Expression of the tachykinin receptor mRNAs in healthy human colon

Neurokinin 3 Receptor Antagonists Compared With Serotonin Norepinephrine Reuptake Inhibitors for Non-Hormonal Treatment of Menopausal Hot Flushes: A Systematic Qualitative Review

Introduction

Hot flushes/flashes (HFs) or other vasomotor symptoms affect between 45 and 97% of women during menopause. Hormone replacement therapy (HRT) is effective at alleviating menopausal symptoms, but some women cannot or prefer not to take HRT. Since current non-hormonal options have suboptimal efficacy/tolerability, there is a pressing need for an effective, well-tolerated alternative. The neurokinin 3 receptor (NK3R) has recently been implicated in the generation of menopausal HFs and represents a novel therapeutic target to ameliorate HF symptoms. This review aims to assess if NK3R antagonists (NK3Ras) are more effective than Serotonin Norepinephrine Reuptake Inhibitors (SNRIs)—currently a common choice for non-hormonal treatment of menopausal HFs.

Methods

Studies were identified after systematically searching Ovid MEDLINE and EMBASE databases based on PRISMA guidelines. Trial quality and bias were assessed. Key efficacy outcomes (HF frequency, HF severity and number of night-time awakenings/night-sweats) and selected safety outcomes were extracted and analysed.

Results

Seven SNRI and four NK3Ra placebo-controlled randomised trials (plus four follow-up reports) were included in this review. NK3Ra administration resulted in a larger reduction from baseline in HF frequency, HF severity and night-sweats compared to SNRIs. Five of seven SNRI trials showed a reduction in HF frequency that was statistically significant (by 48–67% from baseline at weeks 8 or 12) whereas all NK3Ra trials showed a statistically significant reduction in HF frequency (by 62–93% from baseline at weeks 2, 4 or 12). While SNRI trials reported poor tolerability, particularly nausea, NK3Ra trials reported good tolerability overall, although two trials reported elevation in transaminases.

Conclusion

NK3Ras trials show encouraging efficacy and tolerability/safety. Completion of phase 3 NK3Ra trials are required to confirm efficacy and uphold safety/tolerability data but phase 2 results suggest that NK3Ras are more effective than SNRIs for non-hormonal treatment of menopausal HFs.

Fezolinetant in the treatment of vasomotor symptoms associated with menopause

Introduction: Although international clinical practice guidelines recognize a continued role for menopausal hormone therapy (HT), particularly for symptomatic women <60 years of age or within 10 years of menopause, safety and tolerability concerns have discouraged HT use due to potential links with a perceived increased risk of hormone-dependent cancers, and an established risk of stroke and venous thromboembolism. There is therefore a need for safe, effective non-hormonal therapy for relief of menopausal vasomotor symptoms (VMS).Areas covered: This narrative review summarizes the dataset accrued for fezolinetant, a neurokinin-3 receptor (NK3R) antagonist in clinical development for menopause-associated VMS.Expert opinion: Altered signaling in neuroendocrine circuits at menopause leads to VMS wherein NK3R activity plays a key role to modulate the thermoregulatory center in a manner conducive to triggering the 'hot flash' response. Thus, a new generation of NK3R antagonists has entered clinical development to specifically target the mechanistic basis of VMS. Fezolinetant is the most advanced NK3R antagonist in terms of stage of clinical development. Results to date have demonstrated rapid and substantial reduction in VMS frequency and severity and associated improvements in health-related quality of life. NK3R antagonists offer a non-hormonal alternative to HT for the treatment of menopause-related VMS.

Prognostic Implications of Novel Gene Signatures in Gastric Cancer Microenvironment

Background

Increasing studies have shown the important clinical role of immune and stromal cells in gastric cancer microenvironment. Based on information of immune and stromal cells in The Cancer Genome Atlas, this study aimed to construct a prognostic risk assessment model for gastric cancer.

Material/Methods

Based on the immune/structural scores, differentially expressed genes (DEGs) were filtered and analyzed. Afterwards, DEGs associated with prognosis were screened and the risk assessment model was constructed in the training set. Moreover, the validity of the model was verified both in the testing set and the overall sample.

Results

In this study, patients were divided into high-score and low-score groups based on immune/stromal score, and 919 DEGs were identified. By applying least absolute shrinkage and selection operator (LASSO) and Cox analysis, 10 mRNAs were selected to form a prognostic risk assessment model, risk score=(0.294*SLC17A9) + (−0.477*FERMT3) + (0.866*NRP1) + (0.350*MMRN1) + (0.381*RNASE1) + (0.189*TRIB3) + (0.230*PGAP3) + (0.087*MAGEA3) + (0.182*TACR2) + (0.368*CYP51A1). In the training set, the low-risk group divided by the model was found to have better overall survival, and the prediction efficiency of the model was demonstrated to be good. Multivariate Cox analysis indicated that the model could work as a prognostic factor independently. Similar results were shown in the testing group and overall patients cohort group. Finally, the risk assessment model and other clinical variables were integrated to construct a nomogram.

Conclusions

In general, this study constructs a prognostic risk assessment model for gastric cancer, which could improve the prognosis stratification of patients combined with other clinical indicators.

Treatment of Menopausal Vasomotor Symptoms With Fezolinetant, a Neurokinin 3 Receptor Antagonist: A Phase 2a Trial

CONTEXT

The thermoregulatory center in the hypothalamus is stimulated by neurokinin 3 receptor (NK3R) activation and inhibited by estrogen-negative feedback. This balance is disrupted in menopause, producing vasomotor symptoms (VMSs).

OBJECTIVE

To evaluate safety and efficacy of the NK3R antagonist fezolinetant in menopausal VMSs.

DESIGN

Twelve-week, double-blind, randomized, placebo-controlled study.

SETTING

Eight Belgian centers from September 2015 to October 2016.

PARTICIPANTS

Generally healthy menopausal women aged 40 to 65 years with moderate/severe VMSs.

INTERVENTIONS

Subjects were randomized (1:1) to 90 mg of fezolinetant twice daily or placebo for 12 weeks.

MAIN OUTCOME MEASURES

Subjects captured VMS severity and frequency using an electronic diary. The primary outcome was change from baseline to week 12 in total VMS score with fezolinetant vs placebo. Secondary outcomes included timing of changes in frequency and severity of moderate/severe VMSs and quality-of-life assessments at weeks 4, 8, and 12. Pharmacodynamic and pharmacokinetic effects were assessed, as were safety and tolerability.

RESULTS

Of 122 subjects screened, 87 were randomized and 80 (92%) completed the study. At week 12, fezolinetant significantly reduced total VMS score vs placebo (-26.5 vs -12.2, P < 0.001) and decreased mean frequency of moderate/severe VMSs by five episodes per day vs placebo. Severity and frequency of moderate/severe VMSs were reduced from the first day of treatment. Improvements were achieved in all quality-of-life measures. Fezolinetant was well tolerated. The most common fezolinetant-related adverse event was gastrointestinal disorder (n = 6).

CONCLUSIONS

Fezolinetant rapidly and significantly reduced moderate/severe VMSs, supporting its potential as an effective nonhormonal treatment option for menopausal women.

The expression of tachykinin receptors in the human lower esophageal sphincter

Mammalian tachykinins are a family of neuropeptides which are potent modulators of smooth muscle function with a significant contractile effect on human smooth muscle preparations. Tachykinins act via three distinct G protein-coupled neurokinin (NK) receptors, NK1, NK2 and NK3, coded by the genes TACR1, TACR2 and TACR3 respectively. The purpose of this paper was to measure the mRNA and protein expression of these receptors and their isoforms in the clasp and sling fibers of the human lower esophageal sphincter complex and circular muscle from the adjacent distal esophagus and proximal stomach. We found differences in expression between the different receptors within these muscle types, but the rank order of the receptor expression did not differ between the different muscle types. The rank order of the mRNA expression was TACR2 (α isoform)>TACR2 (β isoform)>TACR1 (short isoform)>TACR1 (long isoform)>TACR3. The rank order of the protein expression was NK2>NK1>NK3. This is the first report of the measurement of the transcript and protein expression of the tachykinin receptors and their isoforms in the muscles of the human lower esophageal sphincter complex. The results provide evidence that the tachykinin receptors could contribute to the regulation of the human lower esophageal sphincter, particularly the TACR2 α isoform which encodes the functional isoform of the tachykinin NK2 receptor was the most highly expressed of the tachykinin receptors in the muscles associated with the lower esophageal sphincter.

Targeting tachykinin receptors for the treatment of functional gastrointestinal disorders with a focus on irritable bowel syndrome

BACKGROUND

Tachykinins (TKs) are a family of endogenous peptides widely expressed in the central and in the peripheral nervous systems as well as in the gastrointestinal (GI) tract. They act as full agonists at three different membrane receptors neurokinin (NK) 1, NK2, and NK3, which are G protein-coupled receptors and in the GI tract are expressed both on neurons and effector cells.

PURPOSE

This article reviews the literature concerning the role of TKs in the GI tract function in physiological and pathological conditions and their potential relevance in the treatment of functional GI disorders with particular reference to irritable bowel syndrome (IBS). The efficacy of NK1 antagonists in chemotherapy-induced and postoperative nausea and vomiting is well established. While pharmacodynamic studies have reported conflicting and negative results concerning the effects of NK1 and of NK3 antagonists, respectively, on the GI tract function in humans, clinical studies applying the NK3 antagonist talnetant in IBS-D were negative. Pharmacodynamic studies applying NK2 antagonists have suggested a role for antagonism of NK2 receptors in modulation of GI chemical-induced altered motility and of stress-induced altered bowel habits. Clinical studies and in particular a recently completed Phase 2 study have reported that the NK2 antagonist ibodutant is effective and safe in treating symptoms of D-IBS, especially in females.

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

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

Neurokinin-2 receptor polymorphism predicts lymph node metastasis in colorectal cancer patients

To analyze the single nucleotide polymorphisms (SNPs) of two subtypes of neurokinin (NK) receptors, NK1R and NK2R (also known as TAC1R and TAC2R), in colorectal cancer (CRC), peripheral blood samples were collected from 199 CRC patients. Direct-sequencing was performed to identify the NK1R rs10198644 and NK2R rs4644560 SNPs. Genotype results were correlated with clinical factors. The allele frequencies of NK1R rs10198644 GC, CC and GG were 52, 17 and 31%, respectively, while that of NK2R rs4644560 GC, CC, and GG were 36, 50 and 14%, respectively. Patients with NK2R rs4644560 GC exhibited more positive lymph nodes than those with CC (mean, 2.2 vs. 1.3; P=0.016). Further analysis highlighted that the number of positive lymph nodes was also increased in the NK2R rs4644560 GC/NK1R rs10198644 GG group compared with the NK2R rs4644560 GG/NK1R rs10198644 GG group (mean, 2.2 vs. 0.9; P=0.04). These data suggested that the NK2R rs4644560 GC polymorphism alone or combination with NK1R rs10198644 GG may be a promising prognostic marker of lymph node metastasis in CRC patients.

Frequent promoter hypermethylation of tachykinin-1 and tachykinin receptor type 1 is a potential biomarker for head and neck cancer

AIM

The aim of this study was to define TAC1 and TACR1 methylation profiles for head and neck squamous cell carcinoma (HNSCC) tumors at diagnosis and follow-up and to evaluate their prognostic significance and value as a biomarker of recurrence.

MATERIALS AND METHODS

TAC1 and TACR1 expression was measured in a panel of cell lines by quantitative RT-PCR. The TAC1 and TACR1 promoter methylation status was determined by quantitative methylation-specific PCR.

RESULTS

Methylation was associated with TAC1 and TACR1 transcription inhibition. TAC1 methylation in 49/100 (49 %) of HNSCC tumor specimens significantly correlated with p16 methylation (P = 0.010), E-cadherin methylation (P = 0.041), galanin methylation (P = 0.037), and disease-free survival (P = 0.002). Stage III and IV patients manifesting TAC1 hypermethylation had significantly shorter survivals than did patients without TAC1 methylation (P = 0.022). TACR1 methylation in 34/100 (34 %) cases was significantly correlated with galanin methylation (P = 0.014) and GALR1 methylation (P = 0.004). TAC1 promoter hypermethylation was statistically correlated with reduced disease-free survival (log-rank test, P = 0.002). In multivariate logistic-regression analysis, methylation of TAC1 and of the gene pair TAC1 and TACR1 was associated with an odds ratio for recurrence of 3.35 (95 % CI, 1.37-8.19; P = 0.008) and 5.09 (95 % CI, 1.44-18.02; P = 0.011), respectively.

CONCLUSION

CpG hypermethylation is a likely mechanism of TAC1 and TACR1 gene inactivation, supporting the hypothesis that TAC1 and TACR1 play a role in the tumorigenesis of HNSCC and that this hypermethylation may serve as an important biomarker.

Association of genetic variants in tachykinins pathway genes with colorectal cancer risk

PURPOSE

This study aims to explore the associations of polymorphisms in tachykinin, precursor 1 (TAC1), tachykinin receptor 1 (TACR1), and tachykinin receptor 2 (TACR2) genes and their interactions with the risk of colorectal cancer (CRC) among Chinese population.

METHODS

A population-based case-control study which included 394 cases and 393 cancer-free controls was carried out. A total of 19 tagSNPs in the three genes were chosen based on HapMap and NCBI datasets and genotyped by SNPshot assay. Multiple logistic regression models were applied to evaluate the associations of SNPs with CRC after adjustment for potential covariates. Furthermore, generalized multifactor dimensionality reduction (GMDR) method was used to test the interactive effect among three genes on CRC.

RESULTS

Compared with those carrying rs3755457 CC/CT or rs12477554 TT/CT genotype, individuals carrying homozygous variants had higher risk of colorectal cancer (adjusted OR = 1.80, 95 % CI = 1.03-3.13, P = 0.039 for rs3755457; adjusted OR = 1.73, 95 % CI = 1.07-2.79, P = 0.024 for rs12477554). As for rs10198644, GG genotype was associated with a 1.72-fold (95 % CI = 0.37-0.88) decreased risk when compared with the common CC genotype. Moreover, the GMDR analysis indicated that the best interactive model included five polymorphisms: rs2072100 (TAC1), rs10198644 (TACR1), rs2193409 (TACR1), rs3771810 (TACR1), and rs4644560 (TACR2).

CONCLUSIONS

Our study suggests that tachykinins pathway genes may participate in the development of CRC and the potential interactions among the three genes on CRC may exist, which has to be confirmed in future larger studies.

Bidirectional regulation of human colonic smooth muscle contractility by tachykinin NK(2) receptors

In this study, we attempted to clarify the mechanism of tachykinin-induced motor response in isolated smooth muscle preparations of the human colon. Fresh specimens of normal colon were obtained from patients suffering from colonic cancer. Using mucosa-free smooth muscle strips, smooth muscle tension with circular direction was monitored isometrically. Substance P (SP), neurokinin A (NKA), and neurokinin B (NKB) produced marked contraction. All of these contractions were inhibited by saredutant, a selective NK(2)-R antagonist, but not by CP122721, a selective NK(1)-R antagonist or talnetant, a selective NK(3)-R antagonist. βAla(8)-NKA(4-10) induced concentration-dependent contraction similar to NKA, but Sar(9)-Met(11)-SP and Met-Phe(7)-NKB did not cause marked contraction. Colonic contraction induced by βAla(8)-NKA(4-10) was completely blocked by saredutant, but not by atropine. Tetrodotoxin or N(G)-nitro-L-arginine methyl ester pretreatment significantly enhanced βAla(8)-NKA(4-10)-induced contraction. Immunohistochemical analysis showed that the NK(2)-R was expressed on the smooth muscle layers and myenteric plexus where it was also co-expressed with neuronal nitric oxide synthase in the myenteric plexus. These results suggest that the NK(2)-R is a major contributor to tachykinin-induced smooth muscle contraction in human colon and that the NK(2)-R-mediated response consists of an excitatory component via direct action on the smooth muscle and an inhibitory component possibly via nitric oxide neurons.

Expression of tachykinins and their receptors in plaque psoriasis with pruritus

BACKGROUND Various mediators of pruritus have been suggested that might be responsible for the mechanism of pruritus in psoriasis.

OBJECTIVES

To study the expression levels of members of the tachykinin family, substance P and neurokinin (NK) A and their receptors, NK-1 and NK-2, in psoriasis and to correlate their expression with the intensity of pruritus. A possible correlation with chronic stress and depression was also evaluated.

METHODS

Biopsies were obtained from 28 patients with chronic plaque psoriasis; the majority had pruritus. The samples were taken from lesional and nonlesional areas on the back and also from 10 healthy controls, for immunohistochemistry staining, and from lesional skin for radioimmunoassay. Prior to biopsy, the clinical severity of the psoriasis of each patient was assessed by the Psoriasis Area and Severity Index (PASI) and the intensity of pruritus was measured by using a visual analogue scale (VAS). Levels of depression and stress were measured using Beck's Depression Inventory (BDI) and the salivary cortisol test, respectively.

RESULTS

Substance P-, NKA- and NK-2 receptor-immunoreactive nerves, and non-neuronal inflammatory cells positive for substance P and NKA and their respective receptors, NK-1 and NK-2, were numerous in psoriasis compared with healthy controls. The numbers of substance P-positive nerves and NK-2 receptor-positive cells in lesional skin were significantly correlated to pruritus intensity. The cortisol ratio was inversely correlated with the number of NK-1 receptor-immunoreactive inflammatory cells in lesional and nonlesional psoriasis skin. There was also a positive correlation between the BDI score and the number of substance P-positive cells in nonlesional skin and with NK-1 receptor-positive cells in lesional and nonlesional skin.

CONCLUSIONS

Tachykinins may play a role in psoriasis per se, in addition to pruritus in this disease. Targeting the combined NK-1 and NK-2 receptors might be a possible treatment.