Deleterious effects of social isolation on neuroendocrine-immune status, and cancer progression in rats.

Accumulating evidence indicates that social isolation (SI) in humans and rodents is associated with increased cancer incidence and mortality, yet mediating mechanisms remain elusive. Here, we examine the neuroendocrine and immunological consequences of SI and its short- and long-term physiological impacts in naïve and cancer-bearing rats. Findings indicate that isolated animals experienced a significant decrease in weight compared to controls. Specifically, females showed a marked weight decrease during the first week of isolation. Isolated rats had significantly higher numbers of MADB106 experimental pulmonary metastases. Although mortality rates were higher in isolated tumor-bearing rats, unexpectedly, they exhibited a reduced growth rate of orthotopically implanted MADB106 tumors. Transcriptomic analyses of these excised tumors indicated a major downregulation in the expression of various genes, including those associated with pro-metastatic processes (e.g., EMT). In naïve rats (no cancer), levels of IL-6 increased, and total IgG levels decreased under SI conditions. A mixed effect was found for TNFα, which increased in females and decreased in males. In the central nervous system, isolated rats showed altered gene expression in key brain regions associated with stress responses and social behavior. The paraventricular nucleus of the thalamus emerged as a significantly affected region, along with the bed nucleus of the stria terminalis. Changes were observed in the expression of oxytocin, serotonin, and dopamine receptors. Isolated rats also exhibited greater alterations in hypothalamic-pituitary-adrenal (HPA) axis-related regulation and an increase in plasma CORT levels. Our study highlights the profound impact of SI on metastatic processes. Additionally, the potential detrimental effects of SI on thermoregulation were discussed, emphasizing the importance of social thermoregulation in maintaining physiological stability and highlighting the need to avoid single-caging practices in research. We report neuro-immune interactions and changes in brain gene expression, highlighting the need for further research into these underlying processes to improve outcomes in animal models and potential interventions for cancer patients through increased social support.

Peri-operative individually tailored psychological intervention in breast cancer patients improves psychological indices and molecular biomarkers of metastasis in excised tumors.

Perioperative stress and inflammatory signaling can invigorate pro-metastatic molecular processes in patients' tumors, potentially worsening long-term survival. Yet, it is unknown whether pre-operative psychotherapeutic interventions can attenuate such effects. Herein, three weeks before surgery, forty women diagnosed with stage I-III invasive ductal/lobular breast carcinoma were randomized to a 6-week one-on-one psychological intervention (6 meetings with a medical psychologist and bi-weekly phone calls) versus standard nursing-staff-attention. The intervention protocol was individually tailored based on evaluation of patients' emotional, cognitive, physiological, and behavioral stress response-patterns, and also included psychoeducation regarding medical treatments and recruitment of social support. Resected primary tumors were subjected to whole-genome RNA sequencing and bioinformatic analyses, assessing a priori hypothesized cancer-relevant molecular signatures. Self-report questionnaires (BSI-18, Hope-18, MSPSS, and a stress-scale) were collected three (T1) and one (T2) week before surgery, a day before (T3) and after (T4) surgery, and three weeks (T5) and 3-months (T6) following surgery. The intervention reduced distress (GSI), depression, and somatization scores (BSI-18: p < 0.01, p < 0.05, p < 0.05; T5 vs. T1). Additionally, tumors from treated patients (vs. controls) showed: (i) decreased activity of transcription control pathways involved in adrenergic and glucocorticoid signaling (CREB, GR) (p < 0.001), pro-inflammatory signaling (NFkB) (p < 0.01), and pro-malignant signaling (ETS1, STAT and GATA families) (p < 0.001, p < 0.01, p < 0.005); (ii) increased M1 macrophage polarization (p < 0.05), and CD4+ T cell activity (p < 0.01); and an unexpected increase in epithelial-to-mesenchymal-transition (EMT) signature (p < 0.005). This is the first randomized controlled trial to show beneficial effects of a psychological perioperative intervention on tumor pro-metastatic molecular biomarkers.

Perioperative escape from dormancy of spontaneous micro-metastases: A role for malignant secretion of IL-6, IL-8, and VEGF, through adrenergic and prostaglandin signaling.

We recently showed that a minimally-invasive removal of MDA-MB-231HM primary tumors (PTs) and elimination of their secreted factors (including IL-6, IL-8, VEGF, EGF, PDGF-aa, MIF, SerpinE1, and M-CSF), caused regression of spontaneous micro-metastases into a non-growing dormant state. To explore the underlying mechanisms and potential clinical ramifications of this phenomenon, we herein used the MDA-MB-231HM human breast cancer cell-line, in-vitro, and in vivo following orthotopic implantation in immune-deficient BALB/C nu/nu mice. Employing bioluminescence imaging, we found that adding laparotomy to minimally-invasive removal of the PT caused an outbreak of micro-metastases. However, perioperative ß-adrenergic and COX-2 inhibition, using propranolol + etodolac, maintained metastatic dormancy following laparotomy. In-vitro, ß-adrenergic agonists (epinephrine or metaproterenol) and prostaglandin-E2 markedly increased MDA-MB-231HM secretion of the pro-metastatic factors IL-6, IL-8, and VEGF, whereas cortisol reduced their secretion, effects that were maintained even 12 h after the washout of these agonists. In-vivo, laparotomy elevated IL-6 and IL-8 levels in both plasma and ex-vivo PT spontaneous secretion, whereas perioperative propranolol + etodolac administration blocked these effects. Similar trends were evident for EGF and MIF. Promoter-based bioinformatics analyses of excised PT transcriptomes implicated elevated NF-kB activity and reduced IRF1 activity in the gene regulatory effects of laparotomy, and these effects were inhibited by pre-surgical propranolol + etodolac. Taken together, our findings suggest a novel mechanism of post-operative metastatic outbreak, where surgery-induced adrenergic and prostanoid signaling increase the secretion of pro-metastatic factors, including IL-6, IL-8, and VEGF, from PT and possibly residual malignant tissue, and thereby prevent residual disease from entering dormancy.

ß2-adrenergic signaling promotes higher-affinity B cells and antibodies.

Stress-induced ß2-adrenergic receptor (ß2AR) activation in B cells increases IgG secretion; however, the impact of this activation on antibody affinity and the underlying mechanisms remains unclear. In the current study, we demonstrate that stress in mice following ovalbumin (OVA) or SARS-CoV-2 RBD immunization significantly increases both serum and surface-expressed IgG binding to the immunogen, while concurrently reducing surface IgG expression and B cell clonal expansion. These effects were abolished by pharmacological ß2AR blocking or when the experiments were conducted in ß2AR -/- mice. In the second part of our study, we used single B cell sorting to characterize the monoclonal antibodies (mAbs) generated following ß2AR activation in cultured RBD-stimulated B cells from convalescent SARS-CoV-2 donors. Ex vivo ß2AR activation increased the affinities of the produced anti-RBD mAbs by 100-fold compared to mAbs produced by the same donor control cultures. Consistent with the mouse experiments, ß2AR activation reduced both surface IgG levels and the frequency of expanded clones. mRNA sequencing revealed a ß2AR-dependent upregulation of the PI3K pathway and B cell receptor (BCR) signaling through AKT phosphorylation, as well as an increased B cell motility. Overall, our study demonstrates that stress-mediated ß2AR activation drives changes in B cells associated with BCR activation and higher affinity antibodies.

Prophylactic TLR9 stimulation reduces brain metastasis through microglia activation.

Brain metastases are prevalent in various types of cancer and are often terminal, given the low efficacy of available therapies. Therefore, preventing them is of utmost clinical relevance, and prophylactic treatments are perhaps the most efficient strategy. Here, we show that systemic prophylactic administration of a toll-like receptor (TLR) 9 agonist, CpG-C, is effective against brain metastases. Acute and chronic systemic administration of CpG-C reduced tumor cell seeding and growth in the brain in three tumor models in mice, including metastasis of human and mouse lung cancer, and spontaneous melanoma-derived brain metastasis. Studying mechanisms underlying the therapeutic effects of CpG-C, we found that in the brain, unlike in the periphery, natural killer (NK) cells and monocytes are not involved in controlling metastasis. Next, we demonstrated that the systemically administered CpG-C is taken up by endothelial cells, astrocytes, and microglia, without affecting blood-brain barrier (BBB) integrity and tumor brain extravasation. In vitro assays pointed to microglia, but not astrocytes, as mediators of CpG- C effects through increased tumor killing and phagocytosis, mediated by direct microglia-tumor contact. In vivo, CpG-C-activated microglia displayed elevated mRNA expression levels of apoptosis-inducing and phagocytosis-related genes. Intravital imaging showed that CpG-C-activated microglia cells contact, kill, and phagocytize tumor cells in the early stages of tumor brain invasion more than nonactivated microglia. Blocking in vivo activation of microglia with minocycline, and depletion of microglia with a colony-stimulating factor 1 inhibitor, indicated that microglia mediate the antitumor effects of CpG-C. Overall, the results suggest prophylactic CpG-C treatment as a new intervention against brain metastasis, through an essential activation of microglia.

Spontaneous regression of micro-metastases following primary tumor excision: a critical role for primary tumor secretome.

BACKGROUND: Numerous case studies have reported spontaneous regression of recognized metastases following primary tumor excision, but underlying mechanisms are elusive. Here, we present a model of regression and latency of metastases following primary tumor excision and identify potential underlying mechanisms. RESULTS: Using MDA-MB-231HM human breast cancer cells that express highly sensitive luciferase, we monitored early development stages of spontaneous metastases in BALB/c nu/nu mice. Removal of the primary tumor caused marked regression of micro-metastases, but not of larger metastases, and in vivo supplementation of tumor secretome diminished this regression, suggesting that primary tumor-secreted factors promote early metastatic growth. Correspondingly, MDA-MB-231HM-conditioned medium increased in vitro tumor proliferation and adhesion and reduced apoptosis. To identify specific mediating factors, cytokine array and proteomic analysis of MDA-MB-231HM secretome were conducted. The results identified significant enrichment of angiogenesis, growth factor binding and activity, focal adhesion, and metalloprotease and apoptosis regulation processes. Neutralization of MDA-MB-231HM-secreted key mediators of these processes, IL-8, PDGF-AA, Serpin E1 (PAI-1), and MIF, each antagonized secretome-induced proliferation. Moreover, their in vivo simultaneous blockade in the presence of the primary tumor arrested the development of micro-metastases. Interestingly, in the METABRIC cohort of breast cancer patients, elevated expression of Serpin E1, IL-8, or the four factors combined predicted poor survival. CONCLUSIONS: These results demonstrate regression and latency of micro-metastases following primary tumor excision and a crucial role for primary tumor secretome in promoting early metastatic growth in MDA-MB-231HM xenografts. If generalized, such findings can suggest novel approaches to control micro-metastases and minimal residual disease.

Perioperative COX2 and ß-adrenergic blockade improves biomarkers of tumor metastasis, immunity, and inflammation in colorectal cancer: A randomized controlled trial.

BACKGROUND: Preclinical studies have implicated excess release of catecholamines and prostaglandins in the mediation of prometastatic processes during surgical treatment of cancer. In this study, we tested the combined perioperative blockade of these pathways in patients with colorectal cancer (CRC). METHODS: In a randomized, double-blind, placebo-controlled biomarker trial involving 34 patients, the ß-blocker propranolol and the COX2-inhibitor etodolac were administered for 20 perioperative days, starting 5 days before surgery. Excised tumors were subjected to whole genome messenger RNA profiling and transcriptional control pathway analyses. RESULTS: Drugs were well-tolerated, with minor complications in both the treatment group and the placebo group. Treatment resulted in a significant improvement (P < .05) of tumor molecular markers of malignant and metastatic potential, including 1) reduced epithelial-to-mesenchymal transition, 2) reduced tumor infiltrating CD14+ monocytes and CD19+ B cells, and 3) increased tumor infiltrating CD56+ natural killer cells. Transcriptional activity analyses indicated a favorable drug impact on 12 of 19 a priori hypothesized CRC-related transcription factors, including the GATA, STAT, and EGR families as well as the CREB family that mediates the gene regulatory impact of ß-adrenergic- and prostaglandin-signaling. Alterations observed in these transcriptional activities were previously associated with improved long-term clinical outcomes. Three-year recurrence rates were assessed for long-term safety analyses. An intent-to-treat analysis revealed that recurrence rates were 12.5% (2/16) in the treatment group and 33.3% (6/18) in the placebo group (P = .239), and in protocol-compliant patients, recurrence rates were 0% (0/11) in the treatment group and 29.4% (5/17) in the placebo group (P = .054). CONCLUSIONS: The favorable biomarker impacts and clinical outcomes provide a rationale for future randomized placebo-controlled trials in larger samples to assess the effects of perioperative propranolol/etodolac treatment on oncological clinical outcomes.

Prevention of liver metastases through perioperative acute CpG-C immune stimulation.

Following excision of colorectal tumors, metastatic disease is prevalent, primarily occurs in the liver, and is highly predictive of poor prognosis. The perioperative period is now recognized as critical in determining the incidence of postoperative metastases and long-term cancer outcomes. Thus, various perioperative prophylactic interventions are currently studied during this time frame. However, immune stimulation during the perioperative period has rarely been attempted due to specific contraindications to surgery and various adverse effects. Here, to prevent liver metastases, we perioperatively employed a TLR-9 agonist, CpG-C, which exhibits minimal pyrogenic and other adverse effects in patients. We found that marginating-hepatic (MH) cells in BALB/c mice contained high percentage of NK cells, but exhibited negligible NK cytotoxicity, as previously reported in humans. However, a single CpG-C administration (25-100 µg/mouse) doubled MH-NK cell numbers, increased NK cell activation and maturation markers (NKp46, CD11b), decreased the inhibitory NKG2A ligand, and dramatically increased MH-NK-cell cytotoxicity against the syngeneic CT26 colon cancer line. Moreover, in operated mice, this innocuous intervention also markedly improved resistance to CT26 and MC38 hepatic metastases in BALB/c and C57BL/6 mice, respectively. Beneficial effects of CpG-C were mediated through activation of MH-NK cells, as indicated by an in vivo NK depletion study. Last, CpG-C protected against surgery-induced suppression of MH-NK cytotoxicity and improved their activation indices. Thus, we suggest that systemic perioperative CpG-C treatment should be considered and studied as a novel therapeutic approach to improve long-term cancer outcomes in colorectal cancer patients.

Perioperative biobehavioral interventions to prevent cancer recurrence through combined inhibition of ß-adrenergic and cyclooxygenase 2 signaling.

Evidence suggests that excess perioperative activation of the sympathetic nervous system and the consequent release of catecholamines (ie, epinephrine and norepinephrine) in the context of cancer surgery and inflammation may significantly facilitate prometastatic processes. This review first presents biomedical processes that make the perioperative timeframe pivotal in determining long-term cancer outcomes nonproportionally to its short duration (days to weeks). Then, it analyzes the various mechanisms via which the excess release of catecholamines can facilitate the progression of cancer metastases in this context by directly affecting the malignant tissues and by regulating, via indirect pathways, immunological and other mechanisms that affect metastatic progression in the tumor microenvironment and systemically. In addition, this review addresses the need to supplement ß-adrenoreceptor blockade with cyclooxygenase 2 inhibition, especially during surgery and shortly thereafter, because similar mechanisms are simultaneously activated by surgery-induced inflammatory responses. Importantly, this review presents translational and clinical evidence showing that perioperative ß-adrenoreceptor blockade and cyclooxygenase 2 inhibition can reduce the prometastatic process and cancer recurrence, and the clinical feasibility and safety of this approach are demonstrated as well. Lastly, alternative psychophysiological approaches to the use of ß-adrenergic blockers are presented because a substantial portion of patients have medical contraindications to this pharmacological treatment. The adaptation of existing psychophysiological interventions to the perioperative period and principles for constructing new approaches are discussed and exemplified. Overall, pharmacobehavioral interventions, separately or in combination, could transform the perioperative timeframe from being a prominent facilitator of metastatic progression to an opportunity for arresting or eliminating residual disease, potentially improving long-term survival rates in cancer patients.

Deleterious synergistic effects of distress and surgery on cancer metastasis: Abolishment through an integrated perioperative immune-stimulating stress-inflammatory-reducing intervention.

The perioperative period holds disproportionate impact on long-term cancer outcomes. Nevertheless, perioperative interventions to improve long-term cancer outcomes are not clinical routines, including perioperative stress-reducing or immune-stimulating approaches. Here, mimicking the clinical setting of pre-operative distress, followed by surgery, we examined the separate and combined effects of these events on the efficacy of pre-operative immune stimulation in rats and mice, and on post-operative resistance to tumor metastasis of the syngeneic mammary adenocarcinoma MADB106 in F344 rats and the CT26 colon carcinoma in Balb/C mice. The novel immune stimulating agents, GLA-SE or CpG-C (TLR-4 and TLR-9 agonists, respectively), were employed pre-operatively. Sixteen hours of pre-operative behavioral stressors (i) lowered CpG-C induced plasma IL-12 levels, and reduced resistance to MADB106 and CT-26 experimental metastases, and (ii) worsened the deleterious effects of laparotomy on metastasis in both tumor models. In rats, these effects of pre-operative stress were further studied and successfully abolished by the glucocorticoid receptor antagonist RU-486. Additionally, in vitro studies indicated the dampening effect of corticosterone on immune stimulation. Last, we tested a perioperative integrated intervention in the context of pre-operative stress and laparotomy, based on (i) antagonizing the impact of glucocorticoids before surgery, (ii) activating anti-metastatic immunity perioperatively, and (iii) blocking excessive operative and post-operative adrenergic and prostanoid responses. This integrated intervention successfully and completely abolished the deleterious effects of stress and of surgery on post-operative resistance to experimental metastasis. Such and similar integrated approaches can be studied clinically in cancer patients.

Perioperative inhibition of ß-adrenergic and COX2 signaling in a clinical trial in breast cancer patients improves tumor Ki-67 expression, serum cytokine levels, and PBMCs transcriptome.

Catecholamines and prostaglandins are secreted abundantly during the perioperative period in response to stress and surgery, and were shown by translational studies to promote tumor metastasis. Here, in a phase-II biomarker clinical trial in breast cancer patients (n = 38), we tested the combined perioperative use of the ß-blocker, propranolol, and the COX2-inhibitor, etodolac, scheduled for 11 consecutive perioperative days, starting 5 days before surgery. Blood samples were taken before treatment (T1), on the mornings before and after surgery (T2&T3), and after treatment cessation (T4). Drugs were well tolerated. Results based on a-priori hypotheses indicated that already before surgery (T2), serum levels of pro-inflammatory IL-6, CRP, and IFNγ, and anti-inflammatory, cortisol and IL-10, increased. At T2 and/or T3, drug treatment reduced serum levels of the above pro-inflammatory cytokines and of TRAIL, as well as activity of multiple inflammation-related transcription factors (including NFκB, STAT3, ISRE), but not serum levels of cortisol, IL-10, IL-18, IL-8, VEGF and TNFα. In the excised tumor, treatment reduced the expression of the proliferation marker Ki-67, and positively affected its transcription factors SP1 and AhR. Exploratory analyses of transcriptome modulation in PBMCs revealed treatment-induced improvement at T2/T3 in several transcription factors that in primary tumors indicate poor prognosis (CUX1, THRa, EVI1, RORa, PBX1, and T3R), angiogenesis (YY1), EMT (GATA1 and deltaEF1/ZEB1), proliferation (GATA2), and glucocorticoids response (GRE), while increasing the activity of the oncogenes c-MYB and N-MYC. Overall, the drug treatment may benefit breast cancer patients through reducing systemic inflammation and pro-metastatic/pro-growth biomarkers in the excised tumor and PBMCs.

Sensory Deprivation Triggers Synaptic and Intrinsic Plasticity in the Hippocampus.

Hippocampus, a temporal lobe structure involved in learning and memory, receives information from all sensory modalities. Despite extensive research on the role of sensory experience in cortical map plasticity, little is known about whether and how sensory experience regulates functioning of the hippocampal circuits. Here, we show that 9 ± 2 days of whisker deprivation during early mouse development depresses activity of CA3 pyramidal neurons by several principal mechanisms: decrease in release probability, increase in the fraction of silent synapses, and reduction in intrinsic excitability. As a result of deprivation-induced presynaptic inhibition, CA3-CA1 synaptic facilitation was augmented at high frequencies, shifting filtering properties of synapses. The changes in the AMPA-mediated synaptic transmission were accompanied by an increase in NR2B-containing NMDA receptors and a reduction in the AMPA/NMDA ratio. The observed reconfiguration of the CA3-CA1 connections may represent a homeostatic adaptation to augmentation in synaptic activity during the initial deprivation phase. In adult mice, tactile disuse diminished intrinsic excitability without altering synaptic facilitation. We suggest that sensory experience regulates computations performed by the hippocampus by tuning its synaptic and intrinsic characteristics.

Maintaining unperturbed cerebral blood flow is key in the study of brain metastasis and its interactions with stress and inflammatory responses.

Blood-borne brain metastases are associated with poor prognosis, but little is known about the interplay between cerebral blood flow, surgical stress responses, and the metastatic process. The intra-carotid inoculation approach, traditionally used in animal studies, involves permanent occlusion of the common carotid artery (CCA). Herein we introduced a novel intra-carotid inoculation approach that avoids CCA ligation, namely - assisted external carotid artery inoculation (aECAi) - and compared it to the traditional approach in C57/BL6 mice, assessing cerebral blood flow; particle distribution; blood-brain barrier (BBB) integrity; stress, inflammatory and immune responses; and brain tumor retention and growth. Doppler flowmetry and two-photon imaging confirmed that only in the traditional approach regional and capillary cerebral blood flux were significantly reduced. Corticosterone and plasma IL-6 levels were higher in the traditional approach, splenic numbers of NK, CD3+, granulocytes, and dendritic cells were lower, and many of these indices were more profoundly affected by surgical stress in the traditional approach. BBB integrity was unaffected. Administration of spherical beads indicated that CCA ligation significantly limited brain distribution of injected particles, and inoculation of D122-LLC syngeneic tumor cells resulted in 10-fold lower brain tumor-cell retention in the traditional approach. Last, while most of the injected tumor cells were arrested in extra-cranial head areas, our method improved targeting of brain-tissue by 7-fold. This head versus brain distribution difference, commonly overlooked, cannot be detected using in vivo bioluminescent imaging. Overall, it is crucial to maintain unperturbed cerebral blood flow while studying brain metastasis and interactions with stress and inflammatory responses.

Intraoperative use of dexmedetomidine is associated with decreased overall survival after lung cancer surgery.

BACKGROUND AND AIMS: The aim is to evaluate the association between the use of intraoperative dexmedetomidine with an increase in recurrence-free survival (RFS) and overall survival (OS) after nonsmall cell lung cancer (NSCLC) surgery. MATERIAL AND METHODS: This was a propensity score-matched (PSM) retrospective study. Single academic center. The study comprised patients with Stage I through IIIa NSCLC. Patients were excluded if they were younger than 18 years. Primary outcomes of the study were RFS and OS. RFS and OS were evaluated using univariate and multivariate Cox proportional hazards models after PSM (n = 251/group) to assess the association between intraoperative dexmedetomidine use and the primary outcomes. The value of P < 0.05 was considered statistically significant. RESULTS: After PSM and adjusting for significant covariates, the multivariate analysis demonstrated no association between the use of dexmedetomidine and RFS (hazard ratio [HR] [95% confidence interval (CI)]: HR = 1.18, 95% CI: 0.91-1.53; P = 0.199). The multivariate analysis also demonstrated an association between the administration of dexmedetomidine and reduced OS (HR = 1.28, 95% CI: 1.03-1.59; P = 0.024). CONCLUSIONS: This study demonstrated that the intraoperative use of dexmedetomidine to NSCLC patients was not associated with a significant impact on RFS and but worsening OS. A randomized controlled study should be conducted to confirm the results of this study.

Perioperative treatment with the new synthetic TLR-4 agonist GLA-SE reduces cancer metastasis without adverse effects.

The use of TLR agonists as an anti-cancer treatment is gaining momentum given their capacity to activate various host cellular responses through the secretion of inflammatory cytokines and type-I interferons. It is now also recognized that the perioperative period is a window of opportunity for various interventions aiming at reducing the risk of cancer metastases-the major cause of cancer related death. However, immune-stimulatory approach has not been used perioperatively given several contraindications to surgery. To overcome these obstacles, in this study, we used the newly introduced, fully synthetic TLR-4 agonist, Glucopyranosyl Lipid-A (GLA-SE), in various models of cancer metastases, and in the context of acute stress or surgery. Without exerting evident adverse effects, a single systemic administration of GLA-SE rapidly and dose dependently elevated both innate and adaptive immunity in the circulation, lungs and the lymphatic system. Importantly, GLA-SE treatment led to reduced metastatic development of a mammary adenocarcinoma and a colon carcinoma by approximately 40-75% in F344 rats and BALB/c mice, respectively, at least partly through elevating marginating-pulmonary NK cell cytotoxicity. GLA-SE is safe and well tolerated in humans, and currently is used as an adjuvant in phase-II clinical trials. Given that the TLR-4 receptor and its signaling cascade is highly conserved throughout evolution, our current results suggest that GLA-SE may be a promising immune stimulatory agent in the context of oncological surgeries, aiming to reduce long-term cancer recurrence.

Reducing liver metastases of colon cancer in the context of extensive and minor surgeries through ß-adrenoceptors blockade and COX2 inhibition.

Liver metastases are a major cause of colorectal cancer death, and the perioperative period is believed to critically affect the metastatic process. Here we tested whether blocking excess release of catecholamines and prostaglandins during surgical procedures of different extent can reduce experimental liver metastasis of the syngeneic CT26 colon cancer in female and male BALB/c mice. Animals were either treated with the beta-blocker, propranolol, the COX-2 inhibitor, etodolac, both drugs, or vehicle. The role of NK cells in controlling CT26 hepatic metastasis and in mediating the effect of the drugs was assessed by in vivo depletion or stimulation of NK cells, using anti-asialo GM1 or CpG-C, respectively. Surgical extent was manipulated by adding laparotomy to small incision, extending surgical duration, and enabling hypothermia. The results indicated that combined administration of propranolol and etodolac, but neither drug alone, significantly improved host resistance to metastasis. These beneficial effects occurred in both minor and extensive surgeries, in both sexes, and in two tumor inoculation approaches. NK cell-mediated anti-CT26 activity is involved in mediating the beneficial effects of the drugs. Specifically, CpG-C treatment, known to profoundly activate mice marginating-hepatic NK cytotoxicity, reduced CT26 hepatic metastases; and NK-depletion increased metastases and prevented the beneficial effects of the drugs. Overall, given prevalent perioperative psychological and physiological stress responses in patients, and ample prostaglandin release by colorectal tumors and injured tissue, propranolol and etodolac could be tested clinically in laparoscopic and open colorectal surgeries, attempting to reduce patients' metastatic disease.

The misleading nature of in vitro and ex vivo findings in studying the impact of stress hormones on NK cell cytotoxicity.

In vitro and ex vivo studies assessing the impact of stress hormones on immune competence commonly replace the natural milieu of leukocytes with an artificial medium, excluding plasma factors, hormones, and cytokines. Given prevalent inconsistencies between in vitro, ex vivo, and in vivo findings, we studied whether such procedures could yield misleading outcomes regarding the impact of stress hormones on NK cell cytotoxicity (NKCC), using fresh human whole blood samples. We found that in the presence of plasma 10-30-fold higher concentrations of cortisol, epinephrine, and prostaglandin-E2 (PGE2) were required to reach suppression levels evident in the context of artificial medium. Importantly, whereas the NK suppressive effects of PGE2 occurred immediately and remained stable upon prolonged exposure, the suppressive effects of cortisol slowly increased over time. Last, to simulate the exclusion of stress factors in the ex vivo approach, we subjected whole blood to stress hormones (as occurs in vivo), and abruptly removed them. We found that the effects of epinephrine and PGE2 quickly disappeared, while the effects of cortisol persisted. Overall, these findings demonstrate the potential misleading nature of in vitro and ex vivo procedures, and specifically suggest that (i) the common in vitro findings of profound suppression of NKCC by stress hormones are overestimation of their direct effects expected in vivo; and (ii) the common ex vivo approach cannot reflect the direct in vivo suppressive effects of epinephrine and PGE2 on NKCC, while inflating the effects of glucocorticoids. Some of these fallacies may be circumvented by using non-delayed whole blood NKCC assays in humans.

In vivo suppression of NK cell cytotoxicity by stress and surgery: glucocorticoids have a minor role compared to catecholamines and prostaglandins.

Most in vitro and ex-vivo studies indicate a profound suppression of NK cell cytotoxicity (NKCC) by glucocorticoids; while catecholamines and prostaglandins were reported both to suppress and to enhance NKCC. However, methodological considerations hinder our ability to deduce from these findings to the impact of endogenous release of these factors on in vivo levels of NKCC and their implications to NK-dependent resistance to pathologies in living humans or animals. Here we used an in vivo approach that sensitively and specifically reflects NKCC in living F344 rats, based on lung clearance of NK-sensitive tumor cells (MADB106), and based on comparing effects between NK-intact and NK-depleted rats. To study the role of corticosterone, epinephrine, and prostaglandins, we administered these factors to rats, or antagonized their endogenous release following different stress paradigms or surgery. The results indicated that endogenous or exogenous elevated corticosterone levels can suppress in vivo NKCC levels, but only under some conditions, and mostly secondarily to the NK-suppressing impact of epinephrine. Specifically, corticosterone-induced NKCC suppression occurred (i) only under prolonged, but not short exposure to stress, and mainly in males; (ii) was smaller than the prominent impact of epinephrine; (iii) was mostly ascribed to corticosterone-induced potentiation of the effects of epinephrine or/and prostaglandins; and (iv) was completely abolished through antagonizing epinephrine or/and prostaglandins. Overall, these findings markedly limit the significance of stress/surgery-induced corticosterone release in the in vivo suppression of NKCC, and highlight the blockade of epinephrine or/and prostaglandins as effective and clinically feasible approaches to overcome such immuno-suppressive effects.

Impact of surgical extent and sex on the hepatic metastasis of colon cancer.

PURPOSE: Extensive oncological surgeries were previously suggested to increase cancer recurrence rates. We herein studied the impact of different surgical procedures and sex on colorectal cancer liver metastasis, employing several tumor inoculation approaches in BALB/c mice. METHODS: Experimental hepatic metastases of the syngeneic CT26 colorectal cancer line were induced either by intra-portal inoculation or intra-splenic inoculation, employing different tumor loads. Following intra-splenic inoculation, the entire spleen or an injected hemi-spleen was removed. Additionally, the magnitude of the surgical trauma accompanying the injection procedure was manipulated. RESULTS: Increasing the surgical trauma by adding laparotomy or extending the length of the surgery and hypothermia did not significantly affect the number of liver metastases or liver weight for any of the injection methods and tumor loads. The development of metastasis was significantly greater in males than in females under all conditions studied--a difference not explained by the direct effects of sex hormones on in vitro CT26 proliferation or vitality. CONCLUSION: Concurring with less controlled clinical observations, the surgical extensiveness did not significantly affect CT26 hepatic metastasis, potentially due to a ceiling effect of the surgical trauma on the metastatic process. The sexual dimorphism observed for the CT26 metastasis should be investigated in the context of surgical stress and considering anti-CT26 immunoreactivity.