Exogenous norepinephrine attenuates the efficacy of sunitinib in a mouse cancer model

Role of transforming growth factor-β1 pathway in angiogenesis induced by chronic stress in colorectal cancer

BACKGROUND

Chronic stress can induce stress-related hormones; norepinephrine (NE) is considered to have the highest potential in cancer. NE can stimulate the expression of hypoxia-inducible factor-1α (HIF-1α), which is associated with vascular endothelial growth factor (VEGF) secretion and tumor angiogenesis. However, the underlying mechanisms are poorly understood.

METHODS

Tumor-bearing mice were subjected to chronic restraint stress and treated with normal saline, human monoclonal VEGF-A neutralizing antibody bevacizumab, or β-adrenergic receptor (β-AR) antagonist (propranolol). Tumor growth and vessel density were also evaluated. Human colorectal adenocarcinoma cells were treated with NE, propranolol, or the inhibitor of transforming growth factor-β (TGF-β) receptor Type I kinase (Ly2157299) in vitro. TGF-β1 in mouse serum and cell culture supernatants was quantified using ELISA. The expression of HIF-1α was measured using Real time-PCR and western blotting. Cell migration and invasion were tested.

RESULTS

Chronic restraint stress attenuated the efficacy of bevacizumab and promoted tumor growth and angiogenesis in a colorectal tumor model. Propranolol blocked this effect and inhibited TGF-β1 elevation caused by chronic restraint stress or NE. NE upregulated HIF-1α expression, which was reversed by propranolol or Ly2157299. Propranolol and Ly2157199 blocked NE-stimulated cancer cell migration and invasion.

CONCLUSIONS

Our results demonstrate the effect of NE on tumor angiogenesis and the critical role of TGF-β1 signaling during this process. In addition, β-AR/TGF-β1 signaling/HIF-1α/VEGF is a potential signaling pathway. This study also indicates that psychosocial stress might be a risk factor which weakens the efficacy of anti-angiogenic therapy.

The sympathetic nervous system shapes the tumor microenvironment to impair chemotherapy response

The tumor microenvironment influences cancer progression and response to treatments, which ultimately impacts the survival of patients with cancer. The sympathetic nervous system (SNS) is a core component of solid tumors that arise in the body. In addition to influencing cancer progression, a role for the SNS in the effectiveness of cancer treatments is beginning to emerge. This review explores evidence that the SNS impairs chemotherapy efficacy. We review findings of studies that evaluated the impact of neural ablation on chemotherapy outcomes and discuss plausible mechanisms for the impact of neural signaling on chemotherapy efficacy. We then discuss implications for clinical practice, including opportunities to block neural signaling to improve response to chemotherapy.

The neural addiction of cancer

The recently uncovered key role of the peripheral and central nervous systems in controlling tumorigenesis and metastasis has opened a new area of research to identify innovative approaches against cancer. Although the 'neural addiction' of cancer is only partially understood, in this Perspective we discuss the current knowledge and perspectives on peripheral and central nerve circuitries and brain areas that can support tumorigenesis and metastasis and the possible reciprocal influence that the brain and peripheral tumours exert on one another. Tumours can build up local autonomic and sensory nerve networks and are able to develop a long-distance relationship with the brain through circulating adipokines, inflammatory cytokines, neurotrophic factors or afferent nerve inputs, to promote cancer initiation, growth and dissemination. In turn, the central nervous system can affect tumour development and metastasis through the activation or dysregulation of specific central neural areas or circuits, as well as neuroendocrine, neuroimmune or neurovascular systems. Studying neural circuitries in the brain and tumours, as well as understanding how the brain communicates with the tumour or how intratumour nerves interplay with the tumour microenvironment, can reveal unrecognized mechanisms that promote cancer development and progression and open up opportunities for the development of novel therapeutic strategies. Targeting the dysregulated peripheral and central nervous systems might represent a novel strategy for next-generation cancer treatment that could, in part, be achieved through the repurposing of neuropsychiatric drugs in oncology.

Chronic stress in solid tumor development: from mechanisms to interventions

Chronic stress results in disturbances of body hormones through the neuroendocrine system. Cancer patients often experience recurrent anxiety and restlessness during disease progression and treatment, which aggravates disease progression and hinders treatment effects. Recent studies have shown that chronic stress-regulated neuroendocrine systems secret hormones to activate many signaling pathways related to tumor development in tumor cells. The activated neuroendocrine system acts not only on tumor cells but also modulates the survival and metabolic changes of surrounding non-cancerous cells. Current clinical evidences also suggest that chronic stress affects the outcome of cancer treatment. However, in clinic, there is lack of effective treatment for chronic stress in cancer patients. In this review, we discuss the main mechanisms by which chronic stress regulates the tumor microenvironment, including functional regulation of tumor cells by stress hormones (stem cell-like properties, metastasis, angiogenesis, DNA damage accumulation, and apoptotic resistance), metabolic reprogramming and immune escape, and peritumor neuromodulation. Based on the current clinical treatment framework for cancer and chronic stress, we also summarize pharmacological and non-pharmacological therapeutic approaches to provide some directions for cancer therapy.

Psychological distress and eustress in cancer and cancer treatment: Advances and perspectives

Facing cancer diagnosis, patients with cancer are prone to psychological stress and consequent psychological disorders. The association between psychological stress and cancer has long been a subject of high interest. To date, preclinical studies have gradually uncovered the promotive effects of psychological distress on tumor hallmarks. In contrast, eustress may exert suppressive effects on tumorigenesis and beneficial effects on tumor treatment, which brings a practicable means and psychosocial perspective to cancer treatment. However, the underlying mechanisms remain incompletely understood. Here, by focusing on the hypothalamic-pituitary-adrenal axis and the sympathetic nervous system, as well as stress-related crucial neurotransmitters and hormones, we highlight the effects of distress and eustress on tumorigenesis, the tumor microenvironment, and tumor treatment. We also discuss the findings of clinical studies on stress management in patients with cancer. Last, we summarize questions that remain to be addressed and provide suggestions for future research directions.

Chronic Stress: Impacts on Tumor Microenvironment and Implications for Anti-Cancer Treatments

Chronic stress is common among cancer patients due to the psychological, operative, or pharmaceutical stressors at the time of diagnosis or during the treatment of cancers. The continuous activations of the hypothalamic-pituitary-adrenal (HPA) axis and the sympathetic nervous system (SNS), as results of chronic stress, have been demonstrated to take part in several cancer-promoting processes, such as tumorigenesis, progression, metastasis, and multi-drug resistance, by altering the tumor microenvironment (TME). Stressed TME is generally characterized by the increased proportion of cancer-promoting cells and cytokines, the reduction and malfunction of immune-supportive cells and cytokines, augmented angiogenesis, enhanced epithelial-mesenchymal transition, and damaged extracellular matrix. For the negative effects that these alterations can cause in terms of the efficacies of anti-cancer treatments and prognosis of patients, supplementary pharmacological or psychotherapeutic strategies targeting HPA, SNS, or psychological stress may be effective in improving the prognosis of cancer patients. Here, we review the characteristics and mechanisms of TME alterations under chronic stress, their influences on anti-cancer therapies, and accessory interventions and therapies for stressed cancer patients.

Stress and cancer: mechanisms, significance and future directions

The notion that stress and cancer are interlinked has dominated lay discourse for decades. More recent animal studies indicate that stress can substantially facilitate cancer progression through modulating most hallmarks of cancer, and molecular and systemic mechanisms mediating these effects have been elucidated. However, available clinical evidence for such deleterious effects is inconsistent, as epidemiological and stress-reducing clinical interventions have yielded mixed effects on cancer mortality. In this Review, we describe and discuss specific mediating mechanisms identified by preclinical research, and parallel clinical findings. We explain the discrepancy between preclinical and clinical outcomes, through pointing to experimental strengths leveraged by animal studies and through discussing methodological and conceptual obstacles that prevent clinical studies from reflecting the impacts of stress. We suggest approaches to circumvent such obstacles, based on targeting critical phases of cancer progression that are more likely to be stress-sensitive; pharmacologically limiting adrenergic-inflammatory responses triggered by medical procedures; and focusing on more vulnerable populations, employing personalized pharmacological and psychosocial approaches. Recent clinical trials support our hypothesis that psychological and/or pharmacological inhibition of excess adrenergic and/or inflammatory stress signalling, especially alongside cancer treatments, could save lives.

The Adrenergic Nerve Network in Cancer

The central and autonomic nervous systems interact and converge to build up an adrenergic nerve network capable of promoting cancer. While a local adrenergic sympathetic innervation in peripheral solid tumors influences cancer and stromal cell behavior, the brain can participate to the development of cancer through an intermixed dysregulation of the sympathoadrenal system, adrenergic neurons, and the hypothalamo-pituitary-adrenal axis. A deeper understanding of the adrenergic nerve circuitry within the brain and tumors and its interactions with the microenvironment should enable elucidation of original mechanisms of cancer and novel therapeutic strategies.

Impact of Concomitant Cardiovascular Medication on Survival of Metastatic Renal Cell Carcinoma Patients Treated with Sunitinib or Pazopanib in the First Line

BACKGROUND

Patients with metastatic renal cell carcinoma (mRCC) are often elderly and have various comorbidities, including cardiovascular diseases. Although these patients have extensive co-exposure to targeted therapy and cardiovascular drugs, the impact of this co-exposure on outcomes for patients with mRCC remains unclear.

OBJECTIVE

Our objective was to evaluate the association between the use of cardiovascular medication and survival of patients with mRCC.

METHODS

The study included 343 consecutive patients with mRCC treated with sunitinib or pazopanib in the first line. Clinical data obtained from the Renal Cell Carcinoma Information System (RENIS) clinical registry and hospital information systems were retrospectively analyzed. Progression-free survival (PFS) and overall survival (OS) were compared according to the use of common medications, including antihypertensives (i.e., β-blockers [BBs], angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, and diuretics), acetylsalicylic acid (aspirin), statins, and proton pump inhibitors.

RESULTS

The univariate Cox analysis evaluating the impact of the assessed comedications on patient survival revealed that only BBs were significantly associated with PFS (hazard ratio [HR] 0.533, p < 0.001) and OS (HR 0.641, p = 0.006). The median PFS and OS for users of BBs was 18.39 and 37.60 months versus 8.16 and 20.4 months for patients not using BBs (p < 0.001 and p < 0.001, respectively). The Cox multivariate analysis showed that the use of BBs was a significant factor for both PFS (HR 0.428, p = 0.001) and OS (HR 0.518, p = 0.001).

CONCLUSIONS

The results of this retrospective study suggest that the use of BBs is associated with favorable outcomes for patients with mRCC treated with sunitinib or pazopanib in the first line.

Neurobiology of Cancer: Introduction of New Drugs in the Treatment and Prevention of Cancer

Research on the neurobiology of cancer, which lies at the border of neuroscience and oncology, has elucidated the mechanisms and pathways that enable the nervous system to modulate processes associated with cancer initiation and progression. This research has also shown that several drugs which modulate interactions between the nervous system and the tumor micro- and macroenvironments significantly reduced the progression of cancer in animal models. Encouraging results were also provided by prospective clinical trials investigating the effect of drugs that reduce adrenergic signaling on the course of cancer in oncological patients. Moreover, it has been shown that reducing adrenergic signaling might also reduce the incidence of cancer in animal models, as well as in humans. However, even if many experimental and clinical findings have confirmed the preventive and therapeutic potential of drugs that reduce the stimulatory effect of the nervous system on processes related to cancer initiation and progression, several questions remain unanswered. Therefore, the aim of this review is to critically evaluate the efficiency of these drugs and to discuss questions that need to be answered before their introduction into conventional cancer treatment and prevention.

Topical 2'-Hydroxyflavanone for Cutaneous Melanoma

2′-hydroxyflavanone (2HF) is a dietary flavonoid with anticancer activity towards multiple cancers. Here, we report that topically applied 2HF inhibits the growth of intradermal implants of melanoma in immunocompetent mice. 2HF induced apoptosis and inhibited the growth of the human SK-MEL-24 as well as murine B16-F0 and B16-F10 melanoma cell lines in vitro. Apoptosis was associated with depletion of caspase-3, caspase-9, and PARP1 in B16-F0 and SK-MEL-24 cells. Caspase-9 and MEKK-15 were undetected even in untreated B16-F10 cells. Signaling proteins TNFα, and phospho-PDGFR-β were depleted in all three cell lines; MEKK-15 was depleted by 2HF in SK-MEL-24 cells. 2HF enhanced sunitinib (an MEK and PDGFR-β inhibitor) and AZD 2461 (a PARP1 inhibitor) cytotoxicity. 2HF also depleted the Ral-regulated, stress-responsive, antiapoptotic endocytic protein RLIP76 (RALBP1), the inhibition of which has previously been shown to inhibit B16-F0 melanoma growth in vivo. Functional inhibition of RLIP76 was evident from inhibition of epidermal growth factor (EGF) endocytosis by 2HF. We found that topically applied 2HF–Pluronic Lecithin Organogel (PLO) gel inhibited B16-F0 and B16-F10 tumors implanted in mice and caused no overt toxicity despite significant systemic absorption. 2HF treatment reduced phospho-AKT, vimentin, fibronectin, CDK4, cyclinB1, and BCL2, whereas it increased BIM and phospho-AMPK in excised tumors. Several cancer signals are controlled by endocytosis, a process strongly inhibited by RLIP76 depletion. We conclude that 2HF–PLO gel may be useful for topical therapy of cutaneous metastases of melanoma and could enhance the antineoplastic effects of sunitinib and PARP1 inhibitors. The mechanism of action of 2HF in melanoma overlaps with RLI76 inhibitors.

β-Adrenoceptors as drug targets in melanoma: novel preclinical evidence for a role of β3 -adrenoceptors

Stress plays a role in tumourigenesis through catecholamines acting at β-adrenoceptors including β₁ -, β₂ - and β₃ -adrenoceptors, and the use of β-adrenoceptor antagonists seems to counteract tumour growth and progression. Preclinical evidence and meta-analysis data demonstrate that melanoma shows a positive response to β-adrenoceptor blockers and in particular to propranolol acting mainly at β₁ - and β₂ -adrenoceptors. Although evidence suggesting that β₃ -adrenoceptors may play a role as a therapeutic target in infantile haemangiomas has been recently reviewed, a comprehensive analysis of the data available from preclinical studies supporting a possible role of β₃ -adrenoceptors in melanoma was not available. Here, we review data from the literature demonstrating that propranolol may be effective at counteracting melanoma growth, and we provide preclinical evidence that β₃ -adrenoceptors may also play a role in the pathophysiology of melanoma, thus opening the door for further clinical assays trying to explore β₃ -adrenoceptor blockers as novel alternatives for its treatment. LINKED ARTICLES: This article is part of a themed section on Adrenoceptors-New Roles for Old Players. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.14/issuetoc.

Norepinephrine inhibits the cytotoxicity of NK92‑MI cells via the β2‑adrenoceptor/cAMP/PKA/p‑CREB signaling pathway

Norepinephrine (NE) can regulate natural killer (NK) cell activity, but the mechanism remains unclear. In the present study the roles of adrenergic receptors (ARs) in inhibiting NK92‑MI cells‑mediated cytotoxicity by NE were investigated. To examine the effect of NE on NK92‑MI cytotoxicity, a lactate dehydrogenase‑release cytotoxicity assay was used to determine the cytotoxicity of NK92‑MI cells against K562 cells. To evaluate the possible function of the α, β1 and β2 AR in mediating NE‑induced effects, NK92‑MI cells were pre‑incubated with phenol‑amine, CGP20712A and ICI118551 prior to stimulation by NE. To evaluate the role of cyclic adenosine monophosphate (cAMP)‑protein kinase A (PKA) signaling pathway in the inhibitory effect on cytotoxicity of NK92‑MI cell by NE, NK92‑MI cells were pre‑incubated with PKA inhibitor Rp‑8‑Br‑cAMP prior to stimulation by NE. It was demonstrated that NE decreased cytotoxicity and downregulated the expression of perforin, granzyme B and interferon (IFN)‑γ of NK92‑MI cells in a dose‑dependent manner. Blocking NE functional receptors by ARs antagonists, particularly of β2 AR antagonist, suppressed the inhibitory effect of NE on cytotoxicity and expression of perforin, granzyme B, IFN‑γ of NK92‑MI cells significantly. Blockade of β2 AR in NE treated NK92‑MI cells resulted in a reduction of the expression of phosphorylated (p)‑cAMP‑responsive element‑binding protein (CREB) and intracellular cAMP concentration. Inhibiting the activity of PKA by Rp‑8‑Br‑cAMP in NE treated NK92‑MI cells resulted in increased cytotoxicity. The results of the present study suggest that NE can inhibit cytotoxicity and expression of perforin, granzyme B, IFN‑γ of NK92‑MI cell mainly via the β2‑AR/cAMP/PKA/p‑CREB signaling pathway.

Role of the Nervous System in Tumor Angiogenesis

The development of cancer involves an intricate process, wherein many identified and unidentified factors play a role. Tumor angiogenesis, growth of new blood vessels, is one of the major prerequisites for tumor growth as tumor cells rely on adequate oxygen and nutrient supply as well as the removal of waste products. Growth factors including VEGF orchestrate the development of angiogenesis. In addition, nervous system via the release of neurotransmitters contributes to tumor angiogenesis. The nervous system governs functional activities of many organs, and, as tumors are not independent organs within an organism, this system is integrally involved in tumor growth and progression via regulating tumor angiogenesis. Various neurotransmitters have been reported to play an important role in tumor angiogenesis.

Propranolol enhanced the anti-tumor effect of sunitinib by inhibiting proliferation and inducing G0/G1/S phase arrest in malignant melanoma

Both sunitinib, a multi-target tyrosine kinase inhibitor (TKI) and propranolol, a non-selective β-blocker, have proven therapeutic effects on malignant melanoma (MM). This study reports a synergistic effect of propranolol and sunitinib upon A375, P8 MM cell lines and mice xenografts. Cell viability assays detected a significant decrease of sunitinib IC50 in combination with propranolol, which was confirmed by a colony formation assay. Western blot showed that propranolol and sunitinib combination significantly down-regulated phospho-Rb, phospho-ERK, Cyclin D1, and Cyclin E, but had no effect on Bax, Bcl-2, or cleaved PARP expression. The average tumor size of propranolol and low-dose sunitinib (Sun L) combination treated mice was reduced and similar to high-dose sunitinib treated A375 xenografts. The Ki67 index was significantly reduced in propranolol and Sun L combination treated group compared with single Sun L treated group. This synergistic effect between propranolol and sunitinib to inhibit MM proliferation was through suppressing ERK/Cyclin D1/Rb/Cyclin E pathways and inducing G0/G1/S phase arrest, rather than by inducing tumor cell apoptosis.

Effects of trauma, hemorrhagic shock, and chronic stress on lung vascular endothelial growth factor

BACKGROUND

Vascular endothelial growth factor (VEGF) and its receptors (VEGFR-1 and VEGFR-2) regulate vascular permeability and endothelial cell survival. We hypothesized that hemorrhagic shock (HS) and chronic stress (CS) would increase expression of lung VEGF and its receptors, potentiating pulmonary edema in lung tissue.

MATERIALS AND METHODS

Male Sprague-Dawley rats aged 8-9 wk were randomized: naïve control, lung contusion (LC), LC followed by HS (LCHS), and LCHS with CS in a restraint cylinder for 2 h/d (LCHS/CS). Animals were sacrificed on days 1 and 7. Expressions of lung VEGF, VEGFR-1, and VEGFR-2 were determined by polymerase chain reaction. Lung Injury Score (LIS) was graded on light microscopy by inflammatory cell counts, interstitial edema, pulmonary edema, and alveolar integrity (range: 0 = normal; 8 = severe injury).

RESULTS

Seven days after LC, lung VEGF and VEGFR-1 were increased, and lung tissue healed (LIS: 0.8 ± 0.8). However, 7 d after LCHS and LCHS/CS, lung VEGF and VEGFR-1 expressions were decreased. VEGFR-2 was also decreased after LCHS/CS. LIS was elevated 7 d after LCHS and LCHS/CS (6.5 ± 1.0 and 8.2 ± 0.8). Increased LIS after LCHS and LCHS/CS was because of higher inflammatory cell counts, increased interstitial edema, and loss of alveolar integrity, whereas pulmonary edema was unchanged.

CONCLUSIONS

Elevation of lung VEGF and VEGFR-1 expressions after LC alone was associated with healing of injured lung tissue. Expressions of VEGF, VEGFR-1, and VEGFR-2 were reduced after LCHS and LCHS/CS, and injured lung tissue did not heal. Persistent lung injury after severe trauma was because of inflammation rather than pulmonary edema.

Stress, catecholaminergic system and cancer

Stress as a modern civilization factor significantly affects our lives. While acute stress might have a positive effect on the organism, chronic stress is usually detrimental and might lead to serious health complications. It is known that stress induced by the physical environment (temperature-induced cold stress) can significantly impair the efficacy of cytotoxic chemotherapies and the anti-tumor immune response. On the other hand, epidemiological evidence has shown that patients taking drugs known as β-adrenergic antagonists ("β-blockers"), which are commonly prescribed to treat arrhythmia, hypertension, and anxiety, have significantly lower rates of several cancers. In this review, we summarize the current knowledge about catecholamines as important stress hormones in tumorigenesis and discuss the use of β-blockers as the potential therapeutic agents.

Adrenergic receptor β2 activation by stress promotes breast cancer progression through macrophages M2 polarization in tumor microenvironment

Stress and its related hormones epinephrine (E) and norepinephrine (NE) play a crucial role in tumor progression. Macrophages in the tumor microenvironment (TME) polarized to M2 is also a vital pathway for tumor deterioration. Here, we explore the underlying role of macrophages in the effect of stress and E promoting breast cancer growth. It was found that the weight and volume of tumor in tumor bearing mice were increased, and dramatically accompanied with the rising E level after chronic stress using social isolation. What is most noteworthy, the number of M2 macrophages inside tumor was up-regulated with it. The effects of E treatment appear to be directly related to the change of M2 phenotype is reproduced in vitro. Moreover, E receptor ADRβ2 involved in E promoting M2 polarization was comprehended simultaneously. Our results imply psychological stress is influential on specific immune system, more essential for the comprehensive treatment against tumors. [BMB Reports 2015; 48(5): 295-300]

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.

Tivantinib induces G2/M arrest and apoptosis by disrupting tubulin polymerization in hepatocellular carcinoma

BACKGROUND

Tivantinib has been described as a highly selective inhibitor of MET and is currently in a phase III clinical trial for the treatment of hepatocellular carcinoma (HCC). However, the mechanism of tivantinib anti-tumor effect has been questioned by recent studies.

RESULTS

We show that tivantinib indiscriminately inhibited MET dependent and independent HCC cells proliferation. In contrast, other MET inhibitors, JNJ-38877605 and PHA-665752, just specifically inhibited the growth of MET dependent HCC cells. Tivantinib neither inhibit constitutive MET phosphorylation nor HGF-induced MET phosphorylation in HCC cells. In the microtubule polymerization analysis, tivantinib affected microtubule dynamics by a mechanism as a microtubule depolymerizer. Interesting, unlike other microtubule-targeting agents, paclitaxel and vincristine, tivantinib showed similar anti-proliferative activity in parental and multidrug-resistant cells. Further studies demonstrated that tivantinib induced a G2/M arrest and promoted apoptosis by both intrinsic and extrinsic pathway. The in vivo efficacy evaluation showed that tivantinib exhibited a good anti-tumor growth activity with anti-proliferative and pro-apoptotic effects.

CONCLUSIONS

The potent anti-tumor activity of tivantinib in HCC was achieved by targeting microtubule. Tivantinib treatment for patients with HCC should not be selected based on MET status.

Norepinephrine induced epithelial-mesenchymal transition in HT-29 and A549 cells in vitro

PURPOSE

Norepinephrine (NE) has been implicated in epithelial-mesenchymal transition (EMT) of cancer cells. However, the underlying mechanism is poorly understood. The goal of this study was to explore the effect of NE on cancer cell EMT and to investigate the potential mechanism.

METHODS

HT-29 and A549 cells were treated with NE, β-adrenergic receptor (β-AR) antagonist (propranolol) or inhibitor of transforming growth factor-β (TGF-β) receptor type I kinase (Ly2157299). Morphology of cells was observed with optical and electron microscope and immunofluorescence staining. Cellular migration and invasion were tested with transwell migration assay and Matrigel invasion assay, respectively. TGF-β1 and cyclic adenosine monophosphate (cAMP) were quantified. EMT markers and signaling pathway were measured by RT-PCR and western blot.

RESULTS

NE stimulated TGF-β1 secretion and intracellular cAMP synthesis, induced morphological alterations in HT-29 and A549 cells, and enhanced their ability of migration and invasion. EMT markers induction was observed in NE-treated cancer cells. The effect of NE could be inhibited by propranolol or Ly2157299. β-AR/TGF-β1 signaling/p-Smad3/Snail and β-AR/TGF-β1 signaling/HIF-1α/Snail were two signaling pathways.

CONCLUSION

These findings demonstrated that TGF-β1 signaling pathway was a significant factor of NE-induced cancer cells EMT. The data also suggested that psychological stress might be a risk factor which enhances the ability of migration or invasion of cancer cells.

Sympathetic nervous system regulation of the tumour microenvironment

The peripheral autonomic nervous system (ANS) is known to regulate gene expression in primary tumours and their surrounding microenvironment. Activation of the sympathetic division of the ANS in particular modulates gene expression programmes that promote metastasis of solid tumours by stimulating macrophage infiltration, inflammation, angiogenesis, epithelial-mesenchymal transition and tumour invasion, and by inhibiting cellular immune responses and programmed cell death. Haematological cancers are modulated by sympathetic nervous system (SNS) regulation of stem cell biology and haematopoietic differentiation programmes. In addition to identifying a molecular basis for physiologic stress effects on cancer, these findings have also identified new pharmacological strategies to inhibit cancer progression in vivo.

The effect of chronic stress on anti-angiogenesis of sunitinib in colorectal cancer models

Epidemiological and experimental evidence has shown that psychological stress can propel cancer progression. However, its role in anti-angiogenic therapy is not well understood. We previously found that exogenous norepinephrine attenuated the effect of sunitinib, a multi-targeted anti-angiogenic agent, in a mouse melanoma model. Here, we further evaluated the effects of chronic stress on sunitinib therapy in colorectal cancer models. We found that chronic restraint stress markedly weakened the efficacy of sunitinib, primarily through promoting the expression of vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8) to stimulate tumor angiogenesis in vivo. This effect could be sufficiently mimicked by exogenous norepinephrine and blocked by the β-antagonist propranolol. In vitro, norepinephrine up-regulated expression of VEGF and IL-8 in sunitinib-treated cancer cells mainly through the β-adrenoceptor-cAMP-PKA signaling pathway. Norepinephrine also abrogated sunitinib-induced inhibition of cancer cell migration, but had no effect on direct anti-proliferative activity of sunitinib on cancer cells. These findings suggest that psychological stress might attenuate anti-angiogenic therapy primarily through activating beta-adrenergic signaling to promote tumor angiogenesis. It is also suggested that β-blockers might improve anti-angiogenic outcome under psychological stress.