Stress hormones promote growth of B16-F10 melanoma metastases: an interleukin 6- and glutathione-dependent mechanism

Prospective associations of leucocyte subtypes and obesity with the risk of developing cutaneous malignant melanoma in the UK Biobank cohort

BACKGROUND

Obesity is associated with chronic low-grade inflammation, which is linked to cancer development. Abdominal obesity (a body mass index, ABSI), however, has unusually been associated inversely with cutaneous malignant melanoma (CMM), while general obesity (body mass index, BMI) is associated positively. Leucocytes participate in inflammation and are higher in obesity, but prospective associations of leucocytes with cutaneous malignant melanoma are unclear.

METHODS

We examined the prospective associations of neutrophil, lymphocyte, and monocyte counts (each individually), as well as the prospective associations of ABSI and BMI, with cutaneous malignant melanoma in UK Biobank. We used multivariable Cox proportional hazards models and explored heterogeneity according to sex, menopausal status, age (≥ 50 years at recruitment), smoking status, ABSI (dichotomised at the median: ≥73.5 women; ≥79.8 men), BMI (normal weight, overweight, obese), and time to diagnosis.

RESULTS

During a mean follow-up of 10.2 years, 2174 CMM cases were ascertained in 398,450 participants. There was little evidence for associations with neutrophil or lymphocyte counts. Monocyte count, however, was associated inversely in participants overall (HR = 0.928; 95%CI: 0.888-0.971; per one standard deviation increase; SD = 0.144*109/L women; SD = 0.169*109/L men), specifically in older participants (HR = 0.906; 95%CI: 0.862-0.951), and more clearly in participants with low ABSI (HR = 0.880; 95%CI: 0.824-0.939), or with BMI ≥ 25 kg/m2 (HR = 0.895; 95%CI: 0.837-0.958 for overweight; HR = 0.923; 95%CI: 0.848-1.005 for obese). ABSI was associated inversely in pre-menopausal women (HR = 0.810; 95%CI: 0.702-0.935; SD = 4.95) and men (HR = 0.925; 95%CI: 0.867-0.986; SD = 4.11). BMI was associated positively in men (HR = 1.148; 95%CI: 1.078-1.222; SD = 4.04 kg/m2). There was little evidence for heterogeneity according to smoking status. The associations with monocyte count and BMI were retained to at least 8 years prior to diagnosis, but the association with ABSI was observed up to 4 years prior to diagnosis and not for longer follow-up time.

CONCLUSIONS

Monocyte count is associated prospectively inversely with the risk of developing CMM in older individuals, while BMI is associated positively in men, suggesting a mechanistic involvement of factors related to monocytes and subcutaneous adipose tissue in melanoma development. An inverse association with ABSI closer to diagnosis may reflect reverse causality or glucocorticoid resistance.

Targeting beta-adrenergic receptor pathways in melanoma: how stress modulates oncogenic immunity

The intricate pathways of the sympathetic nervous system hold an inherently protective role in the setting of acute stress. This is achieved through dynamic immunomodulatory and neurobiological networks. However, excessive and chronic exposure to these stress-induced stimuli appears to cause physiologic dysfunction through several mechanisms that may impair psychosocial, neurologic, and immunologic health. Numerous preclinical observations have identified the beta-2 adrenergic receptor (β2-AR) subtype to possess the strongest impact on immune dysfunction in the setting of chronic stressful stimuli. This prolonged expression of β2-ARs appears to suppress immune surveillance and promote tumorigenesis within multiple cancer types. This occurs through several pathways, including (1) decreasing the frequency and function of CD8 + T-cells infiltrating the tumor microenvironment (TME) via inhibition of metabolic reprogramming during T cell activation, and (2) establishing an immunosuppressive profile within the TME including promotion of an exhausted T cell phenotype while simultaneously enhancing local and paracrine metastatic potential. The use of nonselective β-AR antagonists appears to reverse many chronic stress-induced tumorigenic pathways and may also provide an additive therapeutic benefit for various immune checkpoint modulating agents including commonly utilized immune checkpoint inhibitors. Here we review the translational and clinical observations highlighting the foundational hypotheses that chronic stress-induced β-AR signaling promotes a pro-tumoral immunophenotype and that blockade of these pathways may augment the therapeutic response of immune checkpoint inhibition within the scope of melanoma.

Crosstalk Between Peripheral Innervation and Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive lethal malignancy, characterized by late diagnosis, aggressive growth, and therapy resistance, leading to a poor overall prognosis. Emerging evidence shows that the peripheral nerve is an important non-tumor component in the tumor microenvironment that regulates tumor growth and immune escape. The crosstalk between the neuronal system and PDAC has become a hot research topic that may provide novel mechanisms underlying tumor progression and further uncover promising therapeutic targets. In this review, we highlight the mechanisms of perineural invasion and the role of various types of tumor innervation in the progression of PDAC, summarize the potential signaling pathways modulating the neuronal-cancer interaction, and discuss the current and future therapeutic possibilities for this condition.

Survival Mechanisms of Metastatic Melanoma Cells: The Link between Glucocorticoids and the Nrf2-Dependent Antioxidant Defense System

Circulating glucocorticoids increase during stress. Chronic stress, characterized by a sustained increase in serum levels of cortisol, has been associated in different cases with an increased risk of cancer and a worse prognosis. Glucocorticoids can promote gluconeogenesis, mobilization of amino acids, fat breakdown, and impair the body's immune response. Therefore, conditions that may favor cancer growth and the acquisition of radio- and chemo-resistance. We found that glucocorticoid receptor knockdown diminishes the antioxidant protection of murine B16-F10 (highly metastatic) melanoma cells, thus leading to a drastic decrease in their survival during interaction with the vascular endothelium. The BRAF^V600E mutation is the most commonly observed in melanoma patients. Recent studies revealed that VMF/PLX40-32 (vemurafenib, a selective inhibitor of mutant BRAF^V600E) increases mitochondrial respiration and reactive oxygen species (ROS) production in BRAF^V600E human melanoma cell lines. Early-stage cancer cells lacking Nrf2 generate high ROS levels and exhibit a senescence-like growth arrest. Thus, it is likely that a glucocorticoid receptor antagonist (RU486) could increase the efficacy of BRAF-related therapy in BRAF^V600E-mutated melanoma. In fact, during early progression of skin melanoma metastases, RU486 and VMF induced metastases regression. However, treatment at an advanced stage of growth found resistance to RU486 and VMF. This resistance was mechanistically linked to overexpression of proteins of the Bcl-2 family (Bcl-xL and Mcl-1 in different human models). Moreover, melanoma resistance was decreased if AKT and NF-κB signaling pathways were blocked. These findings highlight mechanisms by which metastatic melanoma cells adapt to survive and could help in the development of most effective therapeutic strategies.

Harnessing in situ glutathione for effective ROS generation and tumor suppression via nanohybrid-mediated catabolism dynamic therapy

The overexpression of glutathione (GSH) in cancer cells has long been regarded as the primary obstacle for reactive oxygen species (ROS)-involved anti-tumor therapies. To solve this issue, a ferric ion and selenite-codoped calcium phosphate (Fe/Se-CaP) nanohybrid here is fabricated to catabolize endogenous GSH, instead of directly deleting it, to trigger a ROS storm for tumor suppression. The selenite component in Fe/Se-CaP can catabolize GSH to superoxide anion (O₂^•-) and hydroxyl radicals (•OH) via cascade catalytic reactions, elevating oxidative stress while destroying antioxidant system. The doped Fe can further catalyze the soaring hydrogen peroxide (H₂O₂) originated from O₂^•- to •OH via Fenton reactions. Collectively, Fe/Se-CaP mediated self-augmented catabolism dynamic therapy finally induces apoptosis of cancer cells owing to the significant rise of ROS and, combined with CaP adjuvant, evokes adaptive immune responses to suppress tumor progression, providing an innovative train of thought for ROS-involved anti-tumor therapies.

Therapeutic combination silencing VEGF and SOX10 increases the antiangiogenic effect in the mouse melanoma model B16-F10 - in vitro and in vivo studies

INTRODUCTION

Gene therapy is an innovative form of treatment of genetic diseases, in which psiRNA molecules silencing specific genes are applied.

AIM

The study evaluated the anti-tumour effect of psiRNA silencing preparations of the vascular endothelial growth factor (VEGF) and Sry-related HMG-Box gene 10 (SOX10) on melanoma (B16-F10) by inhibiting angiogenesis.

MATERIAL AND METHODS

The preparations based on plasmid vectors psiRNA silencing the gene SOX10 and VEGF that form complexes with cationic lipid (psiRNA/carrier) have been developed. psiRNA preparations were tested on the mouse melanoma cell line B16-F10, both in vitro and in vivo. The silencing activity of transfected melanoma cells with the obtained psiRNA preparations was examined using the qPCR and Western blot methods. The anti-tumour activity of psiRNA preparations on melanoma tumour cells was then evaluated in a mouse in vivo model.

RESULTS

In vitro studies have shown that the B16-F10 cells efficiently transfect non-viral preparations - psiRNA: Lyovec (74-89%). Worth mentioning is the fact that silencing SOX10 in B16-F10 melanoma cells increases the expression of the COL18A1 gene (compared to the preparation inhibiting only VEGF), which codes the endostatin to stop angiogenesis. In vivo results show that the level of haemoglobin in tumours of mice treated with psiRNA formulations was over 6 times lower than controls and tumour mass was 60-80% lower.

CONCLUSIONS

The novel study proves that simultaneous inhibition of SOX10 and VEGF enhances the antiangiogenic action and thus contributes to a significant halt of disease development. In addition, these data expand knowledge about SOX10 regulation and functions.

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.

Depression accelerates gastric cancer invasion and metastasis by inducing a neuroendocrine phenotype via the catecholamine/β2 -AR/MACC1 axis

Background

Depression is a common, easily ignored, accompanied disease of gastric cancer (GC) patients and is often observed with elevated plasma catecholamine levels. Depression frequently promotes GC progression and leads to poor clinical outcomes; however, the molecular mechanisms underlying depression‐induced GC progression remain poorly understood. We aimed to study the effects of depression on GC progression and explore possible mechanisms mediating the action of depression‐associated catecholamines on GC.

Methods

Depression states of GC patients were graded using the Patient Health Questionnaire‐9, and plasma catecholamine levels were examined by high performance liquid chromatography coupled with tandem mass spectrometry. Migrative and invasive GC cells were examined using transwell assays, and metastatic GC niches were imaged using bioluminescence technology in a depression mouse model established with chronic unpredictable mild stress. Mouse depression‐like behaviors were assessed through sucrose preference, forced swimming, and tail suspension tests. Characteristics of the neuroendocrine phenotype were observed via RT‐PCR, Western blotting, flow cytometry, and transmission electron microscopy.

Results

Fifty‐one GC patients (age: 53.61 ± 1.79 years; cancer duration: 3.71 ± 0.33 months; depression duration: 2.37 ± 0.38 months; male‐to‐female ratio: 1.55:1) were enrolled in the study. Depression grade was significantly higher in GC patients showing higher plasma levels of catecholamines (epinephrine: P = 0.018; noradrenaline: P = 0.009), higher oncogene metastasis‐associated in colon cancer‐1 (MACC1) level (P = 0.018), and metastasis (P < 0.001). Further, depression‐associated catecholamine specifically bound to the beta‐2 adrenergic receptor (β₂‐AR) and upregulated MACC1 expression, and thus promoting neuroendocrine phenotypic transformation through direct binding between MACC1 and synaptophysin. Eventually, the neuroendocrine phenotypic transformation accelerated GC invasion in vitro and metastasis in vivo. However, β₂‐AR antagonist ICI‐118,551 or MACC1 silencing effectively blocked the catecholamine‐induced neuroendocrine phenotypic transformation and eliminated depression‐enhanced GC migration and invasion. Moreover, β₂‐AR blocking or MACC1 silencing prevented GC metastasis attributed to a neuroendocrine phenotype in a depression mouse model.

Conclusions

Catecholamine‐induced neuroendocrine phenotypes of GC cells led to depression‐accelerated GC invasion and metastasis via the β₂‐AR/MACC1 axis, while β₂‐AR antagonist or MACC1 silencing could reverse it, showing promising potential therapeutic strategies for improving the outcome of GC patients with comorbid depression.

Inhibition of the NRF2/KEAP1 Axis: A Promising Therapeutic Strategy to Alter Redox Balance of Cancer Cells

Significance: The nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (NRF2/KEAP1) pathway is a crucial and highly conserved defensive system that is required to maintain or restore the intracellular homeostasis in response to oxidative, electrophilic, and other types of stress conditions. The tight control of NRF2 function is maintained by a complex network of biological interactions between positive and negative regulators that ultimately ensure context-specific activation, culminating in the NRF2-driven transcription of cytoprotective genes. Recent Advances: Recent studies indicate that deregulated NRF2 activation is a frequent event in malignant tumors, wherein it is associated with metabolic reprogramming, increased antioxidant capacity, chemoresistance, and poor clinical outcome. On the other hand, the growing interest in the modulation of the cancer cells' redox balance identified NRF2 as an ideal therapeutic target. Critical Issues: For this reason, many efforts have been made to identify potent and selective NRF2 inhibitors that might be used as single agents or adjuvants of anticancer drugs with redox disrupting properties. Despite the lack of specific NRF2 inhibitors still represents a major clinical hurdle, the researchers have exploited alternative strategies to disrupt NRF2 signaling at different levels of its biological activation. Future Directions: Given its dualistic role in tumor initiation and progression, the identification of the appropriate biological context of NRF2 activation and the specific clinicopathological features of patients cohorts wherein its inactivation is expected to have clinical benefits, will represent a major goal in the field of cancer research. In this review, we will briefly describe the structure and function of the NRF2/ KEAP1 system and some of the most promising NRF2 inhibitors, with a particular emphasis on natural compounds and drug repurposing. Antioxid. Redox Signal. 34, 1428-1483.

Neuroendocrine Factors in Melanoma Pathogenesis

Simple Summary

Melanoma is a very aggressive and fatal malignant tumor. While curable if diagnosed in its early stages, advanced melanoma, despite the complex therapeutic approaches, is associated with one of the highest mortality rates. Hence, more and more studies have focused on mechanisms that may contribute to melanoma development and progression. Various studies suggest a role played by neuroendocrine factors which can act directly on tumor cells, modulating their proliferation and metastasis capability, or indirectly through immune or inflammatory processes that impact disease progression. However, there are still multiple areas to explore and numerous unknown features to uncover. A detailed exploration of the mechanisms by which neuroendocrine factors can influence the clinical course of the disease could open up new areas of biomedical research and may lead to the development of new therapeutic approaches in melanoma.

Abstract

Melanoma is one of the most aggressive skin cancers with a sharp rise in incidence in the last decades, especially in young people. Recognized as a significant public health issue, melanoma is studied with increasing interest as new discoveries in molecular signaling and receptor modulation unlock innovative treatment options. Stress exposure is recognized as an important component in the immune-inflammatory interplay that can alter the progression of melanoma by regulating the release of neuroendocrine factors. Various neurotransmitters, such as catecholamines, glutamate, serotonin, or cannabinoids have also been assessed in experimental studies for their involvement in the biology of melanoma. Alpha-MSH and other neurohormones, as well as neuropeptides including substance P, CGRP, enkephalin, beta-endorphin, and even cellular and molecular agents (mast cells and nitric oxide, respectively), have all been implicated as potential factors in the development, growth, invasion, and dissemination of melanoma in a variety of in vitro and in vivo studies. In this review, we provide an overview of current evidence regarding the intricate effects of neuroendocrine factors in melanoma, including data reported in recent clinical trials, exploring the mechanisms involved, signaling pathways, and the recorded range of effects.

Dexamethasone Induces the Expression and Function of Tryptophan-2-3-Dioxygenase in SK-MEL-28 Melanoma Cells

Tryptophan-2,3-dioxygenase (TDO) is one of the key tryptophan-catabolizing enzymes with immunoregulatory properties in cancer. Contrary to expectation, clinical trials showed that inhibitors of the ubiquitously expressed enzyme, indoleamine-2,3-dioxygenase-1 (IDO1), do not provide benefits in melanoma patients. This prompted the hypothesis that TDO may be a more attractive target. Because the promoter of TDO harbors glucocorticoid response elements (GREs), we aimed to assess whether dexamethasone (dex), a commonly used glucocorticoid, modulates TDO expression by means of RT-PCR and immunofluorescence and function by assessing cell proliferation and migration as well as metalloproteinase activity. Our results show that, in SK-Mel-28 melanoma cells, dex up-regulated TDO and its downstream effector aryl hydrocarbon receptor (AHR) but not IDO1. Furthermore, dex stimulated cellular proliferation and migration and potentiated MMP2 activity. These effects were inhibited by the selective TDO inhibitor 680C91 and enhanced by IDO1 inhibitors. Taken together, our results demonstrate that the metastatic melanoma cell line SK-Mel-28 possesses a functional TDO which can also modulate cancer cell phenotype directly rather than through immune suppression. Thus, TDO appears to be a promising, tractable target in the management or the treatment of melanoma progression.

Role of adrenergic receptor signalling in neuroimmune communication

Neuroimmune communication plays a crucial role in maintaining homeostasis and promptly responding to any foreign insults. Sympathetic nerve fibres are innervated into all the lymphoid organs (bone marrow, thymus, spleen, and lymph nodes) and provide a communication link between the central nervous system (CNS) and ongoing immune response in the tissue microenvironment. Neurotransmitters such as catecholamines (epinephrine and norepinephrine) bind to adrenergic receptors present on most immune and non-immune cells, establish a local neuroimmune-communication system, and help regulate the ongoing immune response. The activation of these receptors varies with the type of receptor-activated, target cell, the activation status of the cells, and timing of activation. Activating adrenergic receptors, specifically β-adrenergic signalling in immune cells leads to activation of the cAMP-PKA pathway or other non-canonical pathways. It predominantly leads to immune suppression such as inhibition of IL-2 secretion and a decrease in macrophages phagocytosis. This review discusses the expression of different adrenergic receptors in various immune cells, signalling, and how it modulates immune cell function and contributes to health and diseases. Understanding the neuroimmune communication through adrenergic receptor signalling in immune cells could help to design better strategies to control inflammation and autoimmunity.

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Primary and secondary lymphoid organs are innervated with sympathetic nerve fibres.

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Adrenergic receptor expression on immune and non-immune cells establishes a local neuroimmune communication system.

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Adrenergic receptor signalling in immune cells controls the differentiation and function of various immune cells.

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Modulating adrenergic receptor signalling with a specific agonist or antagonist also affect the immune response.

Stress reduction strategies in breast cancer: review of pharmacologic and non-pharmacologic based strategies

Breast cancer is the most common cancer diagnosed in women. It is associated with multiple symptoms in both patients and caregivers, such as stress, anxiety, depression, sleep disturbance, and fatigue. Stress appears to promote cancer progression via activation of the sympathetic nervous system releasing epinephrine and norepinephrine as well as activation of hypothalamic-pituitary-adrenal axis releasing cortisol. These stress hormones have been shown to promote the proliferation of cancer cells. This review focuses on stress-reducing strategies which may decrease cancer progression by abrogating these pathways, with a main focus on the β-adrenergic signaling pathway. Patients utilize both non-pharmacologic and pharmacologic strategies to reduce stress. Non-pharmacologic stress-reduction strategies include complementary and alternative medicine techniques, such as meditation, yoga, acupuncture, exercise, use of natural products, support groups and psychology counseling, herbal compounds, and multivitamins. Pharmacologic strategies include abrogating the β2-adrenergic receptor signaling pathway to antagonize epinephrine and norepinephrine action on tumor and immune cells. β-Blocker drugs may play a role in weakening the pro-migratory and pro-metastatic effects induced by stress hormones in cancer and strengthening the anti-tumor immune response. Preclinical models have shown that non-selective β1/2-blocker use is associated with a decrease in tumor growth and metastases and clinical studies have suggested their positive impact on decreasing breast cancer recurrence and mortality. Thus, non-pharmacological approaches, along with pharmacological therapies part of clinical trials are available to cancer patients to reduce stress, and have promise to break the cycle of cancer and stress.

β3-Adrenoceptors as Putative Regulator of Immune Tolerance in Cancer and Pregnancy

Understanding the mechanisms of immune tolerance is currently one of the most important challenges of scientific research. Pregnancy affects the immune system balance, leading the host to tolerate embryo alloantigens. Previous reports demonstrated that β-adrenergic receptor (β-AR) signaling promotes immune tolerance by modulation of NK and Treg, mainly through the activation of β2-ARs, but recently we have demonstrated that also β3-ARs induce an immune-tolerant phenotype in mice bearing melanoma. In this report, we demonstrate that β3-ARs support host immune tolerance in the maternal microenvironment by modulating the same immune cells populations as recently demonstrated in cancer. Considering that β3-ARs are modulated by oxygen levels, we hypothesize that hypoxia, through the upregulation of β3-AR, promotes the biological shift toward a tolerant immunophenotype and that this is the same trick that embryo and cancer use to create an aura of immune-tolerance in a competent immune environment. This study confirms the analogies between fetal development and tumor progression and suggests that the expression of β3-ARs represents one of the strategies to induce fetal and tumor immune tolerance.

Long-Term Programming of CD8 T Cell Immunity by Perinatal Exposure to Glucocorticoids

Early life environmental exposure, particularly during perinatal period, can have a life-long impact on organismal development and physiology. The biological rationale for this phenomenon is to promote physiological adaptations to the anticipated environment based on early life experience. However, perinatal exposure to adverse environments can also be associated with adult-onset disorders. Multiple environmental stressors induce glucocorticoids, which prompted us to investigate their role in developmental programming. Here, we report that perinatal glucocorticoid exposure had long-term consequences and resulted in diminished CD8 T cell response in adulthood and impaired control of tumor growth and bacterial infection. We found that perinatal glucocorticoid exposure resulted in persistent alteration of the hypothalamic-pituitary-adrenal (HPA) axis. Consequently, the level of the hormone in adults was significantly reduced, resulting in decreased CD8 T cell function. Our study thus demonstrates that perinatal stress can have long-term consequences on CD8 T cell immunity by altering HPA axis activity.

Can stress promote the pathophysiology of brain metastases? A critical review of biobehavioral mechanisms

Chronic stress can promote tumor growth and progression through immunosuppressive effects and bi-directional interactions between tumor cells and their microenvironment. β-Adrenergic receptor signaling plays a critical role in mediating stress-related effects on tumor progression. Stress-related mechanisms that modulate the dissemination of tumor cells to the brain have received scant attention. Brain metastases are highly resistant to chemotherapy and contribute considerably to morbidity and mortality in various cancers, occurring in up to 20% of patients in some cancer types. Understanding the mechanisms promoting brain metastasis could help to identify interventions that improve disease outcomes. In this review, we discuss biobehavioral, sympathetic, neuroendocrine, and immunological mechanisms by which chronic stress can impact tumor progression and metastatic dissemination to the brain. The critical role of the inflammatory tumor microenvironment in tumor progression and metastatic dissemination to the brain, and its association with stress pathways are delineated. We also discuss translational implications for biobehavioral and pharmacological interventions.

Melanoma in the liver: Oxidative stress and the mechanisms of metastatic cell survival

Metastatic melanoma is a fatal disease with a rapid systemic dissemination. The most frequent target sites are the liver, bone, and brain. Melanoma metastases represent a heterogeneous cell population, which associates with genomic instability and resistance to therapy. Interaction of melanoma cells with the hepatic sinusoidal endothelium initiates a signaling cascade involving cytokines, growth factors, bioactive lipids, and reactive oxygen and nitrogen species produced by the cancer cell, the endothelium, and also by different immune cells. Endothelial cell-derived NO and H₂O₂ and the action of immune cells cause the death of most melanoma cells that reach the hepatic microvascularization. Surviving melanoma cells attached to the endothelium of pre-capillary arterioles or sinusoids may follow two mechanisms of extravasation: a) migration through vessel fenestrae or b) intravascular proliferation followed by vessel rupture and microinflammation. Invading melanoma cells first form micrometastases within the normal lobular hepatic architecture via a mechanism regulated by cross-talk with the stroma and multiple microenvironment-related molecular signals. In this review special emphasis is placed on neuroendocrine (systemic) mechanisms as potential promoters of liver metastatic growth. Growing metastatic cells undergo functional and metabolic changes that increase their capacity to withstand oxidative/nitrosative stress, which favors their survival. This adaptive process also involves upregulation of Bcl-2-related antideath mechanisms, which seems to lead to the generation of more resistant cell subclones.

Oxidative stress and antioxidants in the pathophysiology of malignant melanoma

The high number of somatic mutations in the melanoma genome associated with cumulative ultra violet (UV) exposure has rendered it one of the most difficult of cancers to treat. With new treatment approaches based on targeted and immune therapies, drug resistance has appeared as a consistent problem. Redox biology, including reactive oxygen and nitrogen species (ROS and RNS), plays a central role in all aspects of melanoma pathophysiology, from initiation to progression and to metastatic cells. The involvement of melanin production and UV radiation in ROS/RNS generation has rendered the melanocytic lineage a unique system for studying redox biology. Overall, an elevated oxidative status has been associated with melanoma, thus much effort has been expended to prevent or treat melanoma using antioxidants which are expected to counteract oxidative stress. The consequence of this redox-rebalance seems to be two-fold: on the one hand, cells may behave less aggressively or even undergo apoptosis; on the other hand, cells may survive better after being disseminated into the circulating system or after drug treatment, thus resulting in metastasis promotion or further drug resistance. In this review we summarize the current understanding of redox signaling in melanoma at cellular and systemic levels and discuss the experimental and potential clinic use of antioxidants and new epigenetic redox modifiers.

The Highlighted Role of GAPDH and Nitric-Oxide Synthase Regulator Activity in Proton Beam Irradiated Melanoma BLM Cells

Introduction: The human melanoma is a type of invasive tumor the treatment of which is challenging. To better understand the proton irradiation mechanisms as one of the widely applied therapy for this type of cancer, bioinformatics analysis of proteomics outcome could be beneficial. Methods: Protein-protein interaction network analysis of the differentially expressed proteins (DEPs) of melanoma BLM (BRO lung metastasis) cells in the treatment of 3 Gy dosage proton therapy was performed in this study via Cytoscape V.3.7.2. and its integrated plug-ins. Results: Eighteen DEPs were searched for network constructions and limited numbers of query +neighbor proteins were found central. The hub-bottlenecks (i.e. central nodes) were GAPDH, ACTB, ALB, AKT1, TP53, and EGFR. The fist mentioned proteins were from DEPs. The enrichment analysis of these elements identified nitric-oxide synthase regulator activity and the positive regulation of the norepinephrine uptake that may be the key to the mechanisms of proton therapy. Conclusion: In conclusion, the identified central nodes (EGFR, TP53, ALB, AKT1, GAPDH, and ACTB) and the related biological terms are the critical affected genes and biological terms in the irradiated melanoma cells.

The Role of β-Blockers in Melanoma

Melanoma is one of the most aggressive and less chemotherapy-responsive human cancers, representing a major public health issue worldwide. The early diagnosis still represents the best approach in order to reduce mortality, especially in advanced stages. Preclinical evidence, collected through several in vitro and in vivo models, has been accumulating about the pathophysiological involvement of β-adrenoceptors in melanoma progression. This involvement has been paralleled by the evidence that drugs blocking β-adrenoceptors (β-blockers) may have a relevant role in the treatment of melanoma and in the prevention of its progression. β-blockers are a class of drugs extensively used in clinical practice, not limited to cardiovascular therapeutics. Evidence collected through retrospective and prospective observational studies suggests that treatment with β-blockers, mainly propranolol, is able to delay melanoma progression. Although conclusive evidence is still lacking, current knowledge proposes β-blockers as an opportunity for antitumor treatment in melanoma. Clinical trials are needed in order to prove their claimed efficacy. Graphical Abstract.

Elevated Expression Levels of PC3-Secreted Microprotein (PSMP) in Prostate Cancer Associated With Increased Xenograft Growth and Modification of Immune-Related Microenvironment

Prostate cancer (PCa), especially metastatic PCa, is one of the main cancer types accounting for male mortality worldwide. Over decades, researchers have tried to search for effective curative methods for PCa, but many attempts have failed. The therapeutic failure of PCa is usually due to off-target or side effects; thus, finding a key molecule that could prevent PCa metastatic progression has become the most important goal for curing aggressive PCa. In this study, we collected hundreds of PCa tissues and serum and urine samples from patients to verify the upregulated expression of PC3-secreted microprotein (PSMP) in PCa tumor tissues with high Gleason scores. According to biopsy results, PSMP expression was found related to extraprostatic extension (EPE), contributing to PCa metastasis. Mechanistically, recombinant PSMP protein could promote the proliferation both in vitro and in vivo, and rhPSMP could promote epithelial–mesenchymal transition (EMT) of PC3 in vitro. Additionally, PSMP could also influence cytokine production in the xenograft model and monocyte migration and macrophage polarization in vitro. Our most important finding was that neutralizing antibodies against PSMP could suppress xenograft PC3 growth and promote the survival of PC3 metastatic mice model, providing an effective option to cure human PCa.

A Short-Term High-Fat Diet Alters Glutathione Levels and IL-6 Gene Expression in Oxidative Skeletal Muscles of Young Rats

Obesity and ensuing disorders are increasingly prevalent worldwide. High-fat diets (HFD) and diet-induced obesity have been shown to induce oxidative stress and inflammation while altering metabolic homeostasis in many organs, including the skeletal muscle. We previously observed that 14 days of HFD impairs contractile functions of the soleus (SOL) oxidative skeletal muscle. However, the mechanisms underlying these effects are not clarified. In order to determine the effects of a short-term HFD on skeletal muscle glutathione metabolism, young male Wistar rats (100–125 g) were fed HFD or a regular chow diet (RCD) for 14 days. Reduced (GSH) and disulfide (GSSG) glutathione levels were measured in the SOL. The expression of genes involved in the regulation of glutathione metabolism, oxidative stress, antioxidant defense and inflammation were measured by RNA-Seq. We observed a significant 25% decrease of GSH levels in the SOL muscle. Levels of GSSG and the GSH:GSSG ratio were similar in both groups. Further, we observed a 4.5 fold increase in the expression of pro-inflammatory cytokine interleukin 6 (IL-6) but not of other cytokines or markers of inflammation and oxidative stress. We hereby demonstrate that a short-term HFD significantly lowers SOL muscle GSH levels. This effect could be mediated through the increased expression of IL-6. Further, the skeletal muscle antioxidant defense could be impaired under cellular stress. We surmise that these early alterations could contribute to HFD-induced insulin resistance observed in longer protocols.

The Influence of Psychological Stress on the Initiation and Progression of Diabetes and Cancer

CONTEXT

Psychological stress can be considered a risk factor for the initiation and progression of many pathological conditions, including type 1 and 2 diabetes mellitus and cancer.

OBJECTIVES

The aim of this review article was to evaluate the molecular and cellular mechanisms linking psychological stress to the onset and progression of diabetes and cancer.

EVIDENCE ACQUISITION

The current review was conducted to survey and analyze studies related to the effects of psychological stress on diabetes and cancer.

RESULTS

Psychological stress may make individuals prone to the development of diabetes through the impairment of the hypothalamic-pituitary-adrenal (HPA) axis function, sympathetic nerves system (SNS), lipid profile, cytokines balance, renin-angiotensin system (RAS), and insulin signaling pathway. Additionally, psychological stress can contribute to the development of cancer through the perturbation in the HPA axis, SNS function, and cytokines balance. Psychological stress is also capable of decreasing the levels of oxytocin and dopamine, leading to an increased risk of cancer in susceptible individuals.

CONCLUSIONS

It seems that psychological stress plays a significant role in the onset and progression of diabetes and cancer. The identification of the pathways triggered by psychological stress would open up a new avenue for the understanding of molecular mechanisms by which diabetes and cancer could be managed or even prevented.

Glucocorticoids promote the development of azoxymethane and dextran sulfate sodium-induced colorectal carcinoma in mice

BACKGROUND

Stress has been suggested as a promoter of tumor growth and development. Glucocorticoids (GCs) are the main stress hormones and widely prescribed as drugs. However, the effect of GCs on the development and progression of colorectal carcinoma (CRC) is unclear.

METHODS

We evaluated the effect of corticosterone (CORT) on azoxymethane and dextran sulfate sodium (AOM/DSS)-induced carcinogenesis in the colorectum of C57BL/6 strain mice. Plasma level of CORT was detected by radioimmunoassay. The expression of proliferation markers (Ki-67 and PCNA), nuclear factor (NF)-κB p65 and phosphoto-p65 (P-p65), as well as cyclooxygenase (COX)-2 were determined by immunohistochemistry. Inflammation in colorectum was evaluated by histopathology.

RESULTS

CORT feeding in drinking water of mice not only significantly elevated plasma CORT concentration, but also significantly increased the incidence and neoplasms burden (number and size of neoplasms) in colorectum. CORT also significant enhanced the expression of cell proliferation marker (Ki-67 and PCNA), NF-κB p65 and P-p65 as well as COX-2 in colorectal neoplasm of AOM/DSS-treated mice.

CONCLUSION

In this study, we have found for the first time that CORT at stress level potentially promotes the growth and development of AOM/DSS-induced colorectal adenoma and carcinoma in mice. Up-regulation of NF-κB and COX-2 may be involved in the promoting effect of CORT.

Glucocorticoids promote transition of ductal carcinoma in situ to invasive ductal carcinoma by inducing myoepithelial cell apoptosis

BACKGROUND

The microenvironment and stress factors like glucocorticoids have a strong influence on breast cancer progression but their role in the first stages of breast cancer and, particularly, in myoepithelial cell regulation remains unclear. Consequently, we investigated the role of glucocorticoids in ductal carcinoma in situ (DCIS) in breast cancer, focusing specially on myoepithelial cells.

METHODS

To clarify the role of glucocorticoids at breast cancer onset, we evaluated the effects of cortisol and corticosterone on epithelial and myoepithelial cells using 2D and 3D in vitro and in vivo approaches and human samples.

RESULTS

Glucocorticoids induce a reduction in laminin levels and favour the disruption of the basement membrane by promotion of myoepithelial cell apoptosis in vitro. In an in vivo stress murine model, increased corticosterone levels fostered the transition from DCIS to invasive ductal carcinoma (IDC) via myoepithelial cell apoptosis and disappearance of the basement membrane. RU486 is able to partially block the effects of cortisol in vitro and in vivo. We found that myoepithelial cell apoptosis is more frequent in patients with DCIS+IDC than in patients with DCIS.

CONCLUSIONS

Our findings show that physiological stress, through increased glucocorticoid blood levels, promotes the transition from DCIS to IDC, particularly by inducing myoepithelial cell apoptosis. Since this would be a prerequisite for invasive features in patients with DCIS breast cancer, its clinical management could help to prevent breast cancer progression to IDC.

SOX30 Inhibits Tumor Metastasis through Attenuating Wnt-Signaling via Transcriptional and Posttranslational Regulation of β-Catenin in Lung Cancer

Although high mortality of lung cancer is greatly due to distant metastasis, the mechanism of this metastasis remains unclear. Here, we investigate in lung cancer that SOX30 is sharply under-expressed in metastatic tumors compared with non-metastatic tumors, and suppresses plenty of metastasis related processes or pathways. SOX30 strongly inhibits tumor cell metastasis in vitro and in vivo. Sox30 deficiency promotes lung metastasis in Sox30^−/− mice and this uncontrollable lung-metastasis is re-inhibited upon Sox30 re-expression. Mechanistically, SOX30 diminishes Wnt-signaling via directly transcriptional repressing β-catenin or interacting with β-catenin to compete with TCF for binding to β-catenin. The carboxyl-terminus of SOX30 is required for attenuating β-catenin transcriptional activity, whereas the amino-terminus of SOX30 is required for its interaction with β-catenin protein. Enhance of β-catenin attenuates the anti-metastatic role of SOX30. Moreover, Sox30 deficiency promotes tumor metastasis and reduces survival of mice. In addition, nuclear SOX30 expression is closely associated with metastasis and represents a favorable independent prognostic biomarker of lung cancer patients. Altogether, these results highlight an important role and mechanism of SOX30 in lung cancer metastasis, providing a potential therapeutic target for anti-metastasis.

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SOX30 is closely associated with lung cancer metastasis, and strongly inhibits cancer cell metastasis in vitro and in vivo.

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SOX30 suppresses cancer metastasis via transcriptional repressing β-catenin or competing with TCF for β-catenin binding.

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SOX30 deficiency promotes tumor long-distance metastasis and reduces overall survival of mice and lung cancer patients.

The high mortality of lung cancer is largely due to distant-metastases. However, the mechanism of this metastasis remains unclear. Here, we demonstrate that SOX30 strongly inhibits lung cancer metastasis in vitro and in vivo. As an important metastatic suppressor, SOX30 prevents long-distant metastases and causes fine prognosis inhibiting Wnt-signaling via transcriptional repressing β-catenin or competing with TCF for interaction with β-catenin. This study provides useful information for effective therapies against tumor-metastasis. Considering key role of β-catenin in tumor-metastasis and ineffective treatment using inhibitors against β-catenin, it is a potential choice to suppress Wnt/β-catenin activity via targeting the upstream SOX30.

Involvement of upregulation of fibronectin in the pro‑adhesive and pro‑survival effects of glucocorticoid on melanoma cells

Glucocorticoids (GCs) are important stress hormones, which are used as a concomitant medication during malignant tumor chemotherapy. Clinical and preclinical studies have linked GCs to melanoma growth and progression. However, the effects and mechanism of action of GCs on the adhesion and survival of melanoma cells are still unknown. In the present study the effect of dexamethasone (Dex), a synthetic GC, on fibronectin (FN) expression and its roles in regulating the adhesion and survival of melanoma cells were investigated. It was revealed that Dex significantly increased the levels of intracellular and secreted FN in melanoma cell lines by increasing glucocorticoid receptor‑mediated FN protein stability. Additionally, it was demonstrated that Dex (100 nM) significantly promoted the adhesion and survival of melanoma cells. Silencing FN expression abrogated the pro‑adhesive and pro‑survival effects of Dex in melanoma cells. Extracellular FN significantly enhanced melanoma cell adhesion and survival in the presence of cisplatin, whereas partially blocking extracellular FN signaling with a CD44 antibody significantly reduced FN‑enhanced adhesion and survival. This indicated that the upregulation of FN contributed to the pro‑survival effect of Dex by enhancing cell adhesion. It was also observed that activation of the PI3K/AKT signaling pathway by extracellular FN was involved in the FN‑mediated increase in melanoma cell survival. These findings increase understanding of the possible mechanisms by which GCs regulate melanoma cell adhesion and survival.

Up-regulation of Rho-associated kinase 1/2 by glucocorticoids promotes migration, invasion and metastasis of melanoma

Although glucocorticoids (GCs) regulate proliferation, differentiation and apoptosis of tumor cells, their influence on metastasis of tumor cells is poorly understood. Melanoma is a type of skin cancers with high metastasis. We investigated the effect of GCs on metastasis of melanoma cells and its mechanism. We found that GCs significantly promoted the adhesion, migration, invasion of melanoma cells in vitro and lung metastasis in experimental melanoma metastasis mice. Dexamethasone (Dex), a synthetic GC, did not change the RhoA, RhoB and RhoC signalings, but significantly increased the expression and activity of Rho-associated kinase 1/2 (ROCK1/2). The effect of Dex was to increase ROCK1/2 stability mediated by glucocorticoid receptor. Inhibiting ROCK1/2 activity with Y-27632, a ROCK1/2 inhibitor abrogated the pro-migration and pro-metastasis effects of GCs in vitro and in vivo, indicating that ROCK1/2 mediated the pro-metastasis effects of GCs. Activation of PI3K/AKT also contributed to the pro-migration and pro-invasion effects of Dex partially through up-regulating ROCK1/2 expression. Additionally, Dex also down-regulated the expression of tissue inhibitors of matrix metalloproteinase-2. Taken together, our findings provide new data to understand the possible promoting roles and mechanisms of GCs in melanoma metastasis.

Polyphenolic Phytochemicals in Cancer Prevention and Therapy: Bioavailability versus Bioefficacy

Natural polyphenols are organic chemicals which contain phenol units in their structures. They show antitumor properties. However, a key problem is their short half-life and low bioavailability under in vivo conditions. Still, definitively demonstrating the human benefits of isolated polyphenolic compounds (alone or in combination) using modern scientific methodology has proved challenging. The most common discrepancy between experimental and clinical observations is the use of nonphysiologically relevant concentrations of polyphenols in mechanistic studies. Thus, it remains highly controversial how applicable underlying mechanisms are with bioavailable concentrations and biological half-life. The present Perspective analyses proposed antitumor mechanisms, in vivo reported antitumor effects, and possible mechanisms that may explain discrepancies between bioavailability and bioefficacy. Polyphenol metabolism and possible toxic side effects are also considered. Our main conclusion emphasizes that these natural molecules (and their chemical derivatives) indeed can be very useful, not only as cancer chemopreventive agents but also in oncotherapy.

Enhancing circadian clock function in cancer cells inhibits tumor growth

BACKGROUND

Circadian clocks control cell cycle factors, and circadian disruption promotes cancer. To address whether enhancing circadian rhythmicity in tumor cells affects cell cycle progression and reduces proliferation, we compared growth and cell cycle events of B16 melanoma cells and tumors with either a functional or dysfunctional clock.

RESULTS

We found that clock genes were suppressed in B16 cells and tumors, but treatments inducing circadian rhythmicity, such as dexamethasone, forskolin and heat shock, triggered rhythmic clock and cell cycle gene expression, which resulted in fewer cells in S phase and more in G1 phase. Accordingly, B16 proliferation in vitro and tumor growth in vivo was slowed down. Similar effects were observed in human colon carcinoma HCT-116 cells. Notably, the effects of dexamethasone were not due to an increase in apoptosis nor to an enhancement of immune cell recruitment to the tumor. Knocking down the essential clock gene Bmal1 in B16 tumors prevented the effects of dexamethasone on tumor growth and cell cycle events.

CONCLUSIONS

Here we demonstrated that the effects of dexamethasone on cell cycle and tumor growth are mediated by the tumor-intrinsic circadian clock. Thus, our work reveals that enhancing circadian clock function might represent a novel strategy to control cancer progression.

Repurposing Drugs in Oncology (ReDO)-Propranolol as an anti-cancer agent

Propranolol (PRO) is a well-known and widely used non-selective beta-adrenergic receptor antagonist (beta-blocker), with a range of actions which are of interest in an oncological context. PRO displays effects on cellular proliferation and invasion, on the immune system, on the angiogenic cascade, and on tumour cell sensitivity to existing treatments. Both pre-clinical and clinical evidence of these effects, in multiple cancer types, is assessed and summarised and relevant mechanisms of action outlined. In particular there is evidence that PRO is effective at multiple points in the metastatic cascade, particularly in the context of the post-surgical wound response. Based on this evidence the case is made for further clinical investigation of the anticancer effects of PRO, particularly in combination with other agents. A number of trials are on-going, in different treatment settings for various cancers.

Sympathectomy reduces tumor weight and affects expression of tumor-related genes in melanoma tissue in the mouse

Accumulated evidence indicates that sympathetic nerves may potentiate tumor growth, including melanoma. To elucidate possible mechanisms for this effect, we performed chemical sympathectomy by intraperitoneal (i.p.) injection of the neurotoxin 6-hydroxydopamine hydrobromide (100 mg/kg of body weight); in nine adult male C57BL/6J mice; nine control mice received i.p. vehicle (VEH). Seven days later, all mice were injected subcutaneously with 3 × 10(3) B16-F10 melanoma cells. Mice were euthanized 20 d after injection of melanoma cells, for measurement of tumor weight and expression of genes related to sympathetic signaling, apoptosis, hypoxia and angiogenesis in tumor tissue. To assess potential involvement of the hypothalamo-pituitary-adrenocortical axis in the effect of sympathectomy on melanoma growth, concentrations of plasma corticosterone and level of glucocorticoid receptor mRNA in tumor tissue were determined. We found that sympathectomy significantly attenuated melanoma growth (tumor weight 0.29 ± 0.16 g versus 1.02 ± 0.30 g in controls; p < 0.05). In tumor tissue from sympathectomized mice, we found significantly increased gene expression (measured by real-time PCR), relative to VEH-injected controls, of tyrosine hydroxylase, neuropeptide Y and glucocorticoid receptor (all p < 0.05), and alpha1, beta1 and beta3 adrenergic receptors (all p < 0.025), and factors related to apoptosis (Bcl-2 and caspase-3; p < 0.05) and hypoxia (hypoxia inducible factor 1 alpha) (p = 0.005). Plasma corticosterone concentrations were significantly elevated (p < 0.05) in these mice. Our findings indicate that sympathectomy induces complex changes in the tumor microenvironment reducing melanoma growth. Such complex changes should be considered in the prediction of responses of cancer patients to interventions affecting sympathetic signaling in tumor tissue and its environment.

Expression of several cytokines in prostate cancer: Correlation with clinical variables of patients. Relationship with biochemical progression of the malignance

BACKGROUND

This work is focused on finding new markers that complement or diagnoses currently used towards improving knowledge histological and statistical aspects that allow us to predict the local stage carcinomas and to identify and understand all the factors related to the progression of this disease.

MATERIALS AND METHODS

Prostates were obtained from: normal prostates from 20 men, diagnosis of BPH (Benign Prostatic Hyperplasia) from 35 men and prostate cancer from 86 men. We studied the behavior of cytokines that have been implicated in inflammatory processes: TNF-alfa, IL-6, IL-1, EGF and TGF-B. Expression of these cytokines and its receptors was analyzed by immunohistochemistry. Spearman's test, Kaplan-Meier curves, univariate and multivariate Cox proportional hazard regression analyses were performed.

RESULTS

Spearman's analysis showed that there was at least one correlation between TGFB-B, IL-6, gp-130, IL-1B, IL-1R, IL-1RII and clinic pathological feature (preoperative serum PSA, clinical t stage, pathological t stage, positive surgical margins, biochemical progression, survival). Immunostaining score was correlated with some of the clinicopathological feature. In Cox multivariate analysis between the prognostic variables (pathological T stage, Gleason score and lymph node) and immunohistochemical parameters (TGF-B, IL-1a, intensity TGFBRI and intensity TGFBRII) only the expression of IL-1a was retained as independent predictors of biochemical progression after radical prostatectomy.

CONCLUSIONS

Our results suggest a role for prostatic expression of TGF-B, IL-1a, TGFBRI and TGFBRII as prognostic markers for prostate cancer. The rational combination of novel agents directed toward the inactivation of TGF-B, IL-1a, TGFBRI and TGFBRII could disrupt complementary tumor cell proliferation pathways.

Prevention of pancreatic cancer in a hamster model by cAMP decrease

Smoking and alcoholism are risk factors for the development of pancreatitis-associated pancreatic ductal adenocarcinoma (PDAC). We have previously shown that these cancers overexpressed stress neurotransmitters and cyclic adenosine monophosphate (cAMP) while the inhibitory neurotransmitter γ-aminobutyric acid (GABA) was suppressed. Using a hamster model, the current study has tested the hypothesis that cAMP decrease by GABA supplementation in the drinking water prevents the development of pancreatitis-associated PDAC. Our data reveal strong preventive effects of GABA supplementation on the development of PDAC and pancreatic intraductal neoplasia (PanIN). ELISA assays and immunohistochemistry revealed significant decreases in the levels of cAMP and interleukin 6 accompanied by reductions in the expression of several cancer stem cell markers and phosphorylated signaling proteins, which stimulate cell proliferation, and migration in pancreatic exocrine cells of GABA treated animals. We conclude that cAMP decrease by GABA supplementation inhibits multiple cancer stimulating pathways in cancer stem cells, differentiated cancer cells and the immune system, identifying this approach as promising novel tool for the prevention of PDAC in individuals with a history of smoking and alcoholism.

Pterostilbene Decreases the Antioxidant Defenses of Aggressive Cancer Cells In Vivo: A Physiological Glucocorticoids- and Nrf2-Dependent Mechanism

AIMS

Polyphenolic phytochemicals have anticancer properties. However, in mechanistic studies, lack of correlation with the bioavailable concentrations is a critical issue. Some reports had suggested that these molecules downregulate the stress response, which may affect growth and the antioxidant protection of malignant cells. Initially, we studied this potential underlying mechanism using different human melanomas (with genetic backgrounds correlating with most melanomas), growing in nude mice as xenografts, and pterostilbene (Pter, a natural dimethoxylated analog of resveratrol).

RESULTS

Intravenous administration of Pter decreased human melanoma growth in vivo. However, Pter, at levels measured within the tumors, did not affect melanoma growth in vitro. Pter inhibited pituitary production of the adrenocorticotropin hormone (ACTH), decreased plasma levels of corticosterone, and thereby downregulated the glucocorticoid receptor- and nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-dependent antioxidant defense system in growing melanomas. Exogenous corticosterone or genetically induced Nrf2 overexpression in melanoma cells prevented the inhibition of tumor growth and decreased antioxidant defenses in these malignant cells. These effects and mechanisms were also found in mice bearing different human pancreatic cancers. Glutathione depletion (selected as an antimelanoma strategy) facilitated the complete elimination by chemotherapy of melanoma cells isolated from mice treated with Pter.

INNOVATION

Although bioavailability-related limitations may preclude direct anticancer effects in vivo, natural polyphenols may also interfere with the growth and defense of cancer cells by downregulating the pituitary gland-dependent ACTH synthesis.

CONCLUSIONS

Pter downregulates glucocorticoid production, thus decreasing the glucocorticoid receptor and Nrf2-dependent signaling/transcription and the antioxidant protection of melanoma and pancreatic cancer cells. Antioxid. Redox Signal. 24, 974-990.

A blast without power - cell death induced by the tuberculosis-necrotizing toxin fails to elicit adequate immune responses

In this study, we deploy a doxycycline-dependent suicide switch integrated in a tumor challenge model. With this experimental setup, we characterized the immunological consequences of cells dying by four distinct cell death stimuli in vivo. We observed that apoptotic cell death induced by expression of the truncated form of BH3 interacting-domain death agonist (tBid) and a constitutively active form of caspase 3 (revC3), respectively, showed higher immunogenicity than cell death induced by expression of the tuberculosis-necrotizing toxin (TNT). Our data indicate that the early release of ATP induces the silent clearance of dying cells, whereas the simultaneous presence of 'find me' signals and danger-associated molecular patterns (DAMPs) promotes inflammatory reactions and increased immunogenicity. This proposed model is supported by findings showing that the production and release of high concentrations of IL-27 by bone-marrow-derived macrophages (BMDM) is limited to BMDM exposed to those forms of death that simultaneously released ATP and the DAMPs heat-shock protein 90 (HSP90) and high-mobility group box-1 protein (HMGB1). These results demonstrate that the tissue microenvironment generated by dying cells may determine the subsequent immune response.

Stress, metabolism and cancer: integrated pathways contributing to immune suppression

The potential for immune cells to control cancers has been recognized for many decades, but only recently has real excitement begun to spread through the oncology community following clear evidence that therapeutic blockade of specific immune-suppressive mechanisms is enough to make a real difference in survival for patients with several different advanced cancers. However, impressive and encouraging as these new clinical data are, it is clear that more effort should be devoted toward understanding the full spectrum of factors within cancer patients, which have the potential to block or weaken antitumor activity by immune cells. The goal of this brief review is to highlight recent literature revealing interactive stress and metabolic pathways, particularly those mediated by the sympathetic nervous system, which may conspire to block immune cells from unleashing their full killing potential. There is exciting new information regarding the role of neurogenesis by tumors and adrenergic signaling in cancer progression (including metabolic changes associated with cachexia and lipolysis) and in regulation of immune cell function and differentiation. However, much more work is needed to fully understand how the systemic metabolic effects mediated by the brain and nervous system can be targeted for therapeutic efficacy in the setting of immunotherapy and other cancer therapies.

The role of stress and beta-adrenergic system in melanoma: current knowledge and possible therapeutic options

PURPOSE

The aim of the present review was to discuss recent findings on the role of beta-adrenergic system in melanoma, in order to provide information on the biological responses elicited by its activation and its potential application for melanoma treatment.

METHODS

A literature search was performed, and evidences regarding the involvement of stress and beta-adrenergic system in cancer and melanoma were found and discussed.

RESULTS

Our search pointed out that beta-adrenergic system is a key regulator of important biological processes involved in the onset and progression of some solid tumors. In the last decade, functional beta-adrenoceptors have been also identified on melanoma cells, as well as on their microenvironment cells. Similarly to other common cancers too, the activation of such adrenoceptors by catecholamines, usually released under stress conditions, has been found to trigger pro-tumorigenic pathways contributing to cell proliferation and motility, immune system regulation, apoptosis, epithelial-mesenchymal transition, invasion and neoangiogenesis.

CONCLUSIONS

The biological evidences we found clarify and sustain the clinical evidences reporting the involvement of chronic stress in melanoma onset and progression. In such scenario, it is conceivable that a therapeutic approach targeting beta-adrenergic system could constitute a novel and promising strategy for melanoma treatment.

Use of proteins as biomarkers and their role in carcinogenesis

Summary: Improved diagnostic methods and medical therapies are necessary for early detection and treatment and an improved prognosis. It is thus vital to both examine and evaluate the role of the various existing proteins as biomarkers in carcinogenesis and to assess the contribution of these proteins in anti-cancer activity, for consideration in therapeutic strategies. It is essential to both examine and evaluate the role of the various existing proteins as biomarkers in carcinogenesis and to assess the contribution of these proteins in anti-cancer activity, for consideration in therapeutic strategies. The purpose of this review is twofold. Firstly, it is to evaluate recent data about which proteins can be utilized as biomarkers in carcinogenesis. The proteins reviewed include: CPTP, IL-6, CCN, and S100. Secondly, it is to evaluate the contribution of dietary proteins in cancer activity. Specifically, how whey protein, soy proteins and lectin, a phytochemical could be useful in cancer prevention and treatment.

Recent Findings: Whey protein, present in dairy products, is an excellent source of the sulphur amino acid cysteine, the rate limiting substrate in glutathione synthesis. Notably, this protein survives digestion and has been shown to have anti-carcinogenic properties in animal studies. Lectins are phytochemicals present in plant foods, and have active components which alters cancer initiation, promotion and progression. Lectins have been characterized as a useful tool in biochemistry, cell biology, immunology and in diagnostic and therapeutic purposes in cancer research. Soy proteins contain various compounds, including isoflavones, protease inhibitors and protein kinase inhibitors, which have been proven effective in tumor growth inhibition. They have therefore, been greatly emphasized in cancer prevention and treatment. It has been proved that soy food consumption was associated with decreased risk of death and recurrence of breast cancer. CPTP is a recently discovered protein whose main role is to transport C1P, a pro-inflammatory molecule. The discovery of CPTP may shine a light on the mechanism of inflammatory diseases, and hopefully offer a potential target for therapeutic purposes in cancer research. Interleukin-6 is a multifunctional cytokine that affects the activity of cancer cells. It is involved in tumor growth, and elevated levels is associated with an increased risk of cancer. S100B is a well-established biomarker for malignant melanoma, and useful in assessing tumor load, stage and prognosis for patients with this disease. Other members of this family of proteins include S100A4, which has been associated with several malignancies and S100A2, which has been found to be decreased in some cancers. CCN are a group of regulatory proteins, located in the extracellular matrix (maricellular). They are involved in cellular adhesion, mitogenesis, chemotaxis, cell survival, and wound healing. CCN proteins are also able to modulate the signals of several proteins, which may also influence skeletal development and angiogenesis. Many of the functions of these proteins are thus also related to tumor growth. Furthermore, CCN interacts with estrogen in the development of cancer, and is implicated in some breast and ovarian cancers.

Infantile hemangiomas, retinopathy of prematurity and cancer: a common pathogenetic role of the β-adrenergic system

The serendipitous demonstration that the nonselective β-adrenergic receptor (β-AR) antagonist propranolol promotes the regression of infantile hemangiomas (IHs) aroused interest around the involvement of the β-adrenergic system in angiogenic processes. The efficacy of propranolol was related to the β2-AR blockade and the consequent inhibition of the production of vascular endothelial growth factor (VEGF), suggesting the hypothesis that propranolol could also be effective in treating retinopathy of prematurity (ROP), a retinal pathology characterized by VEGF-induced neoangiogenesis. Consequent to the encouraging animal studies, a pilot clinical trial showed that oral propranolol protects newborns from ROP progression, even though this treatment is not sufficiently safe. Further, animal studies clarified the role of β3-ARs in the development of ROP and, together with several preclinical studies demonstrating the key role of the β-adrenergic system in tumor progression, vascularization, and metastasis, prompted us to also investigate the participation of β3-ARs in tumor growth. The aim of this review is to gather the recent findings on the role of the β-adrenergic system in IHs, ROP, and cancer, highlighting the fact that these different pathologies, triggered by different pathogenic noxae, share common pathogenic mechanisms characterized by the presence of hypoxia-induced angiogenesis, which may be contrasted by targeting the β-adrenergic system. The mechanisms characterizing the pathogenesis of IHs, ROP, and cancer may also be active during the fetal-neonatal development, and a great contribution to the knowledge on the role of β-ARs in diseases characterized by chronic hypoxia may come from research focusing on the fetal and neonatal period.

A nervous tumor microenvironment: the impact of adrenergic stress on cancer cells, immunosuppression, and immunotherapeutic response

Long conserved mechanisms maintain homeostasis in living creatures in response to a variety of stresses. However, continuous exposure to stress can result in unabated production of stress hormones, especially catecholamines, which can have detrimental health effects. While the long-term effects of chronic stress have well-known physiological consequences, recent discoveries have revealed that stress may affect therapeutic efficacy in cancer. Growing epidemiological evidence reveals strong correlations between progression-free and long-term survival and β-blocker usage in cancer patients. In this review, we summarize the current understanding of how the catecholamines, epinephrine and norepinephrine, affect cancer cell survival and tumor progression. We also highlight new data exploring the potential contributions of stress to immunosuppression in the tumor microenvironment and the implications of these findings for the efficacy of immunotherapies.

Inhibition of human melanoma growth by a non-cardioselective β-blocker

Recently, retrospective studies provided conflicting results on the benefit of β-adrenoceptor-blockers (β-blockers) on melanoma progression. Most of these studies did not define the β-blocker used, making it difficult to understand the source of discrepancies between results. Therefore, we investigated the effect of non-cardioselective and cardioselective β-blockers on melanoma progression at the cellular, molecular, and tumor levels. Here we show that the non-cardioselective β-blocker propranolol hydrochloride (propranolol) inhibits proliferation and induces apoptosis in primary cell cultures derived from a primary and a metastasis of human melanoma and in melanoma cell lines. In contrast, the cardioselective β-blocker metoprolol tartrate hardly affects melanoma cell survival or proliferation. We further highlight that a daily treatment with propranolol slows down tumor development in immunodeficient mice transplanted with human melanoma cells. RNA microarrays, quantitative PCR, and histochemistry analyses showed that propranolol regulates the expression of different genes involved in tumor angiogenesis, cell death, or proliferation. Thus, our results suggest that non-cardioselective β-blockers affect melanoma progression, and bring first clues about the pathways involved in this antitumor effect.

Melanoma tumors alter proinflammatory cytokine production and monoamine brain function, and induce depressive-like behavior in male mice

Depression is a commonly observed disorder among cancer patients; however, the mechanisms underlying the relationship between these disorders are not well known. We used an animal model to study the effects of tumor development on depressive-like behavior manifestation, proinflammatory cytokine expression, and central monoaminergic activity. Male OF1 mice were inoculated with B16F10 melanoma tumor cells and subjected to a 21-day behavioral evaluation comprising the novel palatable food (NPF) test and tail suspension test (TST). The mRNA expression levels of proinflammatory cytokines, interleukin (IL)-1β and IL-6, and tumor necrosis factor-alpha (TNF-α), were measured in the hypothalamus and hippocampus and the levels of IL-6 and TNF-α were measured in the blood plasma. We similarly determined the monoamine turnover in various brain areas. The tumors resulted in increasing the immobility in TST and the expression level of IL-6 in the hippocampus. These increases corresponded with a decrease in dopaminergic activity in the striatum and a decrease in serotonin turnover in the prefrontal cortex. Similarly, a high level of tumor development produced increases in the brain expression levels of IL-6 and TNF-α and plasma levels of IL-6. Our findings suggest that these alterations in inflammatory cytokines and monoaminergic system function might be responsible for the manifestation of depressive-like behaviors in tumor-bearing mice.

A role for cAMP-driven transactivation of EGFR in cancer aggressiveness - therapeutic implications

In many common cancers, production of cAMP boosts cancer proliferation, survival, and aggressiveness, reflecting the fact that, through mechanisms that require further clarification, cAMP can promote tyrosine phosphorylation, notably transactivation of the epidermal growth factor receptor (EGFR). Hormones which activate adenylate cyclase in many cancers include PGE2 - often produced by cox-2 activity within tumors - and adrenergic hormones, acting on beta2 receptors. NSAID cyclooxygenase inhibitors, including low-dose aspirin, clearly reduce risk for many adenocarcinomas, but the impact of cox-2 inhibitors in clinical cancer therapy remains somewhat equivocal. There is increasing evidence that increased sympathetic drive, often reflecting psychic stress or tobacco usage, increases risk for, and promotes the aggressiveness of, many cancers. The non-specific beta antagonist propranolol shows cancer-retardant activity in pre-clinical rodent studies, especially in stressed animals, and a limited amount of epidemiology concludes that concurrent propranolol usage is associated with superior prognosis in breast cancer, ovarian cancer, and melanoma. Epidemiology correlating increased resting heart rate with increased total cancer mortality can be interpreted as compelling evidence that increased sympathetic drive encourages the onset and progression of common cancers. Conversely, hormones which inhibit adenylate cyclase activity in cancers may have potential for cancer control; GABA, which can be administered as a well-tolerated nutraceutical, has potential in this regard. Combination regimens intended to down-regulate cancer cAMP levels, perhaps used in conjunction with EGFR inhibitors, may have considerable potential for suppressing the contribution of cAMP/EGFR to cancer aggressiveness. This model also predicts that certain other hormones which activate adenylate cylase in various tissue may play a yet-unsuspected role in cancer induction and spread.

Glucocorticoid receptor knockdown decreases the antioxidant protection of B16 melanoma cells: an endocrine system-related mechanism that compromises metastatic cell resistance to vascular endothelium-induced tumor cytotoxicity

We previously reported an interorgan system in which stress-related hormones (corticosterone and noradrenaline), interleukin-6, and glutathione (GSH) coordinately regulate metastatic growth of highly aggressive B16-F10 melanoma cells. Corticosterone, at levels measured in tumor-bearing mice, also induces apoptotic cell death in metastatic cells with low GSH content. In the present study we explored the potential role of glucocorticoids in the regulation of metastatic cell death/survival during the early stages of organ invasion. Glucocorticoid receptor (GCR) knockdown decreased the expression and activity of γ-glutamylcysteine synthetase (γ-GCS), the rate-limiting step in GSH synthesis, in metastatic cells in vivo independent of the tumor location (liver, lung, or subcutaneous). The decrease in γ-GCS activity was associated with lower intracellular GSH levels. Nrf2- and p53-dependent down-regulation of γ-GCS was associated with a decrease in the activities of superoxide dismutase 1 and 2, catalase, glutathione peroxidase, and glutathione reductase, but not of the O₂⁻-generating NADPH oxidase. The GCR knockdown-induced decrease in antioxidant protection caused a drastic decrease in the survival of metastatic cells during their interaction with endothelial cells, both in vitro and in vivo; only 10% of cancer cells attached to the endothelium survived compared to 90% survival observed in the controls. This very low rate of metastatic cell survival was partially increased (up to 52%) in vivo by inoculating B16-F10 cells preloaded with GSH ester, which enters the cell and delivers free GSH. Taken together, our results indicate that glucocorticoid signaling influences the survival of metastatic cells during their interaction with the vascular endothelium.

Running for time: circadian rhythms and melanoma

Circadian timing system includes an input pathway transmitting environmental signals to a core oscillator that generates circadian signals responsible for the peripheral physiological or behavioural events. Circadian 24-h rhythms regulate diverse physiologic processes. Deregulation of these rhythms is associated with a number of pathogenic conditions including depression, diabetes, metabolic syndrome and cancer. Melanoma is a less common type of skin cancer yet more aggressive often with a lethal ending. However, little is known about circadian control in melanoma and exact functional associations between core clock genes and development of melanoma skin cancer. This paper, therefore, comprehensively analyses current literature data on the involvement of circadian clock components in melanoma development. In particular, the role of circadian rhythm deregulation is discussed in the context of DNA repair mechanisms and influence of UV radiation and artificial light exposure on cancer development. The role of arylalkylamine N-acetyltransferase (AANAT) enzyme and impact of melatonin, as a major output factor of circadian rhythm, and its protective role in melanoma are discussed in details. We hypothesise that further understanding of clock genes' involvement and circadian regulation might foster discoveries in the field of melanoma diagnostics and treatment.

Gold (I) N-heterocyclic carbene complex inhibits mouse melanoma growth by p53 upregulation

BACKGROUND

Cancer treatment using gold (I) complexes is becoming popular. In this study, a gold (I) N-heterocyclic complex designated as complex 3 was synthesized, its cytotoxicity was examined, and its anti-melanoma activity was evaluated in vitro and in vivo.

METHODS

Viability of cancer cells was determined by MTT assay upon treatment with various concentrations of a gold (I) N-heterocyclic carbene complex (complex 3) in a dose and time dependent manner. Mouse melanoma cells B16F10 were selected for further apoptotic studies, including flowcytometric analysis of annexin binding, cell cycle arrest, intracellular ROS generation and loss in the mitochondrial membrane potential. ELISA based assays were done for caspase activities and western blots for determining the expression of various survival and apoptotic proteins. Immunocytology was performed to visualize the translocation of p53 to the nucleus. B16F10 cells were inoculated into mice and post tumor formation, complex 3 was administered. Immunohistology was performed to determine the expressions of p53, p21, NF-κB (p65 and p50), MMP-9 and VEGF. Student's t test was used for determining statistical significance. The survival rate data were analyzed by Kaplan-Meier plots.

RESULTS

Complex 3 markedly inhibited the growth of HCT 116, HepG2, and A549, and induced apoptosis in B16F10 cells with nuclear condensation, DNA fragmentation, externalization of phosphatidylserine, activation of caspase 3 and caspase 9, PARP cleavage, downregulation of Bcl-2, upregulation of Bax, cytosolic cytochrome c elevation, ROS generation, and mitochondrial membrane potential loss indicating the involvement of an intrinsic mitochondrial death pathway. Further, upregulation of p53, p-p53 (ser 15) and p21 indicated the role of p53 in complex 3 mediated apoptosis. The complex reduced tumor size, and caused upregulation of p53 and p21 along with downregulation of NF-κB (p65 and p50), VEGF and MMP-9. These results suggest that it induced anti-melanoma effect in vitro and in vivo by modulating p53 and other apoptotic factors.

CONCLUSIONS

The gold (I) N-heterocyclic carbene complex (C22H26N6AuO2PF6) designated as complex 3 induced ROS and p53 dependent apoptosis in B16F10 cells involving the mitochondrial death pathway along with suppression of melanoma tumor growth by regulating the levels of pro and anti apoptotic factors (p53, p21, NF-κB, VEGF and MMP-9).

Interleukin-6 cytokine: a multifunctional glycoprotein for cancer

Interleukin 6 is a multifunctional cytokine. Its increased levels have been associated with elevated cancer risk, and also these levels have been found to be a prognostic factor for several cancer types. In addition, increased levels have been found in coronary heart disease, insulin resistant patients, advance stage cancer patients, atopy/asthma and in patients with blood circulating micrometastasis. Additionally several studies with different types of cancers have been performed to identify the correlation between interleukin-6 levels, stage, treatment response and severity of symptoms. The influence of interleukin-6 is performed mainly through the janus kinase-signal transducer and activator of transcription-zinc finger protein 1-2 signaling pathway. As a result, the increased levels of interleukin-6 are responsible for enhanced neo-angiogenesis, inhibition of cancer cell apoptosis and deregulation of the control mechanisms in the microenvironment. In addition, increased levels of inteleukin-6 have been found to increase the production of collagen and a-actin which induce interstitial lung disease. In the current mini review we will present information regarding the interleukin-6 and published results in several cancer studies and finally we will comment in future treatment approaches blocking this cytokine in cancer patients.