The role of neurokinin-1 receptor in the microenvironment of inflammation and cancer

Expression of substance P, neurokinin 1 receptor, Ki-67 and pyruvate kinase M2 in hormone receptor negative breast cancer and evaluation of impact on overall survival

BACKGROUND

Chronic inflammation is a hallmark of cancer, and it can be stimulated by many factors. Substance P (SP), through binding to neurokinin 1 receptor (NK1R), and pyruvate kinase M2 (PKM2) play critical roles in cancer development and progression via modulating the tumor microenvironment. This study aimed to investigate the prognostic significance of SP and PKM2 in combination with NK1R and Ki-67 in hormone receptor negative (HR-ve) breast cancer.

METHODS

Immunohistochemical expression levels of SP, NK1R, PKM2, and Ki-67 were measured in 144 paraffin-embedded breast cancer tissues (77 h -ve and 67 h + ve). SP, NK1R, and PKM2 were scored semiquantitatively, while Ki-67 was obtained by the percentage of total number of tumor cells with nuclear staining. The optimal cutoff value for SP, NK1R, PKM2, and Ki-67 were assessed by Cutoff Finder.

RESULTS

High SP expression in HR -ve breast cancer was associated with TNM stage (p = 0.020), pT stage (p = 0.035), pN stage (p = 0.002), axillary lymph node metastasis (p = 0.003), and NK1R expression level (p = 0.010). In HR + ve breast cancer, SP expression was associated with HER2 status (p = 0.001) and PKM2 expression level (p = 0.012). Regarding PKM2 expression level, it significantly associated with HER2 status (p = 0.001) and history of DCIS (p = 0.046) in HR-ve tumors, and with HER2 status (p < 0.001) and SP expression level (p = 0.012) in HR + ve tumors. Survival analysis revealed that high SP level negatively impacted overall survival in HR-ve tumors that had low NK1R level (p = 0.021). Moreover, high SP negatively impacted overall survival in HR-ve tumors that had low Ki-67 level (p = 0.005). High PKM2 negatively impacted overall survival in HR-ve cases with low SP (p = 0.047).

CONCLUSION

Combined expression levels of SP with NK1R or Ki-67, and PKM2 with SP could be used to predict survival in breast cancer patients with HR-ve tumors. Our findings suggest a role of SP/NK1R pathway and PKM2 in HR-ve breast cancer pathogenesis which should be further investigated to unveil the underlying molecular mechanisms.

Preparation and Characterization of Aprepitant Solid Dispersion with HPMCAS-LF

This study focused on improving the physicochemical characteristics of aprepitant with poor water solubility by preparing solid dispersion (SD). To prepare the SD with HPMCAS-LF, the solvent evaporation method was applied. Based on dissolution analysis, the dissolution rate of SD increased by five times compared with aprepitant. In addition, scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), and differential scanning calorimetry (DSC) results suggested the presence of amorphous-form aprepitant inside SD. According to Fourier transform infrared (FTIR) spectroscopy, intermolecular hydrogen bonds were detected between polymer and aprepitant. The Caco-2 cell experiment proved that SD did not lower the transepithelial electrical resistance (TEER) values but improved the permeation amount of aprepitant. Additionally, the SD of aprepitant displayed excellent stability.

Upregulated expression of substance P and NK1R in blood monocytes and B cells of patients with allergic rhinitis and asthma

Increased expression of substance P (SP) and neurokinin-1 receptor (NK1R) has been noticed in patients with allergic rhinitis (AR) and allergic asthma (AA). However, little is known of the expression of SP and NK1R in monocytes and B cells of AR and AA. In the present study, the expression levels of SP and NK1R were determined by flow cytometry and mouse AR and AA models. The results showed that both percentages of SP+ monocytes and SP+ B cells, and mean fluorescence intensity (MFI) of SP in monocytes were elevated in the blood of AA and AR combined with AA (ARA) patients. Similarly, the percentages of NK1R+ monocytes were elevated in the blood of AR, AA, and ARA patients. Allergens Artemisia sieversiana wild allergen extract (ASWE), house dust mite extract (HDME), and Platanus pollen allergen extract (PPE) increased the expression density of SP molecules (determined by MFI) in an individual monocyte of AR patients. HDME and PPE appeared to enhance SP and NK1R expression in the B cells of ARA and AR patients. In the mouse AR and AA models, the percentages of NK1R+ monocytes and B cells were elevated in blood following OVA (ovalbumin) sensitization and challenge. Knocking out the FcεRI molecule completely abolished the OVA-induced upregulation of expression of NK1R in monocytes and B cells of AA mice. In conclusion, upregulated expressions of SP and NK1R may contribute to the pathogenesis of airway allergy.

The Effect of Blocking Neurokinin-1 Receptor by Aprepitant on the Inflammatory and Apoptosis Pathways in Human Ovarian Cancer Cells

Ovarian cancer is the seventh most common cancer globally, and the second most common cancer among women with significant mortality. Toward this end, it is shown that substance P (SP) is involved in tumor initiation and progression through the neurokinin-1 receptor (NK1R). However, the exact molecular mechanism of the SP/NK1R system in ovarian cancer is not yet fully clarified. In this in vitro study, we decided to investigate the effect of the SP/NK1R system and blockage of NK1R by its specific antagonist (Aprepitant) on the proliferation of ovarian cancer cells as well as the alteration of inflammatory pathways. Our results revealed that Aprepitant stimulated apoptotic cell death and attenuated inflammation of ovarian cancer cells through the NF-kB and P53 signaling pathways. After treatment with Aprepitant, the expression of downstream anti-apoptotic genes related to the NF-kB pathway (survivine and bcl2) was decreased. However, we indicated the positive effect of SP on the proliferation of ovarian cancer cells by inducing the expression of NF-kB protein and NF-kB anti-apoptotic target genes. Moreover, Pro-apoptotic p53 target genes (P21 and Bax) were increased through aprepitant treatment, while SP attenuated these genes' expression. Besides, ROS generation in ovarian cancer cells after treatment with SP induced, while blocking of NK1R with Aprepitant reduced the level of ROS generation. Given this, our data suggest that this NK1R might be used as an important therapeutic target in ovarian cancer and Aprepitant could be considered a new drug in ovarian cancer therapy.

GA&HA-Modified Liposomes for Co-Delivery of Aprepitant and Curcumin to Inhibit Drug-Resistance and Metastasis of Hepatocellular Carcinoma

Background

Tumor microenvironment (TME) plays a vital role in the development of hepatocellular carcinoma (HCC). Mounting evidence indicates that peripheral nerves could induce a shift from quiescent hepatic stellate cells (HSCs) to cancer-associated fibroblasts (CAFs) by secreting substance P (SP). The anti-tumor strategy by targeting “SP-HSCs-HCC” axis might be an effective therapy to inhibit tumor growth and metastasis.

Objective

In this study, we prepared novel liposomes (CUR-APR/HA&GA-LPs) modified with hyaluronic acid (HA) and glycyrrhetinic acid (GA) for co-delivery aprepitant (APR) and curcumin (CUR), in which APR was chosen to inhibit the activation of HSCs by blocking SP/neurokinin-1 receptor (NK-1R), and CUR was used to induce apoptosis of tumor cells.

Results

To mimic the TME, we established “SP+HSCs+HCC” co-cultured cell model in vitro. The results showed that CUR-APR/HA&GA-LPs could be taken up by CAFs and HCC simultaneously, and inhibit tumor cell migration. Meanwhile, the “SP+m-HSCs+HCC” co-implanted mice model was established to evaluate the anti-tumor effect in vivo. The results showed that CUR-APR/HA&GA-LPs could inhibit tumor proliferation and metastasis, and reduce extracellular matrix (ECM) deposition and tumor angiogenesis, indicating a superior anti-HCC effect.

Conclusion

Overall, the combination therapy based on HA&GA-LPs could be a potential nano-sized formulation for anti-HCC therapy.

The role of the PI3K/AKT signalling pathway in the corneal epithelium: recent updates

Phosphatidylinositol 3 kinase (PI3K)/AKT (also called protein kinase B, PKB) signalling regulates various cellular processes, such as apoptosis, cell proliferation, the cell cycle, protein synthesis, glucose metabolism, and telomere activity. Corneal epithelial cells (CECs) are the outermost cells of the cornea; they maintain good optical performance and act as a physical and immune barrier. Various growth factors, including epidermal growth factor receptor (EGFR) ligands, insulin-like growth factor 1 (IGF1), neurokinin 1 (NK-1), and insulin activate the PI3K/AKT signalling pathway by binding their receptors and promote antiapoptotic, anti-inflammatory, proliferative, and migratory functions and wound healing in the corneal epithelium (CE). Reactive oxygen species (ROS) regulate apoptosis and inflammation in CECs in a concentration-dependent manner. Extreme environments induce excess ROS accumulation, inhibit PI3K/AKT, and cause apoptosis and inflammation in CECs. However, at low or moderate levels, ROS activate PI3K/AKT signalling, inhibiting apoptosis and stimulating proliferation of healthy CECs. Diabetes-associated hyperglycaemia directly inhibit PI3K/AKT signalling by increasing ROS and endoplasmic reticulum (ER) stress levels or suppressing the expression of growth factors receptors and cause diabetic keratopathy (DK) in CECs. Similarly, hyperosmolarity and ROS accumulation suppress PI3K/AKT signalling in dry eye disease (DED). However, significant overactivation of the PI3K/AKT signalling pathway, which mediates inflammation in CECs, is observed in both infectious and noninfectious keratitis. Overall, upon activation by growth factors and NK-1, PI3K/AKT signalling promotes the proliferation, migration, and anti-apoptosis of CECs, and these processes can be regulated by ROS in a concentration-dependent manner. Moreover, PI3K/AKT signalling pathway is inhibited in CECs from individuals with DK and DED, but is overactivated by keratitis.

Substance P and Neurokinin 1 Receptor in Chronic Inflammation and Cancer of the Head and Neck: A Review of the Literature

Head and neck cancer is a growing worldwide public health problem, accounting for approximately 1,500,000 new cases and 500,000 deaths annually. Substance P (SP) is a peptide of the tachykinin family, which has roles related to a large number of physiological mechanisms in humans. The implications of SP in carcinogenesis have recently been reported through the stimulation of the neurokinin 1 receptor (NK1R), or directly, through the effects derived from the constitutive activation of NK1R. Consequently, SP/NK1R seems to play relevant roles in cancer, upregulating cell proliferation, cell migration and chronic inflammation, among other oncogenic actions. Furthermore, there is growing evidence pointing to a central role for SP in tumour progression, singularly so in laryngeal and oral squamous cell carcinomas. The current narrative review of the literature focuses on the relationship between the SP/NK1R system and chronic inflammation and cancer in the head-and-neck region. We described a role for SP/NK1R in the transition from chronic inflammation of the head and neck mucosa, to preneoplastic and neoplastic transformation and progression.

Investigation of the Role of Neurokinin-1 Receptor Inhibition Using Aprepitant in the Apoptotic Cell Death through PI3K/Akt/NF-κB Signal Transduction Pathways in Colon Cancer Cells

Background

Colorectal cancer (CRC) is recognized as one of the most common malignancies with a high mortality rate worldwide, supporting the necessity for an effective novel antitumor drug to improve current therapy's effectiveness. Substance P (SP) is the essential member of the tachykinins (TKs) family, which binds to the specific receptors, known as neurokinin-1 receptor (NK1R), exerting its multiple influences such as tumor cell proliferation, angiogenesis, and metastasis. Aprepitant, as a specific NK1R antagonist, is suggested as a novel antitumor agent, promoting apoptotic processes in tumor cells; however, the exact antitumor mechanism of aprepitant on molecular signaling in CRC is not entirely known.

Method

The resazurin assay was conducted to assess the cytotoxic effects of aprepitant on the viability of the CRC cell line (SW480). The level of reactive oxygen species (ROS) was measured after 24-hour treatment with SP and aprepitant. PI/annexin V-FITC staining was conducted to assess apoptosis. Also, the expression of NF-κB antiapoptotic target genes and proapoptotic p53 target genes was measured by real-time- (RT-) PCR assay. Western blotting assay was performed to determine the expression of PI3k/AKT/NF-κB proteins.

Results

We found that aprepitant stimulates apoptotic cell death and attenuates the PI3K/Akt pathway and its downstream proapoptotic target gene, including NF-κB in SW480 cells. Also, the obtained results from the quantitative RT-PCR assay showed that aprepitant could decrease the level of mRNA of NF-κB antiapoptotic target genes.

Conclusion

Towards this end, this study suggests that SP/NK1R system plays a vital role in the development of CRC, and pharmaceutical targeting of NK1R using aprepitant might be a promising treatment against CRC.

Carbohydrate-Based NK1R Antagonists with Broad-Spectrum Anticancer Activity

NK1R antagonists, investigated for the treatment of several pathologies, have shown encouraging results in the treatment of several cancers. In the present study, we report on the synthesis of carbohydrate-based NK1R antagonists and their evaluation as anticancer agents against a wide range of cancer cells. All of the prepared compounds, derived from either d-galactose or l-arabinose, have shown high affinity and NK1R antagonistic activity with a broad-spectrum anticancer activity and an important selectivity, comparable to Cisplatin. This strategy has allowed us to identify the galactosyl derivative 14α, as an interesting hit exhibiting significant NK1R antagonist effect (kinact 0.209 ± 0.103 μM) and high binding affinity for NK1R (IC50 = 50.4 nM, Ki = 22.4 nM by measuring the displacement of [125I] SP from NK1R). Interestingly, this galactosyl derivative has shown marked selective cytotoxic activity against 12 different types of cancer cell lines.

Elinzanetant (NT-814), a Neurokinin 1,3 Receptor Antagonist, Reduces Estradiol and Progesterone in Healthy Women

CONTEXT

The ideal therapy for endometriosis (EM) and uterine fibroids (UFs) would suppress estrogenic drive to the endometrium and myometrium, while minimizing vasomotor symptoms and bone loss associated with current treatments. An integrated neurokinin-kisspeptin system involving substance P and neurokinin B acting at the neurokinin (NK) receptors 1 and 3, respectively, modulates reproductive hormone secretion and represents a therapeutic target.

OBJECTIVE

This work aimed to assess the effects of the novel NK1,3 antagonist elinzanetant on reproductive hormone levels in healthy women.

METHODS

A randomized, single-blinded, placebo-controlled study was conducted in 33 women who attended for 2 consecutive menstrual cycles. In each cycle blood samples were taken on days 3 or 4, 9 or 10, 15 or 16, and 21 or 22 to measure serum reproductive hormones. In cycle 2, women were randomly assigned to receive once-daily oral elinzanetant 40, 80, 120 mg, or placebo (N = 8 or 9 per group).

RESULTS

Elinzanetant dose-dependently lowered serum luteinizing hormone, estradiol (120 mg median change across cycle: -141.4 pmol/L, P = .038), and luteal-phase progesterone (120 mg change from baseline on day 21 or 22: -19.400 nmol/L, P = .046). Elinzanetant 120 mg prolonged the cycle length by median of 7.0 days (P = .023). Elinzanetant reduced the proportion of women with a luteal-phase serum progesterone concentration greater than 30 nmol/L (a concentration consistent with ovulation) in a dose-related manner in cycle 2 (P = .002). Treatment did not produce vasomotor symptoms.

CONCLUSION

NK1,3 receptor antagonism with elinzanetant dose-dependently suppressed the reproductive axis in healthy women, with the 120-mg dose lowering estradiol to potentially ideal levels for UFs and EM. As such, elinzanetant may represent a novel therapy to manipulate reproductive hormone levels in women with hormone-driven disorders.

Seeding of breast cancer cell line (MDA-MB-231LUC+) to the mandible induces overexpression of substance P and CGRP throughout the trigeminal ganglion and widespread peripheral sensory neuropathy throughout all three of its divisions

Some types of cancer are commonly associated with intense pain even at the early stages of the disease. The mandible is particularly vulnerable to metastasis from breast cancer, and this process has been studied using a bioluminescent human breast cancer cell line (MDA-MB-231^LUC+). Using this cell line and anatomic and neurophysiologic methods in the trigeminal ganglion (TG), we examined the impact of cancer seeding in the mandible on behavioral evidence of hypersensitivity and on trigeminal sensory neurons. Growth of cancer cells seeded to the mandible after arterial injection of the breast cancer cell line in Foxn1 animals (allogeneic model) induced behavioral hypersensitivity to mechanical stimulation of the whisker pad and desensitization of tactile and sensitization of nociceptive mechanically sensitive afferents. These changes were not restricted to the site of metastasis but extended to sensory afferents in all three divisions of the TG, accompanied by widespread overexpression of substance P and CGRP in neurons through the ganglion. Subcutaneous injection of supernatant from the MDA-MB-231^LUC+ cell culture in normal animals mimicked some of the changes in mechanically responsive afferents observed with mandibular metastasis. We conclude that released products from these cancer cells in the mandible are critical for the development of cancer-induced pain and that the overall response of the system greatly surpasses these local effects, consistent with the widespread distribution of pain in patients. The mechanisms of neuronal plasticity likely occur in the TG itself and are not restricted to afferents exposed to the metastatic cancer microenvironment.

The Effects of Chemotherapeutics on the Ovarian Cancer Microenvironment

High-grade serous ovarian cancer (HGSOC) is characterized by a complex and dynamic tumor microenvironment (TME) composed of cancer-associated fibroblasts (CAFs), immune cells, endothelial cells, and adipocytes. Although most approved therapies target cancer cells, a growing body of evidence suggests that chemotherapeutic agents have an important role in regulating the biology of the diverse cells that compose the TME. Understanding how non-transformed cells respond and adapt to established therapeutics is necessary to completely comprehend their action and develop novel therapeutics that interrupt undesired tumor-stroma interactions. Here, we review the effects of chemotherapeutic agents on normal cellular components of the host-derived TME focusing on CAFs. We concentrate on therapies used in the treatment of HGSOC and synthesize findings from studies focusing on other cancer types and benign tissues. Agents such as platinum derivatives, taxanes, and PARP inhibitors broadly affect the TME and promote or inhibit the pro-tumorigenic roles of CAFs by modifying the bidirectional cross-talk between tumor and stromal cells in the tumor organ. While most chemotherapy research focuses on cancer cells, these studies emphasize the need to consider all cell types within the tumor organ when evaluating chemotherapeutics.

The Mechanisms of Action of Botulinum Toxin Type A in Nociceptive and Neuropathic Pathways in Cancer Pain

BACKGROUND

Botulinum toxin type A (BoNT-A) is widely employed for cosmetic purposes and in the treatment of certain diseases such as strabismus, hemifacial spasm and focal dystonia among others. BoNT-A effect mainly acts at the muscular level by inhibiting the release of acetylcholine at presynaptic levels consequently blocking the action potential in the neuromuscular junction. Despite the great progress in approval and pharmaceutical usage, improvement in displacing BoNT-A to other pathologies has remained very limited. Patients under diagnosis of several types of cancer experience pain in a myriad of ways; it can be experienced as hyperalgesia or allodynia, and the severity of the pain depends, to some degree, on the place where the tumor is located. Pain relief in patients diagnosed with cancer is not always optimal, and as the disease progresses, transition to more aggressive drugs, like opioids is sometimes unavoidable. In recent years BoNT-A employment in cancer has been explored, as well as an antinociceptive drug; experiments in neuropathic, inflammatory and acute pain have been carried out in animal models and humans. Although its mechanism has not been fully known, evidence has shown that BoNT-A inhibits the secretion of pain mediators (substance P, Glutamate, and calcitonin gene related protein) from the nerve endings and dorsal root ganglion, impacting directly on the nociceptive transmission through the anterolateral and trigeminothalamic systems.

AIM

The study aimed to collect available literature regarding molecular, physiological and neurobiological evidence of BoNT-A in cancer patients suffering from acute, neuropathic and inflammatory pain in order to identify possible mechanisms of action in which the BoNT-A could impact positively in pain treatment.

CONCLUSION

BoNT-A could be an important neo-adjuvant and coadjuvant in the treatment of several types of cancer, to diminish pro-tumor activity and secondary pain.

The Effect of SP/NK1R on the Expression and Activity of Catalase and Superoxide Dismutase in Glioblastoma Cancer Cells

Introduction

Glioblastoma is the most malignant brain tumor with different therapeutic protocols, including surgery, radiotherapy, and chemotherapy. Substance P (SP), a peptide released by sensory nerves, increases cellular excitability by activating the neurokinin-1 receptor (NK1R) in several human tumor cells. Aprepitant is a potent and long-lasting NK1R antagonist, considered a new agent for inhibiting proliferation and induction of apoptosis in malignant cells. This study aimed to evaluate the effects of the SP/NK1R system on the expression and activity of catalase and superoxide dismutase (SOD) in the glioblastoma U87 cancer cell line.

Methods

Cytotoxicity was measured by the resazurin test, 24 hours after treatment, with increasing aprepitant concentrations. The production of reactive oxygen species (ROS) was also measured 24 hours after treatment with SP and aprepitant. Enzymes activity of catalase and SOD was measured using the corresponding assay kits. Real-time PCR also measured their expression.

Results

Aprepitant significantly reduced the viability of U87 cells in a concentration-dependent manner. ROS production was significantly reduced, and the activity of catalase and SOD increased after treatment with aprepitant. The expression of catalase and SOD enzymes also increased significantly in the presence of aprepitant.

Conclusion

The present study showed that aprepitant inhibited SP's oxidizing effects via inducing the antioxidant effects of catalase and SOD in the U87 cell line. Therefore, this drug might be introduced as a potential candidate for controlling glioblastoma cancer in animal models and clinical trials.

Design and Application of Receptor-Targeted Fluorescent Probes Based on Small Molecular Fluorescent Dyes

In recent years, a variety of receptor-targeted fluorescent probes have been developed and widely used to realize the visualization of certain receptors, which facilitates the early diagnosis and treatment of diseases. In this Review, we focus on the recent achievements in design, chemical structure, imaging characterization, and potential applications of receptor-targeted fluorescent probes from the past 10 years. The development and application of receptor-targeted fluorescent probes will expand our knowledge of the distribution and function of disease-related receptors, shed light on the drug discovery for clinical diseases where receptors are implicated, and feed into the diagnosis and treatment of a plethora of diseases, including tumors.

Can aprepitant used for nausea and vomiting be good gastrointestinal complaints?

Aprepitant is a selective SP/NK-1 receptor antagonist and used in postoperative and chemotherapeutics induced emesis and vomiting. The aim of our study is to show aprepitant may have beneficial effects on gastrointestinal complaints in cancer patients undergoing chemotherapeutics by indomethacin-induced gastric ulcer model. A total of 48 rats were fasted 24 h for ulcer experiment. Aprepitant doses of 5, 10, 20, and 40 mg/kg were evaluated for their antiulcer activity. Omeprazole (20 mg/kg) was used as a positive control group. Six hours after 25 mg/kg indomethacin administration, all stomachs were dissected out. After macroscopic analyses, tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), COX-1, and COX-2 mRNA levels and SOD activity, and GSH and MDA levels of stomachs were determined. Histopathological examinations were evaluated. Aprepitant administration exerted 48.14%, 49.62%, 65.92%, and 76.77% ulcer inhibition effects at 5, 10, 20, and 40 mg/kg, respectively. Aprepitant administration decreased oxidative stress and inflammatory parameters in stomach tissues dose dependently. Aprepitant administration increased stomach COX-2 mRNA levels at 20 and 40 mg/kg doses. Although aprepitant appears to be disadvantageous in terms of treating gastric ulcer due to COX enzyme inhibition according to the previous studies, aprepitant has been shown to have ulcer healing effect in our study. When aprepitant is given as an anti-nausea and vomiting drug to cancer patients undergoing chemotherapy, we can argue that it will not be necessary to add a new gastric protective agent as it also shows beneficial effects in gastrointestinal complaints.

Detection of neurokinin-1 receptor by immunohistochemistry in canine mammary gland tumours

Canine mammary gland tumour (cMGT) is the most common tumour in intact female dogs. Surgery is the only effective treatment for cMGT, and dogs with metastasis at the time of diagnosis or those diagnosed at an advanced stage have poorer prognosis. Thus, novel diagnostic biomarkers and therapeutic targets are needed. Neurokinin‐1 receptor (NK‐1 receptor) is involved in cancer progression and has been detected in various malignant tumours including breast cancer in humans. Furthermore, NK‐1 receptor antagonists inhibit cancer progression. We evaluated NK‐1 receptor expression in malignant and benign cMGT compared with that in normal mammary gland tissues and analysed the relationship between the expression of NK‐1 receptor and histopathological type or malignancy grade. Specimens from 34 malignant MGT and 35 benign MGT cases were used for immunohistochemistry and scored according to intensity and percentage. Healthy margins from each tumour were used as internal controls. The scores for NK‐1 receptor intensity, percentage of positive cells and overall immunohistochemistry were higher in malignant MGT than in benign MGT and normal tissue (p < .000). NK‐1 receptor expression was not correlated with either malignancy grade or histopathological type. Expression of the NK‐1 receptor in malignant MGT was higher than that in benign MGT and normal tissues. Thus, NK‐1 receptor could be considered a novel therapeutic target for cMGT. Further studies using other quantitative tests such as western blotting or PCR and the evaluation of substance P in patient tumour tissue or serum are needed.

The NK-1R Antagonist Aprepitant Prevents LPS-Induced Oxidative Stress and Inflammation in RAW264.7 Macrophages

Background

The macrophage is one of the most important types of immune cells that protect against harmful stimuli. Macrophage activation plays a pivotal role in the progression and development of various inflammatory diseases. The neurokinin 1 receptor (NK-1R) is a G protein-coupled receptor that plays an important role in inflammatory diseases. Aprepitant is a kind of NK-1R antagonist. The purpose of this study is to determine the protective effect of aprepitant in lipopolysaccharide (LPS)-induced inflammatory responses in macrophages.

Methods

We examined the anti-inflammatory and anti-oxidant effects of aprepitant in LPS-treated RAW264.7 macrophages by using real-time PCR, ELISA, and Western blot analysis. We also assessed cellular oxidative stress signaling by measuring the levels of cellular MDA, total ROS, and NADPH oxidase expression. Cellular NO production was measured by DAF-FM DA staining. The inhibitory effect of aprepitant against NF-κB signaling was evaluated by luciferase assay and Western blot analysis.

Results

The expression of NK-1R is increased in LPS-induced macrophages, suggesting a potential role of the receptor in the inflammatory response. We show that aprepitant protects macrophages against oxidative stress by reducing the generation of ROS and the expression of NOX-4. Furthermore, aprepitant inhibits the secretion of pro-inflammatory cytokines and chemotactic factors by mediating the NF-κB signaling pathway.

Conclusion

The NK-1R receptor antagonist aprepitant acts as an anti-inflammatory agent, indicating that the blockage of the NK-1R pathway in macrophages has the potential to suppress inflammation.

Evaluation of serum level of substance P and tissue distribution of NK-1 receptor in colorectal cancer

Colorectal cancer (CRC) is known as the most common form of malignancies in the world and its occurrence is annually increasing. Due to the relatively high death rates in patients, finding better diagnostic and prognostic factors are required. Substance P (SP) belongs to the tachykinin family that acts as an immunomodulator by binding to the neurokinin-1 receptor (NK1R). The interaction of SP with NK1R might be involved in tumor cell proliferation, angiogenesis, and migration. Hence, this study was aimed to evaluate the serum SP level and tissue distribution of NK1Rs in CRC. Also, we assessed the relationship between tissue distribution of NK1R and some different tumor characteristics, including tumor size, and lymph node status. Recruiting 38 patients primarily diagnosed with CRC, the tissue distribution of NK1R was immunohistochemically evaluated in tumor tissues and their adjacent normal tissue. The serum level of SP was measured using an ELISA method in both cases and healthy control group. The SP value was significantly increased in the serum of patients in comparison with the healthy group (p = 0.001). Tumor tissues expressed a higher number of NK1R than adjacent normal tissues (p = 0.01) considering both the percentage of stained cells and intensity of staining. However, there was not any statistically significant relevance between NK1R distribution and tumor characteristics. The SP/NK1R system is involved in tumorigenesis of CRC, and might be suggested as a potent prognostic or diagnostic factor, or a new target in the treatment of CRC.

Evaluation of Receptor Affinity, Analgesic Activity and Cytotoxicity of a Hybrid Peptide, AWL3020

In the present contribution we report design, synthesis and evaluation of receptor affinity, analgesic activity and cytotoxicity of a hybrid peptide, AWL3020. The peptide includes two pharmacophores, one of δ-opioid receptor (δOR) agonists and one of neurokinin-1 receptor (NK1R) antagonists. The design was motivated by the desire to obtain a compound with strong analgesic action and potential additional antiproliferative action. The compound displays high δOR affinity (IC50 = 29.5 nM). On the other hand, it has only poor affinity for the NK1R (IC50 = 70.28 μM). The substance shows good analgesic action which is however weaker than that of morphine. Regarding the effect on proliferation, the compound exhibits no pro-proliferative action in the assayed range. In higher concentrations, it has also cytotoxic activity. This effect is however not selective. The strongest effect of AWL3020 was found for melanoma MeW164 cell line (EC50 = 46.27 μM in reduction of cell numbers after a few days of incubation; EC50 = 37.78 μM in MTT assay).

The Added Value of Diagnostic and Theranostic PET Imaging for the Treatment of CNS Tumors

This review highlights the added value of PET imaging in Central Nervous System (CNS) tumors, which is a tool that has rapidly evolved from a merely diagnostic setting to multimodal molecular diagnostics and the guidance of targeted therapy. PET is the method of choice for studying target expression and target binding behind the assumedly intact blood-brain barrier. Today, a variety of diagnostic PET tracers can be used for the primary staging of CNS tumors and to determine the effect of therapy. Additionally, theranostic PET tracers are increasingly used in the context of pharmaceutical and radiopharmaceutical drug development and application. In this approach, a single targeted drug is used for PET diagnosis, upon the coupling of a PET radionuclide, as well as for targeted (nuclide) therapy. Theranostic PET tracers have the potential to serve as a non-invasive whole body navigator in the selection of the most effective drug candidates and their most optimal dose and administration route, together with the potential to serve as a predictive biomarker in the selection of patients who are most likely to benefit from treatment. PET imaging supports the transition from trial and error medicine to predictive, preventive, and personalized medicine, hopefully leading to improved quality of life for patients and more cost-effective care.

Evaluation of serum level of substance P and tissue distribution of NK-1 receptor in breast cancer

Breast cancer is the second leading cause of cancer death in women with increasing incidence. Hence, finding a diagnostic factor and/or potential drug target could lead to an earlier diagnosis or a more effective therapeutic protocol. It is shown that substance P (SP) through its receptor neurokinin-1 (NK1R) could initiate tumor cell proliferation, angiogenesis, and migration. This was a case-control study on 41 women with breast cancer and 34 healthy controls. Serum level of SP was measured using an ELISA method, and immunohistochemistry staining was performed to study NK1R expression in different cell compartments. Assessing serum SP values of patients showed significantly higher levels than those of healthy individuals. However, no significant correlation was found between SP levels and tumor criteria, but between SP and HER-2. Moreover, the percentage, intensity of staining as well as tissue distribution of NK1R were significantly higher in tumor tissues as compared with controls. Increased serum SP levels and NK1R tissue distribution were observed in patients with breast cancer as compared with their controls, highlighting the involvement of SP/NK1R complex in breast cancer incidence. NK1R profound expression in tumor cell cytoplasm and its significant correlation with the majority of cancer features can be of importance to be taken into consideration as a possible potential therapeutic target in future targeted therapeutic strategies. Furthermore, cytoplasmic expression of NK1R can be suggested as a potent prognostic factor as it has shown significant correlation with TNM and tumor grade.

Neuropeptide-induced modulation of carcinogenesis in a metastatic breast cancer cell line (MDA-MB-231LUC+)

Background

Metastatic cancer to bone is well-known to produce extreme pain. It has been suggested that the magnitude of this perceived pain is associated with disease progression and poor prognosis. These data suggest a potential cross-talk between cancer cells and nociceptors that contribute not only to pain, but also to cancer aggressiveness although the underlying mechanisms are yet to be stablished.

Methods

The in vitro dose dependent effect of neuropeptides (NPs) (substance P [SP], calcitonin gene-related peptide and neurokinin A [NKA]) and/or its combination, on the migration and invasion of MDA-MB-231^LUC+ were assessed by wound healing and collagen-based cell invasion assays, respectively. The effect of NPs on the expression of its receptors (SP [NK1] and neurokinin A receptors [NK2], CALCRL and RAMP1) and kininogen (high-molecular-weight kininogen) release to the cell culture supernatant of MDA-MB-231^LUC+, were measured using western-blot analysis and an ELISA assay, respectively. Statistical significance was tested using one-way ANOVA, repeated measures ANOVA, or the paired t-test. Post-hoc testing was performed with correction for multiple comparisons as appropriate.

Results

Our data show that NPs strongly modify the chemokinetic capabilities of a cellular line commonly used as a model of metastatic cancer to bone (MDA-MB-231^LUC+) and increased the expression of their receptors (NK1R, NK2R, RAMP1, and CALCRL) on these cells. Finally, we demonstrate that NPs also trigger the acute release of HMWK (Bradykinin precursor) by MDA-MB-231^LUC+, a molecule with both tumorigenic and pro-nociceptive activity.

Conclusions

Based on these observations we conclude that NPs exposure modulates this breast cancer cellular line aggressiveness by increasing its ability to migrate and invade new tissues. Furthermore, these results also support the pro nociceptive and cancer promoter role of the peripheral nervous system, during the initial stages of the disease.

Evaluation of serum level of substance P and tissue distribution of NK-1 receptor in endometrial cancer

Substance P (SP), a neuropeptide belonging to the tachykinin family, exerts different biological activities mainly through neurokinin-1 receptor (NK1R). The role of SP/NK1R system in tumoral growth and spread is reported in several cancers. We aimed to evaluate the serum SP concentration and NK1R tissue distribution in endometrial cancer, and to study the relationship between these factors with tumor size, lymph node involvement, disease stage and cancer grade. Recruiting 22 patients with endometrial cancer and 21 patients with leiomyoma as the control group, serum SP concentration was measured using an ELISA method, and NK1R tissue distributions were immunohistochemically analyzed. Serum SP concentration in patients was significantly higher than the control group (p-value = 0.005). The expression level of NK1R in tumoral tissue was more than normal tissue (p-value < 0.001). The NK1R expression had a significant relationship with lymph node involvement (p-value = 0.005) and disease stage (p-value = 0.017). The NK1R expression was higher in more advanced and less-differentiated tumors. SP/NK1R system seems to play a role in tumor growth and development in endometrial cancer. As well, the NK1R expression increased in endometrial cancer, and may be considered as a prognostic factor; but further studies are needed in this field.

Enhanced expressions of neurodegeneration-associated factors, UPS impairment, and excess Aβ accumulation in the hippocampus of mice with persistent cerebral toxocariasis

BACKGROUND

Toxocariasis is a worldwide zoonotic parasitic disease mainly caused by Toxocara canis. Humans can be infected by accidental ingestion of T. canis embryonated ovum-contaminated food, water, or encapsulated larvae in paratenic hosts' viscera or meat. Since humans and mice are paratenic hosts of T. canis, the wandering larvae might cause mechanical tissue damage and excretory-secretory antigens may trigger inflammatory injuries to local organs. Long-term residence of T. canis larvae in a paratenic host's brain may cause cerebral toxocariasis (CT) that contributes to cerebral damage, neuroinflammation and neuropsychiatric disorders in mice and clinical patients. Since the hippocampus has been long recognized as being responsible for learning and memory functions, parasitic invasion of this site may cause neuroinflammatory and neurodegenerative disorders. The present study intended to assess pathological changes, expressions of neurodegeneration-associated factors (NDAFs), including transforming growth factor (TGF)-β1, S100B, glial fibrillary acidic protein (GFAP), transglutaminase type 2 (TG2), claudin-5, substance P (SP) and interleukin (IL)-1β, and the ubiquitin-proteasome system (UPS) function in the hippocampus and associated cognitive behavior in ICR mice orally inoculated with a high, medium or low-dose of T. canis embryonated ova during a 20-week investigation.

RESULTS

Results indicated although there were insignificant differences in learning and memory function between the experimental mice and uninfected control mice, possibly because the site where T. canis larvae invaded was the surrounding area but not the hippocampus per se. Nevertheless, enhanced expressions of NDAF, persistent UPS impairment and excess amyloid β (Aβ) accumulation concomitantly emerged in the experimental mice hippocampus at 8, 16 and 20 weeks post-infection.

CONCLUSIONS

We thus postulate that progressive CT may still progress to neurodegeneration due to enhanced NDAF expressions, persistent UPS impairment and excess Aβ accumulation in the hippocampus.

Substance P induces plasticity and synaptic tagging/capture in rat hippocampal area CA2

The hippocampal area Cornu Ammonis (CA) CA2 is important for social interaction and is innervated by Substance P (SP)-expressing supramammillary (SuM) nucleus neurons. SP exerts neuromodulatory effects on pain processing and central synaptic transmission. Here we provide evidence that SP can induce a slowly developing NMDA receptor- and protein synthesis-dependent potentiation of synaptic transmission that can be induced not only at entorhinal cortical (EC)-CA2 synapses but also at long-term potentiation (LTP)-resistant Schaffer collateral (SC)-CA2 synapses. In addition, SP-induced potentiation of SC-CA2 synapses transforms a short-term potentiation of EC-CA2 synaptic transmission into LTP, consistent with the synaptic tagging and capture hypothesis. Interestingly, this SP-induced potentiation and associative interaction between the EC and SC inputs of CA2 neurons is independent of the GABAergic system. In addition, CaMKIV and PKMζ play a critical role in the SP-induced effects on SC-CA2 and EC-CA2 synapses. Thus, afferents from SuM neurons are ideally situated to prime CA2 synapses for the formation of long-lasting plasticity and associativity.

Up-regulated expression of substance P in CD8+ T cells and NK1R on monocytes of atopic dermatitis

BACKGROUND

Large numbers of CD8⁺ T cells were observed in atopic dermatitis (AD) skin, and monocytes from AD patients showed increased prostaglandin E2 production. However, little is known about the expression of substance P (SP) and its receptor NK1R in blood leukocytes of patients with AD.

OBJECTIVE

To explore the expression of SP and NK1R in leukocytes of AD and the influence of allergens on SP and NK1R expression.

METHODS

The expression levels of SP and NK1R in patients with AD were examined by flow cytometry, ELISA and a mouse AD model.

RESULTS

The plasma SP level was 4.9-fold higher in patients with AD than in HC subjects. Both the percentage of SP expression in the population and mean fluorescence intensity (MFI) of SP expression were elevated in CD8⁺ T cells in the blood of AD patients. However, both the CD14⁺NK1R⁺ population and MFI of NK1R expression on CD14⁺ cells were enhanced in the blood of AD patients. Allergens ASWE, HDME and PPE failed to up-regulate SP expression in CD8⁺ T cells. However, allergens ASWE and HDME both enhanced NK1R expression on CD14⁺ blood leukocytes regardless of AD or HC subjects. OVA-sensitized AD mice showed an elevated proportion and MFI of SP-expressing CD8⁺ T cells in the blood, which agrees with the SP expression situation in human AD blood. Injection of SP into mouse skin did not up-regulate NK1R expression on monocytes.

CONCLUSIONS

An elevated plasma SP level, up-regulated expression of SP and NK1R indicate that the SP/NK1R complex is important in the development of AD. Therefore, SP and NK1R antagonist or blocker agents may help to treat patients with AD. Trial registration Registration number: ChiCTR-BOC-16010279; Registration date: Dec., 28, 2016; retrospectively registered.

Design, Synthesis, and Evaluation of a Neurokinin-1 Receptor-Targeted Near-IR Dye for Fluorescence-Guided Surgery of Neuroendocrine Cancers

The neurokinin-1 receptor (NK1R) is implicated in the growth and metastasis of many tumors, including cancers of the brain (e.g., gliomas, glioblastomas, and astrocytomas), skin (e.g., melanomas), and neuroendocrine tissues (cancers of the breast, stomach, pancreas, larynx, and colon). Because overexpression of NK1R has been reported in most of these malignancies, we have undertaken designing an NK1R-targeted near-infrared (NIR) fluorescent dye for fluorescence-guided surgeries of these cancers. We demonstrate here that an NK1R-binding ligand linked to the NIR dye LS288 selectively accumulates in NK1R-expressing tumor xenografts with high affinity (Kd = 13 nM), allowing intraoperative imaging of these cancers in live mice. Because tumor accumulation is nearly quantitatively blocked by excess unlabeled ligand, and because NK1R-negative tumors and normal tissues display virtually no uptake, we conclude that the observed tumor retention is NK1R-mediated. Results on the synthesis, in vitro characterization, and animal testing of NK1R-targeted NIR dye are presented.

Substance P and Antagonists of the Neurokinin-1 Receptor in Neuroinflammation Associated with Infectious and Neurodegenerative Diseases of the Central Nervous System

This review addresses the role that substance P (SP) and its preferred receptor neurokinin-1 (NK1R) play in neuroinflammation associated with select bacterial, viral, parasitic, and neurodegenerative diseases of the central nervous system. The SP/NK1R complex is a key player in the interaction between the immune and nervous systems. A common effect of this interaction is inflammation. For this reason and because of the predominance in the human brain of the NK1R, its antagonists are attractive potential therapeutic agents. Preventing the deleterious effects of SP through the use of NK1R antagonists has been shown to be a promising therapeutic strategy, as these antagonists are selective, potent, and safe. Here we evaluate their utility in the treatment of different neuroinfectious and neuroinflammatory diseases, as a novel approach to clinical management of CNS inflammation.

Antagonist of the neurokinin-1 receptor curbs neuroinflammation in ex vivo and in vitro models of Lyme neuroborreliosis

Background

Lyme neuroborreliosis (LNB) can affect both the peripheral (PNS) and the central nervous systems (CNS); it is caused by the spirochete Borrelia burgdorferi. The neuropeptide substance P (SP) is an important mediator of both neuroinflammation and blood-brain barrier dysfunction, through its NK₁ receptor. Increased levels of SP have been shown to correlate with cell death. The present study used both ex vivo and in vitro models of experimentation to determine if the inflammatory mediator production and concomitant cell death caused by exposure of neural tissues and cells to B. burgdorferi could be attenuated by treatment with a NK₁ receptor antagonist.

Methods

We incubated normal rhesus frontal cortex tissue explants (CNS) and primary cultures of rhesus dorsal root ganglia cells (PNS) with live B. burgdorferi and tested the effectiveness of the NK₁ receptor antagonist L703,606 in attenuating inflammatory immune responses and neuronal and glial damage. Culture supernatants and tissue lysates were subjected to multiplex ELISA to quantify immune mediators, while the cells were evaluated for apoptosis by the in situ TUNEL assay. In addition, we identified immune mediators and producer cells in tissue sections by immunofluorescence staining and confocal microscopy.

Results

Co-incubation of both CNS tissues and PNS cells with the NK₁ receptor antagonist attenuated bacterially induced increases in inflammatory cytokine and chemokine production, particularly, IL-6, CXCL8, and CCL2, and reduced apoptosis levels. Confocal microscopy confirmed that neurons and glial cells are sources of these immune mediators. These results suggest that NK₁R antagonist treatment is able to reduce downstream pro-inflammatory signaling, thereby indicating that its systemic administration may slow disease progression.

Conclusions

We propose that SP contributes to neurogenic inflammation in LNB, and provide data to suggest that an NK₁ receptor antagonist may represent a novel neuroprotective therapy.

Truncated neurokinin-1 receptor is an ubiquitous antitumor target in hepatoblastoma, and its expression is independent of tumor biology and stage

The substance P (SP; also known as TAC1)/neurokinin-1 receptor (NK1R; also known as TACR1) complex is a critical part in the development of cancer. Therefore, NK1R antagonists, such as the clinical drug aprepitant, are currently under investigation as future anticancer agents. In a previous study, NK1R (TACR1) was identified as a potent anticancer target in hepatoblastoma (HB). However, little is known regarding the exact distribution of this target among HB subsets and whether it correlates with clinical features and prognosis. In the present study, mRNA was isolated from 47 children with HB, and reverse transcription-quantitative polymerase chain reaction was performed on the samples to analyze the expression of full-length-TACR1 (fl-TACR1) and truncated-TACR1 (tr-TACR1). These data were correlated with data obtained from 9 tumor-free controls, as well as with the presence of metastasis, PRETEXT, vascular invasion, histology, age of diagnosis, multifocality, CTNNB1 mutation, gender and overall survival. Additionally, the present study investigated a recently described 16-gene signature characterizing HB known to correlate with prognosis. Compared with tumor-free liver tissue, tumorous tissue expressed TACR1 significantly higher for the truncated version (P=0.0301), and by trend also for the full-length version. Accordingly, the expression of fl-TACR1 correlated with the expression of the truncated version (P=0.0074). Furthermore, a low expression of fl-TACR1 correlated with characteristics of the 16-gene signature known to predict prognosis (P=0.0222). However, there was no correlation between tr-TACR1 and the tumor characteristics investigated, including outcome, although a clear trend was observed for some tumor characteristics. The current results reinforced the previously described findings that in HB, tr-TACR1 is overexpressed compared with tumor-free liver tissue. Furthermore, to the best of our knowledge, the present study demonstrated for the first time that tr-TACR1 is expressed ubiquitously among the different subsets of HB. Therefore, NK1R may serve as a potent anticancer target in a large variety of patients with HB, independent of tumor biology and clinical stage.

G-Protein-Coupled Receptors: Next Generation Therapeutic Targets in Head and Neck Cancer?

Therapeutic outcome in head and neck squamous cell carcinoma (HNSCC) is poor in most advanced cases. To improve therapeutic efficiency, novel therapeutic targets and prognostic factors must be discovered. Our studies have identified several G protein-coupled receptors (GPCRs) as promising candidates. Significant epigenetic silencing of GPCR expression occurs in HNSCC compared with normal tissue, and is significantly correlated with clinical behavior. Together with the finding that GPCR activity can suppress tumor cell growth, this indicates that GPCR expression has potential utility as a prognostic factor. In this review, we discuss the roles that galanin receptor type 1 (GALR1) and type 2 (GALR2), tachykinin receptor type 1 (TACR1), and somatostatin receptor type 1 (SST1) play in HNSCC. GALR1 inhibits proliferation of HNSCC cells though ERK1/2-mediated effects on cell cycle control proteins such as p27, p57, and cyclin D1, whereas GALR2 inhibits cell proliferation and induces apoptosis in HNSCC cells. Hypermethylation of GALR1, GALR2, TACR1, and SST1 is associated with significantly reduced disease-free survival and a higher recurrence rate. Although their overall activities varies, each of these GPCRs has value as both a prognostic factor and a therapeutic target. These data indicate that further study of GPCRs is a promising strategy that will enrich pharmacogenomics and prognostic research in HNSCC.

Substance P enhances microglial density in the substantia nigra through neurokinin-1 receptor/NADPH oxidase-mediated chemotaxis in mice

The distribution of microglia varies greatly throughout the brain. The substantia nigra (SN) contains the highest density of microglia among different brain regions. However, the mechanism underlying this uneven distribution remains unclear. Substance P (SP) is a potent proinflammatory neuropeptide with high concentrations in the SN. We recently demonstrated that SP can regulate nigral microglial activity. In the present study, we further investigated the involvement of SP in modulating nigral microglial density in postnatal developing mice. Nigral microglial density was quantified in wild-type (WT) and SP-deficient mice from postnatal day 1 (P1) to P30. SP was detected at high levels in the SN as early as P1 and microglial density did not peak until around P30 in WT mice. SP-deficient mice (TAC1(-/-)) had a significant reduction in nigral microglial density. No differences in the ability of microglia to proliferate were observed between TAC1(-/-) and WT mice, suggesting that SP may alter microglial density through chemotaxic recruitment. SP was confirmed to dose-dependently attract microglia using a trans-well culture system. Mechanistic studies revealed that both the SP receptor neurokinin-1 receptor (NK1R) and the superoxide-producing enzyme NADPH oxidase (NOX2) were necessary for SP-mediated chemotaxis in microglia. Furthermore, genetic ablation and pharmacological inhibition of NK1R or NOX2 attenuated SP-induced microglial migration. Finally, protein kinase Cδ (PKCδ) was recognized to couple SP/NK1R-mediated NOX2 activation. Altogether, we found that SP partly accounts for the increased density of microglia in the SN through chemotaxic recruitment via a novel NK1R-NOX2 axis-mediated pathway.

Treatment with the NK1 antagonist emend reduces blood brain barrier dysfunction and edema formation in an experimental model of brain tumors

The neuropeptide substance P (SP) has been implicated in the disruption of the blood-brain barrier (BBB) and development of cerebral edema in acute brain injury. Cerebral edema accumulates rapidly around brain tumors and has been linked to several tumor-associated deficits. Currently, the standard treatment for peritumoral edema is the corticosteroid dexamethasone, prolonged use of which is associated with a number of deleterious side effects. As SP is reported to increase in many cancer types, this study examined whether SP plays a role in the genesis of brain peritumoral edema. A-375 human melanoma cells were injected into the right striatum of male Balb/c nude mice to induce brain tumor growth, with culture medium injected in animals serving as controls. At 2, 3 or 4 weeks following tumor cell inoculation, non-treated animals were perfusion fixed for immunohistochemical detection of Albumin, SP and NK1 receptor. A further subgroup of animals was treated with a daily injection of the NK1 antagonist Emend (3 mg/kg), dexamethasone (8 mg/kg) or saline vehicle at 3 weeks post-inoculation. Animals were sacrificed a week later to determine BBB permeability using Evan's Blue and brain water content. Non-treated animals demonstrated a significant increase in albumin, SP and NK1 receptor immunoreactivity in the peritumoral area as well as increased perivascular staining in the surrounding brain tissue. Brain water content and BBB permeability was significantly increased in tumor-inoculated animals when compared to controls (p<0.05). Treatment with Emend and dexamethasone reduced BBB permeability and brain water content when compared to vehicle-treated tumor-inoculated mice. The increase in peritumoral staining for both SP and the NK1 receptor, coupled with the reduction in brain water content and BBB permeability seen following treatment with the NK1 antagonist Emend, suggests that SP plays a role in the genesis of peritumoral edema, and thus warrants further investigation as a potential anti-edematous treatment.

Neurokinin-1 receptor expression and antagonism by the NK-1R antagonist maropitant in canine melanoma cell lines and primary tumour tissues

We interrogated the neurokinin-1 receptor (NK-1R)/substance P (SP) pathway in canine melanoma tumour tissues and cell lines. NK-1R messenger RNA (mRNA) and protein expression were observed in the majority of tumour tissues. Immunohistochemical assessment of archived tissue sections revealed NK-1R immunoreactivity in 11 of 15 tumours, which may have diagnostic, prognostic and therapeutic utility. However, we were unable to identify a preclinical in vitro cell line or in vivo xenograft model that recapitulates NK-1R mRNA and protein expression documented in primary tumours. While maropitant inhibited proliferation and enhanced apoptosis in cell lines, in the absence of documented NK-1R expression, this may represent off-target effects. Furthermore, maropitant failed to suppress tumour growth in a canine mouse xenograft model derived from a cell line expressing mRNA but not protein. While NK-1R represents a novel target, in the absence of preclinical models, in-species clinical trials will be necessary to investigate the therapeutic potential for antagonists such as maropitant.

Neuroimmune pathways in alcohol consumption: evidence from behavioral and genetic studies in rodents and humans

Immune or brain proinflammatory signaling has been linked to some of the behavioral effects of alcohol. Immune signaling appears to regulate voluntary ethanol intake in rodent models, and ethanol intake activates the immune system in multiple models. This bidirectional link raises the possibility that consumption increases immune signaling, which in turn further increases consumption in a feed-forward cycle. Data from animal and human studies provide overlapping support for the involvement of immune-related genes and proteins in alcohol action, and combining animal and human data is a promising approach to systematically evaluate and nominate relevant pathways. Based on rodent models, neuroimmune pathways may represent unexplored, nontraditional targets for medication development to reduce alcohol consumption and prevent relapse. Peroxisome proliferator-activated receptor agonists are one class of anti-inflammatory medications that demonstrate antiaddictive properties for alcohol and other drugs of abuse. Expression of immune-related genes is altered in animals and humans following chronic alcohol exposure, and the regulatory influences of specific mRNAs, microRNAs, and activated cell types are areas of intense study. Ultimately, the use of multiple datasets combined with behavioral validation will be needed to link specific neuroimmune pathways to addiction vulnerability.

Tumor targeting and imaging with dual-peptide conjugated multifunctional liposomal nanoparticles

BACKGROUND

The significant progress in nanotechnology provides a wide spectrum of nanosized material for various applications, including tumor targeting and molecular imaging. The aim of this study was to evaluate multifunctional liposomal nanoparticles for targeting approaches and detection of tumors using different imaging modalities. The concept of dual-targeting was tested in vitro and in vivo using liposomes derivatized with an arginine-glycine-aspartic acid (RGD) peptide binding to αvβ3 integrin receptors and a substance P peptide binding to neurokinin-1 receptors.

METHODS

For liposome preparation, lipids, polyethylene glycol building blocks, DTPA-derivatized lipids for radiolabeling, lipid-based RGD and substance P building blocks and imaging labels were combined in defined molar ratios. Liposomes were characterized by photon correlation spectroscopy and zeta potential measurements, and in vitro binding properties were tested using fluorescence microscopy. Standardized protocols for radiolabeling were developed to perform biodistribution and micro-single photon emission computed tomography/computed tomography (SPECT/CT) studies in nude mice bearing glioblastoma and/or melanoma tumor xenografts. Additionally, an initial magnetic resonance imaging study was performed.

RESULTS

Liposomes were radiolabeled with high radiochemical yields. Fluorescence microscopy showed specific cellular interactions with RGD-liposomes and substance P-liposomes. Biodistribution and micro-SPECT/CT imaging of (111)In-labeled liposomal nanoparticles revealed low tumor uptake, but in a preliminary magnetic resonance imaging study with a single-targeted RGD-liposome, uptake in the tumor xenografts could be visualized.

CONCLUSION

The present study shows the potential of liposomes as multifunctional targeted vehicles for imaging of tumors combining radioactive, fluorescent, and magnetic resonance signaling. Specific in vitro tumor targeting by fluorescence microscopy and radioactivity was achieved. However, biodistribution studies in an animal tumor model revealed only moderate tumor uptake and no additive effect using a dual-targeting approach.

Nerve-derived transmitters including peptides influence cutaneous immunology

Clinical observations suggest that the nervous and immune systems are closely related. For example, inflammatory skin disorders; such as psoriasis, atopic dermatitis, rosacea and acne; are widely believed to be exacerbated by stress. A growing body of research now suggests that neuropeptides and neurotransmitters serve as a link between these two systems. Neuropeptides and neurotransmitters are released by nerves innervating the skin to influence important actors of the immune system, such as Langerhans cells and mast cells, which are located within close anatomic proximity. Catecholamines and other sympathetic transmitters that are released in response to activation of the sympathetic nervous system are also able to reach the skin and affect immune cells. Neuropeptides appear to direct the outcome of Langerhans cell antigen presentation with regard to the subtypes of Th cells generated and neuropeptides induce the degranulation of mast cells, among other effects. Additionally, endothelial cells, which release many inflammatory mediators and express cell surface molecules that allow leukocytes to exit the bloodstream, appear to be regulated by certain neuropeptides and transmitters. This review focuses on the evidence that products of nerves have important regulatory activities on antigen presentation, mast cell function and endothelial cell biology. These activities are highly likely to have clinical and therapeutic relevance.