HIF-1alpha links beta-adrenoceptor agonists and pancreatic cancer cells under normoxic condition

Anaerobic Glycolysis and Ischemic Stroke: From Mechanisms and Signaling Pathways to Natural Product Therapy

Ischemic stroke is a serious condition that results in high rates of illness and death. Anaerobic glycolysis becomes the primary means of providing energy to the brain during periods of low oxygen levels, such as in the aftermath of an ischemic stroke. This process is essential for maintaining vital brain functions and has significant implications for recovery following a stroke. Energy supply by anaerobic glycolysis and acidosis caused by lactic acid accumulation are important pathological processes after ischemic stroke. Numerous natural products regulate glucose and lactate, which in turn modulate anaerobic glycolysis. This article focuses on the relationship between anaerobic glycolysis and ischemic stroke, as well as the associated signaling pathways and natural products that play a therapeutic role. These natural products, which can regulate anaerobic glycolysis, will provide new avenues and perspectives for the treatment of ischemic stroke in the future.

Harnessing adrenergic blockade in stress-promoted TNBC in vitro and solid tumor in vivo: disrupting HIF-1α and GSK-3β/β-catenin driven resistance to doxorubicin

Sympathetic activation triggered by chronic stress afflicting cancer survivors is an emerging modulator of tumorigenesis. Adrenergic blockade was previously associated with improving response to doxorubicin (DOX) in triple-negative breast cancer (TNBC), yet the precise underlying mechanisms remain obscure. The resilience of cancer stem cells (CSCs) during chemotherapy fosters resistance and relapse. Hypoxia-inducible factor-1α (HIF-1α) and β-catenin are intertwined transcriptional factors that enrich CSCs and evidence suggests that their expression could be modulated by systemic adrenergic signals. Herein, we aimed to explore the impact of adrenoreceptor blockade using carvedilol (CAR) on DOX and its potential to modulate CSCs overcoming chemoresistance. To achieve this aim, in vitro studies were conducted using adrenaline-preincubated MDA-MB-231 cells and in vivo studies using a chronic restraint stress-promoted solid tumor mouse model. Results revealed that adrenaline increased TNBC proliferation and induced a phenotypic switch reminiscent of CSCs, as evidenced by enhanced mammosphere formation. These results paralleled an increase in aldehyde dehydrogenase-1 (ALDH-1) and Nanog expression levels as well as HIF-1α and β-catenin upsurge. In vivo, larger tumor volumes were observed in mice under chronic stress compared to their unstressed counterparts. Adrenergic blockade using CAR, however, enhanced the impact DOX had on halting TNBC cell proliferation and tumor growth via enhanced apoptosis. CAR also curbed HIF-1α and β-catenin tumor levels subsequently suppressing ALDH-1 and SOX2. Our study unveils a central role for HIF-1α linking stress-induced sympathetic activation fueling CSC enrichment via the β-catenin pathway. It also highlights novel insights into CAR's capacity in reversing DOX chemoresistance in TNBC.

Outcome of stress on G protein-coupled receptors and hypoxia inducible factor-1α

Stress drives neuroendocrine signals with detrimental effects to the intestinal homeostasis. The aim of this study was to evaluate the effect of stress on intestinal hypoxia response elements, including G protein-coupled receptor 41 (GPR41), GPR43, and hypoxia inducible factor (HIF)-1α. Groups of five BALB/c mice were subjected to acute (2 h per day) and chronic (2 h per day for 4 days) stress induced by restraint, and the results were compared to those of an unstressed control group. Whole mucosal samples from the colon were collected to evaluate the expression of GPR41, GPR43 and HIF-1α using Western blot chemiluminescent analysis. Compared to the control group, in the chronic stress group the expression of GPR43 (P = 0.0092) and HIF-1α (P < 0.0001) were significantly lower and the expression of GPR41 was similar (P = 0.9184); acute stress significantly increased HIF-1α expression (P = 0.0030) and increased GPR41 expression (P = 0.0937), without affecting GPR43 (P = 0.9184). These findings offer insights into the modulation of hypoxia response elements under stress conditions and their pharmacological implications for developing drugs that mitigate the effects of stress on intestinal homeostasis.

HIF-1, an important regulator in potential new therapeutic approaches to ischemic stroke

Ischemic stroke is a leading cause of disability and mortality worldwide due to the narrow therapeutic window of the only approved therapies like intravenous thrombolysis and thrombectomy. Hypoxia inducible factor-1α (HIF-1α) is a sensitive regulator of oxygen homeostasis, and its expression is rapidly induced after hypoxia/ischemia. It plays an extensive role in the pathophysiology of stroke by regulating multiple pathways including glucose metabolism, angiogenesis, neuronal survival, neuroinflammation and blood brain barrier regulation. Here, we give a brief overview of the HIF-1α-targeting strategies currently under investigation and summarise recent research on how HIF-1α is regulated in various brain cells, including neurons and microglia, at various stages in ischemic stroke. The roles of HIF-1 in stroke varies with ischemic time and degree of ischemia, are still up for debate. More focus has been placed on prospective HIF-1α targeting drugs, such as HIF-1α activator, HIF-1α stabilizers, and natural compounds. In this review, we have highlighted the regulation of HIF-1α in the novel therapeutic approaches for treatment of stroke.

S100a9 inhibits Atg9a transcription and participates in suppression of autophagy in cardiomyocytes induced by β1-adrenoceptor autoantibodies

BACKGROUND

Cardiomyocyte death induced by autophagy inhibition is an important cause of cardiac dysfunction. In-depth exploration of its mechanism may help to improve cardiac dysfunction. In our previous study, we found that β1-adrenergic receptor autoantibodies (β1-AAs) induced a decrease in myocardial autophagy and caused cardiomyocyte death, thus resulting in cardiac dysfunction. Through tandem mass tag (TMT)-based quantitative proteomics, autophagy-related S100a9 protein was found to be significantly upregulated in the myocardial tissue of actively immunized mice. However, whether S100a9 affects the cardiac function in the presence of β1-AAs through autophagy and the specific mechanism are currently unclear.

METHODS

In this study, the active immunity method was used to establish a β1-AA-induced mouse cardiac dysfunction model, and RT-PCR and western blot were used to detect changes in gene and protein expression in cardiomyocytes. We used siRNA to knockdown S100a9 in cardiomyocytes. An autophagy PCR array was performed to screen differentially expressed autophagy-related genes in cells transfected with S100a9 siRNA and negative control siRNA. Cytoplasmic nuclear separation, co-immunoprecipitation (Co-IP), and immunofluorescence were used to detect the binding of S100a9 and hypoxia inducible factor-1α (HIF-1α). Finally, AAV9-S100a9-RNAi was injected into mice via the tail vein to knockdown S100a9 in cardiomyocytes. Cardiac function was detected via ultrasonography.

RESULTS

The results showed that β1-AAs induced S100a9 expression. The PCR array indicated that Atg9a changed significantly in S100a9siRNA cells and that β1-AAs increased the binding of S100a9 and HIF-1α in cytoplasm. Knockdown of S100a9 significantly improved autophagy levels and cardiac dysfunction.

CONCLUSION

Our research showed that β1-AAs increased S100a9 expression in cardiomyocytes and that S100a9 interacted with HIF-1α, which prevented HIF-1α from entering the nucleus normally, thus inhibiting the transcription of Atg9a. This resulted in autophagy inhibition and cardiac dysfunction.

Emerging Roles of the Nervous System in Gastrointestinal Cancer Development

Simple Summary

Nerve–cancer cross-talk has increasingly become a focus of the oncology field, particularly in gastrointestinal (GI) cancers. The indispensable roles of the nervous system in GI tumorigenesis and malignancy have been dissected by epidemiological, experimental animal and mechanistic data. Herein, we review and integrate recent discoveries linking the nervous system to GI cancer initiation and progression, and focus on the molecular mechanisms by which nerves and neural receptor pathways drive GI malignancy.

Abstract

Our understanding of the fascinating connection between nervous system and gastrointestinal (GI) tumorigenesis has expanded greatly in recent years. Recent studies revealed that neurogenesis plays an active part in GI tumor initiation and progression. Tumor-driven neurogenesis, as well as neurite outgrowth of the pre-existing peripheral nervous system (PNS), may fuel GI tumor progression via facilitating cancer cell proliferation, chemoresistance, invasion and immune escape. Neurotransmitters and neuropeptides drive the activation of various oncogenic pathways downstream of neural receptors within cancer cells, underscoring the importance of neural signaling pathways in GI tumor malignancy. In addition, neural infiltration also plays an integral role in tumor microenvironments, and contributes to an environment in favor of tumor angiogenesis, immune evasion and invasion. Blockade of tumor innervation via denervation or pharmacological agents may serve as a promising therapeutic strategy against GI tumors. In this review, we summarize recent findings linking the nervous system to GI tumor progression, set the spotlight on the molecular mechanisms by which neural signaling fuels cancer aggressiveness, and highlight the importance of targeting neural mechanisms in GI tumor therapy.

Adrenergic-Angiogenic Crosstalk in Head and Neck Cancer: Mechanisms and Therapeutic Implications

Head and neck squamous cell carcinomas (HNSCC) are loco-regionally aggressive tumors that often lead to debilitating changes in appearance, speech, swallowing and respiratory function in patients. It is therefore critical to develop novel targeted treatment strategies that can effectively target multiple components within the tumor microenvironment. In this regard, there has been an increased recognition of the role of neural signaling networks as mediators of disease progression in HNSCC. Here, we summarize the current knowledge on the mechanisms of adrenergic signaling in HNSCC specifically focusing on neurovascular crosstalk and the potential of targeting the adrenergic-angiogenic axis through repurposing of FDA-approved drugs against HNSCC.

Pathophysiologic Role of Neurotransmitters in Digestive Diseases

Neurotransmitters are special molecules that serve as messengers in chemical synapses between neurons, cells, or receptors, including catecholamines, serotonin, dopamine, and other neurotransmitters, which play an important role in both human physiology and pathology. Compelling evidence has indicated that neurotransmitters have an important physiological role in various digestive diseases. They act as ligands in combination with central or peripheral receptors, and transmits signals through chemical synapses, which are involved in regulating the physiological and pathological processes of the digestive tract organs. For instance, neurotransmitters regulate blood circulation and affect intestinal movement, nutrient absorption, the gastrointestinal innate immune system, and the microbiome. In this review, we will focus on the role of neurotransmitters in the pathogenesis of digestive tract diseases to provide novel therapeutic targets for new drug development in digestive diseases.

Assessment of Epinephrine and Norepinephrine in Gastric Carcinoma

The aim of our study was to assess the sympathetic nervous system’s involvement in the evolution of gastric carcinoma in patients by analyzing the mediators of this system (epinephrine and norepinephrine), as well as by analyzing the histological expression of the norepinephrine transporter (NET). We conducted an observational study including 91 patients diagnosed with gastric carcinoma and an additional 200 patients without cancer between November 2017 and October 2018. We set the primary endpoint as mortality from any cause in the first two years after enrolment in the study. The patients were monitored by a 24-h Holter electrocardiogram (ECG) to assess sympathetic or parasympathetic predominance. Blood was also collected from the patients to measure plasma free metanephrine (Meta) and normetanephrine (N-Meta), and tumor histological samples were collected for the analysis of NET expression. All of this was performed prior to the application of any antineoplastic therapy. Each patient was monitored for two years. We found higher heart rates in patients with gastric carcinoma than those without cancer. Regarding Meta and N-Meta, elevated levels were recorded in the patients with gastric carcinoma, correlating with the degree of tumor differentiation and other negative prognostic factors such as tumor invasion, lymph node metastasis, and distant metastases. Elevated Meta and N-Meta was also associated with a poor survival rate. All these data suggest that the predominance of the sympathetic nervous system’s activity predicts increased gastric carcinoma severity.

Highlighting the Potential for Chronic Stress to Minimize Therapeutic Responses to Radiotherapy through Increased Immunosuppression and Radiation Resistance

Ionizing radiation has been used in the treatment of cancer for more than 100 years. While often very effective, there is still a great effort in place to improve the efficacy of radiation therapy for controlling the progression and recurrence of tumors. Recent research has revealed the close interaction between nerves and tumor progression, especially nerves of the autonomic nervous system that are activated by a variety of stressful stimuli including anxiety, pain, sleep loss or depression, each of which is likely to be increased in cancer patients. A growing literature now points to a negative effect of chronic stressful stimuli in tumor progression. In this review article, we present data on the potential for adrenergic stress to influence the efficacy of radiation and in particular, its potential to influence the anti-tumor immune response, and the frequency of an "abscopal effect" or the shrinkage of tumors which are outside an irradiated field. We conclude that chronic stress can be a major impediment to more effective radiation therapy through mechanisms involving immunosuppression and increased resistance to radiation-induced tumor cell death. Overall, these data highlight the potential value of stress reduction strategies to improve the outcome of radiation therapy. At the same time, objective biomarkers that can accurately and objectively reflect the degree of stress in patients over prolonged periods of time, and whether it is influencing immunosuppression and radiation resistance, are also critically needed.

Impact of a natural disaster on access to care and biopsychosocial outcomes among Hispanic/Latino cancer survivors

Cancer is the leading cause of death in Puerto Rico (PR). Hurricane Maria (HM) and its aftermath lead to widespread devastation on the island, including the collapse of the healthcare system. Medically fragile populations, such as cancer survivors, were significantly affected. The goal of this study was to assess the impact of HM on barriers to care, emotional distress, and inflammatory biomarkers among cancer survivors in PR. This exploratory longitudinal study was conducted in health care facilities and community support groups from PR. Cancer survivors (n = 50) and non-cancer participants (n = 50) completed psychosocial questionnaires and provided blood samples that were used to assess inflammatory cytokines levels. Among this cohort, we identified 41 matched cancer survivors/non-cancer participants pairs. Data were analyzed through descriptive, frequencies, correlational, and regression analyses. Cancer survivors that were affected by HM reported increased barriers in accessing medical care, which were directly associated with anxiety, perceived stress, and post-traumatic symptomatology. Moreover, being a cancer survivor, predicted more barriers to receiving health care, especially in the first six weeks after the event, after which the effect was attenuated. Several inflammatory cytokines, such as CD31, BDNF, TFF3, Serpin E-1, VCAM-1, Vitamin D BP, and PDGF-AA, were significantly upregulated in cancer survivors while MMP9 and Osteopontin both had significant positive correlations with barriers to care. HM significantly impacted Puerto Ricans psychosocial well-being. Cancer survivors had significant barriers to care and showed increased serum inflammatory cytokines but did not show differences in anxiety, stress, and post-traumatic symptoms compared to non-cancer participants.

Gpr97 Exacerbates AKI by Mediating Sema3A Signaling

Background G protein-coupled receptors (GPCRs) participate in a variety of physiologic functions, and several GPCRs have critical physiologic and pathophysiologic roles in the regulation of renal function. We investigated the role of Gpr97, a newly identified member of the adhesion GPCR family, in AKI.Methods AKI was induced by ischemia-reperfusion or cisplatin treatment in Gpr97-deficient mice. We assessed renal injury in these models and in patients with acute tubular necrosis by histologic examination, and we conducted microarray analysis and in vitro assays to determine the molecular mechanisms of Gpr97 function.Results Gpr97 was upregulated in the kidneys from mice with AKI and patients with biopsy-proven acute tubular necrosis compared with healthy controls. In AKI models, Gpr97-deficient mice had significantly less renal injury and inflammation than wild-type mice. Gpr97 deficiency also attenuated the AKI-induced expression of semaphorin 3A (Sema3A), a potential early diagnostic biomarker of renal injury. In NRK-52E cells subjected to oxygen-glucose deprivation, siRNA-mediated knockdown of Gpr97 further increased the expression of survivin and phosphorylated STAT3 and reduced toll-like receptor 4 expression. Cotreatment with recombinant murine Sema3A protein counteracted these effects. Finally, additional in vivo and in vitro studies, including electrophoretic mobility shift assays and luciferase reporter assays, showed that Gpr97 deficiency attenuates ischemia-reperfusion-induced expression of the RNA-binding protein human antigen R, which post-transcriptionally regulates Sema3A expression.Conclusions Gpr97 is an important mediator of AKI, and pharmacologic targeting of Gpr97-mediated Sema3A signaling at multiple levels may provide a novel approach for the treatment of AKI.

Propranolol inhibits the proliferation, migration and tube formation of hemangioma cells through HIF-1α dependent mechanisms

The aim of this study was to investigate the mechanism of propranolol on the regression of hemangiomas. Propranolol-treated hemangioma tissues were collected and the expression of hypoxia inducible factor-1α (HIF-1α) was examined. We also established HIF-1α overexpression and knockdown hemangioma cells, and determined the effects of HIF-1α on the hemangioma cells proliferation, apoptosis, migration and tube formation. Significantly increased HIF-1α level was found in the hemangioma tissues compared to that in normal vascular tissues, whereas propranolol treatment decreased the HIF-1α level in hemangioma tissues in a time- and dose-dependent manner. Moreover, propranolol treatment significantly decreased cell proliferation, migration and tube formation as well as promoted cell apoptosis in HIF-1α overexpression and knockdown hemangioma cells. Propranolol suppressed the cells proliferation, migration and tube formation of hemangioma cells through HIF-1α dependent mechanisms. HIF-1α could serve as a novel target in the treatment of hemangiomas.

β2-adrenogenic signaling regulates NNK-induced pancreatic cancer progression via upregulation of HIF-1α

Cigarette smoking is a risk factor for pancreatic cancer. It is suggested that 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a tobacco-specific nitrosamine, mediates the carcinogenic action of cigarette smoking by promoting cancer growth. In the present study, we show that smoking, HIF-1α expression and β2-adrenogenic receptor (β2-AR) expression are negatively correlated with the overall survival of pancreatic cancer patients. Moreover, HIF-1α expression and β2-AR expression are positively correlated with smoking status, different histological differentiation and among the tumor node metastasis (TNM) stages in pancreatic cancer patients. NNK increases HIF-1α expression in pancreatic cancer in vitro and in vivo. Furthermore, knockdown of HIF-1α and ICI118, 551 (a β2-AR selective antagonist) abrogates NNK-induced pancreatic cancer proliferation and invasion in vitro and inhibits NNK-induced pancreatic cancer growth in vivo. However, using CoCl2 (a HIF-1α stabilizing agent which decreases HIF-1α degradation under normoxia conditions) reverses ICI118, 551 induced effects under NNK exposure. Thus, our data indicate that β2-AR signaling regulates NNK-induced pancreatic cancer progression via upregulation of HIF-1α. Taken together, β2-AR signaling and HIF-1α may represent promising therapeutic targets for preventing smoking induced pancreatic cancer progression.

Recent Advances on the Role of G Protein-Coupled Receptors in Hypoxia-Mediated Signaling

G protein-coupled receptors (GPCRs) are cell surface proteins mainly involved in signal transmission; however, they play a role also in several pathophysiological conditions. Chemically heterogeneous molecules like peptides, hormones, lipids, and neurotransmitters activate second messengers and induce several biological responses by binding to these seven transmembrane receptors, which are coupled to heterotrimeric G proteins. Recently, additional molecular mechanisms have been involved in GPCR-mediated signaling, leading to an intricate network of transduction pathways. In this regard, it should be mentioned that diverse GPCR family members contribute to the adaptive cell responses to low oxygen tension, which is a distinguishing feature of several illnesses like neoplastic and cardiovascular diseases. For instance, the G protein estrogen receptor, namely G protein estrogen receptor (GPER)/GPR30, has been shown to contribute to relevant biological effects induced by hypoxia via the hypoxia-inducible factor (HIF)-1α in diverse cell contexts, including cancer. Likewise, GPER has been found to modulate the biological outcome of hypoxic/ischemic stress in both cardiovascular and central nervous systems. Here, we describe the role exerted by GPCR-mediated signaling in low oxygen conditions, discussing, in particular, the involvement of GPER by a hypoxic microenvironment.

Gd-Metallofullerenol Nanomaterial Suppresses Pancreatic Cancer Metastasis by Inhibiting the Interaction of Histone Deacetylase 1 and Metastasis-Associated Protein 1

The treatment of pancreatic cancer frequently fails due to local recurrence and hepatic metastasis. Our previous study found that Gd@C82(OH)22 can suppress pancreatic cancer by inhibiting MMP-2/9 expression. In this study, we further explored the epigenetic mechanism of Gd@C82(OH)22 in human pancreatic cancer metastasis. Gd@C82(OH)22 suppressed tumor metastasis through down-regulation of metastasis-associated protein 1 (MTA1), HDAC1, HIF-1α, and MMP-2/9 and up-regulation of reversion-cysteine protein with the Kazal motif (RECK). The level of acetylation was increased in the promoter region of the RECK gene after Gd@C82(OH)22 treatment. The interaction of MTA1, HDAC1, and HIF-1α was inhibited by Gd@C82(OH)22. Furthermore, large-scale molecular dynamics simulations revealed Gd@C82(OH)22 could serve as an effective HDAC inhibitor to the protein-protein association between HDAC1 and MTA1, especially through MTA1's SANT and ELM2 dimerization domains. Our findings implicate Gd@C82(OH)22 as a novel HDAC inhibitor acting to increase RECK expression by suppressing the MTA1/HDAC1 co-repressor complex. Gd@C82(OH)22 may serve as a potential HDAC1 inhibitor to suppress pancreatic cancer cell invasion and metastasis both in vitro and in vivo. According to computer analysis and experimental validation, Gd@C82(OH)22 activates RECK expression by inhibiting the interaction of HDAC1 and MTA1.

Propranolol represses infantile hemangioma cell growth through the β2-adrenergic receptor in a HIF-1α-dependent manner

Propranolol, as a non-selective blocker of the β-adrenergic receptor (AR), is utilised as the first-line treatment for infantile hemangiomas. However, the underlying mechanism remains poorly understood. The present study was designed to investigate the molecular basis of propranolol on the regression of infantile hemangiomas using a proliferating infantile hemangioma-derived endothelial cell line. In infantile hemangioma patients, we found that propranolol significantly decreased the expression levels of the hypoxia inducible factor (HIF)-1α in serum and urine, as well as in hemangioma tissues. In vitro analysis revealed that propranolol reduces the expression of HIF-1α in hemangioma cells in a dose- and time-dependent manner, mainly by acting on β2-AR. Interestingly, it was observed that overexpression of HIF-1α apparently abrogated the inhibitory effects of propranolol on vascular endothelial growth factor (VEGF) expression and cell growth. Our data further demonstrated that propranolol inhibited the signal transducer and activator of transcription 3 (STAT3), a critical oncogenic signaling molecule, and the anti-apoptotic protein Bcl-2. Additionally, overexpression of HIF-1α significantly reversed the inhibitory effects of propranolol on STAT3 signaling. In a mouse xenograft hemangioma model, overexpression of HIF-1α significantly attenuated the therapeutic effects of propranolol and inhibited propranolol-induced hemangioma cell apoptosis. Moreover, the protein levels of VEGF, phosphorylated STAT3, total STAT3 and Bcl-2 were significantly upregulated by HIF-1α overexpression in propranolol-treated nude mice bearing hemangiomas. Collectively, our data provide evidence that propranolol may regress infantile hemangiomas by suppressing VEGF and STAT3 signaling pathways in an HIF-1α-dependent manner.

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.

Central and peripheral nervous systems: master controllers in cancer metastasis

Central and sympathetic nervous systems govern functional activities of many organs. Solid tumors like organs are also innervated by sympathetic nerve fibers. Neurotransmitters released from sympathetic nerve fibers can modulate biological behaviors of tumor cells. Multiple physiologic processes of tumor development may be dominated by central and sympathetic nervous systems as well. Recent studies suggest that dysfunction of central and sympathetic nervous systems and disorder of the hormone network induced by psychological stress may influence malignant progression of cancer by inhibiting the functions of immune system, regulating metabolic reprogramming of tumor cells, and inducing interactions between tumor and stromal cells. Over-release of inflammatory cytokines by tumors may aggravate emotional disorder, triggering the vicious cycles in tumor microenvironment and host macroenvironment. It is reasonable to hypothesize that cancer progression may be controlled by central and sympathetic nervous systems. In this review, we will focus on the recent information about the impacts of central and sympathetic nervous systems on tumor invasion and metastasis.

Novel regulatory program for norepinephrine-induced epithelial-mesenchymal transition in gastric adenocarcinoma cell lines

Norepinephrine and epinephrine, catecholamine hormones that are major mediators for chronic stress-induced cancers, are implicated in the progression of a number of cancer cells, including gastric adenocarcinoma. However, the underlying mechanisms of these hormones have not been well elucidated. Epithelial–mesenchymal transition (EMT) is a crucial event responsible for cancer cell invasion and metastasis. The hypothesis regarding whether the promotive effects of norepinephrine (NE) on cancer are in part due to its ability to induce an EMT program has not been proven. In this study, we show that NE does not only obviously induce EMT alterations in the morphological characteristics of gastric adenocarcinoma cells, but also increases the markers of EMT, including vimentin expression, and decreases E-cadherin expression, further resulting in cell motility and invasiveness. We also reveal that these actions are mainly mediated through the activation of β₂-AR–HIF-1α–Snail signaling pathways. In summary, this study implies that NE induces EMT in gastric adenocarcinoma through the regulation of β₂-AR–HIF-1α–Snail activity. The data provide a new perspective on chronic stress in a negative social and psychological state, which may be a risk factor for cancer development and progression.

EMT: a novel regulatory program for stress hormone norepinephrine. EMT and gastric adenocarcinoma.

Role of abnormal lipid metabolism in development, progression, diagnosis and therapy of pancreatic cancer

There is growing evidence that metabolic alterations play an important role in cancer development and progression. The metabolism of cancer cells is reprogrammed in order to support their rapid proliferation. Elevated fatty acid synthesis is one of the most important aberrations of cancer cell metabolism. An enhancement of fatty acids synthesis is required both for carcinogenesis and cancer cell survival, as inhibition of key lipogenic enzymes slows down the growth of tumor cells and impairs their survival. Based on the data that serum fatty acid synthase (FASN), also known as oncoantigen 519, is elevated in patients with certain types of cancer, its serum level was proposed as a marker of neoplasia. This review aims to demonstrate the changes in lipid metabolism and other metabolic processes associated with lipid metabolism in pancreatic ductal adenocarcinoma (PDAC), the most common pancreatic neoplasm, characterized by high mortality. We also addressed the influence of some oncogenic factors and tumor suppressors on pancreatic cancer cell metabolism. Additionally the review discusses the potential role of elevated lipid synthesis in diagnosis and treatment of pancreatic cancer. In particular, FASN is a viable candidate for indicator of pathologic state, marker of neoplasia, as well as, pharmacological treatment target in pancreatic cancer. Recent research showed that, in addition to lipogenesis, certain cancer cells can use fatty acids from circulation, derived from diet (chylomicrons), synthesized in liver, or released from adipose tissue for their growth. Thus, the interactions between de novo lipogenesis and uptake of fatty acids from circulation by PDAC cells require further investigation.

Role of connexins in infantile hemangiomas

The circulatory system is one of the first systems that develops during embryogenesis. Angiogenesis describes the formation of blood vessels as a part of the circulatory system and is essential for organ growth in embryogenesis as well as repair in adulthood. A dysregulation of vessel growth contributes to the pathogenesis of many disorders. Thus, an imbalance between pro- and antiangiogenic factors could be observed in infantile hemangioma (IH). IH is the most common benign tumor during infancy, which appears during the first month of life. These vascular tumors are characterized by rapid proliferation and subsequently slower involution. Most IHs regress spontaneously, but in some cases they cause disfigurement and systemic complications, which requires immediate treatment. Recently, a therapeutic effect of propranolol on IH has been demonstrated. Hence, this non-selective β-blocker became the first-line therapy for IH. Over the last years, our understanding of the underlying mechanisms of IH has been improved and possible mechanisms of action of propranolol in IH have postulated. Previous studies revealed that gap junction proteins, the connexins (Cx), might also play a role in the pathogenesis of IH. Therefore, affecting gap junctional intercellular communication is suggested as a novel therapeutic target of propranolol in IH. In this review we summarize the current knowledge of the molecular processes, leading to IH and provide new insights of how Cxs might be involved in the development of these vascular tumors.

Hypoxia-inducing factors as master regulators of stemness properties and altered metabolism of cancer- and metastasis-initiating cells

Accumulating lines of experimental evidence have revealed that hypoxia-inducible factors, HIF-1α and HIF-2α, are key regulators of the adaptation of cancer- and metastasis-initiating cells and their differentiated progenies to oxygen and nutrient deprivation during cancer progression under normoxic and hypoxic conditions. Particularly, the sustained stimulation of epidermal growth factor receptor (EGFR), insulin-like growth factor-1 receptor (IGF-1R), stem cell factor (SCF) receptor KIT, transforming growth factor-β receptors (TGF-βRs) and Notch and their downstream signalling elements such as phosphatidylinositol 3′-kinase (PI3K)/Akt/molecular target of rapamycin (mTOR) may lead to an enhanced activity of HIFs. Moreover, the up-regulation of HIFs in cancer cells may also occur in the hypoxic intratumoral regions formed within primary and secondary neoplasms as well as in leukaemic cells and metastatic prostate and breast cancer cells homing in the hypoxic endosteal niche of bone marrow. The activated HIFs may induce the expression of numerous gene products such as induced pluripotency-associated transcription factors (Oct-3/4, Nanog and Sox-2), glycolysis- and epithelial-mesenchymal transition (EMT) programme-associated molecules, including CXC chemokine receptor 4 (CXCR4), snail and twist, microRNAs and angiogenic factors such as vascular endothelial growth factor (VEGF). These gene products in turn can play critical roles for high self-renewal ability, survival, altered energy metabolism, invasion and metastases of cancer cells, angiogenic switch and treatment resistance. Consequently, the targeting of HIF signalling network and altered metabolic pathways represents new promising strategies to eradicate the total mass of cancer cells and improve the efficacy of current therapies against aggressive and metastatic cancers and prevent disease relapse.

Propranolol induces regression of hemangioma cells through HIF-1α-mediated inhibition of VEGF-A

OBJECTIVE

To investigate the mechanism of propranolol on regression of infantile hemangiomas.

BACKGROUND

Propranolol has been found to be effective in treatment of severe hemangiomas of infancy. However, its mechanism of action is as yet unknown.

METHODS

Cultured proliferating and involuting hemangioma endothelial cells were treated with varying concentrations of propranolol for up to 4 days. Analysis was performed using cell viability, migration, and tubulogenesis assays, as well as quantitative RT-PCR and flow cytometry. Western blots and ELISA assays were used to assess protein expression.

RESULTS

Treatment with propranolol led to a dose dependent cytotoxic effect in hemangioma endothelial cells with decreased cell viability, migration, and tubulogenesis. This cytotoxic effect was VEGF (vascular endothelial growth factor) dependent, as demonstrated by decreased VEGF, VEGF-R1, and VEGF-R2 production. Decreased signaling through the VEGF pathway resulted in downregulation of PI3/Akt and p38/MAPK activity. Decreased VEGF activity was mediated through the hypoxia inducible factor (HIF)-1α pathway but not through NF-κβ signaling.

CONCLUSIONS

Collectively, these data suggest that propranolol exerts its suppressive effects on hemangiomas through the HIF-1α-VEGF-A angiogenesis axis, with effects mediated through the PI3/Akt and p38/MAPK pathways. These findings provide a plausible mechanism of action of propranolol on regression of infantile hemangiomas.

Therapeutic potential of perineural invasion, hypoxia and desmoplasia in pancreatic cancer

Pancreatic cancer is one of the most fatal human malignancies. Though a relatively rare malignancy, it remains one of the deadliest tumors, with an extremely high mortality rate. The prognosis of patients with pancreatic cancer remains poor; only patients with small tumors and complete resection have a chance of a complete cure. Pancreatic cancer responds poorly to conventional therapies, including chemotherapy and irradiation. Tumor-specific targeted therapy is a relatively recent addition to the arsenal of anti-cancer therapies. It is important to find novel targets to distinguish tumor cells from their normal counterparts in therapeutic approaches. In the past few decades, studies have revealed the molecular mechanisms of pancreatic tumorigenesis, growth, invasion and metastasis. The proteins that participate in the pathophysiological processes of pancreatic cancer might be potential targets for therapy. This review describes the main players in perineural invasion, hypoxia and desmoplasia and the molecular mechanisms of these pathophysiological processes.

Effect of mesenchymal stem cells on hypoxia-induced desensitization of β2-adrenergic receptors in rat osteosarcoma cells

The β2-adrenergic receptor (β2AR) mediates the effects of chronic stress in several neoplasms, however, β2AR signaling is impaired by hypoxia in various tissues. While hypoxia is a common feature significant in the progression of solid tumors, little is known about the effect of hypoxia on β2AR signaling in the tumor microenvironment. Previously, it has been reported that the systemic administration of mesenchymal stem cells (MSCs) increased the engraftment and metastatic colonization of rat osteosarcoma (OS) cells. In the current study, the effect of MSCs on the hypoxia-induced desensitization of the β2AR in OS cells was investigated. Epinephrine, norepinephrine and isoproterenol increased the cellular proliferation of the rat OS cell line COS1NR and rat MSCs in a dose-dependent and β2AR antagonist-sensitive manner. While isoproterenol had significant proliferative effects on MSCs under normoxic and hypoxic conditions, COS1NR cells did not respond under hypoxic conditions. A sensitivity assay for the β2AR revealed that hypoxia impaired the sensitivity of COS1NR cells, whereas hypoxia did not affect MSCs. An immunoassay revealed no significant change in the expression of hypoxia-inducible factor-1α (HIF1α) in COS1NR cells, whilst an immunoassay demonstrated a 15% increase in MSCs following isoproterenol stimulation. In COS1NR cells co-cultured with MSCs under hypoxic conditions, isoproterenol caused a significant increase in proliferation and this effect was inhibited by an anti-interleukin (IL)-6 antibody. A tumor formation assay in syngeneic rats revealed that the systemic administration of MSCs enhances the growth of OS and the effect of MSCs was inhibited by IL-6 neutralization. In conclusion, MSCs are resistant to the hypoxia-induced desensitization to β2AR. Hypoxia caused a siginificant desensitization of the β2AR in COS1NR cells alone, whereas MSCs may support tumor progression through cellular interactions.

β2-adrenoceptor blockage induces G1/S phase arrest and apoptosis in pancreatic cancer cells via Ras/Akt/NFκB pathway

Background

Smoking and stress, pancreatic cancer (PanCa) risk factors, stimulate nitrosamine 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and catecholamines production respectively. NNK and catecholamine bind the β-adrenoceptors and induce PanCa cell proliferation; and we have previously suggested that β-adrenergic antagonists may suppress proliferation and invasion and stimulate apoptosis in PanCa. To clarify the mechanism of apoptosis induced by β₂-adrenergic antagonist, we hypothesize that blockage of the β₂-adrenoceptor could induce G₁/S phase arrest and apoptosis and Ras may be a key player in PanCa cells.

Results

The β₁ and β₂-adrenoceptor proteins were detected on the cell surface of PanCa cells from pancreatic carcinoma specimen samples by immunohistochemistry. The β₂-adrenergic antagonist ICI118,551 significantly induced G₁/S phase arrest and apoptosis compared with the β₁-adrenergic antagonist metoprolol, which was determined by the flow cytometry assay. β₂-adrenergic antagonist therapy significantly suppressed the expression of extracellular signal-regulated kinase, Akt, Bcl-2, cyclin D1, and cyclin E and induced the activation of caspase-3, caspase-9 and Bax by Western blotting. Additionally, the β₂-adrenergic antagonist reduced the activation of NFκB in vitro cultured PanCa cells.

Conclusions

The blockage of β₂-adrenoceptor markedly induced PanCa cells to arrest at G₁/S phase and consequently resulted in cell death, which is possibly due to that the blockage of β₂-adrenoceptor inhibited NFκB, extracellular signal-regulated kinase, and Akt pathways. Therefore, their upstream molecule Ras may be a key factor in the β₂-adrenoceptor antagonist induced G₁/S phase arrest and apoptosis in PanCa cells. The new pathway discovered in this study may provide an effective therapeutic strategy for PanCa.

β2-adrenoceptor blocker synergizes with gemcitabine to inhibit the proliferation of pancreatic cancer cells via apoptosis induction

The stimulation of β2-adrenoceptor, which is a major mediator for chronic stress-induced cancers, has been implicated in the progression in the number of cancer cells, including pancreatic cancer, which remains one of the most aggressive and lethal diseases worldwide. Whether β-adrenoceptor antagonists potentiate gemcitabine, a standard first-line treatment for advanced pancreatic cancer that offers only modest benefit due to acquired chemoresistance, has not been elucidated. Thus, we studied the antiproliferative and apoptotic effects and the underlying mechanisms of gemcitabine combined with the β2-adrenoceptor blocker ICI 118551 (1-[2,3-(dihydro-7-methyl-1H-iden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol), in human pancreatic cancer BxPC-3 and MIA PaCa-2 cells. Results show that ICI 118551 significantly synergized the antiproliferative and pro-apoptotic effects induced by gemcitabine in both BxPC-3 and MIA PaCa-2 cells (P<0.05 combination vs. control or gemcitabine alone). When cells were treated with the combination of gemcitabine and ICI 118551, NF-κB activation was blocked; the expression of Bax protein was substantially increased; and Bcl-2 protein was downregulated. Taken together, the data suggest that ICI 118551 potentiates the antiproliferative effects of gemcitabine by inducing apoptosis in pancreatic cancer cells. Our study implies that this combination may be an effective therapeutic strategy for pancreatic cancer.

{Beta}2-adrenergic receptor agonists inhibit the proliferation of 1321N1 astrocytoma cells

Astrocytomas and glioblastomas have been particularly difficult to treat and refractory to chemotherapy. However, significant evidence has been presented that demonstrates a decrease in astrocytoma cell proliferation subsequent to an increase in cAMP levels. The 1321N1 astrocytoma cell line, as well as other astrocytomas and glioblastomas, expresses β(2)-adrenergic receptors (β(2)-ARs) that are coupled to G(s) activation and consequent cAMP production. Experiments were conducted to determine whether the β(2)-AR agonist (R,R')-fenoterol and other β(2)-AR agonists could attenuate mitogenesis and, if so, by what mechanism. Receptor binding studies were conducted to characterize β(2)-AR found in 1321N1 and U118 cell membranes. In addition, cells were incubated with (R,R')-fenoterol and analogs to determine their ability to stimulate intracellular cAMP accumulation and inhibit [(3)H]thymidine incorporation into the cells. 1321N1 cells contain significant levels of β(2)-AR as determined by receptor binding. (R,R')-fenoterol and other β(2)-AR agonists, as well as forskolin, stimulated cAMP accumulation in a dose-dependent manner. Accumulation of cAMP induced a decrease in [(3)H]thymidine incorporation. There was a correlation between concentration required to stimulate cAMP accumulation and inhibit [(3)H]thymidine incorporation. U118 cells have a reduced number of β(2)-ARs and a concomitant reduction in the ability of β(2)-AR agonists to inhibit cell proliferation. These studies demonstrate the efficacy of β(2)-AR agonists for inhibition of growth of the astrocytoma cell lines. Because a significant portion of brain tumors contain β(2)-ARs to a greater extent than whole brain, (R,R')-fenoterol, or some analog, may be useful in the treatment of brain tumors after biopsy to determine β(2)-AR expression.