocytes exhibited a faster cell cycle progression with reduced G₀–G₁, and highly increased S and slightly increased G₂/M cell populations compared to the Opn4^WT counterparts. Expression of specific cell cycle-related genes in Opn4^KO melanocytes exhibited alterations that corroborate a faster cell cycle progression. We also found significant modification in gene and protein expression levels of important regulators of melanocyte physiology. PER1 protein level was higher while BMAL1 and REV-ERBα decreased in Opn4^KO melanocytes compared to Opn4^WT cells. Interestingly, the gene expression of microphthalmia-associated transcription factor (MITF) was upregulated in Opn4^KO melanocytes, which is in line with a higher proliferative capability. Taken altogether, we demonstrated that OPN4 regulates cell proliferation, cell cycle, and affects the expression of several important factors of the melanocyte physiology; thus, arguing for a putative tumor suppression role in melanocytes.

The circadian clock and diseases of the skin

Organisms have an evolutionarily conserved internal rhythm that helps them anticipate and adapt to daily changes in the environment. Synchronized to the light-dark cycle with a period of around 24 hours, the timing of the circadian clock is set by light-triggering signals sent from the retina to the suprachiasmatic nucleus. Other inputs, including food intake, exercise, and temperature, also affect clocks in peripheral tissues, including skin. Here, we review the intricate interplay between the core clock network and fundamental physiological processes in skin such as homeostasis, regeneration, and immune- and stress responses. We illustrate the effect of feeding time on the skin circadian clock and skin functions, a previously overlooked area of research. We then discuss works that relate the circadian clock and its disruption to skin diseases, including skin cancer, sunburn, hair loss, aging, infections, inflammatory skin diseases, and wound healing. Finally, we highlight the promise of circadian medicine for skin disease prevention and management.

Circadian disruption induced by tumor development in a murine model of melanoma

The circadian system induces oscillations in most physiological variables, with periods close to 24 hours. Dysfunctions in clock-controlled body functions, such as sleep disorders, as well as deregulation of clock gene expression or glucocorticoid levels have been observed in cancer patients. Moreover, these disorders have been associated with a poor prognosis or worse response to treatment. This work explored the circadian rhythms at behavioral and molecular levels in a murine melanoma model induced by subcutaneous inoculation of B16 tumoral cells. We observed that the presence of the tumors induced a decrease in the robustness of the locomotor activity rhythms and in the amount of nighttime activity, together with a delay in the acrophase and in the activity onset. Moreover, these differences were more marked when the tumor size was larger than in the initial stages of the tumorigenesis protocol. In addition, serum glucocorticoids, which exhibit strong clock-controlled rhythms, lost their circadian patterns. Similarly, the rhythmic expression of the clock genes Bmal1 and Cry1 in the hypothalamic Suprachiasmatic Nuclei (SCN) were also deregulated in mice carrying tumors. Altogether, these results suggest that tumor-secreted molecules could modulate the function of the central circadian pacemaker (SCN). This could account for the worsening of the peripheral biological rhythms such as locomotor activity or serum glucocorticoids. Since disruption of the circadian rhythms might accelerate tumorigenesis, monitoring circadian patterns in cancer patients could offer a new tool to get a better prognosis for this disease.

The Impact of the Circadian Clock on Skin Physiology and Cancer Development

Skin cancers are growing in incidence worldwide and are primarily caused by exposures to ultraviolet (UV) wavelengths of sunlight. UV radiation induces the formation of photoproducts and other lesions in DNA that if not removed by DNA repair may lead to mutagenesis and carcinogenesis. Though the factors that cause skin carcinogenesis are reasonably well understood, studies over the past 10–15 years have linked the timing of UV exposure to DNA repair and skin carcinogenesis and implicate a role for the body’s circadian clock in UV response and disease risk. Here we review what is known about the skin circadian clock, how it affects various aspects of skin physiology, and the factors that affect circadian rhythms in the skin. Furthermore, the molecular understanding of the circadian clock has led to the development of small molecules that target clock proteins; thus, we discuss the potential use of such compounds for manipulating circadian clock-controlled processes in the skin to modulate responses to UV radiation and mitigate cancer risk.

Efficacy and Safety of Systemic and Locoregional Cisplatin Chronotherapy in Rats with Ovarian Carcinoma

Aim

Alterations in circadian rhythms caused by tumor growth are thought to be clinically relevant as they affect the prognosis and treatment response. We aimed to evaluate the chronotherapeutic approach in rats with ovarian cancer receiving cisplatin intravenously (IV) or with hyperthermic intraperitoneal chemoperfusion (HIPEC) and to assess daily variations in tumor and intestinal epithelium proliferation.

Methods

In the pilot study, we used 12 intact rats and 12 rats with transplantable ovarian cancer, which were euthanized at ZT0 (08:00, lights on), ZT6, ZT12 and ZT18. In the main study, we used 45 rats with transplantable ovarian cancer. Animals were randomized into five groups: control, HIPEC with cisplatin at ZT0 (08:00), HIPEC with cisplatin at ZT12 (20:00), IV cisplatin at ZT0 and IV cisplatin at ZT12. We assessed the proliferation rate of tumor and small intestinal epithelium, apoptosis in small intestinal epithelium, and levels of γ-H2AX (DNA damage/repair marker) in kidneys and liver. Survival was calculated in each group.

Results

Ascitic ovarian cancer disrupted daily variations in intestinal epithelium proliferation and DNA damage/repair in rats. Ovarian carcinoma exhibited no daily variation in mitotic activity. In animals receiving IV cisplatin, massive cell damage in the renal medulla and cystic changes within renal tubules were observed, unlike in rats receiving HIPEC. Tumor mitotic activity was lower in morning-treated groups. The median survival of rats in the control group was 8.5 days (95% CI 6.0–22.0), in HIPEC at ZT0 40.5 days (95% CI 28.0–47.0, p<0.001) and in HIPEC at ZT12 32.0 days (95% CI 28.0–37.0, p<0.001).

Conclusion

In a rat model, ovarian tumor growth disrupted daily variations in intestinal epithelium proliferation and caused genotoxic stress in tumor-free tissues. HIPEC with cisplatin at ZT0 had a better efficacy/toxicity profile than HIPEC with cisplatin at ZT12 and IV administration at both time points.

Daily Lifestyle and Cutaneous Malignancies

Daily lifestyle is a fundamental part of human life and its influence accumulates daily in the human body. We observe that a good daily lifestyle has a beneficial impact on our health; however, the actual effects of individual daily lifestyle factors on human skin diseases, especially skin cancers, have not been summarized. In this review, we focused on the influence of daily lifestyle on the development of skin cancer and described the detailed molecular mechanisms of the development or regulation of cutaneous malignancies. Several daily lifestyle factors, such as circadian rhythm disruption, smoking, alcohol, fatty acids, dietary fiber, obesity, and ultraviolet light, are known to be associated with the risk of cutaneous malignancies, malignant melanoma, squamous cell carcinoma, basal cell carcinoma, and Merkel cell carcinoma. Although the influence of some daily lifestyles on the risk of skin cancers is controversial, this review provides us a better understanding of the relationship between daily lifestyle factors and skin cancers.

An Immunometabolic Shift Modulates Cytotoxic Lymphocyte Activation During Melanoma Progression in TRPA1 Channel Null Mice

Melanoma skin cancer is extremely aggressive with increasing incidence and mortality. Among the emerging therapeutic targets in the treatment of cancer, the family of transient receptor potential channels (TRPs) has been reported as a possible pharmacological target. Specifically, the ankyrin subfamily, representing TRPA1 channels, can act as a pro-inflammatory hub. These channels have already been implicated in the control of intracellular metabolism in several cell models, but little is known about their role in immune cells, and how it could affect tumor progression in a process known as immune surveillance. Here, we investigated the participation of the TRPA1 channel in the immune response against melanoma tumor progression in a mouse model. Using Trpa1 ^+/+ and Trpa1 ^-/- animals, we evaluated tumor progression using murine B16-F10 cells and assessed isolated CD8+ T cells for respiratory and cytotoxic functions. Tumor growth was significantly reduced in Trpa1 ^-/- animals. We observed an increase in the frequency of circulating lymphocytes. Using a dataset of CD8+ T cells isolated from metastatic melanoma patients, we found that TRPA1 reduction correlates with several immunological pathways. Naïve CD8+ T cells from Trpa1 ^+/+ and Trpa1 ^-/- animals showed different mitochondrial respiration and glycolysis profiles. However, under CD3/CD28 costimulatory conditions, the absence of TRPA1 led to an even more extensive metabolic shift, probably linked to a greater in vitro killling ability of Trpa1 ^-/- CD8+ T cells. Therefore, these data demonstrate an unprecedented role of TRPA1 channel in the metabolism control of the immune system cells during carcinogenesis.

The circadian clock and metabolic homeostasis: entangled networks

The circadian clock exerts an important role in systemic homeostasis as it acts a keeper of time for the organism. The synchrony between the daily challenges imposed by the environment needs to be aligned with biological processes and with the internal circadian clock. In this review, it is provided an in-depth view of the molecular functioning of the circadian molecular clock, how this system is organized, and how central and peripheral clocks communicate with each other. In this sense, we provide an overview of the neuro-hormonal factors controlled by the central clock and how they affect peripheral tissues. We also evaluate signals released by peripheral organs and their effects in the central clock and other brain areas. Additionally, we evaluate a possible communication between peripheral tissues as a novel layer of circadian organization by reviewing recent studies in the literature. In the last section, we analyze how the circadian clock can modulate intracellular and tissue-dependent processes of metabolic organs. Taken altogether, the goal of this review is to provide a systemic and integrative view of the molecular clock function and organization with an emphasis in metabolic tissues.

Mammalian circadian systems: Organization and modern life challenges

Humans and other mammalian species possess an endogenous circadian clock system that has evolved in adaptation to periodically reoccurring environmental changes and drives rhythmic biological functions, as well as behavioural outputs with an approximately 24-hour period. In mammals, body clocks are hierarchically organized, encompassing a so-called pacemaker clock in the hypothalamic suprachiasmatic nucleus (SCN), non-SCN brain and peripheral clocks, as well as cell-autonomous oscillators within virtually every cell type. A functional clock machinery on the molecular level, alignment among body clocks, as well as synchronization between endogenous circadian and exogenous environmental cycles has been shown to be crucial for our health and well-being. Yet, modern life constantly poses widespread challenges to our internal clocks, for example artificial lighting, shift work and trans-meridian travel, potentially leading to circadian disruption or misalignment and the emergence of associated diseases. For instance many of us experience a mismatch between sleep timing on work and free days (social jetlag) in our everyday lives without being aware of health consequences that may arise from such chronic circadian misalignment, Hence, this review provides an overview of the organization and molecular built-up of the mammalian circadian system, its interactions with the outside world, as well as pathologies arising from circadian disruption and misalignment.

Gender-specific associations between polymorphisms of the circadian gene RORA and cutaneous melanoma susceptibility

BACKGROUND

Melanoma is the deadliest of skin cancers and has an increasing annual incidence worldwide. It is a multi-factorial disease most likely arising from both genetic predisposition and environmental exposure to ultraviolet light. Genetic variability of the components of the biological circadian clock is recognized to be a risk factor for different type of cancers. Moreover, two variants of a clock gene, RORA, have been associated with melanoma patient's prognosis. Our aim is to test the hypothesis that specific single nucleotide polymorphisms (SNPs) of the circadian clock genes may significantly influence the predisposition to develop cutaneous melanoma or the outcome of melanoma patients.

METHODS

We genotyped 1239 subjects, 629 cases of melanoma and 610 healthy controls in 14 known SNPs of seven selected clock genes: AANAT, CLOCK, NPAS2, PER1, PER2, RORA, and TIMELESS. Genotyping was conducted by q-PCR. Multivariate logistic regression was employed for susceptibility of melanoma assessment, modeled additively. Subgroup analysis was performed by gender. For the female subgroup, a further discrimination was performed by age. For prognosis of melanoma assessment, multivariate Cox proportional hazard regression was employed. The Benjamini-Hochberg method was utilized as adjustment for multiple comparisons.

RESULTS

We identified two RORA SNPs statistically significant with respect to the association with melanoma susceptibility. Considering the putative role of RORA as a nuclear steroid hormone receptor, we conducted a subgroup analysis by gender. Interestingly, the RORA rs339972 C allele was associated with a decreased predisposition to develop melanoma only in the female subgroup (OR 0.67; 95% CI 0.51-0.88; P = 0.003) while RORA rs10519097 T allele was associated with a decreased predisposition to develop melanoma only in the male subgroup (OR 0.62; 95% CI 0.44-0.87; P = 0.005). Moreover, the RORA rs339972 C allele had a decreased susceptibility to develop melanoma only in females aged over 50 years old (OR 0.67; 95% CI 0.54-0.83; P = 0.0002). None of the studied SNPs were significantly associated with the prognosis.

CONCLUSIONS

Overall, we cannot ascertain that circadian pathway genetic variation is involved in melanoma susceptibility or prognosis. Nevertheless, we identified an interesting relationship between melanoma susceptibility and RORA polymorphisms acting in sex-specific manner and which is worth further future investigation.

Serum factor(s) from lung adenocarcinoma patients regulates the molecular clock expression

Lung cancer is a leading cause of cancer-associated deaths worldwide. Lung cancer may lead to circadian disruption, which could contribute to the development of lung cancer. Recently, several studies using animal models indicated that tumors influence systemic circadian homeostasis in remote tissues. However, it is unclear whether carcinoma of the lungs influences remote circadian rhythm, whether this effect exists in humans, and whether signals from the tumor travel through the blood. In this study, we used a cell-based assay to determine whether serum from patients with lung adenocarcinoma could modulate the molecular clock. We found that the daily oscillation period of Bmal1 was significantly lengthened following treatment with serum from untreated lung adenocarcinoma patients. In addition, heat inactivation of this serum abolished the effect, suggesting that a heat-sensitive circulating factor(s) is present in the serum of untreated lung adenocarcinoma patients. Using real-time PCR, we also examined the mRNA abundance of Bmal1, Cry1, and Per1 in human osteosarcoma u2os cell line, HUVECs and A549 cell lines. The expression of Bmal1 was changed in A549 cells in the presence of sera from lung adenocarcinoma patients. Our study revealed a direct effect of serum from lung adenocarcinoma patients on the molecular clock.

Possible Association of PER2/PER3 Variable Number Tandem Repeat Polymorphism Variants with Susceptibility and Clinical Characteristics in Pancreatic Cancer

Objective: Pancreatic cancer (PC) is a serious disease with poor outcomes, and its prevalence has been increasing steadily. The circadian rhythm (CR) is involved in multiple physiological events and maintains homeostasis. Alterations in the CR elevate the risk of developing cancer. The present case-control research was carried out to estimate the possible association between PERIOD2/PERIOD3 (PER2/PER3) gene variable number tandem repeat polymorphism (VNTR) variants and PC in the Turkish population. Materials and Methods: A total of 198 subjects (78 patients with PC and 120 healthy controls) were enrolled in this work. Genomic DNA was collected from peripheral blood mononuclear cells, and genotypic analyses was performed using a polymerase chain reaction (PCR) method. Odds ratio (OR) with a 95% confidence interval (95% CI) was calculated using the χ² test. Results: The frequency of the 4R (4 repeats)/3R (3 repeats), 3R/3R genotypes, and 3R allele of PER2 VNTR in patients with PC was significantly higher than in the control group (p = 0003, p = 0.00004, respectively). PER2 VNTR 4/5 genotype was related to perineural invasion (p = 0.040). The genotype and allele distribution of PER3 VNTR variant did not show any statistical difference between the two groups (p > 0.05). The PER2/PER3 VNTR 4/5-4R/3R combined genotype was increased in the patient group (p = 0.013), while 4/5-4R/4R combined genotype was increased in the control group (p = 0.0001). Conclusions: Our work has indicated that PER2 VNTR 3R allele may play a crucial role in the pathogenesis of PC in Turkish patients, which may become a useful marker for predicting the development of PC. Furthermore, the PER2 VNTR genotype seems to be related to perineural invasion in PC.

Metabolic rivalry: circadian homeostasis and tumorigenesis

Circadian rhythms govern a large array of physiological and metabolic functions. Perturbations of the daily cycle have been linked to elevated risk of developing cancer as well as poor prognosis in patients with cancer. Also, expression of core clock genes or proteins is remarkably attenuated particularly in tumours of a higher stage or that are more aggressive, possibly linking the circadian clock to cellular differentiation. Emerging evidence indicates that metabolic control by the circadian clock underpins specific hallmarks of cancer metabolism. Indeed, to support cell proliferation and biomass production, the clock may direct metabolic processes of cancer cells in concert with non-clock transcription factors to control how nutrients and metabolites are utilized in a time-specific manner. We hypothesize that the metabolic switch between differentiation or stemness of cancer may be coupled to the molecular clockwork. Moreover, circadian rhythms of host organisms appear to dictate tumour growth and proliferation. This Review outlines recent discoveries of the interplay between circadian rhythms, proliferative metabolism and cancer, highlighting potential opportunities in the development of future therapeutic strategies.

Neurobiology of Cancer: the Role of β-Adrenergic Receptor Signaling in Various Tumor Environments

The development and progression of cancer depends on both tumor micro- and macroenvironments. In addition, psychosocial and spiritual “environments” might also affect cancer. It has been found that the nervous system, via neural and humoral pathways, significantly modulates processes related to cancer at the level of the tumor micro- and macroenvironments. The nervous system also mediates the effects of psychosocial and noetic factors on cancer. Importantly, data accumulated in the last two decades have clearly shown that effects of the nervous system on cancer initiation, progression, and the development of metastases are mediated by the sympathoadrenal system mainly via β-adrenergic receptor signaling. Here, we provide a new complex view of the role of β-adrenergic receptor signaling within the tumor micro- and macroenvironments as well as in mediating the effects of the psychosocial and spiritual environments. In addition, we describe potential preventive and therapeutic implications.

Melanopsin mediates UVA-dependent modulation of proliferation, pigmentation, apoptosis, and molecular clock in normal and malignant melanocytes

Cutaneous melanocytes and melanoma cells express several opsins, of which melanopsin (OPN4) detects temperature and UVA radiation. To evaluate the interaction between OPN4 and UVA radiation, normal and malignant Opn4WT and Opn4KO melanocytes were exposed to three daily low doses (total 13.2 kJ/m2) of UVA radiation. UVA radiation led to a reduction of proliferation in both Opn4WT cell lines; however, only in melanoma cells this effect was associated with increased cell death by apoptosis. Daily UVA stimuli induced persistent pigment darkening (PPD) in both Opn4WT cell lines. Upon Opn4 knockout, all UVA-induced effects were lost in three independent clones of Opn4KO melanocytes and melanoma cells. Per1 bioluminescence was reduced after 1st and 2nd UVA radiations in Opn4WT cells. In Opn4KO melanocytes and melanoma cells, an acute increase of Per1 expression was seen immediately after each stimulus. We also found that OPN4 expression is downregulated in human melanoma compared to normal skin, and it decreases with disease progression. Interestingly, metastatic melanomas with low expression of OPN4 present increased expression of BMAL1 and longer overall survival. Collectively, our findings reinforce the functionality of the photosensitive system of melanocytes that may subsidize advancements in the understanding of skin related diseases, including cancer.

Coupled network of the circadian clocks: a driving force of rhythmic physiology

The circadian system is composed of coupled endogenous oscillators that allow living beings, including humans, to anticipate and adapt to daily changes in their environment. In mammals, circadian clocks form a hierarchically organized network with a 'master clock' located in the suprachiasmatic nucleus of the hypothalamus, which ensures entrainment of subsidiary oscillators to environmental cycles. Robust rhythmicity of body clocks is indispensable for temporally coordinating organ functions, and the disruption or misalignment of circadian rhythms caused for instance by modern lifestyle is strongly associated with various widespread diseases. This review aims to provide a comprehensive overview of our current knowledge about the molecular architecture and system-level organization of mammalian circadian oscillators. Furthermore, we discuss the regulatory roles of peripheral clocks for cell and organ physiology and their implication in the temporal coordination of metabolism in human health and disease. Finally, we summarize methods for assessing circadian rhythmicity in humans.

Extracellular Acidosis Promotes Metastatic Potency via Decrease of the BMAL1 Circadian Clock Gene in Breast Cancer

Circadian oscillation is an essential process that influences many physiological and biological mechanisms and a decrease of circadian genes is associated with many diseases such as cancer. Despite many efforts to identify the detailed mechanism for decreasing circadian genes and recovering reduced circadian genes in cancer, it is still largely unknown. We found that BMAL1 was reduced in tumor hypoxia-induced acidosis, and recovered by selectively targeting acidic pH in breast cancer cell lines. Surprisingly, BMAL1 was reduced by decrease of protein stability as well as inhibition of transcription under acidosis. In addition, melatonin significantly prevented acidosis-mediated decrease of BMAL1 by inhibiting lactate dehydrogenase-A during hypoxia. Remarkably, acidosis-mediated metastasis was significantly alleviated by BMAL1 overexpression in breast cancer cells. We therefore suggest that tumor hypoxia-induced acidosis promotes metastatic potency by decreasing BMAL1, and that tumor acidosis could be a target for preventing breast cancer metastasis by sustaining BMAL1.

Signalling entrains the peripheral circadian clock

In mammals, 24-h rhythms of behaviour and physiology are regulated by the circadian clock. The circadian clock is controlled by a central clock in the brain's suprachiasmatic nucleus (SCN) that synchronizes peripheral clocks in peripheral tissues. Clock genes in the SCN are primarily entrained by light. Increasing evidence has shown that peripheral clocks are also regulated by light and hormones independent of the SCN. How the peripheral clocks deal with internal signals is dependent on the relevance of a specific cue to a specific tissue. In different tissues, most genes that are under circadian control are not overlapping, revealing the tissue-specific control of peripheral clocks. We will discuss how different signals control the peripheral clocks in different peripheral tissues, such as the liver, gastrointestinal tract, and pancreas, and discuss the organ-to-organ communication between the peripheral clocks at the molecular level.

The molecular clock in the skin, its functionality, and how it is disrupted in cutaneous melanoma: a new pharmacological target?

The skin is the interface between the organism and the external environment, acting as its first barrier. Thus, this organ is constantly challenged by physical stimuli such as UV and infrared radiation, visible light, and temperature as well as chemicals and pathogens. To counteract the deleterious effects of the above-mentioned stimuli, the skin has complex defense mechanisms such as: immune and neuroendocrine systems; shedding of epidermal squamous layers and apoptosis of damaged cells; DNA repair; and pigmentary system. Here we have reviewed the current knowledge regarding which stimuli affect the molecular clock of the skin, the consequences to skin-related biological processes and, based on such knowledge, we suggest some therapeutic targets. We also explored the recent advances regarding the molecular clock disruption in melanoma, its impact on the carcinogenic process, and its therapeutic value in melanoma treatment.

The Cancer Clock Is (Not) Ticking: Links between Circadian Rhythms and Cancer

Circadian rhythms regulate many physiological and behavioral processes, including sleep, metabolism and cell division, which have a 24-h oscillation pattern. Rhythmicity is generated by a transcriptional–translational feedback loop in individual cells, which are synchronized by the central pacemaker in the brain and external cues. Epidemiological and clinical studies indicate that disruption of these rhythms can increase both tumorigenesis and cancer progression. Environmental changes (shift work, jet lag, exposure to light at night), mutations in circadian regulating genes, and changes to clock gene expression are recognized forms of disruption and are associated with cancer risk and/or cancer progression. Experimental data in animals and cell cultures further supports the role of the cellular circadian clock in coordinating cell division and DNA repair, and disrupted cellular clocks accelerate cancer cell growth. This review will summarize studies linking circadian disruption to cancer biology and explore how such disruptions may be further altered by common characteristics of tumors including hypoxia and acidosis. We will highlight how circadian rhythms might be exploited for cancer drug development, including how delivery of current chemotherapies may be enhanced using chronotherapy. Understanding the role of circadian rhythms in carcinogenesis and tumor progression will enable us to better understand causes of cancer and how to treat them.

Tumor Macroenvironment: An Update

Modes of tumor cell interaction include autocrine stimulation, secretion of paracrine growth factors and inhibitors, as well as interaction with the tumor macroenvironment. This evolving concept in tumor pathobiology describes the interaction of a malignant tumor with its host as an extension and addition to its local interaction with tumor cells and surrounding nontransformed cells, the tumor microenvironment. Angiogenesis, which is considered part of the tumor microenvironment, also allows reciprocal interactions between cancer cells and other organs and systems. Well-known examples of tumor endocrine signaling are the paraneoplastic syndromes. In addition, cachexia, a severe complication of tumor growth, results from the systemic reprogramming of the host metabolism as a result of tumor growth and progression. Moreover, recent reports indicate that cancer cells may secrete factors that might play a role in forming premetastatic niches at distant sites. In addition, cancer cells seem to be able to secrete factors influencing and resetting endogenous circadian organizers. The importance of understanding the whole complex interaction of a malignant tumor and its host - the tumor macroenvironment - is of great importance for the better management and treatment of cancer patients.

Interplay between Circadian Clock and Cancer: New Frontiers for Cancer Treatment

Circadian clocks constitute the evolutionary molecular machinery that dictates the temporal regulation of physiology to maintain homeostasis. Disruption of the circadian rhythm plays a key role in tumorigenesis and facilitates the establishment of cancer hallmarks. Conversely, oncogenic processes directly weaken circadian rhythms. Pharmacological modulation of core clock genes is a new approach in cancer therapy. The integration of circadian biology into cancer research offers new options for making cancer treatment more effective, encompassing the prevention, diagnosis, and treatment of this devastating disease. This review highlights the role of the circadian clock in tumorigenesis and cancer hallmarks, and discusses how pharmacological modulation of circadian clock genes can lead to new therapeutic options.

Expression of the Circadian Clock Gene BMAL1 Positively Correlates With Antitumor Immunity and Patient Survival in Metastatic Melanoma

Introduction

Melanoma is the most lethal type of skin cancer, with increasing incidence and mortality rates worldwide. Multiple studies have demonstrated a link between cancer development/progression and circadian disruption; however, the complex role of tumor-autonomous molecular clocks remains poorly understood. With that in mind, we investigated the pathophysiological relevance of clock genes expression in metastatic melanoma.

Methods

We analyzed gene expression, somatic mutation, and clinical data from 340 metastatic melanomas from The Cancer Genome Atlas, as well as gene expression data from 234 normal skin samples from genotype-tissue expression. Findings were confirmed in independent datasets.

Results

In melanomas, the expression of most clock genes was remarkably reduced and displayed a disrupted pattern of co-expression compared to the normal skins, indicating a dysfunctional circadian clock. Importantly, we demonstrate that the expression of the clock gene aryl hydrocarbon receptor nuclear translocator-like protein 1 (BMAL1) positively correlates with patient overall survival and with the expression of T-cell activity and exhaustion markers in the tumor bulk. Accordingly, high BMAL1 expression in pretreatment samples was significantly associated with clinical benefit from immune checkpoint inhibitors. The robust intratumoral T-cell infiltration/activation observed in patients with high BMAL1 expression was associated with a decreased expression of key DNA-repair enzymes, and with an increased mutational/neoantigen load.

Conclusion

Overall, our data corroborate previous reports regarding the impact of BMAL1 expression on the cellular DNA-repair capacity and indicate that alterations in the tumor-autonomous molecular clock could influence the cellular composition of the surrounding microenvironment. Moreover, we revealed the potential of BMAL1 as a clinically relevant prognostic factor and biomarker for T-cell-based immunotherapies.