Identification of an Intravenous Injectable NK1 Receptor Antagonist for Use in Traumatic Brain Injury.

Traumatic brain injuries represent a leading cause of death and disability in the paediatric and adult populations. Moderate-to-severe injuries are associated with blood-brain barrier dysfunction, the development of cerebral oedema, and neuroinflammation. Antagonists of the tachykinin NK1 receptor have been proposed as potential agents for the post-injury treatment of TBI. We report on the identification of EUC-001 as a potential clinical candidate for development as a novel TBI therapy. EUC-001 is a selective NK1 antagonist with a high affinity for the human NK1 receptor (Ki 5.75 × 10-10 M). It has sufficient aqueous solubility to enable intravenous administration, whilst still retaining good CNS penetration as evidenced by its ability to inhibit the gerbil foot-tapping response. Using an animal model of TBI, the post-injury administration of EUC-001 was shown to restore BBB function in a dose-dependent manner. EUC-001 was also able to ameliorate cerebral oedema. These effects were associated with a significant reduction in post-TBI mortality. In addition, EUC-001 was able to significantly reduce functional deficits, both motor and cognitive, that normally follow a severe injury. EUC-001 is proposed as an ideal candidate for clinical development for TBI.

Comparing the Efficacy of Fosnetupitant, an NK1 Receptor Antagonist in CDDP-Based Regimens, with That of Fosaprepitant and Aprepitant: A Retrospective Observational Study.

Existing antiemetic therapy against emetic-risk agents across malignancies 24 h post-dose in the acute period in cisplatin (CDDP)-based regimens yields a satisfactory complete response (CR) rate of ≥90%. However, the control rate after 24 h in the delayed period is unsatisfactory. This study compared the efficacy of fosnetupitant (F-NTP), a neurokinin 1 receptor antagonist, with that of fosaprepitant (F-APR) and aprepitant (APR) in the treatment of patients with cancer at high emetic risk due to chemotherapy. In this retrospective case-control study involving patients receiving cisplatin-containing regimens and neurokinin 1 receptor antagonists, patients were divided into three groups based on prophylactic antiemetic therapy: F-NTP, F-APR, and APR. The CR rate was evaluated for each period up to 168 h and further subdivided into acute (0-24 h), delayed (24-120 h), overall (0-120 h), and beyond-delayed (120-168 h) periods. Eighty-eight patients were included in the F-NTP group, 66 in the F-APR group, and 268 in the APR group. The CR rates at 0-168 and 120-168 h after cisplatin administration were significantly higher in the F-NTP group than in the F-APR and APR groups. After adjusting for confounding factors, F-NTP use was an independent factor in the multivariate analysis. Prophylactic antiemetic therapy, including F-NTP, was effective and well-tolerated during the delayed period. The efficacy of F-NTP in managing chemotherapy-induced nausea and vomiting was superior to those of F-APR and APR during the study period.

Advances in the research and application of neurokinin-1 receptor antagonists. / 神经激肽1å—ä½“æ‹®æŠ—å‰‚çš„ç ”ç©¶ä¸Žåº”ç”¨è¿›å±•.

Recently, the substance P (SP)/neurokinin-1 receptor (NK-1R) system has been found to be involved in various human pathophysiological disorders including the symptoms of coronavirus disease 2019 (COVID-19). Besides, studies in the oncological field have demonstrated an intricate correlation between the upregulation of NK-1R and the activation of SP/NK-1R system with the progression of multiple carcinoma types and poor clinical prognosis. These findings indicate that the modulation of SP/NK-1R system with NK-1R antagonists can be a potential broad-spectrum antitumor strategy. This review updates the latest potential and applications of NK-1R antagonists in the treatment of human diseases and cancers, as well as the underlying mechanisms. Furthermore, the strategies to improve the bioavailability and efficacy of NK-1R antagonist drugs are summarized, such as solid dispersion systems, nanonization, and nanoencapsulation. As a radiopharmaceutical therapeutic, the NK-1R antagonist aprepitant was originally developed as radioligand receptor to target NK-1R-overexpressing tumors. However, combining NK-1R antagonists with other drugs can produce a synergistic effect, thereby enhancing the therapeutic effect, alleviating the symptoms, and improving patients quality of life in several diseases and cancers.

Dexamethasone-sparing on days 2-4 with combined palonosetron, neurokinin-1 receptor antagonist, and olanzapine in cisplatin: a randomized phase III trial (SPARED Trial).

BACKGROUND: This study evaluated the non-inferiority of dexamethasone (DEX) on day 1, with sparing on days 2-4 in cisplatin-based chemotherapy. METHODS: Patients with malignant solid tumors who were treated with cisplatin (≥50 mg/m²) were randomly assigned (1:1) to receive either DEX on days 1-4 (Arm D4) or DEX on day 1 (Arm D1) plus palonosetron, NK-1 RA, and olanzapine (5 mg). The primary endpoint was complete response (CR) during the delayed (24-120 h) phase. The non-inferiority margin was set at -15%. RESULTS: A total of 281 patients were enrolled, 278 of whom were randomly assigned to Arm D4 (n = 139) or Arm D1 (n = 139). In 274 patients were included in the efficacy analysis, the rates of delayed CR in Arms D4 and D1 were 79.7% and 75.0%, respectively (risk difference -4.1%; 95% CI -14.1%-6.0%, P = 0.023). However, patients in Arm D1 had significantly lower total control rates during the delayed and overall phases, and more frequent nausea and appetite loss. There were no significant between-arm differences in the quality of life. CONCLUSION: DEX-sparing is an alternative option for patients receiving cisplatin; however, this revised administration schedule should be applied on an individual basis after a comprehensive evaluation. CLINICAL TRIALS REGISTRY NUMBER: UMIN000032269.

Biological evaluation of carbohydrate-based aprepitant analogs for neuroblastoma treatment.

Different studies using Aprepitant, a NK1R antagonist currently used as a clinical drug for treating chemotherapy-related nausea and vomiting, have demonstrated that pharmacological inhibition of NK1R effectively reduces the growth of several tumor types such as neuroblastoma (NB). In a previous work, we demonstrated that a series of carbohydrate-based Aprepitant analogs, derived from either d-galactose or l-arabinose, have shown high affinity and NK1R antagonistic activity with a broad-spectrum anticancer activity and an important selectivity. In this new study, we explore the selective cytotoxic effects of these derivatives for the treatment of NB. Furthermore, we describe the design and stereoselective synthesis of a new generation of d-glucose derivatives as Aprepitant analogs, supported by docking studies. This approach showed that most of our carbohydrate-based analogs are significantly more selective than Aprepitant. The galactosyl derivative 2α, has demonstrated a marked in vitro selective cytotoxic activity against NB, with IC50 values in the same range as those of Aprepitant and its prodrug Fosaprepitant. Interestingly, the derivative 2α has shown similar apoptotic effect to that of Aprepitant. Moreover, we can select the glucosyl amino derivative 10α as an interesting hit exhibiting higher in vitro cytotoxic activity against NB than Aprepitant, being 1.2 times more selective.

2023 updated MASCC/ESMO Consensus recommendations: Prevention of nausea and vomiting following moderately emetic risk antineoplastic agents.

PURPOSE: Review the literature to update the MASCC guidelines from 2015 for controlling nausea and vomiting with systemic cancer treatment of moderate emetic potential. METHODS: A systematic literature review was completed using Medline, Embase, and Scopus databases. The literature search was done from June 2015 to January 2023 of the management of antiemetic prophylaxis for anticancer therapy of moderate emetic potential. RESULTS: Of 342 papers identified, 19 were relevant to update recommendations about managing antiemetic prophylaxis for systemic cancer treatment regimens of moderate emetic potential. Important practice changing updates include the use of emetic prophylaxis based on a triple combination of neurokinin (NK)1 receptor antagonist, 5-HT3 receptor antagonist, and steroids for patients undergoing carboplatin (AUC ≥ 5) and women < 50 years of age receiving oxaliplatin-based treatment. A double combination of 5-HT3 receptor antagonist and steroids remains the recommended prophylaxis for other MEC. Based on the data in the literature, it is recommended that the administration of steroids should be limited to day 1 in moderately emetogenic chemotherapy regimens, due to the demonstration of non-inferiority between the different regimens. More data is needed on the emetogenicity of new agents at moderate emetogenic risk. Of particular interest would be antiemetic studies with the agents sacituzumab-govitecan and trastuzumab-deruxtecan. Experience to date with these agents indicate an emetogenic potential comparable to carboplatin > AUC 5. Future studies should systematically include patient-related risk assessment in order to define the risk of emesis with MEC beyond the emetogenicity of the chemotherapy and improve the guidelines for new drugs. CONCLUSION: This antiemetic MASCC-ESMO guideline update includes new recommendations considering individual risk factors and the optimization of supportive anti-emetic treatments.

The Repurposing of Non-Peptide Neurokinin-1 Receptor Antagonists as Antitumor Drugs: An Urgent Challenge for Aprepitant.

The substance P (SP)/neurokinin-1 receptor (NK-1R) system is involved in cancer progression. NK-1R, activated by SP, promotes tumor cell proliferation and migration, angiogenesis, the Warburg effect, and the prevention of apoptosis. Tumor cells overexpress NK-1R, which influences their viability. A typical specific anticancer strategy using NK-1R antagonists, irrespective of the tumor type, is possible because these antagonists block all the effects mentioned above mediated by SP on cancer cells. This review will update the information regarding using NK-1R antagonists, particularly Aprepitant, as an anticancer drug. Aprepitant shows a broad-spectrum anticancer effect against many tumor types. Aprepitant alone or in combination therapy with radiotherapy or chemotherapy could reduce the sequelae and increase the cure rate and quality of life of patients with cancer. Current data open the door to new cancer research aimed at antitumor therapeutic strategies using Aprepitant. To achieve this goal, reprofiling the antiemetic Aprepitant as an anticancer drug is urgently needed.

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.

Deciphering specificity and cross-reactivity in tachykinin NK1 and NK2 receptors.

The tachykinin receptors neurokinin 1 (NK1R) and neurokinin 2 (NK2R) are G protein-coupled receptors that bind preferentially to the natural peptide ligands substance P and neurokinin A, respectively, and have been targets for drug development. Despite sharing a common C-terminal sequence of Phe-X-Gly-Leu-Met-NH2 that helps direct biological function, the peptide ligands exhibit some degree of cross-reactivity toward each other's non-natural receptor. Here, we investigate the detailed structure-activity relationships of the ligand-bound receptor complexes that underlie both potent activation by the natural ligand and cross-reactivity. We find that the specificity and cross-reactivity of the peptide ligands can be explained by the interactions between the amino acids preceding the FxGLM consensus motif of the bound peptide ligand and two regions of the receptor: the ß-hairpin of the extracellular loop 2 (ECL2) and a N-terminal segment leading into transmembrane helix 1. Positively charged sidechains of the ECL2 (R177 of NK1R and K180 of NK2R) are seen to play a vital role in the interaction. The N-terminal positions 1 to 3 of the peptide ligand are entirely dispensable. Mutated and chimeric receptor and ligand constructs neatly swap around ligand specificity as expected, validating the structure-activity hypotheses presented. These findings will help in developing improved agonists or antagonists for NK1R and NK2R.

Efficacy and safety of 5HT3RA, DEX, and NK1RA for the prevention of FOLFIRINOX-induced nausea and vomiting in patients with pancreatic cancer: a retrospective cohort study.

PURPOSE: Modified FOLFIRINOX (mFFX), a standard chemotherapy regimen for advanced pancreatic cancer (APC), is expected to be associated with a higher risk of chemotherapy-induced nausea and vomiting (CINV). Herein, we conducted a retrospective cohort study to evaluate the efficacy and safety of a three-drug combination of 5-hydroxytryptamine-3 receptor antagonists (5HT3RA), dexamethasone (DEX), and neurokinin 1 receptor antagonists (NK1RA) for the prevention of CINV during mFFX therapy. METHODS: This study enrolled patients with APC who received mFFX as initial therapy with a combination of 5HT3RA, DEX, and NK1RA as antiemetic prophylaxis. The primary endpoint was the complete response (CR) rate during cycle 1, which was defined as no emetic episodes and no rescue medication use during the overall period (0-120 h). Safety was also evaluated with a focus on hyperglycemia, which is a concern in patients with APC. RESULTS: Seventy patients were eligible for this retrospective analysis. The CR rate during the overall period was 51.4%. Significant nausea, defined as grade 2 or higher, peaked to 77.1% on days 4-5, but remained above 65% until day 7. Hyperglycemia occurred in 37.1% of patients, and 34.3% were grade 3 hyperglycemia. CONCLUSIONS: CINV induced by mFFX was poorly controlled even with prophylactic antiemetic therapy using 5HT3RA, DEX, and NK1RA, and was found to persist beyond 5 days. Enhanced antiemetic measures for mFFX are desirable. However, in patients with diabetes mellitus complications, sparing of steroids and glycemic control should be considered.

An assessment of the effects of neurokinin1 receptor antagonism against nausea and vomiting: Relative efficacy, sites of action and lessons for future drug development.

A broad-spectrum anti-vomiting effect of neurokinin1 receptor antagonists (NK1 RA), shown in pre-clinical animal studies, has been supported by a more limited range of clinical studies in different indications. However, this review suggests that compared with vomiting, the self-reported sensation of nausea is less affected or possibly unaffected (depending on the stimulus) by NK1 receptor antagonism, a common finding for anti-emetics. The stimulus-independent effects of NK1 RAs against vomiting are explicable by actions within the central pattern generator (ventral brainstem) and the nucleus tractus solitarius (NTS; dorsal brainstem), with additional effects on vagal afferent activity for certain stimuli (e.g., highly emetogenic chemotherapy). The central pattern generator and NTS neurones are multifunctional so the notable lack of obvious effects of NK1 RAs on other reflexes mediated by the same neurones suggests that their anti-vomiting action is dependent on the activation state of the pathway leading to vomiting. Nausea requires activation of cerebral pathways by projection of information from the NTS. Although NK1 receptors are present in cerebral nuclei implicated in nausea, and imaging studies show very high receptor occupancy at clinically used doses, the variable or limited ability of NK1 RAs to inhibit nausea emphasizes: (i) our inadequate understanding of the mechanisms of nausea; and (ii) that classification of a drug as an anti-emetic may give a false impression of efficacy against nausea vs. vomiting. We discuss the potential mechanisms for the differential efficacy of NK1 RA and the implications for future development of drugs that can effectively treat nausea, an area of unmet clinical need.

A pharmacological overview of aprepitant for the prevention of postoperative nausea and vomiting.

INTRODUCTION: Post-operative nausea and vomiting (PONV) affects 30% of all patients undergoing surgery and up to 80% of high-risk patients. Antiemetics for PONV prophylaxis target a variety of receptor systems, with varying degrees of efficacy and side effect profile. Neurokinin -1 receptor antagonists are the most recent class of compounds investigated for PONV prophylaxis, with aprepitant being the only one currently approved for this indication. AREAS COVERED: This review covers the pathophysiology of PONV, current recommendations for PONV prophylaxis, pharmacokinetics, and pharmacodynamics of aprepitant, and the evidence for its efficacy in the management of PONV as a single agent and in combination therapy. EXPERT OPINION: Aprepitant is effective for PONV prophylaxis. It has superior antivomiting efficacy, long half-life, and favorable side effect profile. Data on antiemetic combinations involving aprepitant are limited, and it is not clear if the addition of other antiemetics to aprepitant results in improved PONV prophylaxis. The oral route of administration of aprepitant is a potential limitation in a busy clinical practice. However, the recent approval of an intravenous formulation could provide a more convenient route of administration. Aprepitant remains more expensive than other antiemetics, and there are no studies assessing the cost effectiveness of its use.

Neurokinin-1 receptor antagonists for the prevention of postoperative nausea and vomiting.

Despite the availability of several classes of antiemetics, postoperative nausea and vomiting (PONV) remains a substantial burden for patients following surgery, resulting in patient dissatisfaction and prolonged stays in post-anesthesia care units and ultimately increasing the cost of care. Enhanced recovery protocols and PONV management guidelines are now centered on the assessment of the individual patient's risk for developing PONV, as well as multimodal prophylaxis using antiemetics targeting different mechanisms of action. Over the last two decades, the neurokinin-1 receptor (NK1R) has emerged as a therapeutic target for the management of PONV. This review of the literature explains the role of the NK1R and its ligand-substance P-in vomiting, describes the pharmacologic and pharmacokinetic properties of NK1R antagonists (NK1RAs) and summarizes the clinical evidence supporting NK1RAs for PONV prophylaxis in patients undergoing surgery. In particular, we discuss the therapeutic application of NK1RA in PONV prophylaxis protocols owing to their advantages over other antiemetic classes in efficacy, duration of efficacy, safety, pharmacology, and ease of administration. Future studies will be aimed at further investigating the efficacy and safety of NK1RA-based multimodal combinations, particularly among vulnerable populations (e.g., children and elderly).

Aprepitant inhibits the development and metastasis of gallbladder cancer via ROS and MAPK activation.

BACKGROUND: Aprepitant, as a neurokinin-1 receptor (NK-1R) antagonist, originally applied for curing chemotherapy-induced nausea and vomiting, has been reported to have significant antitumor effect on several malignant tumors. However, the effect of aprepitant on gallbladder cancer (GBC) is not clear yet. This study aimed to investigate the anti-tumor activity of aprepitant on GBC and the potential mechanisms. METHODS: The NK-1R expression of gallbladder cancer cells were examined by immunofluorescence. MTT assay, wound healing and transwell migration assay were applied to detect the effect of aprepitant on cell proliferation, migration and invasion. Flow cytometry was used to detect the apoptosis rate. The effects of aprepitant on the expressions of cytokine were examined by real-time quantitative PCR and MAPK activation were detected via immunofluorescence and western blotting. Besides, xenograft model was established to investigate the effect of aprepitant in vivo. RESULTS: Our results indicated that NK-1R was markedly expressed in gallbladder cancer cells and aprepitant effectively inhibited the proliferation, migration and invasion. Furthermore, the apoptosis, ROS and inflammation response were significantly boosted by aprepitant in GBC. Aprepitant induced NF-κB p65 nuclear translocationin and increased the expressions of p-P65, p-Akt, p-JNK, p-ERK and p-P38, as well as the mRNA levels of inflammatory cytokines IL-1ß, IL-6 and TNF-α. Consistently, aprepitant suppressed the growth of GBC in xenograft mice model. CONCLUSION: Our study demonstrated that aprepitant could inhibit the development of gallbladder cancer via inducing ROS and MAPK activation, which suggested that aprepitant may become a promising therapeutic drug against GBC.

The in vitro anti-cancer synergy of neurokinin-1 receptor antagonist, aprepitant, and 5-aminolevulinic acid in glioblastoma.

Glioblastoma multiforme (GBM) is the most malignant type of cerebral neoplasm in adults with a poor prognosis. Currently, combination therapy with different anti-cancer agents is at the forefront of GBM research. Hence, this study aims to evaluate the potential anti-cancer synergy of a clinically approved neurokinin-1 receptor antagonist, aprepitant, and 5-aminolevulinic acid (5-ALA), a prodrug that elicits fluorescent porphyrins in gliomas on U-87 human GBM cells. We found that aprepitant and 5-ALA effectively inhibited GBM cell viability. The combinatorial treatment of these drugs exerted potent synergistic growth inhibitory effects on GBM cells. Moreover, aprepitant and 5-ALA induced apoptosis and altered the levels of apoptotic genes (up-regulation of Bax and P53 along with downregulation of Bcl-2). Furthermore, aprepitant and 5-ALA increased the accumulation of protoporphyrin IX, a highly pro-apoptotic and fluorescent photosensitizer. Aprepitant and 5-ALA significantly inhibited GBM cell migration and reduced matrix metalloproteinases (MMP-2 and MMP-9) activities. Importantly, all these effects were more prominent following aprepitant-5-ALA combination treatment than either drug alone. Collectively, the combination of aprepitant and 5-ALA leads to considerable synergistic anti-proliferative, pro-apoptotic, and anti-migratory effects on GBM cells and provides a firm basis for further evaluation of this combination as a novel therapeutic approach for GBM.

The Role of Substance P Receptor Antagonists in Allergic Rhinitis: Ovalbumin-Induced Rat Model.

OBJECTIVE: Substance P is a peptide from the tachykinin family, which is found in peripheral and central nervous systems, causing vasodilation and increased secretion in the nasal mucosa. In this study, we aimed to investigate whether the experimental model of allergic rhinitis will cause allergic changes in the larynx and to compare the effects of aprepitant, a substance P antagonist, on nasal symptoms in allergic rhinitis, and histopathological changes in the nasal and laryngeal mucosa with antihistamine and leukotriene receptor antagonists (LTRA). STUDY DESIGN: An experimental animal study. METHOD: The study was carried out on 34 healthy 8-12 weeks old female Sprague Dawley rats in 5 groups. The rats in which an experimental allergic rhinitis model was created with ovalbumin were scored by observing their nasal symptoms, and nasal and laryngeal mucous membranes included in the study were evaluated histopathologically after medications. RESULTS: As a result of the analysis of the data obtained from the study, antihistamine and LTRA significantly reduced the symptoms of nose scratching and sneezing, while aprepitant did not affect nasal symptoms. In the histopathological examination of the larynx, effects that would make a significant difference were found in the allergy group when compared to the control group. On the larynx, aprepitant reduced pseudostratification significantly compared to the allergy group. CONCLUSION: Aprepitant provides histopathological changes in the treatment of allergic rhinitis, but does not have sufficient effect on nasal symptoms. The effect of aprepitant on the larynx has not been clearly demonstrated. LEVEL OF EVIDENCE: NA Laryngoscope, 133:2891-2897, 2023.

Neurokinin-1 receptor is highly expressed in cervical cancer and its antagonist induces cervical cancer cell apoptosis.

Neurokinin-1 receptor (NK1R) belongs to tachykinin receptor family. Recent studies have suggested that NK1R was upregulated in cancer tissues including breast cancer, glioma and melanoma. Furthermore, NK1R antagonists have been employed to exert anti-tumor effect and promote cancer cell apoptosis. However, the role of NK1R in cervical cancer remains largely unknown. In this study, we aimed to detect the expression of NK1R in cervical cancer and evaluate the anti-tumor effects of NK1R antagonist on cervical cancer cells. We found that NK1R was highly expressed in cervical cancer tissues than in adjacent normal cervical tissues. Furthermore, by using NK1R antagonist we demonstrated that NK1R antagonist inhibited the viability and induced the apoptosis of cervical cancer cells in a dose-dependent manner, and the mechanism may be related to the inhibition of ERK activation and the regulation of apoptosis proteins Bcl-2 and BAX. In conclusion, these findings suggest that NK1R plays an oncogenic role in cervical cancer and is a promising target for cervical cancer therapy.

Combination Therapy of Chemotherapy or Radiotherapy and the Neurokinin-1 Receptor Antagonist Aprepitant: A New Antitumor Strategy?

BACKGROUND: Although chemotherapy is predominantly used for cancer treatment, it can be ineffective and can induce serious side effects and lead to chemoresistance. It is essential to discover novel drugs that can enhance the antitumor activity and at the same time, counteract the severe side effects, of chemotherapy. The substance P (SP)/neurokinin-1 receptor (NK-1R) interaction system is known to play a key role in the pathogenesis of cancer. Studies with NK-1R antagonists (such as aprepitant) denote that the NK-1R is a potential target for the treatment of cancer. Aprepitant combined with major chemotherapeutic drugs has shown the potential to increase antitumor activity and decrease side effects. OBJECTIVE: Since malignant tumor cancer cells overexpress the NK-1R, this combination therapy is a promising approach for the treatment of all kinds of cancer. Since aprepitant shows potential of being a broad-antitumor drug, the repurposing of this NK-1R antagonist as an antitumor agent is warranted. Studies pertaining to combination therapy of aprepitant/radiotherapy will also be outlined in this review. The aim of this review is to provide an update on combinational studies pertaining to chemotherapy/radiotherapy and NK-1R antagonist in cancer. CONCLUSION: This combination strategy once confirmed, might open the door to a new era in chemotherapy and radiotherapy with greater antitumor activity and fewer side effects. This treatment strategy could possibly translate into higher cure rates, better quality of life and fewer sequelae in cancer patients.

Substance P Exacerbates the Inflammatory and Pro-osteoclastogenic Responses of Murine Osteoclasts and Osteoblasts to Staphylococcus aureus.

Staphylococcus aureus infections of bone tissue are associated with inflammatory bone loss. Resident bone cells, including osteoblasts and osteoclasts, can perceive S. aureus and produce an array of inflammatory and pro-osteoclastogenic mediators, thereby contributing to such damage. The neuropeptide substance P (SP) has been shown to exacerbate microbially induced inflammation at sites such as the gut and the brain and has previously been shown to affect bone cell differentiation and activity. Here we demonstrate that the interaction of SP with its high affinity receptor, neurokinin-1 receptor (NK-1R), expressed on murine osteoblasts and osteoclasts, augments the inflammatory responses of these cells to S. aureus challenge. Additionally, SP alters the production of pro- and anti-osteoclastogenic factors by bacterially challenged bone cells and their proteolytic functions in a manner that would be anticipated to exacerbate inflammatory bone loss at sites of infection. Furthermore, we have demonstrated that the clinically approved NK-1R antagonist, aprepitant, attenuates local inflammatory and pro-osteoclastogenic mediator expression in an in vivo mouse model of post-traumatic staphylococcal osteomyelitis. Taken together, these results indicate that SP/NK-1R interactions could play a significant role in the initiation and/or progression of damaging inflammation in S. aureus bone infections and suggest that the repurposing of currently approved NK-1R antagonists might represent a promising new adjunct therapy for such conditions.