Involvement of substance P and the NK-1 receptor in cancer progression

Neurokinin receptor antagonism: a patent review (2014-present)

INTRODUCTION

The tachykinin family of peptides (substance P, neurokinin A) via the neurokinin-1 (NK-1), NK-2, and NK-3 receptors is involved in many physiological/physiopathological actions. Antagonists of these receptors may be used to treat many human pathologies.

AREAS COVERED

This review offers an overview (from 2014 to present) of the actions exerted by NK receptor (NK-R) antagonists on emesis, pruritus, cardiomyopathy, respiratory tract diseases, bacterial infection, cancer, ocular pain, corneal neovascularization, excess of body fat/weight, conditioned fear, social isolation stress, hot flush, melanogenesis, follicle development, fish reproduction, and sex-hormone-dependent diseases.

EXPERT OPINION

From 2014, no invention has been published using NK-2R antagonists. Although the tachykinin/NK receptor system is involved in a great number of mechanisms, to date, the use of only five NK-1R antagonists have been approved in humans but no NK-2R or NK-3R antagonist. NK receptor antagonists are safe in human trials and are potential therapeutic agents, but this potential is currently minimized. In humans, more studies on molecules acting as NK receptor antagonists and exerting a potential therapeutic action must be carried out. The antipruritic or antitumor action of NK-1R antagonists must be explored in greater depth: the highest safe dose and the time of administration (for a long period of time) of these antagonists must be well established.

Substance P accelerates the progression of human esophageal squamous cell carcinoma via MMP-2, MMP-9, VEGF-A, and VEGFR1 overexpression

Tachykinins such as Substance P (SP) are a group of neuropeptides that are involved in cancer development. Neurokinin-1 receptor (NK-1R) is the main tachykinin receptor mediating the effects of SP, which is overexpressed in human esophageal squamous cell carcinoma (ESCC) and other malignant tissues. However, the effects of SP/NK-1R system on the migration of esophageal cancer cells and angiogenesis is not clear yet. This study seeks to obtain data to address these research gaps. In order to assess the effects of the FDA-approved aprepitant drug, a commercially available NK-1R antagonist, on the viability of KYSE-30 ESCC cells, resazurin assay was performed. The influence of SP/NK-1R system on the migration potential of these cells was examined using scratch assay. The effects of this system on the expression levels of metastatic factors were also examined by RT-PCR and western blot analyses. The half-maximal inhibitory concentration (IC₅₀) value for KYSE-30 cells treated with aprepitant found to be 29.88 μM. Treatment with SP significantly promoted KYSE-30 esophageal cancer cell migration, and aprepitant blocked this effect. In addition, SP significantly induced the expression of matrix metalloproteinase-2 (MMP-2), MMP-9, vascular endothelial growth factor-A (VEGF-A), and VEGF receptor1 (VEGFR1) in the cells, whereas aprepitant inhibited the up-regulation effects caused by SP. SP plays important roles in the development of human esophageal squamous cell carcinoma by promoting cancer cell invasion and enhancing the expression of factors involved in cellular migration and angiogenesis, which can be blocked by the NK-1R antagonist, aprepitant.

The substance P and neurokinin-1 receptor system in human thyroid cancer: an immunohistochemical study

To develop a new therapeutic strategy against thyroid cancer (TC), the expression of both substance P (SP) and neurokinin-1 receptor (NK-1R) must be demonstrated in TC cells. This study aims to examine by immunohistochemistry, the localization of SP and the NK-1R in human TC samples (papillary, follicular, medullary, anaplastic), in metastasis and in healthy thyroid samples. SP and the NK-1R were expressed in all normal and TC samples. In healthy glands, SP was located in follicular cells (nucleus) and colloid and NK-1R in follicular cells (cytoplasm) and stroma. In TC samples, SP was visualized in follicular cells (nucleus and cytoplasm), stroma and colloid and NK-1R in follicular cells (cytoplasm), stroma and colloid. A semiquantitative scoring system (Allred Unit Scoring System) was applied. The expression (Allred total score) of SP and NK-1R was weaker in normal thyroid glands than in TC. In comparison with TC samples, a lower intensity/proportion of SP (nucleus and cytoplasm of follicular cells; stroma) was observed in normal samples. By contrast, in the colloid of TC samples the presence of SP was lower than in normal samples. In comparison with TC samples, the presence of the NK-1R in the cytoplasm of follicular cells and colloid was lower in normal thyroid samples, whereas the expression of this receptor in the stroma was higher. The results reported in this study suggest that the NK-1R could be a new target for the treatment of TC and use of the NK-1R antagonists could serve as a new anti-TC therapeutic strategy.

New insight into the role of substance P/neurokinin-1 receptor system in breast cancer progression and its crosstalk with microRNAs

The neuropeptide substance P (SP) triggers a variety of tumor-promoting signaling pathways through the activation of neurokinin-1receptor (NK1R), a class of neurokinin G protein-coupled receptors superfamily. Recent researches in our and other laboratories have shown the overexpression of both SP and NK1R in breast cancer (BC) patients. SP/NK1R signaling is strongly implicated in the pathogenesis of BC through affecting cell proliferation, migration, metastasis, angiogenesis, and resistance. Therefore, SP/NK1R signaling responses must be rigorously regulated; otherwise, they would contribute to a more aggressive BC phenotype. Recently, microRNAs (miRNAs) as a specific class of epigenetic regulators have been shown to regulate NK1R and thus, controlling SP/NK1R signaling responses in BC. This review summarizes the current knowledge of the role of SP/NK1R signaling and its therapeutic potentials in BC. We also provide an overview regarding the effects of miRNA-mediated NK1R regulatory mechanisms in controlling BC tumorigenesis to gain a clearer view and thus better management of cancer.

Association between Angiotensin-Converting Enzyme Inhibitors and Lung Cancer-A Nationwide, Population-Based, Propensity Score-Matched Cohort Study

Background: Direct evidence of lung cancer risk in Asian users of angiotensin-converting enzyme inhibitors (ACEIs) is lacking. Methods: The ACEI cohort comprised 22,384 patients aged ≥ 18 years with a first prescription of ACEI. The comparison angiotensin receptor blocker (ARB) cohort consisted of age-, sex- and comorbidity-matched patients at a ratio of 1:1. The primary outcome was the incidence of lung cancer, which was evaluated using a proportional hazard model. Results: The overall incidence rates of lung cancer in the ACEI and ARB cohorts were 16.6 and 12.2 per 10,000 person-years, respectively. The ACEI cohort had a significantly higher risk of lung cancer than the ARB cohort (adjusted hazard ratio [aHR]. = 1.36; 95% confidence interval [CI]. = 1.11–1.67). Duration–response and dose–response analyses revealed that compared with patients who did not receive ACEIs, patients who received ACEIs for more than 45 days per year (aHR = 1.87; 95% CI = 1.48–2.36) and patients who received more than 540 defined daily doses of ACEIs per year (aHR =1.80; 95% CI = 1.43–-2.27) had a significantly higher risk of lung cancer. The cumulative incidence of lung cancer was also significantly higher in the ACEI cohort than in the ARB cohort (log-rank test, p = 0.002). Conclusions: ACEI use is associated with an increased risk of lung cancer compared with ARB use. Patients using ARBs have a significantly lower risk of lung cancer than non-ARB users.

Sensory neurons directly promote angiogenesis in response to inflammation via substance P signaling

Blood vessels and nerves travel together to supply most tissues in the body. However, there is a knowledge gap in the mechanisms underlying the direct regulation of angiogenesis by nerves. In the current study, we examined the regulation of angiogenesis by sensory nerves in response to inflammation using the cornea, a normally avascular and densely innervated ocular tissue, as a model. We used desiccating stress as an inflammatory stimulus in vivo and found that sub-basal and epithelial nerve densities in the cornea were reduced in dry eye disease (DED). We established a co-culture system of trigeminal ganglion sensory neurons and vascular endothelial cells (VEC) and found that neurons isolated from mice with DED directly promoted VEC proliferation and tube formation compared with normal controls. In addition, these neurons expressed and secreted higher levels of substance P (SP), a proinflammatory neuropeptide. SP potently promoted VEC activation in vitro and blockade of SP signaling with spantide I, an antagonist of SP receptor Neurokinin-1, significantly reduced corneal neovascularization in vivo. Spantide I and siRNA knockdown of SP abolished the promotion of VEC activation by DED neurons in vitro. Taken together, our data suggested that sensory neurons directly promote angiogenesis via SP signaling in response to inflammation in the cornea.

The role of substance P/neurokinin 1 receptor in the pathogenesis of esophageal squamous cell carcinoma through constitutively active PI3K/Akt/NF-κB signal transduction pathways

One of the most prevalent malignancies is esophageal squamous cell carcinoma (ESCC), which is associated with high morbidity and mortality. Substance P (SP), as one of the peptides released from sensory nerves, causes the enhancement of cellular excitability through the activation of the neurokinin-1 (NK1) receptor in several human tumor cells. Aprepitant, a specific, potent, and long-acting NK1 receptor antagonist, is considered as a novel agent to inhibit proliferation and induce apoptosis in malignant cells. Since the antitumor mechanism of aprepitant in ESCC is not completely understood, we conducted this study and found that aprepitant induced growth inhibition of KYSE-30 cells and arrested cells in the G2/M phase of the cell cycle. Aprepitant also caused apoptotic cell death and inhibited activation of the PI3K/Akt axis and its downstream effectors, including NF-κB in KYSE-30 cells. Besides, quantitative real-time (qRT)-PCR analysis showed a significant down-regulation of NF-κB target genes in KYSE-30 cells, indicating a probable NF-κB-dependent mechanism involved in aprepitant cytotoxicity. Thus, the present study recommends that SP/NK1R system might, therefore, be considered as an emerging and promising therapeutic strategy against ESCC.

miR-206 Promotes Cancer Progression by Targeting Full-Length Neurokinin-1 Receptor in Breast Cancer

Substance P plays a pivotal role in human cancer development and progression by binding to its receptor, neurokinin-1. Neurokinin-1 has 2 isoforms: full-length neurokinin-1 and truncated neurokinin-1, the latter lacking the cytoplasmic terminal 96-amino acid residues of the full-length protein. We have identified 3 candidate miR-206 target sites within the 3′-untranslated region of the full-length neurokinin-1 gene from bioinformatics database searches. In the present study, real-time quantitative polymerase chain reaction was performed to quantify the expression of miR-206, and the expression of neurokinin-1 and full-length neurokinin-1 was detected by immunohistochemistry in 82 clinical cases of breast cancer and paired adjacent normal tissues. The miR-206 target gene was demonstrated by using a dual-luciferase reporter assay, quantitative real-time polymerase chain reaction, and Western blotting. Transwell migration and invasion, colony formation, and proliferation assays were performed to evaluate the effects of miR-206 expression on various aspects of breast cancer cell behavior in vitro. We showed that miR-206 expression is upregulated in breast cancer cell lines and breast cancer tissues when compared to that in adjacent normal tissues, and full-length neurokinin-1 expression inversely correlates with Tumor Lymph Node Metastasis (TNM) stage and lymph node metastasis. Western blotting, quantitative real-time polymerase chain reaction, and dual-luciferase reporter assays demonstrated that miR-206 binds the 3′-untranslated region of full-length neurokinin-1 messenger RNA, regulating protein expression. We showed that the overexpression of miR-206 promotes breast cancer cell invasion, migration, proliferation, and colony formation in vitro. The present study furthers the current understanding of the mechanisms underlying breast cancer pathogenesis and may be useful for the development of novel targeted therapies.

Glioma and Neurokinin-1 Receptor Antagonists: A New Therapeutic Approach

BACKGROUND

In adults, the most lethal and frequent primary brain tumor is glioblastoma. Despite multimodal aggressive therapies, the median survival time after diagnosis is around 15 months. In part, this is due to the blood-brain barrier that restricts common treatments (e.g., chemotherapy). Unfortunately, glioma recurs in 90% of patients. New therapeutic strategies against glioma are urgently required. Substance P (SP), through the neurokinin (NK)-1 receptor, controls cancer cell proliferation by activating c-myc, mitogenactivated protein kinases, activator protein 1 and extracellular signal-regulated kinases 1 and 2. Glioma cells overexpress NK-1 receptors when compared with normal cells. The NK-1 receptor/SP system regulates the proliferation/migration of glioma cells and stimulates angiogenesis, triggering inflammation which contributes to glioma progression. In glioma cells, SP favors glycogen breakdown, essential for glycolysis. By contrast, in glioma, NK-1 receptor antagonists block the proliferation of tumor cells and the breakdown of glycogen and also promote the death (apoptosis) of these cells. These antagonists also inhibit angiogenesis and exert antimetastatic and anti-inflammatory actions.

OBJECTIVE

This review updates the involvement of the NK-1 receptor/SP system in the development of glioma and the potential clinical application of NK-1 receptor antagonists as antiglioma agents.

CONCLUSION

The NK-1 receptor plays a crucial role in glioma and NK-1 receptor antagonists could be used as anti-glioma drugs.

Destined to Die: Apoptosis and Pediatric Cancers

Apoptosis (programmed cell death) is a systematic and coordinated cellular process that occurs in physiological and pathophysiological conditions. Sidestepping or resisting apoptosis is a distinct characteristic of human cancers including childhood malignancies. This review dissects the apoptosis pathways implicated in pediatric tumors. Understanding these pathways not only unraveled key molecules that may serve as potential targets for drug discovery, but also molecular nodes that integrate with other signaling networks involved in processes such as development. This review presents current knowledge of the complex regulatory system that governs apoptosis with respect to other processes in pediatric cancers, so that fresh insights may be derived regarding treatment resistance or for more effective treatment options.

Neurokinin-1 Receptor Antagonists as Anticancer Drugs

Background::

Human tumor cells lines and tumor samples overexpress the neurokinin-1 receptor (NK-1R). Substance P (SP), after binding to NK-1Rs, induces tumor cell proliferation, an antiapoptotic effect and promotes angiogenesis and the migration of cancer cells for invasion and metastasis.

Methods: :

In contrast, NK-1R antagonists block the previous pathophysiological actions mediated by SP. These antagonists promote the death of tumor cells by apoptosis. Peptide and non-peptide NK-1R antagonists have been reported.

Results: :

Peptide NK-1R antagonists show chemical modifications of the SP molecule (L-amino acids being replaced by D-amino acids), whereas non-peptide NK-1R antagonists include numerous compounds with different chemical compositions while showing similar stereochemical features (affinity for the NK- 1R). Currently, there are more than 300 NK-1R antagonists.

Conclusion::

In combination therapy with classic cytostatics, NK-1R antagonists have additive or synergic effects and minimize the side-effects of cytostatics. The effect of NK-1R antagonists as broad-spectrum anticancer drugs is reviewed and the use of these antagonists for the treatment of cancer is suggested.

The Significance of NK1 Receptor Ligands and Their Application in Targeted Radionuclide Tumour Therapy

To date, our understanding of the Substance P (SP) and neurokinin 1 receptor (NK1R) system shows intricate relations between human physiology and disease occurrence or progression. Within the oncological field, overexpression of NK1R and this SP/NK1R system have been implicated in cancer cell progression and poor overall prognosis. This review focuses on providing an update on the current state of knowledge around the wide spectrum of NK1R ligands and applications of radioligands as radiopharmaceuticals. In this review, data concerning both the chemical and biological aspects of peptide and nonpeptide ligands as agonists or antagonists in classical and nuclear medicine, are presented and discussed. However, the research presented here is primarily focused on NK1R nonpeptide antagonistic ligands and the potential application of SP/NK1R system in targeted radionuclide tumour therapy.

Detection of early breast cancer beyond mammographic screening: a promising biomarker panel

Aim: We assessed the suitability of a biomarker panel to improve early detection and individual risk assessment in breast cancer (BC) patients. Materials & methods: PENK, pro-SP, hGH and CA15-3 of 204 BC patients and 68 healthy controls were measured. Results: PENK and human growth hormone concentrations were significantly lower and pro-SP values higher in BC patients compared with controls. C-index increased from 0.628 for CA15-3 alone to 0.754 when all three biomarkers were added to the model. Conclusion: This biomarker panel may improve early detection of BC and influence the assessment of breast imaging. It might be useful for a risk-adapted cancer surveillance or primary prevention program by a more precise determination of an individualized BC risk.

Neurokinin-1 Receptor Antagonists against Hepatoblastoma

Hepatoblastoma (HB) is the most common malignant liver tumor that occurs during childhood. The prognosis of children with HB is favorable when a complete surgical resection of the tumor is possible, but for high-risk patients, the prognosis is much worse. New anti-HB strategies must be urgently developed. The undecapeptide substance P (SP) after binding to the neurokinin-1 receptor (NK-1R), regulates cancer cell proliferation, exerts an antiapoptotic effect, induces cell migration for invasion/metastasis, and triggers endothelial cell proliferation for neoangiogenesis. HB samples and cell lines overexpress NK-1R (the truncated form) and SP elicits HB cell proliferation. One of these strategies could be the use of non-peptide NK-1R antagonists. These antagonists exert, in a concentration-dependent manner, an antiproliferative action against HB cells (inhibit cell proliferation and induce the death of HB cells by apoptosis). NK-1R antagonists exerted a dual effect in HB: Decreased both tumor volume and angiogenic activity. Thus, the SP/NK-1R system is an important target in the HB treatment and NK-1R antagonists could act as specific drugs against HB cells. In this review, we update and discuss the use of NK-1R antagonists in the treatment of HB.

Evaluation of a Neurokinin-1 Receptor-Targeted Technetium-99m Conjugate for Neuroendocrine Cancer Imaging

PURPOSE

Neuroendocrine tumors (NETs) have reasonably high 5-year survival rates when diagnosed at an early stage but are significantly more lethal when discovered only after metastasis. Although several imaging modalities such as computed tomography (CT), positron emission tomography, and magnetic resonance imaging can detect neuroendocrine tumors, their high false positive rates suggest that more specific diagnostic tests are required. Targeted imaging agents such as Octreoscan® have met some of this need for improved specificity, but their inability to image poorly differentiated NETs suggests that improved NET imaging agents are still needed. Because neurokinin 1 receptors (NK1Rs) are widely over-expressed in neuroendocrine tumors, but show limited expression in healthy tissues, we have undertaken to develop an NK1R-targeted imaging agent for improved diagnosis and staging of neuroendocrine tumors.

PROCEDURE

A small molecule NK1R antagonist was conjugated via a flexible spacer to a Tc-99m chelating peptide. After complexation with Tc-99m, binding of the conjugate to human embryonic kidney (HEK293) cells transfected with the human NK1R was evaluated as a function of radioimaging agent concentration. In vivo imaging of HEK293-NK1R tumor xenografts in mice was also performed by single-photon emission computed tomography/computed tomography (γ-SPECT/CT), and the distribution of the conjugate in various tissues was quantified by tissue resection and γ-counting.

RESULTS

NK1R-targeted Tc-99m-based radioimaging agent displayed excellent affinity (K_d = 16.8 nM) and specificity for HEK293-NK1R tumor xenograft. SPECT/CT analysis of tumor-bearing mice demonstrated significant tumor uptake and high tumor to background ratio as early as 2 h post injection.

CONCLUSION

The excellent tumor contrast afforded by our NK1R-targeted radioimaging agent exhibits properties that could improve early diagnosis and staging of many neuroendocrine tumors.

Neurokinin-1 receptor antagonist aprepitant and radiotherapy, a successful combination therapy in a patient with lung cancer: A case report

Lung cancer (LC) is the leading cause of cancer death and is responsible for more than one-quarter (27%) of all cancer deaths. Non-small-cell LC (NSCLC) is the main histological subtype of LC and is the leading cause of mortalities associated with cancer. This case report focused on a patient showing a history of chronic obstructive pulmonary disease (COPD) with a NSCLC squamous cell carcinoma (single mass with a diameter of 8×7 cm, without metastasis). Due to the COPD, neither a surgical treatment (pneumonectomy) nor chemotherapy was possible. After 15 days following the diagnosis, the patient was treated for 45 days with radiotherapy and the neurokinin-1 receptor, aprepitant (compassionate use, 1,140 mg/day). Radiotherapy was administered to the right lung and mediastinum, reaching 50.4 Gy and then overprinted to 65 Gy. In each successive control, the tumor volume decreased and, after 6 months of treatment, the chest computed tomography scan showed that the tumor mass had disappeared. No side-effects were observed during the combination therapy; in contrast, the patient was in very good general health with a weight gain and showing no biochemical analytical alteration. This case report suggests a witness episode to the antitumor effect of aprepitant/radiotherapy against NSCLC. Urgent development is required for clinical trials to test the combination treatment (radiotherapy and aprepitant) as an antitumor therapy for patients with LC.

SP/NK-1R promotes gallbladder cancer cell proliferation and migration

Aberrant substance P/neurokinin‐1 receptor (SP/NK‐1R) system activation plays a critical role in various disorders, however, little is known about the expression and the detailed molecular mechanism of the SP and NK‐1R in gallbladder cancer (GBC). In this study, we firstly analyzed the expression and clinical significance of them in patients with GBC. Then, cellular assays were performed to clarify their biological role in GBC cells. Moreover, we investigated the molecular mechanisms regulated by SP/NK‐1R. Meanwhile, mice xenografted with human GBC cells were analyzed regarding the effects of SP/NK1R complex in vivo. Finally, patient samples were utilized to investigate the effect of SP/NK‐1R. The results showed that SP and NK‐1R were highly expressed in GBC. We found that SP strongly induced GBC cell proliferation, clone formation, migration and invasion, whereas antagonizing NK‐1R resulted in the opposite effects. Moreover, SP significantly enhanced the expression of NF‐κB p65 and the tumor‐associated cytokines, while, Akt inhibitor could reverse these effects. Further studies indicated that decreasing activation of NF‐κB or Akt diminished GBC cell proliferation and migration. In consistent with results, immunohistochemical staining showed high levels of Akt, NF‐κB and cytokines in tumor tissues. Most importantly, the similar conclusion was obtained in xenograft mouse model. Our findings demonstrate that NK‐1R, after binding with the endogenous agonist SP, could induce GBC cell migration and spreading via modulation of Akt/NF‐κB pathway.

LncRNA RMRP silence curbs neonatal neuroblastoma progression by regulating microRNA-206/tachykinin-1 receptor axis via inactivating extracellular signal-regulated kinases

BACKGROUND

Neuroblastoma is the commonest malignancy in neonates. Long non-coding RNA (lncRNA) RNA component of mitochondrial RNA processing endoribonuclease (RMRP) has been reported to be an oncogenic factor in some malignancies. However, its roles and molecular mechanisms in neuroblastoma progression are poor defined.

METHODS

The expression of RMRP, microRNA-206 (miR-206), and tachykinin-1 receptor (TACR1) mRNA was measured by RT-qPCR assay. Protein levels of TACR1, phosphorylated extracellular signal-regulated kinases (ERK) 1/2 (p-ERK1/2) and ERK1/2 were detected by western blot assay. Cell proliferation was assessed by CCK-8 and colony formation assays. Cell migratory and invasive capacities were determined using Transwell migration and invasion assays. The interaction between miR-206 and RMRP or TACR1 was verified by luciferase assay. The roles and molecular mechanisms of RMRP knockdown on the growth of neuroblastoma xenografts were examined in vivo.

RESULTS

RMRP was highly expressed in neuroblastoma tissues. RMRP knockdown inhibited proliferation, migration and invasion in neuroblastoma cells. Moreover, TACR1 was a target of miR-206 and RMRP performed as a molecular sponge of miR-206 to sequester miR-206 from TACR1 in neuroblastoma cells. TACR1 overexpression abrogated the inhibitory effect of RMRP downregulation on neuroblastoma cell progression by activating ERK1/2 pathway. Inhibition of TACR1 and ERK1/2 pathway abated RMRP-mediated pro-proliferation effect in neuroblastoma cells. RMRP knockdown hindered neuroblastoma xenograft growth by regulating miR-206/TACR1 axis via inactivating ERK1/2 pathway in vivo.

CONCLUSION

RMRP knockdown hindered the tumorigenesis and progression of neuroblastoma by regulating miR-206/TACR1 axis via inactivating ERK1/2 pathway, hinting a potential therapeutic target for neuroblastoma.

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.

Vasoactive intestinal peptide increases apoptosis of hepatocellular carcinoma by inhibiting the cAMP/Bcl-xL pathway

Vasoactive intestinal peptide (VIP) is a modulator of inflammatory responses. VIP receptors are expressed in several tumor types, such as colorectal carcinoma. The study described herein was conducted to confirm the presence of VIP and its receptors (VPAC1 and VPAC2) in surgically resected hepatocellular carcinoma (HCC) tissues and in the HCC cell line Huh7. The mechanism responsible for apoptosis of HCC cells was then examined because VIP treatment (10^-10  M) significantly suppressed proliferation of Huh7 cells. In examining apoptosis-related proteins, we found caspase-3 to be significantly increased and Bcl-xL and cyclic AMP (cAMP) response element-binding protein (CREB) to be significantly decreased in Huh7 cells cultured with VIP. Furthermore, the CREB level and phosphorylation were reduced. These effects were reversed by the addition of VIP receptor antagonist or cAMP antagonist Rp-cAMPS. Pretreatment with cAMP analogue blocked the increased apoptosis, suggesting that VIP induces apoptosis via a PKA-independent signaling mechanism. Our data indicate that VIP prevents the progression of HCC by apoptosis through the cAMP/Bcl-xL pathway.

The dual effect of morphine on tumor development

Morphine is a classic opioid drug used for reducing pain and is commonly prescribed as an effective drug to control cancer pain. Morphine has a direct role in the central nervous system to relieve pain, but because of its peripheral functions, morphine also has some side effects, such as nausea, constipation, and addiction (Gupta et al. in Sci World J 2015:10, 2015). In addition to its analgesic effect, the role of morphine in tumor development is an important question that has been investigated for many years with conflicting results. Numerous studies suggest that morphine has a role in both promoting and inhibiting tumor growth. In this extensive review, we attempt to comprehensively understand the effects of morphine and summarize both its positive and negative influences on various aspects of tumors, including tumor growth, angiogenesis, metastasis, inflammation, and immunomodulation.

Neurokinin-1 receptor-based bivalent drugs in pain management: The journey to nowhere?

Hybrid compounds (also known as chimeras, designed multiple ligands, bivalent compounds) are chemical units where two active components, usually possessing affinity and selectivity for distinct molecular targets, are combined as a single chemical entity. The rationale for using a chimeric approach is well documented as such novel drugs are characterized by their enhanced enzymatic stability and biological activity. This allows their use at lower concentrations, increasing their safety profile, particularly when considering undesirable side effects. In the group of synthetic bivalent compounds, drugs combining pharmacophores having affinities toward opioid and neurokinin-1 receptors have been extensively studied as potential analgesic drugs. Indeed, substance P is known as a major endogenous modulator of nociception both in the peripheral and central nervous systems. Hence, synthetic peptide fragments showing either agonism or antagonism at neurokinin 1 receptor were both assigned with analgesic properties. However, even though preclinical studies designated neurokinin-1 receptor antagonists as promising analgesics, early clinical studies revealed a lack of efficacy in human. Nevertheless, their molecular combination with enkephalin/endomorphin fragments has been considered as a valuable approach to design putatively promising ligands for the treatment of pain. This paper is aimed at summarizing a 20-year journey to the development of potent analgesic hybrid compounds involving an opioid pharmacophore and devoid of unwanted side effects. Additionally, the legitimacy of considering neurokinin-1 receptor ligands in the design of chimeric drugs is discussed.

The Neurokinins: Peptidomimetic Ligand Design and Therapeutic Applications

The neurokinins are indisputably essential neurotransmitters in numerous pathoand physiological events. Being widely distributed in the Central Nervous System (CNS) and peripheral tissues, their discovery rapidly promoted them to drugs targets. As a necessity for molecular tools to understand the biological role of this class, endogenous peptides and their receptors prompted the scientific community to design ligands displaying either agonist and antagonist activity at the three main neurokinin receptors, called NK1, NK2 and NK3. Several strategies were implemented for this purpose. With a preference to small non-peptidic ligands, many research groups invested efforts in synthesizing and evaluating a wide range of scaffolds, but only the NK1 antagonist Aprepitant (EMENDT) and its prodrug Fosaprepitant (IVEMENDT) have been approved by the Food Drug Administration (FDA) for the treatment of Chemotherapy-Induced and Post-Operative Nausea and Vomiting (CINV and PONV, respectively). While non-peptidic drugs showed limitations, especially in side effect control, peptidic and pseudopeptidic compounds progressively regained attention. Various strategies were implemented to modulate affinity, selectivity and activity of the newly designed ligands. Replacement of canonical amino acids, incorporation of conformational constraints, and fusion with non-peptidic moieties gave rise to families of ligands displaying individual or dual NK1, NK2 and NK3 antagonism, that ultimately were combined with non-neurokinin ligands (such as opioids) to target enhanced biological impact.

Human acute myeloid leukemia cells express Neurokinin-1 receptor, which is involved in the antileukemic effect of Neurokinin-1 receptor antagonists

The substance P/neurokinin-1 receptor system has been implicated in tumor cell proliferation. Neurokinin-1 receptor has been identified in different solid tumors but not frequently in hematopoietic malignant cells. We investigated the presence of the Neurokinin-1 receptor in acute myeloid leukemia cell lines (KG-1 and HL-60), demonstrating that acute myeloid leukemia cell lines overexpress the truncated Neurokinin-1 receptor isoform compared with lymphocytes from healthy donors. Using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) method, we demonstrated that substance P induced cell proliferation in both acute myeloid leukemia cell lines. We also observed that four different Neurokinin-1 receptor antagonists (L-733,060, L-732,138, CP 96-345 and aprepitant) elicited inhibition of acute myeloid leukemia cell growth lines in a concentration-dependent manner, while growth inhibition was only marginal in lymphocytes; the specific antitumor action of Neurokinin-1 receptor antagonists occurs via the Neurokinin-1 receptor, and leukemia cell death is due to apoptosis. Finally, administration of high doses of daily intraperitoneal fosaprepitant to NOD scid gamma mice previously xenografted with the HL60 cell line increased the median survival from 4 days (control group) to 7 days (treated group) (p = 0.059). Taken together, these findings suggest that Neurokinin-1 receptor antagonists suppress leukemic cell growth and may be considered to be potential antitumor drugs for the treatment of human acute myeloid leukemia.

Synthesis and Evaluation of a Novel 64Cu- and 67Ga-Labeled Neurokinin 1 Receptor Antagonist for in Vivo Targeting of NK1R-Positive Tumor Xenografts

Neurokinin 1 receptor (NK1R) is expressed in gliomas and neuroendocrine malignancies and represents a promising target for molecular imaging and targeted radionuclide therapy. The goal of this study was to synthesize and evaluate a novel NK1R ligand (NK1R-NOTA) for targeting NK1R-expressing tumors. Using a carboxymethyl moiety linked to L-733060 as a starting reagent, NK1R-NOTA was synthesized in a three-step reaction and then labeled with ⁶⁴Cu (or ⁶⁷Ga for in vitro studies) in the presence of CH₃COONH₄ buffer. The radioligand affinity and cellular uptake were evaluated with NK1R-transduced HEK293 cells (HEK293-NK1R) and NK1R nontransduced HEK293 cells (HEK293-WT) and their xenografts. Radiolabeled NK1R-NOTA was obtained with a radiochemical purity of >95% and specific activities of >7.0 GBq/μmol for ⁶⁴Cu and >5.0 GBq/μmol for ⁶⁷Ga. Both ⁶⁴Cu- and ⁶⁷Ga-labeled NK1R-NOTA demonstrated high levels of uptake in HEK293-NK1R cells, whereas co-incubation with an excess of NK1R ligand L-733060 reduced the level of uptake by 90%. Positron emission tomography (PET) imaging showed that [⁶⁴Cu]NK1R-NOTA had a accumulated rapidly in HEK293-NK1R xenografts and a 10-fold lower level of uptake in HEK293-WT xenografts. Radioactivity was cleared by gastrointestinal tract and urinary systems. Biodistribution studies confirmed that the tumor-to-organ ratios were ≥5 for all studied organs at 1 h p.i., except kidneys, liver, and intestine, and that the tumor-to-intestine and tumor-to-kidney ratios were also improved 4 and 20 h post-injection. [⁶⁴Cu]NK1R-NOTA is a promising ligand for PET imaging of NK1R-expressing tumor xenografts. Delayed imaging with [⁶⁴Cu]NK1R-NOTA improves image contrast because of the continuous clearance of radioactivity from normal organs.

Role of the nervous system in cancer metastasis

Cancer remains as one of the leading cause of death worldwide. The development of cancer involves an intricate process, wherein many identified and unidentified factors play a role. Although most studies have focused on the genetic abnormalities which initiate and promote cancer, there is overwhelming evidence that tumors interact within their environment by direct cell-to-cell contact and with signaling molecules, suggesting that cancer cells can influence their microenvironment and bidirectionally communicate with other systems. However, only in recent years the role of the nervous system has been recognized as a major contributor to cancer development and metastasis. The nervous system governs functional activities of many organs, and, as tumors are not independent organs within an organism, this system is integrally involved in tumor growth and progression.

Neuroendocrine Factors and Head and Neck Squamous Cell Carcinoma: An Affair to Remember

Head and neck squamous cell carcinoma (HNSCC) is one of the most aggressive malignancies. Therefore, the major goal of cancer treatment is inhibition of tumor cell growth and of metastasis development. In order to choose the best management option for HNSCC patients, we need to identify reliable prognostic factors and to develop new molecular techniques in order to obtain a better understanding of therapy resistance. By acting as neurohormones, neurotransmitters, or neuromodulators, the neuroendocrine factors are able to signal the maintenance of physiological homeostasis or progression to malignant disease. Certain neuropeptides possess strong antitumor properties acting as tumor suppressors and immunomodulators, providing additional benefits for future potential therapeutic strategies. In light of the current understanding, cancer starts as a localized disease that can be effectively treated if discovered on proper time. Unfortunately, more than often cancer cells migrate to the surrounding tissues generating distant metastases, thus making the prognosis and survival in this stage much worse. As cellular migration is mandatory for tumor invasion and metastasis development, searching for alternate controllers of these processes, such as the neuroendocrine factors, it is an active tremendous task.

Neurokinin-1 receptor blocker CP-99 994 improved emesis induced by cisplatin via regulating the activity of gastric distention responsive neurons in the dorsal motor nucleus of vagus and enhancing gastric motility in rats

BACKGROUND

Nowadays, chemotherapy induced nausea and vomiting (CINV) is still common in patients with cancer. It was reported that substance P mediated CINV via neurokinin-1 (NK₁ ) receptor and antagonists of NK₁ receptor has been proved useful for treating CINV but the mechanism are not fully understood. This study aimed to examine the role of NK₁ receptor blocker, CP-99 994, when administrated into dorsal motor nucleus of vagus (DMNV), on the cisplatin-induced emesis in rats and the possible mechanism.

METHODS

Rats' kaolin intake, food intake, and bodyweight were recorded every day; gastric contraction activity was recorded in conscious rats through a force transducer implanted into the stomach; gastric emptying was monitored using the phenol red method; single unit extracellular firing in the DMNV were recorded.

KEY RESULTS

DMNV microinjection of CP-99 994 reduced the changes of increased kaolin consumption and suppressed food intake in cisplatin-treated rats; enhanced the gastric contraction activity dose-dependently in control and cisplatin-treated rats but enhanced gastric emptying only in cisplatin-treated rats; reduced the firing rate of gastric distention inhibited (GD-I) neurons but increased the firing rate of GD excited (GD-E) neurons in the DMNV. The effects of CP-99 994 on gastric motility and neuronal activity were stronger in cisplatin-treated rats than those of control rats.

CONCLUSIONS AND INFERENCES

Our results suggested that CP-99 994 could improve emesis induced by cisplatin by regulating gastric motility and gastric related neuronal activity in the DMNV.

Does Opioid Use Cause Angiogenesis and Metastasis?

Objective

To provide a comprehensive overview of the potential for morphine to lead to angiogenesis and metastasis.

Background

Morphine is often the treatment of choice for severe cancer-related pain. Small studies have been emerging that indicate that opioids may influence angiogenesis and metastasis, but this has not yet been comprehensively synthesized.

Purpose

To highlight morphine's relationship with angiogenesis and metastasis in in vitro models.

Method

A review of the literature was conducted using PubMed (1966 to 2015) and Cochrane Library (1987 to 2015) electronic databases. The search, as well as consultation with experts, yielded 84 articles for initial review, 12 of which met inclusion for review. Possible theories of the underlying etiology of the metastasis and angiogenesis were recorded.

Results

All studies were assessed using the PRISMA checklist.

Conclusion

This systematic review demonstrates that morphine has a potential causal relationship with angiogenesis and metastasis. This is likely due to multiple etiologies, including immunosuppressive, pro-inflammatory, and pro-angiogenetic.

Substance P Regulation in Epilepsy

Background:

Epilepsy is a common neurological disease characterized by abnormal temporary discharge of neurons in the central nervous system. In recent years, studies have revealed the localization and changes in the density of neuropeptides, such as substance P (SP) in the pathogenesis of epilepsy. This review is a concise overview of SP and their physiologic and pathologic functions on regulating epilepsy, and the underline mechanisms.

Methods:

We research and collect relative online content for reviewing the effects of SP in Epilepsy.

Results:

The SP/NK-1 receptor system may induce seizures and play an important role in status epilepticus and in experimental animal models of epilepsy. Newest studies show that several mechanisms may explain the excitatory effects of the SP/NK-1 receptor signaling pathway in epilepsy. By binding to the NK-1 receptor, NK-1 receptor antagonists may block the pathophysiological effects of SP, and further studies are needed to confirm the possible anti-epileptic activity of NK-1 receptor antagonists.

Conclusion:

SP plays crucial roles on through binding with NK-1 receptor during epilepsy pathologic processing, and the NK-1 receptor is receiving a great attention as a therapeutic target for treating epilepsy. Thus, the use of NK-1 receptor antagonists for the treatment of epilepsy should be investigated in further studies.

Neuropeptide gastrin-releasing peptide induces PI3K/reactive oxygen species-dependent migration in lung adenocarcinoma cells

Nerve fibers and neurotransmitters have increasingly been shown to have a role in tumor progression. Gastrin-releasing peptide is a neuropeptide linked to tumor aggressiveness, acting as an autocrine tumor growth factor by binding to its receptor, gastrin-releasing peptide receptor, expressed by many tumors. Although neuropeptides have been previously linked to tumor cell proliferation, more recent studies have uncovered roles for neuropeptides in chemotaxis and metastasis. Understanding the precise roles of such peptides in cancer is crucial to optimizing targeted therapy design. We have previously described that gastrin-releasing peptide acts directly as a chemotactic factor for neutrophils, dependent on PI3K, ERK, and p38. In this study, we investigated roles for gastrin-releasing peptide in lung adenocarcinoma. We asked if gastrin-releasing peptide would act as a proliferative and/or chemotactic stimulus for gastrin-releasing peptide receptor-expressing tumor cells. In A549 cells, a non-small cell lung carcinoma line, the treatment with gastrin-releasing peptide leads to activation of AKT and ERK1/2, and production of reactive oxygen species. Gastrin-releasing peptide induced migration of A549 cells, dependent on gastrin-releasing peptide receptor and PI3K, but not ERK. However, no proliferation was observed in these cells in response to gastrin-releasing peptide, and gastrin-releasing peptide did not promote resistance to treatment with a chemotherapy drug. Our results suggest that, similar to what happens in neutrophils, gastrin-releasing peptide is a migratory, rather than a proliferative, stimulus, for non-small cell lung carcinoma cells, indicating a putative role for gastrin-releasing peptide and gastrin-releasing peptide receptor in metastasis.

The NK-1 receptor antagonist L-732,138 induces apoptosis in human gastrointestinal cancer cell lines

BACKGROUND

Gastric and colon cancer cells express the neurokinin-1 receptor (NK-1R) and the peptide substance P (SP), after binding to this receptor, elicits the proliferation of gastrointestinal cancer cells and an antiapoptotic effect. In these cells, NK-1R antagonists (L-733,060: a piperidine derivative; aprepitant: a morpholine derivative) block, after binding to the NK-1R, the action of SP and exert an antiproliferative action, both antagonists promote apoptosis and the death of cancer cells. However, it is currently unknown whether tryptophan derivative NK-1R antagonists (e.g., L-732,138) exert an antiproliferative effect against gastrointestinal cancer cells. L-732,138, L-733,060 and aprepitant being structurally unrelated compounds show a high specificity for the NK-1R.

METHODS

To determine the number of viable cells, a Coulter counter was performed. For evaluation of tumor cell viability, an MTS colorimetric method was conducted. For apoptosis, a DAPI stain was carried out.

RESULTS

L-732,138 blocked, in a concentration-dependent manner, the proliferation of gastrointestinal cancer cells (IC₅₀: 75.28 and IC₁₀₀: 127.4 for human SW-403 colon carcinoma cell line; IC₅₀: 76.8 and IC₁₀₀: 157.2 for 23132-87 gastric carcinoma cell line. Level of significance: p≤0.01). The antitumor effect elicited by L-732,138 was via the NK-1R and, in addition, 72.1% and 59.3% apoptotic cells (chromatin condensation and nuclear fragmentation) were respectively found in gastric and colon cancer cell lines when L-732,138 (at IC₁₀₀ concentration) was administered.

CONCLUSION

It seems that the NK-1R is an emerging drug target for the treatment of gastrointestinal cancer and that the tryptophan derivative NK-1R antagonist L-732,138 must be considered as an anticancer drug in gastrointestinal cancer.

Ketamine suppresses the substance P-induced production of IL-6 and IL-8 by human U373MG glioblastoma/astrocytoma cells

The neuropeptide substance P (SP) is an important mediator of neurogenic inflammation within the central and peripheral nervous systems. SP has been shown to induce the expression of pro-inflammatory cytokines implicated in the pathogenesis of several disorders of the human brain via the neurokinin-1 receptor (NK-1R). Ketamine, an intravenous anesthetic agent, functions as a competitive antagonist of the excitatory neurotransmission N-methyl-D‑aspartate (NMDA) receptor, and also antagonizes the NK-1R by interfering with the binding of SP. In the present study, we investigated the anti-inflammatory effects of ketamine on the SP-induced activation of a human astrocytoma cell line, U373MG, which expresses high levels of NK-1R. The results from our experiments indicated that ketamine suppressed the production of interleukin (IL)-6 and IL-8 by the U373MG cells. Furthermore, ketamine inhibited the SP-induced activation of extracellular signal‑regulated kinase (ERK)1/2, p38 mitogen-activated protein kinase (MAPK) and nuclear factor-κB (NF-κB). Taken together, these observations suggest that ketamine may suppress the SP-induced activation (IL-6 and IL-8 production) of U373MG cells by inhibiting the phosphorylation of signaling molecules (namely ERK1/2, p38 MAPK and NF-κB), thereby exerting anti‑inflammatory effects. Thus, ketamine may modulate SP-induced inflammatory responses by NK-1R‑expressing cells through the suppression of signaling molecules (such as ERK1/2, p38 MAPK and NF-κB).

Immunolocalization of substance P and NK-1 receptor in vascular anomalies

The peptide substance P (SP) shows a widespread distribution in both the central and peripheral nervous systems, but it is also ubiquitous in the human body. After binding to the neurokinin-1 (NK-1) receptor, SP regulates tumoral angiogenesis and proliferation. Thus, knowledge of this system is the key for a better understanding and, hence, a better management of many human diseases, including vascular anomalies (VA). This study aims to examine the expression and localization of both SP and the NK-1 receptor in different vascular anomalies using an immunohistochemical technique. Our results demonstrated predominantly nuclear localization of SP in venous malformations and in one haemangioma sample, in contrast with cytoplasmic expression in capillary malformations and rapidly involuting congenital hemangioma (RICH). NK-1 receptor showed a cytoplasmic localization in all VA. In summary, all these findings demonstrate that SP and NK-1 receptor are expressed in VA, with different expression patterns depending on the nature of the anomaly, suggesting that they could play an important role in the pathogenesis of VA.

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.

Inhibition of tachykinin NK1 receptor using aprepitant induces apoptotic cell death and G1 arrest through Akt/p53 axis in pre-B acute lymphoblastic leukemia cells

Increasing number of genetic and cancer biology studies indicated a prominent role for tachykinin NK₁ receptor (NK₁R) in cancer cell growth and survival. Considering the fact that neoplastic lymphoid precursors in acute lymphoblastic leukemia (ALL) carry a three- to four-fold NK₁R expression as compared to normal lymphocytes, using NK₁R antagonist seems to be noteworthy in the treatment of ALL patients. In this study, we found that inhibition of NK₁R with aprepitant, a selective high-affinity antagonist of the human NK₁R, exerts cytotoxic and anti-proliferative effects against pre-B ALL-derived Nalm-6 cells either as single drug or in combination with doxorubicin. Our data showed that treatment of the cells with the inhibitor resulted in apoptotic cell death, at least partly, through abrogation of PI3K/Akt pathway, as revealed by the reduction of phospho/total Akt ratio. In agreement with the inhibitory effect on Akt, we also found that aprepitant increased the expression level of p21 and p27, which in turn leads to the induction of G1 cell cycle arrest. Overall, this study recommends mechanistic pathways by which inhibition of NK₁R can augment apoptotic cell death through a plausible p53-dependent pathway rather than NF-κB-depended mechanism in pre-B ALL cells; however, further studies are needed to better characterize the application of NK₁R inhibition in clinical cancer treatment.

Role of substance P in the cardiovascular system

This article provides an overview of the structure and function of substance P signalling system and its involvement in the cardiovascular regulation. Substance P is an undecapeptide originating from TAC1 gen and belonging to the tachykinin family. The biological actions of substance P are mainly mediated through neurokinin receptor 1 since substance P is the ligand with the highest affinity to neurokinin receptor 1. Substance P is widely distributed within the central and peripheral nervous systems as well as in the cardiovascular system. Substance P is involved in the regulation of heart frequency, blood pressure and in the stretching of vessels. Substance P plays an important role in ischemia and reperfusion and cardiovascular response to stress. Additionally, it has been also implicated in angiogenesis, pain transmission and inflammation. The substance P/neurokinin receptor 1 receptor system is involved in the molecular bases of many human pathological processes. Antagonists of neurokinin receptor 1 receptor could provide clinical solutions for a variety of diseases. Neurokinin receptor 1 antagonists are already used in the prevention of chemotherapy induced nausea and vomiting.

Analysis on correlation between SP and NK-1R and intranasal mucosal contact point headache

CONCLUSION

Distribution of SP and NK-1R, especially NK-1R, in nasal mucosal tissue at contact point was higher compared with non-contact point. It was suggested that SP and NK-1R were associated with mucosal contact point headache.

OBJECTIVES

To observe difference of substance P (SP) and NK-1 receptor (NK-1R) expression in tissues at contact point and non-contact point among the patients with intranasal mucosal contact point headache and speculate the role of SP and NK-1R in mucosal contact point headache.

METHODS

SP and NK-1R in tissues of contact point and non-contact point among 40 patients with intranasal mucosal contact point headache were stained histologically by immunohistochemistry, and the mRNA level was detected by RT-PCR.

RESULTS

SP was located in cytoplasm of acini epithelial cells, distributed in nasal mucosa tissues at both contact point and non-contact point. However, stain intensity was significantly increased at contact point (Z = -2.554, p < 0.05). NK-1R was located in the cytoplasm of acinar epithelial cells, inflammatory cells, and nerve fibers of contact point; only in cytoplasm of acinar epithelial cells and nerve fibers of non-contact point. Tinctorial rate of NK-1R increased significantly at contact point (χ(2) = 40.438, p < 0.01). mRNA level of SP and NK-1R was up-regulated in nasal mucosa at contact point compared with non-contact point.

Neurokinin-1 receptor antagonists as antitumor drugs in gastrointestinal cancer: A new approach

Gastrointestinal (GI) cancer is the term for a group of cancers affecting the digestive system. After binding to the neurokinin-1 (NK-1) receptor, the undecapeptide substance P (SP) regulates GI cancer cell proliferation and migration for invasion and metastasis, and controls endothelial cell proliferation for angiogenesis. SP also exerts an antiapoptotic effect. Both SP and the NK-1 receptor are located in GI tumor cells, the NK-1 receptor being overexpressed. By contrast, after binding to the NK-1 receptor, NK-1 receptor antagonists elicit the inhibition (epidermal growth factor receptor inhibition) of the proliferation of GI cancer cells in a concentration-dependent manner, induce the death of GI cancer cells by apoptosis, counteract the Warburg effect, inhibit cancer cell migration (counteracting invasion and metastasis), and inhibit angiogenesis (vascular endothelial growth factor inhibition). NK-1 receptor antagonists are safe and well tolerated. Thus, the NK-1 receptor could be considered as a new target in GI cancer and NK-1 receptor antagonists (eg, aprepitant) could be a new promising approach for the treatment of GI cancer.

Neuropeptide Y is a physiological substrate of fibroblast activation protein: Enzyme kinetics in blood plasma and expression of Y2R and Y5R in human liver cirrhosis and hepatocellular carcinoma

Fibroblast activation protein (FAP) is a dipeptidyl peptidase (DPP) and endopeptidase that is weakly expressed in normal adult human tissues but is greatly up-regulated in activated mesenchymal cells of tumors and chronically injured tissue. The identities and locations of target substrates of FAP are poorly defined, in contrast to the related protease DPP4. This study is the first to characterize the physiological substrate repertoire of the DPP activity of endogenous FAP present in plasma. Four substrates, neuropeptide Y (NPY), peptide YY, B-type natriuretic peptide and substance P, were analyzed by mass spectrometry following proteolysis in human or mouse plasma, and by in vivo localization in human liver tissues with cirrhosis and hepatocellular carcinoma (HCC). NPY was the most efficiently cleaved substrate of both human and mouse FAP, whereas all four peptides were efficiently cleaved by endogenous DPP4, indicating that the in vivo degradomes of FAP and DPP4 differ. All detectable DPP-specific proteolysis and C-terminal processing of these neuropeptides was attributable to FAP and DPP4, and plasma kallikrein, respectively, highlighting their combined physiological significance in the regulation of these neuropeptides. In cirrhotic liver and HCC, NPY and its receptor Y2R, but not Y5R, were increased in hepatocytes near the parenchymal-stromal interface where there is an opportunity to interact with FAP expressed on nearby activated mesenchymal cells in the stroma. These novel findings provide insights into the substrate specificity of FAP, which differs greatly from DPP4, and reveal a potential function for FAP in neuropeptide regulation within liver and cancer biology.

Antitumor action of temozolomide, ritonavir and aprepitant against human glioma cells

In the effort to find better treatments for glioblastoma we tested several currently marketed non-chemotherapy drugs for their ability to enhance the standard cytotoxic drug currently used to treat glioblastoma- temozolomide. We tested four antiviral drugs- acyclovir, cidofovir, maraviroc, ritonavir, and an anti-emetic, aprepitant. We found no cytotoxicity of cidofovir and discussed possible reasons for discrepancy from previous findings of others. We also found no cytotoxicity from acyclovir or maraviroc also in contradistinction to predictions. Cytotoxicity to glioma cell line GAMG for temozolomide alone was 14%, aprepitant alone 7%, ritonavir alone 14%, while temozolomide + aprepitant was 19%, temozolomide + ritonavir 34%, ritonavir + aprepitant 64 %, and all three, temozolomide + ritonavir + aprepitant 78%. We conclude that a remarkable synergy exists between aprepitant and ritonavir. Given the long clinical experience with these two well-tolerated drugs in treating non-cancer conditions, and the current median survival of glioblastoma of 2 years, a trial is warranted of adding these two simple drugs to current standard treatment with temozolomide.

Biological and Pharmacological Aspects of the NK1-Receptor

The neurokinin 1 receptor (NK-1R) is the main receptor for the tachykinin family of peptides. Substance P (SP) is the major mammalian ligand and the one with the highest affinity. SP is associated with multiple processes: hematopoiesis, wound healing, microvasculature permeability, neurogenic inflammation, leukocyte trafficking, and cell survival. It is also considered a mitogen, and it has been associated with tumorigenesis and metastasis. Tachykinins and their receptors are widely expressed in various human systems such as the nervous, cardiovascular, genitourinary, and immune system. Particularly, NK-1R is found in the nervous system and in peripheral tissues and are involved in cellular responses such as pain transmission, endocrine and paracrine secretion, vasodilation, and modulation of cell proliferation. It also acts as a neuromodulator contributing to brain homeostasis and to sensory neuronal transmission associated with depression, stress, anxiety, and emesis. NK-1R and SP are present in brain regions involved in the vomiting reflex (the nucleus tractus solitarius and the area postrema). This anatomical localization has led to the successful clinical development of antagonists against NK-1R in the treatment of chemotherapy-induced nausea and vomiting (CINV). The first of these antagonists, aprepitant (oral administration) and fosaprepitant (intravenous administration), are prescribed for high and moderate emesis.