Autonomic nervous system and cancer

Atrial fibrillation and ischemic stroke in cancer: the latest scientific evidence, current management, and future directions

Atrial fibrillation is the most common cardiac arrhythmia and is a major risk factor for ischemic stroke. Atrial fibrillation and ischemic stroke are major cardiovascular complications in cancer patients, who have a higher burden and worse outcomes than the general population. Clinical risk stratification scores for stroke and bleeding, commonly used in the general population to estimate thromboembolic and bleeding risk, respectively, are less well validated in cancer patients, who have historically been excluded in clinical trials. There is a lack of consensus opinion on how to effectively risk-stratify cancer patients based on the currently available tools and a need for cancer-specific scores that offer a tailored approach to each patient in order to more effectively stratify ischemic stroke and bleeding risk in this cohort of patients. Cancer-mediated physiologic changes and adverse effects of antineoplastic therapy have been implicated as etiologies of the increased risk for both atrial fibrillation and ischemic stroke. Risk stratifying scores such as CHA2DS2-VASc and HAS-BLED, commonly used in the general population, are less well validated in cancer patients. There is a need for cancer-specific scores that can more effectively stratify ischemic stroke and bleeding risk in cancer patients, although given the heterogeneity of cancers, whether a "one score fits all" is uncertain.

Investigations of In Vitro Anti-Acetylcholinesterase, Anti-Diabetic, Anti-Inflammatory, and Anti-Cancer Efficacy of Garden Cress (Lepidium sativum Linn.) Seed Extracts, as Well as In Vivo Biochemical and Hematological Assays

Background/Objectives: The current research was designed to quantify the active phyto-constituents and investigate the in vitro biological efficiency of different garden cress (Lepidium sativum Linn.) seed extracts against chronic diseases as well as the in vivo toxicities that may be induced in mice upon the administration of each extract at both studied therapeutic doses. Methods: The in vitro biological efficiency of different L. sativum extracts, such as methanolic, aqueous, acetone, and ethyl acetate extracts, was assessed. The inhibition percentage (%) and the median inhibitory concentration (IC50) values of different L. sativum extracts were estimated against acetylcholinesterase enzyme, diabetes mellitus (α-amylase and α-glucosidase enzymes), and inflammation (cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2), and 5-lipoxygenase (5-LOX) enzymes). Additionally, the median inhibitory concentration (IC50) values of different L. sativum extracts against HepG-2, Caco-2, and A549 cells were assessed using 3-(4,5-dimethythiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Moreover, the toxicities that might be induced in mice at hematological (using an automatic blood analyzer) and biochemical levels were evaluated. Results: It was found that the methanolic L. sativum extract possessed the highest in vitro biological activities compared to the other studied extracts. The inhibition percentage values of the methanolic extract were 51.34, 54.35, 44.10, 43.48, and 40.78% against acetylcholinesterase, α-amylase, α-glucosidase, protein denaturation, and proteinase enzymes, respectively. The methanolic extract also exhibited an inhibitory effect against the COX-1 (55.05%), COX-2 (57.30%), and 5-LOX (50.15%) enzymes. Additionally, the methanolic extract possesses the highest cytotoxic activity against HepG-2, Caco-2, and A549 cells, with IC50 values of 52.27, 40.73, and 37.95 μg/mL, respectively. The median lethal doses (LD50) showed that the methanolic extract was safer when administered orally, followed by aqueous and acetone, then ethyl acetate extract. It was found that methanolic, aqueous, and acetone extracts showed no alterations when administered orally at two studied doses (1/10 and 1/20 of LD50) compared to the control. Conclusions: This study concluded that the methanolic extract possessed the highest in vitro biological activities and was safer than the other studied extracts, followed by aqueous, acetone, and then ethyl acetate extract. In the future, the in vivo biological efficacy of the methanolic L. sativum extract will be evaluated, as well as an elucidation of its mechanism against chronic diseases.

Neuroscience of cancer: unraveling the complex interplay between the nervous system, the tumor and the tumor immune microenvironment

The study of the multifaceted interactions between neuroscience and cancer is an emerging field with significant implications for understanding tumor biology and the innovation in therapeutic approaches. Increasing evidence suggests that neurological functions are connected with tumorigenesis. In particular, the peripheral and central nervous systems, synapse, neurotransmitters, and neurotrophins affect tumor progression and metastasis through various regulatory approaches and the tumor immune microenvironment. In this review, we summarized the neurological functions that affect tumorigenesis and metastasis, which are controlled by the central and peripheral nervous systems. We also explored the roles of neurotransmitters and neurotrophins in cancer progression. Moreover, we examined the interplay between the nervous system and the tumor immune microenvironment. We have also identified drugs that target the nervous system for cancer treatment. In this review we present the work supporting that therapeutic agent targeting the nervous system could have significant potential to improve cancer therapy.

Neuroscience in peripheral cancers: tumors hijacking nerves and neuroimmune crosstalk

Cancer neuroscience is an emerging field that investigates the intricate relationship between the nervous system and cancer, gaining increasing recognition for its importance. The central nervous system governs the development of the nervous system and directly affects brain tumors, and the peripheral nervous system (PNS) shapes the tumor microenvironment (TME) of peripheral tumors. Both systems are crucial in cancer initiation and progression, with recent studies revealing a more intricate role of the PNS within the TME. Tumors not only invade nerves but also persuade them through remodeling to further promote malignancy, creating a bidirectional interaction between nerves and cancers. Notably, immune cells also contribute to this communication, forming a triangular relationship that influences protumor inflammation and the effectiveness of immunotherapy. This review delves into the intricate mechanisms connecting the PNS and tumors, focusing on how various immune cell types influence nerve‒tumor interactions, emphasizing the clinical relevance of nerve‒tumor and nerve‒immune dynamics. By deepening our understanding of the interplay between nerves, cancer, and immune cells, this review has the potential to reshape tumor biology insights, inspire innovative therapies, and improve clinical outcomes for cancer patients.

Interactions between MDSCs and the Autonomic Nervous System: Opportunities and Challenges in Cancer Neuroscience

Myeloid-derived suppressor cells (MDSC) are a population of heterogeneous immune cells that are involved in precancerous conditions and neoplasms. The autonomic nervous system (ANS), which is composed of the sympathetic nervous system and the parasympathetic nervous system, is an important component of the tumor microenvironment that responds to changes in the internal and external environment mainly through adrenergic and cholinergic signaling. An abnormal increase of autonomic nerve density has been associated with cancer progression. As we discuss in this review, growing evidence indicates that sympathetic and parasympathetic signals directly affect the expansion, mobilization, and redistribution of MDSCs. Dysregulated autonomic signaling recruits MDSCs to form an immunosuppressive microenvironment in chronically inflamed tissues, resulting in abnormal proliferation and differentiation of adult stem cells. The two components of the ANS may also be responsible for the seemingly contradictory behaviors of MDSCs. Elucidating the underlying mechanisms has the potential to provide more insights into the complex roles of MDSCs in tumor development and lay the foundation for the development of novel MDSC-targeted anticancer strategies.

The Mechanisms Underlying the Beneficial Impact of Aerobic Training on Cancer-Related Fatigue: A Conceptual Review

Cancer-related fatigue (CRF) is a prevalent and persistent issue affecting cancer patients, with a broad impact on their quality of life even years after treatment completion. The precise mechanisms underlying CRF remain elusive, yet its multifaceted nature involves emotional, physical, and cognitive dimensions. The absence of effective medical treatments has prompted researchers to explore integrative models for potential insights. Notably, physical exercise emerges as a promising strategy for managing CRF and related symptoms, as studies showed a reduction in CRF ranging from 19% to 40%. Current recommendations highlight aerobic training at moderate intensity as beneficial, although questions about a dose-response relationship and the importance of exercise intensity persist. Despite the positive impact of exercise on CRF, the underlying mechanisms remain elusive. This review aims to provide a theoretical model explaining how aerobic exercise may alleviate CRF. Focusing on acute exercise effects, this review delves into the potential influence on peripheral and neural inflammation, immune function dysregulation, and neuroendocrine system disruptions. The objective is to enhance our understanding of the intricate relationship between exercise and CRF, ultimately paving the way for tailored interventions and potential pharmacological treatments for individuals unable to engage in physical exercise.

Prediction models for lymph node metastasis in cervical cancer based on preoperative heart rate variability

Background

The occurrence of lymph node metastasis (LNM) is one of the critical factors in determining the staging, treatment and prognosis of cervical cancer (CC). Heart rate variability (HRV) is associated with LNM in patients with CC. The purpose of this study was to validate the feasibility of machine learning (ML) models constructed with preoperative HRV as a feature of CC patients in predicting CC LNM.

Methods

A total of 292 patients with pathologically confirmed CC admitted to the Department of Gynecological Oncology of the First Affiliated Hospital of Bengbu Medical University from November 2020 to September 2023 were included in the study. The patient' preoperative 5-min electrocardiogram data were collected, and HRV time-domain, frequency-domain and non-linear analyses were subsequently performed, and six ML models were constructed based on 32 parameters. Model performance was assessed using the area under the receiver operating characteristic curve (AUC), accuracy, sensitivity, and specificity.

Results

Among the 6 ML models, the random forest (RF) model showed the best predictive performance, as specified by the following metrics on the test set: AUC (0.852), accuracy (0.744), sensitivity (0.783), and specificity (0.785).

Conclusion

The RF model built with preoperative HRV parameters showed superior performance in CC LNM prediction, but multicenter studies with larger datasets are needed to validate our findings, and the physiopathological mechanisms between HRV and CC LNM need to be further explored.

Neurorehabilitation for Adults with Brain and Spine Tumors

Central nervous system (CNS) malignancies (i.e. brain and spine tumors) and their treatments can result in a multitude of neurologic deficits. Patients with CNS malignancies experience physical, cognitive, and psychosocial sequelae that can impact their mobility and quality of life. Neurorehabilitation can play a critical role in maintaining independence, preventing disability, and optimizing safety with activities of daily living. This review provides an overview of the neurorehabilitation approaches for patients with CNS malignancies, neurologic impairments frequently treated, and rehabilitation interventions in various health care settings. In addition, we will highlight rehabilitative outcomes between patients with nononcologic neurologic conditions compared to brain and spine tumors. Finally, we address medical challenges that may impact rehabilitation care in these medically complex cancer patients.

Prognostic role of short-term heart rate variability and deceleration/acceleration capacities of heart rate in extensive-stage small cell lung cancer

Background: Prior research suggests that autonomic modulation investigated by heart rate variability (HRV) might act as a novel predictive biomarker for cancer prognosis, such as in breast cancer and pancreatic cancer. It is not clear whether there is a correlation between autonomic modulation and prognosis in patients with extensive-stage small cell lung cancer (ES-SCLC). Therefore, the purpose of the study was to examine the association between short-term HRV, deceleration capacity (DC) and acceleration capacity (AC) of heart rate and overall survival in patients with ES-SCLC. Methods: We recruited 40 patients with ES-SCLC, and 39 were included in the final analysis. A 5-min resting electrocardiogram of patients with ES-SCLC was collected using a microelectrocardiogram recorder to analyse short-term HRV, DC and AC. The following HRV parameters were used: standard deviation of the normal-normal intervals (SDNN) and root mean square of successive interval differences (RMSSD). Overall survival of patients with ES-SCLC was defined as time from the date of electrocardiogram measurement to the date of death or the last follow-up. Follow-up was last performed on 07 June 2023. There was a median follow-up time of 42.2 months. Results: Univariate analysis revealed that the HRV parameter SDNN, as well as DC significantly predicted the overall survival of ES-SCLC patients (all p < 0.05). Multivariate analysis showed that the HRV parameters SDNN (hazard ratio = 5.254, 95% CI: 1.817-15.189, p = 0.002), RMSSD (hazard ratio = 3.024, 95% CI: 1.093-8.372, p = 0.033), as well as DC (hazard ratio = 3.909, 95% CI: 1.353-11.293, p = 0.012) were independent prognostic factors in ES-SCLC patients. Conclusion: Decreased HRV parameters (SDNN, RMSSD) and DC are independently associated with shorter overall survival in ES-SCLC patients. Autonomic nervous system function (assessed based on HRV and DC) may be a new biomarker for evaluating the prognosis of patients with ES-SCLC.

The natural chalcone cardamonin selectively induces apoptosis in human neuroblastoma cells

Neuroblastoma is the most common extracranial malignant tumor in childhood. Approximately 60% of all patients are classified as high-risk and require intensive treatment including non-selective chemotherapeutic agents leading to severe side effects. Recently, phytochemicals like the natural chalcone cardamonin (CD) have gained attention in cancer research. For the first time, we investigated the selective anti-cancer effects of CD in SH-SY5Y human neuroblastoma cells compared to healthy (normal) fibroblasts (NHDF). Our study revealed selective and dose-dependent cytotoxicity of CD in SH-SY5Y. The natural chalcone CD specifically altered the mitochondrial membrane potential (ΔΨm), as an early marker of apoptosis, in human neuroblastoma cells. Caspase activity was also selectively induced and the amount of cleaved caspase substrates such as PARP was thus increased in human neuroblastoma cells. CD-mediated apoptotic cell death was rescued by pan caspase inhibitor Z-VAD-FMK. The natural chalcone CD selectively induced apoptosis, the programmed cell death, in SH-SY5Y human neuroblastoma cells whereas NHDF being a model for normal (healthy) cells were unaffected. Our data indicates a clinical potential of CD in the more selective and less harmful treatment of neuroblastoma.

High-dose Chemotherapy Impairs Cardiac Autonomic Control of Hospitalized Cancer Patients Undergoing Autologous Hematopoietic Stem Cell Transplantation

BACKGROUND

Autologous hematopoietic stem cell transplantation (HSCT) patients have intermediary and late cardiac autonomic dysfunction, which is an independent mortality predictor. However, it is unknown when this HSCT-related autonomic dysfunction begins during hospitalization for HSCT and whether cardiac autonomic control (CAC) is related to cardiotoxicity in these patients.

PATIENTS AND METHODS

CAC was assessed in 36 autologous-HSCT inpatients (HSCT group) and 23 cancer-free outpatients (CON group) using heart rate variability analysis. The HSCT group was assessed at five time-points from admission to hospital discharge during hospitalization period. The CON group was assessed once. The severity of cardiotoxicity (CTCAE 5.0) and cardiac troponin I were recorded.

RESULTS

The CAC was significantly reduced after high-dose chemotherapy (HDC) (reduction of MNN, SDNN, RMSSD, LFms² and HFnu, and increase of LFnu and LF/HF; P<0.05). At the onset of neutropenia, pNN50 and HFms² were also reduced (P<0.05) compared to the admission ones. Although both groups were similar regarding CAC at hospital admission, the HSCT patients showed impaired CAC at hospital discharge (P<0.05). The LF/HF was positively associated with cardiac troponin I and RMSSD was inversely associated with the severity of cardiotoxicity (P≤0.05).

CONCLUSION

CAC worsened during hospitalization for autologous-HSCT, mainly after HDC. In addition, it seems associated to early signs of cardiotoxicity in these patients.

Cardiovascular Dysautonomia in Patients with Breast Cancer

Breast cancer is the most frequent malignant disease among women, being responsible for a considerable percentage of fatalities and comorbidities every year. Despite advances in early detection and therapy, evidence shows that breast cancer survivors are at increased risk of developing other chronic conditions, such as cardiovascular diseases.

Autonomic dysfunction is an emerging, but poorly understood topic that has been suggested as a risk factor for cardiovascular disease in breast cancer patients. It clinically manifests through persistently elevated heart rates and abnormal heart rate variability, even before any signs of cardiovascular dysfunction appear. Since changes in the left ventricular ejection fraction only manifest when myocardial injury has already occurred, it has been hypothesized that autonomic dysfunction can constitute an early biomarker of cardiovascular impairment in breast cancer patients.

This review focuses on the direct and indirect effects of cancer and its treatment on the autonomic nervous system in breast cancer patients. We highlight the mechanisms potentially involved in cancer and antineoplastic therapy-related autonomic imbalance and review the potential strategies to prevent and/or attenuate autonomic dysfunction.

There are gaps in the current knowledge; more research in this area is needed to identify the relevance of autonomic dysfunction and define beneficial interventions to prevent cardiovascular disease in breast cancer patients.

Effectiveness of Resistance Training on Fatigue in Patients Undergoing Cancer Treatment: A Meta-Analysis of Randomized Clinical Trials

Objective. To assess the effectiveness of the resistance training to improve fatigue levels in people with cancer who are enrolled in adjuvant and/or neoadjuvant treatment. Methods. MEDLINE, Web of Science, Embase, SPORTDiscus, LILACS, CENTRAL, and CINAHL databases were searched from May to December 7, 2021. Randomized clinical trials (RCT) that evaluate the effects of resistance training on fatigue levels in people undergoing cancer treatment were included. The PEDro scale was considered to assess methodological quality of studies, and the evidence was summarized through the GRADE system. The standardized average differences, effect size, and inverse variance model for meta-analysis were calculated. Results. Fifteen RCT for qualitative synthesis and thirteen for meta-analysis were selected. A moderate to high level of evidence of resistance training was identified to improve fatigue in people undergoing cancer treatment. Meta-analysis showed a significant reduction in fatigue ( $\text{SMD}=-0.31$ , $\text{CI}95\%=-0.58$ , -0.12, $P=0.001$ ) after 10 to 35 sessions of resistance training. Conclusion. The 10 to 35 sessions of resistance training are effective in reducing fatigue level in cancer patients who are undergoing cancer treatment and have a moderate level of quality evidence.

Randomized Pilot Trial Using External Yarrow Liver Compress Applications With Metastatic Cancer Patients Suffering From Fatigue: Evaluation of Sympathetic Modulation by Heart Rate Variability Analysis

Background:

Liver compresses are commonly applied in complementary medicine during cancer treatment and are believed to have an energizing effect. We conducted a pilot study to investigate the influence of external application of yarrow liver compresses on the autonomous nervous system by analyzing the heart rate variability (HRV) in metastatic cancer patients undergoing radiation therapy and suffering from cancer-related fatigue (CRF).

Methods:

A randomized pilot trial was undertaken with patients suffering from CRF receiving palliative radiation therapy for bone or brain metastasis over 2 weeks. CRF patients were randomized into an intervention group receiving yarrow liver compresses and a control group receiving no external application. HRV was analyzed at the beginning (T1) and end (T2) period of the study during daytime (d) and nighttime (n) in both groups and quantified using time-, frequency-, and nonlinear dynamics domains.

Results:

A total of 39 patients were randomized between September 2017 and August 2019 and a total of 20 patients (10 per group) were available for analysis. For both groups, significant differences in HRV analyses were found in the comparison over the timeline between the first and second measurement (T1d→T2d) during daytime. Specifically, the intervention group showed decreased HRV and complexity of heart rate regulation, indicating increased sympathetic activity at time T2d, whereas the control group showed increased HRV and complexity of heart rate regulation, indicating increased vagal activity at time T2d. Furthermore, the observed HRV analyses showed almost no significant differences between the 2 groups in a direct comparison at the beginning and the end of the study (exception: T2d).

Conclusions:

Yarrow liver compresses led to increased sympathetic activity during daytime in the intervention group, whereas in the control group, which did not receive any external application, increased parasympathetic activity was observed.

Heart Rate Variability is an Independent Predictor of Lymph Node Metastasis in Patients with Cervical Cancer

Purpose

Heart rate variability (HRV) has been reported as a useful biomarker for prognostic factors in a variety of cancers. The purpose of this study was to explore the predictive value of preoperative HRV for lymph node metastasis (LNM) in patients with cervical cancer (CC).

Patients and Methods

A total of 77 patients with CC were included, including 18 LNM and 59 non-LNM patients. A five-minute resting electrocardiogram (ECG) was collected before surgery for the analysis of HRV time domain, frequency domain and Poincaré plot parameters (ie, SDNN, RMSSD, LF, HF, LF/HF, SD1, SD2 and SD2/SD1). Student’s t-tests and logistic regression were performed to determine the relationship between HRV and LNM.

Results

The LNM group had significantly lower SDNN, LF, and SD2 than the non-LNM group (all p < 0.05; all Cohen’s d > 0.5). Binary logistic regression analysis indicated that SDNN, LF and SD2 were still significantly associated with LNM. Specifically, for each 1 ms decrease in SDNN and SD2 and each 1 logarithmic unit decrease in ln (LF), the odds of LNM increased by 12%, 9%, and 86%, respectively (all p < 0.05).

Conclusion

These findings suggest an association between HRV and CC LNM, and HRV could be a potential noninvasive biomarker for the prediction of LNM in CC patients.

Relationship between Heart Rate Variability and Functional Fitness in Breast Cancer Survivors: A Cross-Sectional Study

Background: Breast cancer is the most common malignancy among women worldwide. The treatments may also cause neuromuscular and skeletal disorders; therefore, the aim of this study was to verify the existence of a relationship between heart rate variability and different functional fitness parameters in women survivors of breast cancer. Methods: This cross-sectional study included 25 women survivors of breast cancer, with a mean ± SD age, height, and body mass of 50.8 ± 8.8 years, 1.6 ± 0.7 m, and 67.1 ± 12.3 kg, respectively. Patients underwent measurements of heart rate variability with time and frequency domain analyses, as well as a “30 s chair-stand test”, “6 min walking test”, “timed up and go test”, and “ball throwing test”. Results: A multiple linear regression analysis showed that from the heart rate variability frequency domain, high frequency explained 21% (R² = 0.21) of the “30 s chair-stand test” performance. Conclusion: The findings of this study highlight high frequency as a predictor of “30 s chair-stand test” performance, regardless of age and time after diagnosis, suggesting its usefulness as a clinical indicator of functionality in breast cancer survivors. This study presents a straightforward and non-invasive methodology predicting functional fitness in women breast cancer survivors potentially applicable to clinical practice.

Can Exercise Reduce the Autonomic Dysfunction of Patients With Cancer and Its Survivors? A Systematic Review and Meta-Analysis

Background: Cancer therapies have increased patient survival rates, but side effects such as cardiotoxicity and neurotoxicity can lead to autonomic nervous and cardiovascular system dysfunction. This would result in a decrease in parasympathetic activity and the enhancement of sympathetic activity. Heart rate variability (HRV), which reflects autonomic modulation, is a valuable physiological tool since it correlates with cancer-related fatigue, stress, depression, and mortality in patients with cancer.

Objective: This study aimed to analyze the effects of exercise programs on the autonomic modulation, measured by the HRV of patients with cancer and its survivors.

Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed, and the quality of the articles was assessed with the Physiotherapy Evidence Database (PEDro) scale. The meta-analysis statistic procedure was performed by using RevMan software version 5.3.

Results: From the 252 articles found, six studies were included in the review involving 272 participants aged 30–75 years. Exercise programs had a mean length of 10.4 ± 4.6 weeks, a frequency of 3 ± 1.4 days/week, and a mean duration of 78 ± 23.9 min. In time-domain HRV measures, exercise may increase in the SD of normal-to-normal intervals [p < 0.00001, with a mean difference (MD) of 12.79 ms from 9.03 to 16.55] and a decreased root mean square of successive R–R interval differences (p = 0.002, with an MD of 13.08 ms from 4.90 to 21.27) in comparison with control groups (CG). The frequency-domain data reveal that the exercise group (EG) improve significantly more than the CGs in low frequency [absolute power: p < 0.0001, with a standardized mean difference (SMD) of 0.97 from 0.61 to 1.34; relative power: p = 0.04, with an MD = −7.70 from −15.4 to −0.36], high-frequency [absolute power: p = 0.001, with a SMD of 1.49 from 0.32 to 2.66; relative power: p = 0.04, with an MD of 8.00 normalized units (n.u.) from 0.20 to 15.80], and low-to-high frequency ratio (p = 0.007 with an MD of −0.32 from −0.55 to −0.09).

Conclusion: Exercise programs could lead to positive effects on the autonomic modulation of patients with cancer and its survivors. More beneficial changes may occur with resistance and endurance workouts. However, due to the low number of interventions performed, further research is needed to substantiate the findings and to provide additional insights regarding the exercise intensity required to increase the autonomic modulation of the patient.

Interactive regulation of laryngeal cancer and neuroscience

Nerve fibres are distributed throughout the body along with blood and lymphatic vessels. The intrinsic morphological characteristics of nerves and the general characteristics of secretions in the tumour microenvironment provide a solid theoretical basis for exploring how neuronal tissue can influence the progression of laryngeal cancer (LC). The central nervous system (CNS) and the peripheral nervous system (PNS) jointly control many aspects of cancer and have attracted widespread attention in the study of the progression, invasion and metastasis of tumour tissue banks. Stress activates the neuroendocrine response of the human hypothalamus-pituitary-adrenal (HPA) axis. LC cells induce nerve growth in the microenvironment by releasing neurotrophic factors (NTFs), and they can also stimulate neurite formation by secreting axons and axon guides. Conversely, nerve endings secrete factors that attract LC cells; this is known as perineural invasion (PNI) and promotes the progression of the associated cancer. In this paper, we summarize the systematic understanding of the role of neuroregulation in the LC tumour microenvironment (TME) and ways in which the TME accelerates nerve growth, which is closely related to the occurrence of LC.

Sympathetic and parasympathetic innervation in cancer: therapeutic implications

PURPOSE

The autonomic nervous system, consisting of sympathetic and parasympathetic/vagal nerves, is known to control the functions of any organ, maintaining whole-body homeostasis under physiological conditions. Recently, there has been increasing evidence linking sympathetic and parasympathetic/vagal nerves to cancers. The present review aimed to summarize recent developments from studies addressing the relationship between sympathetic and parasympathetic/vagal nerves and cancer behavior.

METHODS

Literature review.

RESULTS

Human and animal studies have revealed that sympathetic and parasympathetic/vagal nerves innervate the cancer microenvironment and alter cancer behavior. The sympathetic nerves have cancer-promoting effects on prostate cancer, breast cancer, and melanoma. On the other hand, while the parasympathetic/vagal nerves have cancer-promoting effects on prostate, gastric, and colorectal cancers, they have cancer-suppressing effects on breast and pancreatic cancers. These neural effects may be mediated by β-adrenergic or muscarinic receptors and can be explained by changes in cancer cell behavior, angiogenesis, tumor-associated macrophages, and adaptive antitumor immunity.

CONCLUSIONS

Sympathetic nerves innervating the tumor microenvironment promote cancer progression and are related to stress-induced cancer behavior. The parasympathetic/vagal nerves have variable (promoting or suppressing) effects on different cancer types. Approaches directed toward the sympathetic and parasympathetic/vagal nerves can be developed as a new cancer therapy. In addition to existing pharmacological, surgical, and electrical approaches, a recently developed virus vector-based genetic local neuroengineering technology is a powerful approach that selectively manipulates specific types of nerve fibers innervating the cancer microenvironment and leads to the suppression of cancer progression. This technology will enable the creation of "cancer neural therapy" individually tailored to different cancer types.

Targeting pheochromocytoma/paraganglioma with polyamine inhibitors

BACKGROUND

Pheochromocytomas (PCCs) and paragangliomas (PGLs) are neuroendocrine tumors that are mostly benign. Metastatic disease does occur in about 10% of cases of PCC and up to 25% of PGL, and for these patients no effective therapies are available. Patients with mutations in the succinate dehydrogenase subunit B (SDHB) gene tend to have metastatic disease. We hypothesized that a down-regulation in the active succinate dehydrogenase B subunit should result in notable changes in cellular metabolic profile and could present a vulnerability point for successful pharmacological targeting.

METHODS

Metabolomic analysis was performed on human hPheo1 cells and shRNA SDHB knockdown hPheo1 (hPheo1 SDHB KD) cells. Additional analysis of 115 human fresh frozen samples was conducted. In vitro studies using N¹,N¹¹-diethylnorspermine (DENSPM) and N¹,N¹²- diethylspermine (DESPM) treatments were carried out. DENSPM efficacy was assessed in human cell line derived mouse xenografts.

RESULTS

Components of the polyamine pathway were elevated in hPheo1 SDHB KD cells compared to wild-type cells. A similar observation was noted in SDHx PCC/PGLs tissues compared to their non-mutated counterparts. Specifically, spermidine, and spermine were significantly elevated in SDHx-mutated PCC/PGLs, with a similar trend in hPheo1 SDHB KD cells. Polyamine pathway inhibitors DENSPM and DESPM effectively inhibited growth of hPheo1 cells in vitro as well in mouse xenografts.

CONCLUSIONS

This study demonstrates overactive polyamine pathway in PCC/PGL with SDHB mutations. Treatment with polyamine pathway inhibitors significantly inhibited hPheo1 cell growth and led to growth suppression in xenograft mice treated with DENSPM. These studies strongly implicate the polyamine pathway in PCC/PGL pathophysiology and provide new foundation for exploring the role for polyamine analogue inhibitors in treating metastatic PCC/PGL. PRéCIS: Cell line metabolomics on hPheo1 cells and PCC/PGL tumor tissue indicate that the polyamine pathway is activated. Polyamine inhibitors in vitro and in vivo demonstrate that polyamine inhibitors are promising for malignant PCC/PGL treatment. However, further research is warranted.

Dietary Fat and Cancer-Which Is Good, Which Is Bad, and the Body of Evidence

A high-fat diet (HFD) induces changes in gut microbiota leading to activation of pro-inflammatory pathways, and obesity, as a consequence of overnutrition, exacerbates inflammation, a known risk factor not only for cancer. However, experimental data showed that the composition of dietary fat has a greater impact on the pathogenesis of cancer than the total fat content in isocaloric diets. Similarly, human studies did not prove that a decrease in total fat intake is an effective strategy to combat cancer. Saturated fat has long been considered as harmful, but the current consensus is that moderate intake of saturated fatty acids (SFAs), including palmitic acid (PA), does not pose a health risk within a balanced diet. In regard to monounsaturated fat, plant sources are recommended. The consumption of plant monounsaturated fatty acids (MUFAs), particularly from olive oil, has been associated with lower cancer risk. Similarly, the replacement of animal MUFAs with plant MUFAs decreased cancer mortality. The impact of polyunsaturated fatty acids (PUFAs) on cancer risk depends on the ratio between ω-6 and ω-3 PUFAs. In vivo data showed stimulatory effects of ω-6 PUFAs on tumour growth while ω-3 PUFAs were protective, but the results of human studies were not as promising as indicated in preclinical reports. As for trans FAs (TFAs), experimental data mostly showed opposite effects of industrially produced and natural TFAs, with the latter being protective against cancer progression, but human data are mixed, and no clear conclusion can be made. Further studies are warranted to establish the role of FAs in the control of cell growth in order to find an effective strategy for cancer prevention/treatment.

Beyond the tumour microenvironment

In contrast to the once dominant tumour-centric view of cancer, increasing attention is now being paid to the tumour microenvironment (TME), generally understood as the elements spatially located in the vicinity of the tumour. Thinking in terms of TME has proven extremely useful, in particular because it has helped identify and comprehend the role of nongenetic and noncell-intrinsic factors in cancer development. Yet some current approaches have led to a TME-centric view, which is no less problematic than the former tumour-centric vision of cancer, insofar as it tends to overlook the role of components located beyond the TME, in the 'tumour organismal environment' (TOE). In this minireview, we highlight the explanatory and therapeutic shortcomings of the TME-centric view and insist on the crucial importance of the TOE in cancer progression.