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

Harnessing the synergistic potential of NK1R antagonists and selective COX-2 inhibitors for simultaneous targeting of TNBC cells and cancer stem cells

Triple-negative breast cancer (TNBC) lacks the expression of oestrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), rendering it unresponsive to endocrine therapy and HER2 targeted treatments. Though certain chemotherapeutics targeting the cell cycle have shown efficacy to a certain extent, the presence of chemotherapy-resistant cancer stem cells (CSCs) presents a significant challenge in tackling TNBC. Multiple lines of evidence suggest the upregulation of neuropeptide Substance P (SP), its NK-1 receptor (NK1R) and the Cyclooxygenase-2 (COX-2) enzyme in TNBC patients. Upregulation of the SP/NK1R system and COX-2 influences major signalling pathways involved in cell proliferation, growth, survival, angiogenesis, inflammation, metastasis and stem cell activity. The simultaneous activation and crosstalk between the pathways activated by SP/NK1R and COX-2 consequently increase the levels of key regulators of self-renewal pathways in CSCs, promoting stemness. The combination therapy with NK1R antagonists and COX-2 inhibitors can simultaneously target TNBC cells and CSCs, thereby enhancing treatment efficacy and reducing the risk of recurrence and relapse. This review discusses the rationale for combining NK1R antagonists and COX-2 inhibitors for the better management of TNBC and a novel strategy to deliver drug cargo precisely to the tumour site to address the challenges associated with off-target binding.

Stroke risk in rheumatoid arthritis patients: exploring connections and implications for patient care

Rheumatoid arthritis (RA) can independently increase the risk of stroke, affecting both young and adult RA patients. Recent attention has been drawn to the association between stroke and RA, supported by mounting evidence. Given that stroke is a significant and an urgent public health concern, this review aims to highlight the relationship between stroke and RA, covering mechanisms, underlying risk factors, early detection tools, and treatment implications. By uncovering the connection that links RA to stroke, we can pave the way for targeted healthcare practices and the development of preventive strategies for individuals with RA. Therefore, further research is imperative to deepen our understanding of this association and, ideally, guide treatment decisions for individuals at risk of both RA and stroke.

Neurokinin-2 receptor negatively modulates substance P responses by forming complex with Neurokinin-1 receptor

BACKGROUND

Tachykinins and their cognate receptors, neurokinin receptors (NKs) including NK1, NK2, and NK3 play vital roles in regulating various physiological processes including neurotransmission, nociception, inflammation, smooth muscle contractility, and stimulation of endocrine and exocrine gland secretion. Their abnormal expression has been reported to be associated with neurological disorders, inflammation, and cancer. Even though NKs are expressed in the same cells with their expression being inversely correlated in some conditions, there is no direct evidence to prove their interaction. Understanding the functional crosstalk between NKs in mediated downstream signaling and cellular responses may elucidate the roles of each receptor in pathophysiology.

RESULTS

In this study, we showed that NKs were co-expressed in some cells. However, different from NK3, which only forms homodimerization, we demonstrated a direct interaction between NK1 and NK2 at the protein level using co-immunoprecipitation and NanoBiT-based protein interaction analysis. Through heterodimerization, NK2 downregulated substance P-stimulated NK1 signals, such as intracellular Ca2+ mobilization and ERK phosphorylation, by enhancing β-arrestin recruitment, even at the ligand concentration that could not activate NK2 itself or in the presence of NK1 specific antagonist, aprepitant. In A549 cells with receptors deleted and reconstituted, NK2 exerted a negative effect on substance P/NK1-mediated cell migration.

CONCLUSION

Our study has provided the first direct evidence of an interaction between NK1 and NK2, which highlights the functional relevance of their heterodimerization in cellular responses. Our findings demonstrated that through dimerization, NK2 exerts negative effects on downstream signaling and cellular response mediated by NK1. Moreover, this study has significant implications for understanding the complexity of GPCR dimerization and its effect on downstream signaling and cellular responses. Given the important roles of tachykinins and NKs in pathophysiology, these insights may provide clues for developing NKs-targeting drugs.

Illuminating the structural basis of human neurokinin 1 receptor (NK1R) antagonism through classical all-atoms molecular dynamics simulations

Advances in structural biology have bestowed insights into the pleiotropic effects of neurokinin 1 receptors (NK1R) in diverse patho-physiological processes, thereby highlighting the potential therapeutic value of antagonists directed against NK1R. Herein, we investigate the mode of antagonist recognition to discern the obscure atomic facets germane for the function and molecular determinants of NK1R. To commence discernment of potent antagonists and the conformational changes in NK1R, induced upon antagonist binding, state-of-the-art classical all-atoms molecular dynamics (MD) simulations in lipid mimetic bilayers have been utilized. MD simulations of structural ensembles reveals the involvement of TM5 and TM6 in tight anchoring of antagonists through a network of interhelical hydrogen-bonds, while, the extracellular loop 2 (ECL2) governs the overall size and nature of the pocket, thereby modulating NK1R. Consistent comparison between experiments and MD simulation results discerns the predominant role of TM3, TM4, and TM6 in lipid-NK1R interaction. Correlation between hydrophobic index and helicity of TM domains elucidates their importance in maintaining the structural stability in addition to regulating NK1R antagonism. Taken together, we anticipate that our computational study marks a comprehensive structural basis of NK1R antagonism in lipid bilayers, which may facilitate designing of new therapeutics against associated diseases targeting human neurokinin receptors.

Post COVID-19 complications and follow up biomarkers

Millions of people were infected by the coronavirus disease (COVID-19) epidemic, which left a huge burden on the care of post COVID-19 survivors around the globe. The self-reported COVID-19 symptoms were experienced by an estimated 1.3 million people in the United Kingdom (2% of the population), and these symptoms persisted for about 4 weeks from the beginning of the infection. The symptoms most frequently reported were exhaustion, shortness of breath, muscular discomfort, joint pain, headache, cough, chest pain, cognitive impairment, memory loss, anxiety, sleep difficulties, diarrhea, and a decreased sense of smell and taste in post-COVID-19 affected people. The post COVID-19 complications were frequently related to the respiratory, cardiac, nervous, psychological and musculoskeletal systems. The lungs, liver, kidneys, heart, brain and other organs had been impaired by hypoxia and inflammation in post COVID-19 individuals. The upregulation of substance "P" (SP) and various cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), interleukin 10 (IL-10), interleukin 1 beta (IL-1β), angiotensin-converting enzyme 2 (ACE2) and chemokine C-C motif ligand 3 (CCL3) has muddled respiratory, cardiac, neuropsychiatric, dermatological, endocrine, musculoskeletal, gastrointestinal, renal and genitourinary complications in post COVID-19 people. To prevent these complications from worsening, it was therefore important to study how these biomarkers were upregulated and block their receptors.

The Role of Substance P Within Traumatic Brain Injury and Implications for Therapy

This review examines the role of the neuropeptide substance P within the neuroinflammation that follows traumatic brain injury. It examines it in reference to its preferential receptor, the neurokinin-1 receptor, and explores the evidence for antagonism of this receptor in traumatic brain injury with therapeutic intent. Expression of substance P increases following traumatic brain injury. Subsequent binding to the neurokinin-1 receptor results in neurogenic inflammation, a cause of deleterious secondary effects that include an increased intracranial pressure and poor clinical outcome. In several animal models of TBI, neurokinin-1 receptor antagonism has been shown to reduce brain edema and the resultant rise in intracranial pressure. A brief overview of the history of substance P is presented, alongside an exploration into the chemistry of the neuropeptide with a relevance to its functions within the central nervous system. This review summarizes the scientific and clinical rationale for substance P antagonism as a promising therapy for human TBI.

Comprehensive analysis of the progression mechanisms of CRPC and its inhibitor discovery based on machine learning algorithms

Background: Almost all patients treated with androgen deprivation therapy (ADT) eventually develop castration-resistant prostate cancer (CRPC). Our research aims to elucidate the potential biomarkers and molecular mechanisms that underlie the transformation of primary prostate cancer into CRPC. Methods: We collected three microarray datasets (GSE32269, GSE74367, and GSE66187) from the Gene Expression Omnibus (GEO) database for CRPC. Differentially expressed genes (DEGs) in CRPC were identified for further analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and gene set enrichment analysis (GSEA). Weighted gene coexpression network analysis (WGCNA) and two machine learning algorithms were employed to identify potential biomarkers for CRPC. The diagnostic efficiency of the selected biomarkers was evaluated based on gene expression level and receiver operating characteristic (ROC) curve analyses. We conducted virtual screening of drugs using AutoDock Vina. In vitro experiments were performed using the Cell Counting Kit-8 (CCK-8) assay to evaluate the inhibitory effects of the drugs on CRPC cell viability. Scratch and transwell invasion assays were employed to assess the effects of the drugs on the migration and invasion abilities of prostate cancer cells. Results: Overall, a total of 719 DEGs, consisting of 513 upregulated and 206 downregulated genes, were identified. The biological functional enrichment analysis indicated that DEGs were mainly enriched in pathways related to the cell cycle and metabolism. CCNA2 and CKS2 were identified as promising biomarkers using a combination of WGCNA, LASSO logistic regression, SVM-RFE, and Venn diagram analyses. These potential biomarkers were further validated and exhibited a strong predictive ability. The results of the virtual screening revealed Aprepitant and Dolutegravir as the optimal targeted drugs for CCNA2 and CKS2, respectively. In vitro experiments demonstrated that both Aprepitant and Dolutegravir exerted significant inhibitory effects on CRPC cells (p < 0.05), with Aprepitant displaying a superior inhibitory effect compared to Dolutegravir. Discussion: The expression of CCNA2 and CKS2 increases with the progression of prostate cancer, which may be one of the driving factors for the progression of prostate cancer and can serve as diagnostic biomarkers and therapeutic targets for CRPC. Additionally, Aprepitant and Dolutegravir show potential as anti-tumor drugs for CRPC.

NPFF stimulates human ovarian cancer cell invasion by upregulating MMP-9 via ERK1/2 signaling

Neuropeptide FF (NPFF) belongs to the RFamide peptide family. NPFF regulates a variety of physiological functions by binding to a G protein-coupled receptor, NPFFR2. Epithelial ovarian cancer (EOC) is a leading cause of death among gynecological malignancies. The pathogenesis of EOC can be regulated by many local factors, including neuropeptides, through an autocrine/paracrine manner. However, to date, the expression and/or function of NPFF/NPFFR2 in EOC is undetermined. In this study, we show that the upregulation of NPFFR2 mRNA was associated with poor overall survival in EOC. The TaqMan probe-based RT-qPCR showed that NPFF and NPFFR2 were expressed in three human EOC cells, CaOV3, OVCAR3, and SKOV3. In comparison, NPFF and NPFFR2 expression levels were higher in SKOV3 cells than in CaOV3 or OVCAR3 cells. Treatment of SKOV3 cells with NPFF did not affect cell viability and proliferation but stimulated cell invasion. NPFF treatment upregulates matrix metalloproteinase-9 (MMP-9) expression. Using the siRNA-mediated knockdown approach, we showed that the stimulatory effect of NPFF on MMP-9 expression was mediated by the NPFFR2. Our results also showed that ERK1/2 signaling was activated in SKOV3 cells in response to the NPFF treatment. In addition, blocking the activation of ERK1/2 signaling abolished the NPFF-induced MMP-9 expression and cell invasion. This study provides evidence that NPFF stimulates EOC cell invasion by upregulating MMP-9 expression through the NPFFR2-mediated ERK1/2 signaling pathway.

Angiotensin-Converting Enzyme and Hypertension: A Systemic Analysis of Various ACE Inhibitors, Their Side Effects, and Bioactive Peptides as a Putative Therapy for Hypertension

Hypertension is a major risk factor for heart attack, produce atherosclerosis (hardening of the arteries), congestive heart failure, stroke, kidney infection, blindness, end-stage renal infection, and cardiovascular diseases. Many mechanisms are involved in causing hypertension, i.e., via calcium channels, alpha and beta receptors, and the renin-angiotensin system (RAS). RAS has an important role in blood pressure control and is also involved in the metabolism of glucose, homeostasis, and balance of electrolytes in the body. The components of RAS that are involved in the regulation of blood pressure are angiotensinogen, Ang I (angiotensin I), Ang II (angiotensin II), ACE (angiotensin-converting enzyme), and ACE 2 (angiotensin-converting enzyme 2). These components provide for relevant therapeutic targets for the treatment of hypertension, and various drugs are commercially available that target individual components of RAS. Angiotensin receptor blockers (ARBs) and ACE inhibitors are the most popular among these drugs. ACE is chosen in this review as it makes an important target for blood pressure control because it converts Ang I into Ang II and also acts on the vasodilator, bradykinin, to degrade it into inactive peptides. This review highlights various aspects of blood pressure regulation in the body with a focus on ACE, drugs targeting the components involved in regulation, their associated side effects, and a need to shift to alternative therapy for putative hypertension treatment in the form of bioactive peptides from food.

Chronic pruritus: from pathophysiology to drug design

Pruritus, the most common symptom in dermatology, is an innate response capable of protecting skin against irritants. Nonetheless, when it lasts more than six weeks it is assumed to be a chronic pathology having a negative impact on people's lives. Chronic pruritus (CP) can occur in common and rare skin diseases, having a high prevalence in global population. The existing therapies are unable to counteract CP or are associated with adverse effects, so the development of effective treatments is a pressing issue. The pathophysiological mechanisms underlying CP are not yet completely dissected but, based on current knowledge, involve a wide range of receptors, namely neurokinin 1 receptor (NK1R), Janus kinase (JAK), and transient receptor potential (TRP) ion channels, especially transient receptor potential vanilloid 1 (TRPV1) and transient receptor potential ankyrin 1 (TRPA1). This review will address the relevance of these molecular targets for the treatment of CP and molecules capable of modulating these receptors that have already been studied clinically or have the potential to possibly alleviate this pathology. According to scientific and clinical literature, there is an increase in the expression of these molecular targets in the lesioned skin of patients experiencing CP when compared with non-lesioned skin, highlighting their importance for the development of potential efficacious drugs through the design of antagonists/inhibitors.

Neurokinin-1 Receptor Antagonists as a Potential Novel Therapeutic Option for Osteosarcoma Patients

Osteosarcoma is a bone tumor predominantly affecting children and adolescents with high malignant potential. It is a cause of serious public health challenges due to its high morbidity rates and metastatic potential. Metastasis in osteosarcoma may manifest either during treatment of the primary tumor, shortly after treatment, or a long time after the end of the treatment. So far, there are no therapeutics that can prevent or treat osteosarcoma metastasis. The peptide substance P (SP) and its high-affinity receptor, Neurokinin-1 (NK-1R), are known to positively correlate with osteosarcoma progression. Osteosarcoma cells overexpress NK-1R. SP is known to elicit the proliferation of osteosarcoma cells and induce angiogenesis and migration, leading to the invasion and metastasis of tumor cells. In contrast, NK-1R antagonists, such as aprepitant, inhibit the proliferation and induce the apoptosis of osteosarcoma cells. Aprepitant is also known to inhibit the migration of osteosarcoma cells, as well as reduce the expression levels and activities of transcriptional regulators of metastasis-related genes such as matrix metalloproteinases (MMP-2 and MMP-9), vascular endothelial growth factor (VEGF), and nuclear factor kappa B (NF-κB). These preceding studies highlighted the antimetastatic role of aprepitant in osteosarcoma Moreover, combination therapy consisting of chemotherapy and NK-1R antagonist increases the chemosensitization of osteosarcoma cells. Interestingly, this combination therapy in vitro and in vivo decreases the severe side-effects of chemotherapy and produces neuroprotection, hepatoprotection, nephroprotection, and cardioprotection. In this review, we provide an update on existing data and suggest the need to repurpose aprepitant for use as an antitumor drug for treatment of osteosarcoma, and they suggest the need for phase I and II clinical trials for assessment of its safety/efficacy.

Tachykinin Receptor-Selectivity of the Potential Glioblastoma-Targeted Therapy, DOTA-[Thi8,Met(O2)11]-Substance P

Radiopharmaceutical development hinges on the affinity and selectivity of the biological component for the intended target. An analogue of the neuropeptide Substance P (SP), 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid-[Thi8,Met(O2)11]-SP (DOTA-[Thi8,Met(O2)11]SP), in the theranostic pair [68Ga]Ga-/ [213Bi]Bi-DOTA-[Thi8,Met(O2)11]SP has shown promising clinical results in the treatment of inoperable glioblastoma. As the theranostic targeting component, modifications to SP that affect the selectivity of the resulting analogue for the intended target (neurokinin-1 receptor [NK1R]) could be detrimental to its therapeutic potential. In addition to other closely related tachykinin receptors (neurokinin-2 receptor [NK2R] and neurokinin-3 receptor [NK3R]), SP can activate a mast cell expressed receptor Mas-related G protein-coupled receptor subtype 2 (MRGPRX2), which has been implicated in allergic-type reactions. Therefore, activation of these receptors by SP analogues has severe implications for their therapeutic potential. Here, the receptor selectivity of DOTA-[Thi8,Met(O2)11]SP was examined using inositol phosphate accumulation assay in HEK293-T cells expressing NK1R, NK2R, NK3R or MRGPRX2. DOTA-[Thi8,Met(O2)11]SP had similar efficacy and potency as native SP at NK1R, but displayed greater NK1R selectivity. DOTA-[Thi8,Met(O2)11]SP was unable to elicit significant activation of the other tachykinin receptors nor MRGPRX2 at high concentrations nor did it display antagonistic behaviour at these receptors. DOTA-[Thi8,Met(O2)11]SP, therefore has high potency and selectivity for NK1R, supporting its potential for targeted theranostic use in glioblastoma multiforme and other conditions characterised by NK1R overexpression.

Dipeptidyl peptidase 4 (DPP-4) inhibitors and the risk of lung cancer: current evidence and future directions

INTRODUCTION

Recent evidence has linked long-term use of angiotensin converting enzyme (ACE) inhibitors with the risk of developing lung cancer by increasing levels of substance P (SP) and bradykinin in lung tissue. DPP-4 inhibitors, by virtue of their mechanism of action, may increase the level of SP and pose a similar risk of incident lung cancer. Concomitant use of DPP-4 inhibitors and ACE inhibitors may further exaggerate this plausible risk.

AREA COVERED

Here we discuss both direct and indirect evidence involving mechanisms by which DPP-4 inhibitors may increase the risk of lung cancer in treated patients. We highlight that increased levels of SP with DPP-4 inhibitor monotherapy and raised levels of both SP and bradykinin with add-on ACE inhibitor therapy may further enhance this risk.

EXPERT OPINION

DPP-4 inhibitors are prescribed in type-2 diabetes mellitus patients with or without cardiovascular disease. When used together, ACE inhibitors and DPP-4 inhibitors may act synergistically and further amplify the lung cancer risk. Consequently, physicians should consider this plausible association while prescribing them concomitantly especially in high-risk individuals. Well-planned research studies are required to assess the association of DPP-4 inhibitors with lung cancer and other adverse effects linked to increased levels of SP and bradykinin.

The role of Substance P in the defense line of the respiratory tract and neurological manifestations post COVID-19 infection

Substance P (SP) has been a great interest for scientists due to its unique properties and involvement in various physiological and pathological phenomenon. It took almost a century for the current understanding of this peptide so far. Its role in brain and gut were initially discussed and later on it was widely studied and observed in cardiovascular system, asthma, traumatic brain injury, immune response, vasodilation, behavior, inflammation, arthritis, cancer, airway hyper responsiveness and respiratory disorders. Involvement of SP in sudden perinatal death and COVID-19 has also been discussed which shed light on its vital role in respiratory rhythm regulation and initiation of cytokine storming in COVID-19. This article will provide a comprehensive overview of the researches done to understand the basic functions and involvement of SP in different processes of cell and its association with various diseases. This article describes the historical and scientific journey of SP from its discovery until today, including its future perspectives.

Prognostic Significance of Substance P and Neurokinin-1 Receptor in Bladder Cancer

Background

Bladder cancer is one of the most common genitourinary cancers with significant mortality. Finding reliable tumor markers and potential drug targets can improve early diagnosis, prognosis, and more effective therapeutic protocols. Previous studies have reported the involvement of the substance P (SP)/neurokinin-1 receptor (NK-1R) system in cancers. The potential prognostic role and the interaction of SP and NK-1R in bladder tumor are yet to be elucidated.

Methods

Serum samples from 22 primarily diagnosed patients with bladder cancer as well as 22 healthy controls were examined for SP level using ELISA method. Tissue distribution of NK-1R in tumor samples and their adjacent normal tissues was evaluated through immunohistochemistry.

Results

Serum SP levels in patients with bladder cancer were higher than the healthy group (p< 0.001) and had a significant correlation with NK-1R staining intensity (p< 0.001), percentage of stained cells (p< 0.001), and NK-1R tissue distribution. Also, the immunoreactivity of NK-1R in cancer samples increased significantly without correlation with tumor characteristics. However, no significant association was found between SP and NK-1R levels with clinical characteristics including tumor size (p= 0.33), tumor stage (p= 0.29), grade (p= 0.93), NK-1R staining intensity (p= 0.53), and percentage of stained cells (p= 0.32).

Discussion

According to our findings, despite the lack of association between SP and NK-1R with clinical characteristics of bladder cancer, their serum levels were higher in patients with bladder cancer. Further studies are needed to confirm the potential prognostic role of SP and NK-1R in bladder cancer.

The Potential In Vitro Inhibitory Effects of Neurokinin-1 Receptor (NK-1R) Antagonist, Aprepitant, in Osteosarcoma Cell Migration and Metastasis

Background

Osteosarcoma, the most frequent osteogenic malignancy, has become a serious public health challenge due to its high morbidity rates and metastatic potential. Recently, the neurokinin-1 receptor (NK-1R) is proved to be a promising target in cancer therapy. This study is aimed at determining the effect of aprepitant, a safe and Food and Drug Administration (FDA) approved NK-1R antagonist, on osteosarcoma cell migration and metastasis, and to explore its underlying mechanism of action.

Methods

Colorimetric MTT assay was employed to assess cell viability and cytotoxicity. A wound-healing assay was used to examine migration ability. The desired genes' protein and mRNA expression levels were measured by western blot assay and quantitative real-time PCR (qRT-PCR), respectively. Gelatinase activity was also measured by zymography.

Results

We found that aprepitant inhibited MG-63 osteosarcoma cell viability in a dose-dependent manner. We also observed that aprepitant inhibited the migrative phenotype of osteosarcoma cells and reduced the expression levels and activities of matrix metalloproteinases (MMP-2 and MMP-9). Aprepitant also reduced the expression of an angiogenic factor, VEGF protein, and NF-κB as an important transcriptional regulator of metastasis-related genes.

Conclusion

Collectively, our observations indicate that aprepitant modulates the metastatic behavior of human osteosarcoma cells, which may be applied to an effective therapeutic approach for patients with metastatic osteosarcoma.

Neuropeptides in Cancer: Friend and Foe?

Neuropeptides are small regulatory molecules found throughout the body, most notably in the nervous, cardiovascular, and gastrointestinal systems. They serve as neurotransmitters or hormones in the regulation of diverse physiological processes. Cancer cells escape normal growth control mechanisms by altering their expression of growth factors, receptors, or intracellular signals, and neuropeptides have recently been recognized as mitogens in cancer growth and development. Many neuropeptides and their receptors exist in multiple subtypes, coupling with different downstream signaling pathways and playing distinct roles in cancer progression. The consideration of neuropeptide/receptor systems as anticancer targets is already leading to new biological and diagnostic knowledge that has the potential to enhance the understanding and treatment of cancer. In this review, recent discoveries regarding neuropeptides in a wide range of cancers, emphasizing their mechanisms of action, signaling cascades, regulation, and therapeutic potential, are discussed. Current technologies used to manipulate and analyze neuropeptides/receptors are described. Applications of neuropeptide analogs and their receptor inhibitors in translational studies and radio-oncology are rapidly increasing, and the possibility for their integration into therapeutic trials and clinical treatment appears promising.

The effect of substance P and its specific antagonist (aprepitant) on the expression of MMP-2, MMP-9, VEGF, and VEGFR in ovarian cancer cells

BACKGROUND

Substance P (SP) has a crucial role in cancer initiation and progression via binding to its specific receptor (NK1R). Various evidence confirmed the overexpression of NK1R and SP in the tissue of multiple cancers, including ovarian cancer. Despite numerous studies, the mechanism of the SP/NK1R system on migration and angiogenesis of ovarian cancer cells has not yet been deciphered. In this study, considering the critical factors in cell migration (MMP-2, MMP-9) and angiogenesis (VEGF, VEGFR), we investigated the possible mechanism of this system in inducing migration and angiogenesis of ovarian cancer cells.

METHODS AND RESULTS

First, the resazurin assay was conducted to evaluate the cytotoxic effect of aprepitant (NK1R antagonist) on the viability of A2780 ovarian cancer cells. After that, the impact of this system and aprepitant on the mRNA expression of the factors mentioned above were studied using RT-PCR. Besides, the scratch assay was performed to confirm the effect of the SP/NK-1R system and aprepitant on cell migration. Our results implied that this system induced cell migration and angiogenesis by increasing the mRNA expression of MMP-2, MMP-9, VEGF, and VEGFR. The obtained results from the scratch assay also confirmed the positive effect of this system on cell migration. Meanwhile, the blocking of NK1R by aprepitant suppresses the SP effects on cell migration and angiogenesis.

CONCLUSIONS

Overall, the SP/NK1R system plays a vital role in ovarian cancer progression, and the inhibition of NK1Rusing aprepitant could inhibit the spread of ovarian cancer cells through metastasis and angiogenesis.

Substance P—Friend or Foe

Substance P (SP), a neuropeptide and pain transmitter has multiple roles and is involved in various processes in the body [...]

Neurokinin-1 Receptor (NK-1R) Antagonists as a New Strategy to Overcome Cancer Resistance

Nowadays, the identification of new therapeutic targets that allow for the development of treatments, which as monotherapy, or in combination with other existing treatments can contribute to improve response rates, prognosis and survival of oncologic patients, is a priority to optimize healthcare within sustainable health systems. Recent studies have demonstrated the role of Substance P (SP) and its preferred receptor, Neurokinin 1 Receptor (NK-1R), in human cancer and the potential antitumor activity of NK-1R antagonists as an anticancer treatment. In this review, we outline the relevant studies published to date regarding the SP/NK-1R complex as a key player in human cancer and also evaluate if the repurposing of already marketed NK-1R antagonists may be useful in the development of new treatment strategies to overcome cancer resistance.

The Prognostic Potential of Neurokinin 1 Receptor in Breast Cancer and Its Relationship with Ki-67 Index

Background

Neurokinin 1 receptor (NK1R) is a promising biomarker and therapeutic target in breast cancer. This study was aimed at investigating the expression level of NK1R in breast cancer tissues and its relationship with proliferation index as measured by Ki-67, clinicopathological characteristics of patients, and overall survival rate.

Methods

Immunohistochemical expression of NK1R and Ki-67 was measured in 164 paraffin-embedded breast cancer tissues of four molecular subtypes (42 HER2-enriched, 40 luminal A, 42 luminal B, and 40 triple negative). NK1R was scored semiquantitatively, while Ki-67 was obtained by the percentage of total number of tumor cells with nuclear staining. The optimal cutoff values for NK1R and Ki-67 were assessed by Cutoff Finder. Pearson's Chi-square (χ²) and Fisher's exact tests were used to compare the staining scores between groups. The Kaplan-Meier method with log-rank test was used for survival analysis. ANOVA and Student's t-test were used to compare group means.

Results

A total of 164 patients were included in the study which represented females with invasive ductal carcinoma. NK1R was expressed at high levels in about 34% of investigated cases. The mean Ki-67 level was about 27% and 41.5% of sample had high Ki-67 (expression level > 22%). NK1R expression levels were associated with higher tumor grade (p = 0.021) and high Ki-67 (p = 0.012). NK1R expression negatively impacted overall survival in grade II tumors (p = 0.027).

Conclusion

NK1R contributes to cellular proliferation and is associated with negative prognosis in breast cancer. These findings suggest the potential role of NK1R as a therapeutic target in breast cancer.

In Vitro Biological Evaluation of Aprepitant Based 177Lu-Radioconjugates

Currently, the search for promising NK1R-positive tumor-targeting radiopharmaceuticals based on the structure of small molecular antagonists of neurokinin-1 receptor can be observed. Following this trend, we continued our evaluation of aprepitant-based ¹⁷⁷Lu-radioconjugates in terms of future oncological applications. For this purpose, three novel aprepitant homologues were synthesized to broaden the previously obtained derivative portfolio, functionalized with the DOTA chelator and labeled with ⁶⁸Ga and ¹⁷⁷Lu. The newly evaluated radioconjugates showed the intended significant increase in lipophilicity compared to the previous ones, while maintaining stability in the human serum. Then, in a receptor binding study to the human NK1 receptor, we compared the two series of ¹⁷⁷Lu-radioconjugates of aprepitant with each other and with the reference Substance P derivative currently used in glioblastoma therapy, clearly indicating the high affinity and better binding capacity of the novel radioconjugates. The in vitro experimental results included in the presented study, supported by labeling optimization, radioconjugate characterization and docking modeling of new aprepitant-derived radioagents, confirm our assumptions about the usefulness of aprepitant as a NK1R targeting vector and point out the perspectives for the forthcoming first in vivo trials.

Discovery of a New CaMKII-Targeted Synthetic Lethal Therapy against Glioblastoma Stem-like Cells

Glioblastoma stem-like cells (GSCs) drive tumor initiation, cancer invasion, immune evasion, and therapeutic resistance and are thus a key therapeutic target for improving treatment for glioblastoma multiforme (GBM). We previously identified calcium/calmodulin-dependent protein kinase II (CaMKII) as an emerging molecular target for eliminating GSCs. In this study, we aim to explore a new CaMKII-targeted synthetic lethal therapy for GSCs. Through high-throughput drug combination screening using CaMKII inhibitors and a bioactive compound library in GSCs, neurokinin 1 receptor (NK1R) inhibitors such as SR 140333 and aprepitant are found to be potential anticancer agents that exhibit chemical synthetic lethal interactions with CaMKII inhibitors, including hydrazinobenzoylcurcumin (HBC), berbamine, and KN93. Combined treatment with NK1R and CaMKII inhibitors markedly suppresses the viability and neurosphere formation of U87MG- and U373MG-derived GSCs. In addition, the combination of HBC and NK1R inhibitors significantly inhibits U87MG GSC tumor growth in a chick embryo chorioallantoic membrane (CAM) model. Furthermore, the synthetic lethal interaction is validated using RNA interference of CaMKIIγ and NK1R. Notably, the synthetic lethal effects in GSCs are associated with the activation of caspase-mediated apoptosis by inducing p53 expression and reactive oxygen species generation, as well as the suppression of stemness marker expression by reducing nuclear factor-kappa B (NF-κB) activity. This follows the downregulation of phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling and a decrease in intracellular calcium concentration. Moreover, NK1R affects CaMKIIγ activation. These findings demonstrate that NK1R is a potential synthetic lethal partner of CaMKII that is involved in eradicating GSCs, and they suggest a new CaMKII-targeted combination therapy for treating GBM.

Substance P, A Promising Therapeutic Target in Musculoskeletal Disorders

A large number of studies have focused on the role of substance P (SP) and the neurokinin-1 receptor (NK1R) in the pathogenesis of a variety of medical conditions. This review provides an overview of the role of the SP-NK1R pathway in the pathogenesis of musculoskeletal disorders and the evidence for its role as a therapeutic target for these disorders, which are major public health problems in most countries. To summarize, the brief involvement of SP may affect tendon healing in an acute injury setting. SP combined with an adequate conjugate can be a regenerative therapeutic option in osteoarthritis. The NK1R antagonist is a promising agent for tendinopathy, rheumatoid arthritis, and osteoarthritis. Research on the SP-NK1R pathway will be helpful for developing novel drugs for osteoporosis.

Fibroblast activation protein alpha: Comprehensive detection methods for drug target and tumor marker

Fibroblast activation protein alpha (FAP-α, EC3.4.2. B28), a type II transmembrane proteolytic enzyme for the serine protease peptidase family. It is underexpressed in normal tissues but increased significantly in disease states, especially in neoplasm, which is a potential biomarker to turmor diagnosis. The inhibition of FAP-α activity will retard tumor formation, which is expected to be a promising tumor therapeutic target. At present, although the FAP-α expression detection methods has diversification, a superlative detection means is necessary for the clinical diagnosis. This review covers the discovery and the latest advances in FAP-α, as well as the future research prospects. The tissue distribution, structural characteristics, small-molecule ligands and structure-activity relationship of major inhibitors of FAP-α were summarized in this review. Furthermore, a variety of detection methods including traditional detection methods and emerging probes detection were classified and compared, and the design strategy and kinetic parameters of these FAP-α probe substrates were summarized. In addition, these comprehensive information provides a series of practical and reliable assays for the optimal design principles of FAP-α probes, promoting the application of FAP-α as a disease marker in diagnosis, and a drug target in drug design.

New repurposed rolapitant in nanovesicular systems for lung cancer treatment: Development, in-vitro assessment and in-vivo biodistribution study

Lung cancer is characterized by poor prognosis, and is considered a serious disease that causes a significant mortality. The available conventional chemotherapeutic agents suffer from several limitations; hence, new drug molecules are constantly being sought. In the current study, lipid nanovesicles (LNVs) were selected as a colloidal vehicle for encapsulation of the FDA-approved drug; rolapitant (RP), which is used particularly for the treatment of nausea and vomiting, but is repurposed for the treatment of lung cancer in the current work. RP was loaded into various LNVs (liposomes, ethosomes and transethosomes) using the thin film hydration method, and the LNVs were evaluated for particle size, zeta potential, entrapment efficiency (EE%), storage stability and surface morphology. Besides, the in-vitro drug release, in-vitro cytotoxicity on A549 lung cancer cells, nebulization performance using next generation impactor (NGI), and the in-vivo biodistribution behaviour were evaluated. The selected ethosomal and transethosomal vesicles displayed a particle size less than 400 nm, a positive charge, and EE% exceeding 90% for RP, with a sustained release pattern over 15 days. The in-vivo biodistribution results proved the high lung deposition potential of RP-LNVs with a considerable safety. Besides, the developed RP-LNVs were able to reach the metastatic organs of lung cancer, hence they were proven promising as a possible treatment modality for lung cancer.

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.

The Neurokinin-1 Receptor Is a Target in Pediatric Rhabdoid Tumors

Rhabdoid tumors (RT) are among the most aggressive tumors in early childhood. Overall survival remains poor, and treatment only effectively occurs at the cost of high toxicity and late adverse effects. It has been reported that the neurokinin-1 receptor/ substance P complex plays an important role in cancer and proved to be a promising target. However, its role in RT has not yet been described. This study aims to determine whether the neurokinin-1 receptor is expressed in RT and whether neurokinin-1 receptor (NK1R) antagonists can serve as a novel therapeutic approach in treating RTs. By in silico analysis using the cBio Cancer Genomics Portal we found that RTs highly express neurokinin-1 receptor. We confirmed these results by RT-PCR in both tumor cell lines and in human tissue samples of various affected organs. We demonstrated a growth inhibitory and apoptotic effect of aprepitant in viability assays and flow cytometry. Furthermore, this effect proved to remain when used in combination with the cytostatic cisplatin. Western blot analysis showed an upregulation of apoptotic signaling pathways in rhabdoid tumors when treated with aprepitant. Overall, our findings suggest that NK1R may be a promising target for the treatment of RT in combination with other anti-cancer therapies and can be targeted with the NK1R antagonist aprepitant.

Aprepitant Promotes Caspase-Dependent Apoptotic Cell Death and G2/M Arrest through PI3K/Akt/NF-κB Axis in Cancer Stem-Like Esophageal Squamous Cell Carcinoma Spheres

The antagonists of the neurokinin-1 receptor (NK1R) are known for their anti-inflammatory, anxiolytic, antiemetic, and anticancer activities. Aprepitant, a nonpeptide NK1R antagonist, is used in nausea and vomiting, the most common side effects of cancer chemotherapy in patients. It has been established that NK1R activation by substance P (SP), which links cancer promotion and progression to a neurokinin-mediated environment, became one mechanism that corresponds to the mitogenesis of tumor cells. Therefore, this study is aimed at explaining and evaluating the anticancer impacts of aprepitant on esophageal squamous cancer cell (ESCC) spheres by using in vitro experiments, such as resazurin, ROS, annexin-V binding, RT-PCR, and Western blot analysis. As a result, we showed that aprepitant had strong antiproliferative and cytotoxic effects on ESCC cell spheres. Also, aprepitant caused significant G2-M cell cycle arrest depending on concentration increase. Further, exposure of cells to this agent resulted in caspase -8/-9-dependent apoptotic pathway activation by modifying the expression of genes involved in apoptosis. Besides, treatment of the cells by aprepitant abrogates of the PI3K/Akt pathway, as shown by reducing the level of Akt, induces apoptotic cell death. In summary, pharmacological inhibition of NK1R with aprepitant seems to have a significant chance of treating ESCC as a single agent or in conjunction with other chemotherapeutic drugs.

A Novel Mechanism of Endoplasmic Reticulum Stress- and c-Myc-Degradation-Mediated Therapeutic Benefits of Antineurokinin-1 Receptor Drugs in Colorectal Cancer

The neurokinin-1 receptor (NK-1R) antagonists are approved as treatment for chemotherapy-associated nausea and vomiting in cancer patients. The emerging role of the substance P-NK-1R system in oncogenesis raises the possibility of repurposing well-tolerated NK-1R antagonists for cancer treatment. This study reports that human colorectal cancer (CRC) patients with high NK-1R expression have poor survival, and NK-1R antagonists SR140333 and aprepitant induce apoptotic cell death in CRC cells and inhibit CRC xenograft growth. This cytotoxicity induced by treatment with NK-1R antagonists is mediated by induction of endoplasmic reticulum (ER) stress. ER stress triggers calcium release, resulting in the suppression of prosurvival extracellular signal-regulated kinase (ERK)-c-Myc signaling. Along with ER calcium release, one ER stress pathway mediated by protein kinase RNA-like ER kinase (PERK) is specifically activated, leading to increased expression of proapoptotic C/EBP-homologous protein (CHOP). Moreover, NK-1R antagonists enhance the efficacy of chemotherapy by increasing the sensitivity and overcoming resistance to 5-fluorouracil in CRC cells through the induction of sustained ER stress and the consequent suppression of ERK-c-Myc signaling both in vitro and in vivo. Collectively, the findings provide novel mechanistic insights into the efficacy of NK-1R antagonists either as a single agent or in combination with chemotherapy for cancer treatment.

Prognostic Significance of Substance P/Neurokinin 1 Receptor and Its Association with Hormonal Receptors in Breast Carcinoma

Expression and immunolocalization of Substance P (SP)/Neurokinin-1 Receptor (NK-1R) in breast carcinoma (BC) patients and its association with routine proliferative markers (ER, PR, HER2/neu, and Ki-67) were evaluated. A cross-sectional study was performed on 34 cases of BC. There were 23 cases of group A (grade III), 8 of group B (grade II), and only 3 cases of group C (grade I). All samples were then processed for SP and NK-1R immunohistochemistry for few cases. 14/23 cases (61%) of group A, 7/8 cases (88%) of group B, and 2/3 (67%) cases of group C were SP positive. Overall, strong staining (≥10% tumor cells), labeled as "+3," was observed in 9/14 (64.2%) cases of group A and 1/8 (12.5%) cases of group B. Moderate staining labelled as "+2" (in ≥10% tumor cells) was observed in 3/14 (21.4%) cases of group A and 4/8 (50%) cases of group B. Weak positive staining "+1" was observed in only 2/14 (14.28%) cases of group A, 2/8 (25%) cases of group B, and all 2/2 (100%) cases of group C. SP and NK-1R are overexpressed in breast carcinomas, and there is significant association between the grade of tumor and their overexpression.

Neurokinin-1 Receptor as a potential drug target for COVID-19 treatment

Novel Coronavirus infection (COVID-19) has become a pandemic in these days. It is an acute respiratory and infectious disease with no known etiology and treatment. It is continuously causing losses of precious lives and economy at a global scale on daily basis. It is the need of the hour to find more treatment strategies by either developing a drug or to boost the immune system. This opinion article aims to provide Substance P (SP) as a possible cause of the initiation of cytokine storm developed in COVID-19 infection and to suggest Neurokinin-1 Receptor (NK-1R) antagonist, Aprepitant, as a drug to be used for its treatment. This perspective will provide directions to the Biomedical scientists to explore SP and NK-1R and prepare a drug to alleviate the symptoms and cure the disease. It is very important to work on this perspective at earliest to reach to some conclusion regarding the therapeutic intervention. Clinical studies may also be conducted if proven successful. SP is a neurotransmitter and neuromodulator, released from the trigeminal nerve of brainstem as a result of nociception. It is directly related to the respiratory illness as in COVID-19 infection. It is responsible for the increased inflammation and the signature symptoms associated with this disease. It is the main switch that needs to be switched off by administering Aprepitant along with glucocorticosteroid, dexamethasone.

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.

Substance P Antagonism as a Novel Therapeutic Option to Enhance Efficacy of Cisplatin in Triple Negative Breast Cancer and Protect PC12 Cells against Cisplatin-Induced Oxidative Stress and Apoptosis

Although cisplatin is very effective as a treatment strategy in triple-negative breast cancer (TNBC), it has unwarranted outcomes owing to recurrence, chemoresistance and neurotoxicity. There is critically important to find new, effective and safe therapeutics for TNBC. We determined if SP-receptor antagonism in combination with cisplatin may serve as a novel, more efficacious and safer therapeutic option than existing therapies for TNBC. We used a neuronal cell line (PC12) and two TNBC cell lines (Sum 185 and Sum 159) for these studies. We determined that the levels of cells expressing the high-affinity SP-receptor (neurokinin 1 receptor (NK1R)), as determined by flow-cytometry was significantly elevated in response to cisplatin in all three cells. We determined that treatment with aprepitant, an SP-receptor antagonist decreased cisplatin-induced, loss of viability (studied by MTT assay), production of reactive oxygen species (by DCFDA assay) and apoptosis (by flow-cytometry) in PC12 cells while it was increased in the two TNBC cells. Furthermore, we demonstrated that important genes associated with metastases, inflammation, chemoresistance and cell cycle progression are attenuated by SP-receptor antagonism in the TNBC cell line, Sum 185. These studies implicate that SP-receptor antagonism in combination with cisplatin may possibly serve as a novel, more efficacious and safer therapeutic option than existing therapies for TNBC.

Desensitization of Capsaicin-Sensitive Afferents Accelerates Early Tumor Growth via Increased Vascular Leakage in a Murine Model of Triple Negative Breast Cancer

There is growing interest in the role of nerve-driven mechanisms in tumorigenesis and tumor growth. Capsaicin-sensitive afferents have been previously shown to possess antitumoral and immune-regulatory properties, the mechanism of which is currently poorly understood. In this study, we have assessed the role of these terminals in the triple negative 4T1 orthotopic mouse model of breast cancer. The ultrapotent capsaicin-analogue resiniferatoxin (RTX) was used for the selective, systemic desensitization of capsaicin-sensitive afferents. Growth and viability of orthotopically implanted 4T1 tumors were measured by caliper, in vivo MRI, and bioluminescence imaging, while tumor vascularity and protease enzyme activity were assessed using fluorescent in vivo imaging. The levels of the neuropeptides Calcitonin Gene-Related Peptide (CGRP), Substance P (SP), and somatostatin were measured from tumor tissue homogenates using radioimmunoassay, while tumor structure and peritumoral inflammation were evaluated by conventional use of CD31, CD45 and CD3 immunohistology. RTX-pretreated mice demonstrated facilitated tumor growth in the early phase measured using a caliper, which was coupled with increased tumor vascular leakage demonstrated using fluorescent vascular imaging. The tumor size difference dissipated by day seven. The MRI tumor volume was similar, while the intratumoral protease enzyme activity measured by fluorescence imaging was also comparable in RTX-pretreated and non-pretreated animals. Tumor viability or immunohistopathological profile was measured using CD3, CD31, and CD45 stains and did not differ significantly from the non-pretreated control group. Intratumoral somatostatin, CGRP, and SP levels were similar in both groups. Our results underscore the beneficial, antitumoral properties of capsaicin sensitive nerve terminals in this aggressive model of breast cancer, which is presumed to be due to the inhibition of tumor vascular bed disruption. The absence of any difference in intratumoral neuropeptide levels indicates non-neural sources playing a substantial part in their expression.

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.

Immunohistochemical expression of substance P in breast cancer and its association with prognostic parameters and Ki-67 index

BACKGROUND

The neuropeptide substance P is a potential biomarker and therapeutic target in cancer. The main objectives of this study were to investigate the expression level of substance P in different breast cancer molecular subtypes and identify its association with clinicopathological parameters of patients and with Ki-67 index.

METHODS

A retrospective analysis was performed for a total of 164 paraffin-embedded breast cancer tissue samples [42 Her2/neu-enriched, 40 luminal A, 42 luminal B (triple-positive) and 40 triple negative subtypes]. The tissue microarray slides containing specimens were used to determine the expression of substance p and Ki-67 by immunohistochemical staining.

RESULTS

The mean age of the cohort was 51.35 years. Twenty two percent of cases had low substance P expression levels (TS ≤ 5), while 78% had high expression levels (TS > 5). A significant association was found between SP expression level and breast cancer molecular subtype (p = 0.002), TNM stage (p = 0.034), pN stage (p = 0.013), axillary lymph node metastasis (p = 0.004), ER and PR statuses (p<0.001) and history of DCIS (p = 0.009). The average percentage of Ki-67 expression was 27.05%. When analyzed as a continuous variable, significant differences were observed between the mean Ki-67 scores and molecular subtype (p = 0.001), grade (p = 0.003), pN stage (p = 0.007), axillary lymph node metastasis (p = 0.001), and ER and PR statuses (p <0.001).

CONCLUSION

SP is overexpressed in most of the analyzed tissues and has a negative prognostic value in the breast cancer patients. Besides substance P is a potential therapeutic target in breast cancer.

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.

Substance P Antagonism Prevents Chemotherapy-Induced Cardiotoxicity

Simple Summary

Anthracyclines are a class of chemotherapeutics that are an essential component of many treatment regimens for solid and blood tumors. Doxorubicin (DOX), an anthracycline is broadly considered the most active single agent available for many cancers. However, effective use of anthracyclines is limited due to the possibility of cardiotoxicity, thus causing restrictions on treatment options for treatable cancers. Our studies indicate the SP/NK1R system as a promising novel target and use of NK1R antagonists as a translational tool for prevention of chemotherapy-associated cardiotoxicity in cancer.

Abstract

Background: Doxorubicin (DOX), used in chemotherapeutic regimens in many cancers, has been known to induce, cardiotoxicity and life-threatening heart failure or acute coronary syndromes in some patients. We determined the role of Substance P (SP), a neuropeptide and its high affinity receptor, NK-1R in chemotherapy associated cardiotoxicity in mice. We determined if NK-1R antagonism will prevent DOX-induced cardiotoxicity in vivo. Methods: C57BL/6 mice (6- week old male) were injected intraperitoneally with DOX (5 mg per kilogram of body weight once a week for 5 weeks) with or without treatment with aprepitant (a NK-1R antagonist, Emend, Merck & Co., Kenilworth, NJ, USA). Five different dosages of aprepitant were administered in the drinking water five days before the first injection of DOX and then continued until the end of the experiment. Each of these 5 doses are as follows; Dose 1 = 0.9 µg/mL, Dose 2 = 1.8 µg/mL, Dose 3 = 3.6 µg/mL, Dose 4 = 7.2 µg/mL, Dose 5 = 14.4 µg/mL. Controls consisted of mice injected with PBS (instead of DOX) with or without aprepitant treatment. The experiment was terminated 5 weeks post-DOX administration and various cardiac functional parameters were determined. Following euthanization, we measured heart weight to body weight ratios and the following in the hearts, of mice treated with and without DOX and aprepitant; (a) levels of SP and NK1R, (b) cardiomyocyte diameter (to determine evidence of cardiomyocyte hypertrophy), (c) Annexin V levels (to determine evidence of cardiac apoptosis), and (d) ratios of reduced glutathione (GSH) to oxidized glutathione (GSSG) (to determine evidence of oxidative stress). Results: We demonstrated that the levels of SP and NK1R were significantly increased respectively by 2.07 fold and 1.86 fold in the hearts of mice treated with versus without DOX. We determined that DOX-induced cardiac dysfunction was significantly attenuated by treatment with aprepitant. Cardiac functional parameters such as fractional shortening (FS), ejection fraction (EF) and stroke volume (SV) were respectively decreased by 27.6%, 21.02% and 21.20% compared to the vehicle treated group (All, p < 0.05, ANOVA). Importantly, compared to treatment with DOX alone, treatment with lower doses of aprepitant in DOX treated mice significantly reduced the effects of DOX on FS, EF and SV to values not significantly different from sham (vehicle treated) mice (All, p < 0.05, ANOVA). The levels of, apoptosis marker (Annexin V), oxidative stress (ratio of GSH with GSSG) and cardiomyocyte hypertrophy were respectively increased by 47.61%, 91.43% and 47.54% in the hearts of mice treated with versus without DOX. Compared to the DOX alone group, treatment with DOX and Dose 1, 2 and 3 of aprepitant significantly decreased the levels of each of these parameters (All p < 0.05, ANOVA). Conclusions: Our studies indicate that the SP/NK1-R system is a key mediator that induces, DOX-induced, cardiac dysfunction, cardiac apoptosis, cardiac oxidative stress and cardiomyocyte hypertrophy. These studies implicate that NK-1R antagonists may serve as a novel therapeutic tool for prevention of chemotherapy induced cardiotoxicity in cancer.

Pathogenic role of the SP/ NK1R system in GBM cells through inhibiting the thioredoxin system

OBJECTIVES

Glioblastoma multiforme (GBM), a highly aggressive Grade IV brain tumor, is a significant public health issue due to its poor prognosis and incurability. Neuropeptide substance P (SP) plays a critical role in GBM tumor growth and development via activation of neurokinin-1receptor (NK1R). Moreover, SP is a pro-oxidant factor contributing to oxidative stress in various cell types. However, the link between SP and oxidative stress in cancer cells is not fully investigated. Here, we aimed to identify the effects of SP and NK1R antagonist, aprepitant, on the redox status of GBM cells.

MATERIALS AND METHODS

Resazurin assay was employed to determine the effect of aprepitant on viability of U87 glioblastoma cells. 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA) assay was employed to measure the levels of intracellular reactive oxygen species (ROS). A quantitative real-time polymerase chain reaction was applied to measure the expression of proteins of the thioredoxin system. Commercial kits (ZellBio GmbH) were also used to measure the enzymatic activity of these proteins.

RESULTS

We found that SP increased ROS level in U87 GBM cells, and aprepitant significantly reduced this effect. Furthermore, we found that SP could also affect the thioredoxin system, a central antioxidant enzyme defense system. SP reduced both expression and enzymatic activity of the thioredoxin system's proteins, Trx and thioredoxin reductase (TrxR) and these effects were significantly reduced by aprepitant.

CONCLUSION

Our results indicated that SP activation of NK1R represented a link between oxidative stress and GBM and highlighted the need for further validations in future studies.

Antihypertensive Drugs and Risk of Cancer: Between Scylla and Charybdis

Antihypertensive drugs namely angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, calcium channel blockers, beta blockers, and diuretics are among the most clearly documented regimens worldwide with an overall cardioprotective benefit. Given that malignancy is the second leading cause of mortality, numerous observational studies aimed to investigate the carcinogenic potential of these agents with conflicting results. The purpose of this review was to summarize current data in an effort to explore rare side effects and new mechanisms linking antihypertensive drugs with the risk of developing cancer.

β-endorphin at the intersection of pain and cancer progression: Preclinical evidence

We examined the association between endogenous opioid β-endorphin, cancer progression and pain in a transgenic mouse model of breast cancer, with a rat C3(1) simian virus 40 large tumor antigen fusion gene (C3TAg). C3TAg mice develop ductal epithelial atypia at 8 weeks, progression to intra-epithelial neoplasia at 12 weeks, and invasive carcinoma with palpable tumors at 16 weeks. Consistent with invasive carcinoma at 4 months of age, C3TAg mice demonstrate a significant increase in hyperalgesia compared to younger C3TAg or control FVBN mice without tumors. Our data show that the growing tumor contributes to circulating β-endorphin. As an endogenous ligand of mu opioid receptor, β-endorphin has analgesic activity. Paradoxically, we observed an increase in pain in transgenic breast cancer mice with significantly high circulating and tumor-associated β-endorphin. Increased circulating β-endorphin correlates with increasing tumor burden. β-endorphin induced the activation of mitogenic and survival-promoting signaling pathways, MAPK/ERK 1/2, STAT3 and Akt, observed by us in human MDA-MB-231 cells suggesting a role for β-endorphin in breast cancer progression and associated pain.

Effect of Acrylamide Supplementation on the Population of Vasoactive Intestinal Peptide (VIP)-Like Immunoreactive Neurons in the Porcine Small Intestine

Acrylamide is one of the harmful substances present in food. The present study aimed to establish the effect of acrylamide supplementation in tolerable daily intake (TDI) dose (0.5 µg/kg b.w./day) and a dose ten times higher than TDI (5 µg/kg b.w./day) on the population of vasoactive intestinal peptide-like immunoreactive (VIP-LI) neurons in the porcine small intestine and the degree of the co-localization of VIP with other neuroactive substances (neuronal nitric oxide synthase (nNOS), substance P (SP), and cocaine- and amphetamine-regulated transcript peptide (CART)). In our work, 15 Danish landrace gilts (5 in each experimental group) received capsules (empty or with low or high doses of acrylamide) for a period of 28 days with their morning feeding. Using double immunofluorescence staining, we established that acrylamide supplementation increased the number of neurons showing immunoreactivity towards VIP in all types of enteric nervous system (ENS) plexuses and fragments of the small intestine studied. Moreover, both doses of acrylamide led to changes in the degree of co-localization of VIP with nNOS, SP, and CART in intramural neurons. The observed changes may be the adaptation of neurons to local inflammation, oxidative stress, or the direct toxic effects of acrylamide on intestinal neurons, also referred to as neuronal plasticity.

Triple Negative Breast Cancer: How Neurokinin-1 Receptor Antagonists Could Be Used as a New Therapeutic Approach

Breast cancer (BC) is the most frequently diagnosed cancer and the leading cause of cancer death among females. BC cells not showing HER-2/Neu amplification and not expressing estrogen/ progesterone receptors are named triple-negative BC (TNBC) cells. TNBC represents 10-15% of all BC and is associated with an aggressive clinical course. TNBC patient prognosis, survival and response to current therapies are poor and for this reason, it is crucial to search for new therapeutic targets in TNBC to develop new therapeutic strategies. One of these targets is the neurokinin-1 receptor (NK-1R). It is well known that the substance P (SP)/NK-1R system is involved in cancer progression. TNBC cells overexpress the NK-1R and, after binding to this receptor, SP promotes the proliferation/ migration of TNBC cells. Non-peptide NK-1R antagonists (e.g., aprepitant) are known to exert, via the NK-1R, an antitumor action; TNBC cells die by apoptosis. In this review, we update the data on a promising therapeutic innovation: the use of NK-1R antagonists for the treatment of TNBC patients.

Sensory neurons from dorsal root ganglia regulate endothelial cell function in extracellular matrix remodelling

BACKGROUND

Recent physiological and experimental data highlight the role of the sensory nervous system in bone repair, but its precise role on angiogenesis in a bone regeneration context is still unknown. Our previous work demonstrated that sensory neurons (SNs) induce the osteoblastic differentiation of mesenchymal stem cells, but the influence of SNs on endothelial cells (ECs) was not studied.

METHODS

Here, in order to study in vitro the interplay between SNs and ECs, we used microfluidic devices as an indirect co-culture model. Gene expression analysis of angiogenic markers, as well as measurements of metalloproteinases protein levels and enzymatic activity, were performed.

RESULTS

We were able to demonstrate that two sensory neuropeptides, calcitonin gene-related peptide (CGRP) and substance P (SP), were involved in the transcriptional upregulation of angiogenic markers (vascular endothelial growth factor, angiopoietin 1, type 4 collagen, matrix metalloproteinase 2) in ECs. Co-cultures of ECs with SNs also increased the protein level and enzymatic activity of matrix metalloproteinases 2 and 9 (MMP2/MMP9) in ECs.

CONCLUSIONS

Our results suggest a role of sensory neurons, and more specifically of CGRP and SP, in the remodelling of endothelial cells extracellular matrix, thus supporting and enhancing the angiogenesis process. Video abstract.

The Neurokinin-1 Receptor Antagonist Aprepitant: An Intelligent Bullet against Cancer?

Neurokinin-1 receptor (NK-1R) antagonists exert antitumor action, are safe and do not cause serious side-effects. These antagonists (via the NK-1R) exert multiple actions against cancer: antiproliferative and anti-Warburg effects and apoptotic, anti-angiogenic and antimetastatic effects. These multiple effects have been shown for a broad spectrum of cancers. The drug aprepitant (an NK-1R antagonist) is currently used in clinical practice as an antiemetic. In in vivo and in vitro studies, aprepitant also showed the aforementioned multiple antitumor actions against many types of cancer. A successful combination therapy (aprepitant and radiotherapy) has recently been reported in a patient suffering from lung carcinoma: the tumor mass disappeared and side-effects were not observed. Aprepitant could be considered as an intelligent bullet against cancer. The administration of aprepitant in cancer patients to prevent recurrence and metastasis after surgical procedures, thrombosis and thromboembolism is discussed, as is the possible link, through the substance P (SP)/NK-1R system, between cancer and depression. Our main aim is to review the multiple antitumor actions exerted by aprepitant, and the use of this drug is suggested in cancer patients. Altogether, the data support the reprofiling of aprepitant for a new therapeutic use as an antitumor agent.

Neuropeptide Substance P Enhances Inflammation-Mediated Tumor Signaling Pathways and Migration and Proliferation of Head and Neck Cancers

Head and neck cancers (HNC) are extremely aggressive, highly recurrent, and the sixth most common cancer worldwide. Neuropeptide substance P, along with its primary receptor, neurokinin-1 (NK-1R), is overexpressed in HNC and is a central player in inflammation and growth and metastasis of several cancers. However, the precise SP-mediated signaling that promotes HNC progression remains ill defined. Using a panel of HNC lines, in this study, we investigated the effects of SP on proliferation and migration of HNC. Tumor cells were also treated with SP and alterations in inflammatory cytokines and chemokines, and their cognate receptors were analyzed by real-time PCR. Furthermore, we investigated the role of SP in inducing epithelial-mesenchymal transition (EMT), and matrix metalloproteases that promote tumor invasion. Our results showed that SP significantly increased tumor cell proliferation and migration and induced the expression of several genes that promote tumor growth, invasion, and metastasis which was suppressed by a specific NK1R antagonist L-703606. SP also activated NFκB that was suppressed on inhibiting NK1R. Collectively, our data shows that SP-NK1R-mediated inflammatory signaling comprises an important signaling axis in promoting HNC and may prove to be effective clinical target against HNC cells that are resistant to traditional therapy.

The Neurokinin-1 Receptor Antagonist Aprepitant, a New Drug for the Treatment of Hematological Malignancies: Focus on Acute Myeloid Leukemia

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy. To treat the disease successfully, new therapeutic strategies are urgently needed. One of these strategies can be the use of neurokinin-1 receptor (NK-1R) antagonists (e.g., aprepitant), because the substance P (SP)/NK-1R system is involved in cancer progression, including AML. AML patients show an up-regulation of the NK-1R mRNA expression; human AML cell lines show immunoreactivity for both SP and the NK-1R (it is overexpressed: the truncated isoform is more expressed than the full-length form) and, via this receptor, SP and NK-1R antagonists (aprepitant, in a concentration-dependent manner) respectively exert a proliferative action or an antileukemic effect (apoptotic mechanisms are triggered by promoting oxidative stress via mitochondrial Ca⁺⁺ overload). Aprepitant inhibits the formation of AML cell colonies and, in combination with chemotherapeutic drugs, is more effective in inducing cytotoxic effects and AML cell growth blockade. NK-1R antagonists also exert an antinociceptive effect in myeloid leukemia-induced bone pain. The antitumor effect of aprepitant is diminished when the NF-κB pathway is overactivated and the damage induced by aprepitant in cancer cells is higher than that exerted in non-cancer cells. Thus, the SP/NK-1R system is involved in AML, and aprepitant is a promising antitumor strategy against this hematological malignancy. In this review, the involvement of this system in solid and non-solid tumors (in particular in AML) is updated and the use of aprepitant as an anti-leukemic strategy for the treatment of AML is also mentioned (a dose of aprepitant (>20 mg/kg/day) for a period of time according to the response to treatment is suggested). Aprepitant is currently used in clinical practice as an anti-nausea medication.

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.