Truncated neurokinin-1 receptor is increased in colonic epithelial cells from patients with colitis-associated cancer. Proc Natl Acad Sci U S A. 2011;108:17420-17425. [PMID: 21969570 DOI: 10.1073/pnas.1114275108]

Alternative Splicing at the Crossroad of Inflammatory Bowel Diseases and Colitis-Associated Colon Cancer

The risk of developing colorectal cancer (CRC) is increased in ulcerative colitis patients compared to the general population. This increased risk results from the state of chronic inflammation, a well-known tumour-promoting condition. This review explores the pathologic and molecular characteristics of colitis-associated colon cancer (CAC), emphasizing the distinct features from sporadic CRC. We focus on the key signalling pathways involved in the transition to CAC, highlighting the emerging role of alternative splicing in these processes, namely on how inflammation-induced alternative splicing can significantly contribute to the increased CRC risk observed among UC patients. This review calls for more transcriptomic studies to elucidate the molecular mechanisms through which inflammation-induced alternative splicing drives CAC pathogenesis. A better understanding of these splicing events is crucial as they may reveal novel biomarkers for disease progression and have the potential to target changes in alternative splicing as a therapeutic strategy.

The use of SP/Neurokinin-1 as a Therapeutic Target in Colon and Rectal Cancer

Different studies have highlighted the role of Substance P / Neurokinin 1 Receptor (SP/NK-1R) axis in multiple hallmarks of cancer including cell transformation, proliferation, and migration as well as angiogenesis and metastasis of a wide range of solid tumors including colorectal cancer. Until now, the selective high-affinity antagonist of human SP/NK1-R aprepitant (Emend) has been authorized by the Food and Drug Administration as a low dosage medication to manage and treat chemotherapy-induced nausea. However, increasing evidence in recent years support the potential utility of high doses of aprepitant as an antitumor agent and thus, opening the possibility to the pharmacological repositioning of SP/NK1-R antagonists as an adjuvant therapy to conventional cancer treatments. In this review, we summarize current knowledge on the molecular basis of colorectal cancer as well as the pathophysiological importance of SP/NK1-R and the potential utility of SP/NK-1R axis as a therapeutic target in this malignancy.

Association of Neurokinin-1 Receptor Signaling Pathways with Cancer

BACKGROUND

Numerous biochemical reactions leading to altered cell proliferation cause tumorigenesis and cancer treatment resistance. The mechanisms implicated include genetic and epigenetic changes, modified intracellular signaling, and failure of control mechanisms caused by intrinsic and extrinsic factors alone or combined. No unique biochemical events are responsible; entangled molecular reactions conduct the resident cells in a tissue to display uncontrolled growth and abnormal migration. Copious experimental research supports the etiological responsibility of NK-1R (neurokinin-1 receptor) activation, alone or cooperating with other mechanisms, in cancer appearance in different tissues. Consequently, a profound study of this receptor system in the context of malignant processes is essential to design new treatments targeting NK-1R-deviated activity.

METHODS

This study reviews and discusses recent literature that analyzes the main signaling pathways influenced by the activation of neurokinin 1 full and truncated receptor variants. Also, the involvement of NK-1R in cancer development is discussed.

CONCLUSION

NK-1R can signal through numerous pathways and cross-talk with other receptor systems. The participation of override or malfunctioning NK-1R in malignant processes needs a more precise definition in different types of cancers to apply satisfactory and effective treatments. A long way has already been traveled: the current disposal of selective and effective NK-1R antagonists and the capacity to develop new drugs with biased agonistic properties based on the receptor's structural states with functional significance opens immediate research action and clinical application.

Crosstalk between alternative splicing and inflammatory bowel disease: Basic mechanisms, biotechnological progresses and future perspectives

BACKGROUND

Alternative splicing (AS) is an omnipresent regulatory mechanism of gene expression that enables the generation of diverse splice isoforms from a single gene. Recently, AS events have gained considerable momentum in the pathogenesis of inflammatory bowel disease (IBD).

METHODS

Our review has summarized the complex process of RNA splicing, and firstly highlighted the potential involved molecules that target aberrant splicing events in IBD. The quantitative transcriptome analyses such as microarrays, next-generation sequencing (NGS) for AS events in IBD have been also discussed.

RESULTS

Available evidence suggests that some abnormal splicing RNAs can lead to multiple intestinal disorders during the onset of IBD as well as the progression to colitis-associated cancer (CAC), including gut microbiota perturbations, intestinal barrier dysfunctions, innate/adaptive immune dysregulations, pro-fibrosis activation and some other risk factors. Moreover, current data show that the advanced technologies, including microarrays and NGS, have been pioneeringly employed to screen the AS candidates and elucidate the potential regulatory mechanisms of IBD. Besides, other biotechnological progresses such as the applications of third-generation sequencing (TGS), single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST), will be desired with great expectations.

CONCLUSIONS

To our knowledge, the current review is the first one to evaluate the potential regulatory mechanisms of AS events in IBD. The expanding list of aberrantly spliced genes in IBD along with the developed technologies provide us new clues to how IBD develops, and how these important AS events can be explored for future treatment.

Modulating the tachykinin: Role of substance P and neurokinin receptor expression in ocular surface disorders

Substance P (SP) is a tachykinin expressed by various cells in the nervous and immune systems. SP is predominantly released by neurons and exerts its biological and immunological effects through the neurokinin receptors, primarily the neurokinin-1 receptor (NK1R). SP is essential for maintaining ocular surface homeostasis, and its reduced levels in disorders like diabetic neuropathy disrupt the corneal tissue. It also plays an essential role in promoting corneal wound healing by promoting the migration of keratocytes. In this review, we briefly discuss the structure, expression, and function of SP and its principal receptor NK1R. In addition, SP induces pro-inflammatory effects through autocrine or paracrine action on the immune cells in various ocular surface pathologies, including dry eye disease, herpes simplex virus keratitis, and Pseudomonas keratitis. We provide an in-depth review of the pathogenic role of SP in various ocular surface diseases and several new approaches developed to counter the immune-mediated effects of SP either through modulating its production or blocking its target receptor.

SP/NK1R system regulates carcinogenesis in prostate cancer: Shedding light on the antitumoral function of aprepitant

AIMS

Prostate cancer continues to be one of the main global health issues in men. Neuropeptide substance P (SP) acting via neurokinin-1receptor (NK1R) promotes tumorigenicity in many human malignant tumors. However, its pro-tumorigenic functions and the therapeutic effects of its inhibition in prostate cancer remain unclear.

METHODS

MTT assay was employed for measuring cellular proliferation and cytotoxicity. mRNAs and proteins expression levels were evaluated by qRT-PCR and western blot assay, respectively. Gelatinase activity was assessed by zymography. The migration ability was defined using wound-healing assay. Flow cytometry was employed to evaluate the cell cycle distribution. We also performed an in vivo experiment in a mouse model of prostate cancer to confirm the in vitro therapeutic effect of targeting the SP/NK1R system.

RESULTS

We found a noticeable increase in the expression of the truncated isoform of NK1R as an oncogenic NK1R splice variant in tumor cells. We also demonstrated that SP promotes both proliferative and migrative phenotypes of prostate cancer through modifying cell cycle-related proteins (c-Myc, cyclin D1, cyclin B1, p21), and apoptosis-related genes (Bcl-2 and Bax), promoting cell migration and increasing MMP-2 and MMP-9 expression and activity, while aprepitant administration could remarkably reverse these effects. SP also stimulated tumor growth in vivo, which was correlated with shorter survival times, while aprepitant reversed this effect and led to significantly longer survival time.

SIGNIFICANCE

Our findings suggest that SP/NK1R system may serve as a novel therapeutic target in prostate cancer and support the possible candidacy of aprepitant in future prostate cancer therapy.

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.

Potential in vitro therapeutic effects of targeting SP/NK1R system in cervical cancer

BACKGROUND

Cervical cancer, an aggressive gynecological cancer, seriously threatens women's health worldwide. It is recently reported that neuropeptide substance P (SP) regulates many tumor-associated processes through neurokinin-1 receptor (NK1R). Therefore, we used cervical cancer cell line (HeLa) to investigate the functional relevance of the SP/NK1R system in cervical cancer pathogenesis.

METHODS

Cellular proliferation and cytotoxicity were analyzed by colorimetric MTT assay. Quantitative real-time PCR (qRT-PCR) was used to measure mRNA expression levels of desired genes. Cell cycle distribution and apoptosis were evaluated by flow cytometry. A wound-healing assay was employed to assess migration ability.

RESULTS

We found that the truncated isoform of NK1R(NK1R-Tr) is the dominantly expressed form of the receptor in Hela cells. We also indicated that that SP increased HeLa cell proliferation while treatment with NK1R antagonist, aprepitant, inhibited HeLa cell viability in a dose and time-dependent manner. SP also alters the levels of cell cycle regulators (up-regulation of cyclin B1 along with downregulation of p21) and apoptosis-related genes (up-regulation of Bcl-2 along with downregulation of Bax) while aprepitant reversed these effects. Aprepitant also induced arrest within the G2 phase of the cell cycle and subsequent apoptosis. Furthermore, SP promoted the migrative phenotype of HeLa cells and increased MMP-2 and MMP-9 expression while aprepitant exposure significantly reversed these effects.

CONCLUSION

Collectively, our results indicate the importance of the SP / NK1R system in promoting both proliferative and migrative phenotypes of cervical cancer cells and suggest that aprepitant may be developed as a novel treatment for combating cervical cancer.

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.

What substance P might tell us about the prognosis and mechanism of Parkinson's disease?

The neuropeptide substance P (SP) plays an important role in neurodegenerative disorders, among which Parkinson's disease (PD). In the present work we have reviewed the involvement of SP and its preferred receptor (NK1-R) in motor and non-motor PD symptoms, in both PD animal models and patients. Despite PD is primarily a motor disorder, non-motor abnormalities, including olfactory deficits and gastrointestinal dysfunctions, can represent diagnostic PD predictors, according to the hypothesis that the olfactory and the enteric nervous system represent starting points of neurodegeneration, ascending to the brain via the sympathetic fibers and the vagus nerve. In PD patients, the α-synuclein aggregates in the olfactory bulb and the gastrointestinal tract, as well as in the dorsal motor nucleus of the vagus nerve often co-localize with SP, indicating SP-positive neurons as highly vulnerable sites of degeneration. Considering the involvement of the SP/NK1-R in both the periphery and specific brain areas, this system might represent a neuronal substrate for the symptom and disease progression, as well as a therapeutic target for PD.

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.

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.

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

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

Neurokinin-1 Receptor Antagonists as Anticancer Drugs

Background::

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

Methods: :

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

Results: :

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

Conclusion::

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

MiR-34b/c-5p and the neurokinin-1 receptor regulate breast cancer cell proliferation and apoptosis

OBJECTIVES

MiR-34 is a tumour suppressor in breast cancer. Neurokinin-1 receptor (NK1R), which is the predicted target of the miR-34 family, is overexpressed in many cancers. This study investigated the correlation and clinical significance of miR-34 and NK1R in breast cancer.

MATERIALS AND METHODS

Western blotting, quantitative reverse transcription-PCR (qRT-PCR) and luciferase assays were conducted to analyse the regulation of NK1R by miR-34 in MDA-MB-231, MCF-7, T47D, SK-BR-3 and HEK-293 T cells. MiR-34b/c-5p, full-length NK1R (NK1R-FL) and truncated NK1R (NK1R-Tr) expression in fifty patients were quantified by qRT-PCR and correlated with their clinicopathological parameters. CCK-8 assays, colony formation assays and flow cytometry were used to measure cell proliferation and apoptosis in MDA-MB-231 and MCF-7 cells transfected with miR-34b/c-5p or NK1R-siRNA and before treatment with or without Substance P (SP), an endogenous peptide agonists of NK1R. The effect of NK1R antagonist aprepitant was also investigated. In vivo xenograft models were used to further verify the regulation of NK1R by miR-34b/c-5p.

RESULTS

Expression levels of miR-34b/c-5p and NK1R-Tr, but not NK1R-FL, were associated with enhanced malignant potential, such as tumour stage and Ki67 expression. The overexpression of miR-34b/c-5p or NK1R silencing potently suppressed cell proliferation and induced G2/M phase arrest and the apoptosis of MDA-MB-231 and MCF-7 cells. The NK1R antagonist aprepitant had similar effects. In vivo studies confirmed that miR-34b/c-5p overexpression or NK1R silencing reduced the tumorigenicity of breast cancer. In addition, SP rescued the effects of miR-34b/c-5p overexpression or NK1R silencing on cell proliferation and apoptosis in vitro and in vivo assays.

CONCLUSIONS

MiR-34b/c-5p and NK1R contribute to breast cancer cell proliferation and apoptosis and are potential targets for breast cancer therapeutics.

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

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

Truncation of neurokinin-1 receptor-Negative regulation of substance P signaling

Substance P (SP) is a tachykinin peptide, which triggers intracellular signaling in the nervous and immune systems, as well as, other local and systemic events. The interaction between SP and its receptor, neurokinin-1 receptor (NK1R), results in major downstream cellular actions, which include changes in calcium fluxes, ERK, and p21-activated kinase phosphorylation and NFκB activation. Two naturally occurring variants of the NK1R, the full-length, 407 aa receptor (NK1R-F) and the truncated, 311 aa isoform (NK1R-T), mediate the actions of SP. Receptor truncation partially disrupts signaling motifs of the carboxyl tail, a critical site for mediating NK1R signaling, resulting in a "less-efficient" receptor. Although NK1R-F is the predominant isoform in the central and peripheral nervous systems, NK1R-T is expressed in several tissues and cells, which include monocytes, NK cells, and T-cells. The SP binding domain is not affected by truncation and this site is identical in both NK1R receptor isoforms. However, while cells expressing NK1R-F respond to nanomolar concentrations of SP, monocyte and macrophage activation, mediated through NK1R-T, requires micromolar concentrations of SP in order to elicit signaling responses. Elevated plasma levels of SP are associated with increased inflammatory responses and NK1R antagonists reduce inflammation and cytokine production in vivo. This mini review presents and discusses the novel hypothesis that the expression of NK1R-T on immune system cells prevents immune activation in a milieu, which usually contains low concentrations of SP and, thus, maintains immune homeostasis. In contrast, in the activated neuronal microenvironment, when SP levels reach the threshold at tissue sites, SP promotes immune activation and modulates monocyte/macrophage polarization.

Role of Substance P Neuropeptide in Inflammation, Wound Healing, and Tissue Homeostasis

Substance P (SP) is an undecapeptide present in the CNS and the peripheral nervous system. SP released from the peripheral nerves exerts its biological and immunological activity via high-affinity neurokinin 1 receptor (NK1R). SP is also produced by immune cells and acts as an autocrine or paracrine fashion to regulate the function of immune cells. In addition to its proinflammatory role, SP and its metabolites in combination with insulin-like growth factor-1 are shown to promote the corneal epithelial wound healing. Recently, we showed an altered ocular surface homeostasis in unmanipulated NK1R^-/- mice, suggesting the role of SP-NK1R signaling in ocular surface homeostasis under steady-state. This review summarizes the immunobiology of SP and its effect on immune cells and immunity to microbial infection. In addition, the effect of SP in inflammation, wound healing, and corneal epithelial homeostasis in the eye is discussed.

PanIN Neuroendocrine Cells Promote Tumorigenesis via Neuronal Cross-talk

Nerves are a notable feature of the tumor microenvironment in some epithelial tumors, but their role in the malignant progression of pancreatic ductal adenocarcinoma (PDAC) is uncertain. Here, we identify dense innervation in the microenvironment of precancerous pancreatic lesions, known as pancreatic intraepithelial neoplasms (PanIN), and describe a unique subpopulation of neuroendocrine PanIN cells that express the neuropeptide substance P (SP) receptor neurokinin 1-R (NK1-R). Using organoid culture, we demonstrated that sensory neurons promoted the proliferation of PanIN organoids via SP-NK1-R signaling and STAT3 activation. Nerve-responsive neuroendocrine cells exerted trophic influences and potentiated global PanIN organoid growth. Sensory denervation of a genetically engineered mouse model of PDAC led to loss of STAT3 activation, a decrease in the neoplastic neuroendocrine cell population, and impaired PanIN progression to tumor. Overall, our data provide evidence that nerves of the PanIN microenvironment promote oncogenesis, likely via direct signaling to neoplastic neuroendocrine cells capable of trophic influences. These findings identify neuroepithelial cross-talk as a potential novel target in PDAC treatment. Cancer Res; 77(8); 1868–79. ©2017 AACR.

PanIN Neuroendocrine Cells Promote Tumorigenesis via Neuronal Cross-talk

Nerves are a notable feature of the tumor microenvironment in some epithelial tumors, but their role in the malignant progression of pancreatic ductal adenocarcinoma (PDAC) is uncertain. Here, we identify dense innervation in the microenvironment of precancerous pancreatic lesions, known as pancreatic intraepithelial neoplasms (PanIN), and describe a unique subpopulation of neuroendocrine PanIN cells that express the neuropeptide substance P (SP) receptor neurokinin 1-R (NK1-R). Using organoid culture, we demonstrated that sensory neurons promoted the proliferation of PanIN organoids via SP-NK1-R signaling and STAT3 activation. Nerve-responsive neuroendocrine cells exerted trophic influences and potentiated global PanIN organoid growth. Sensory denervation of a genetically engineered mouse model of PDAC led to loss of STAT3 activation, a decrease in the neoplastic neuroendocrine cell population, and impaired PanIN progression to tumor. Overall, our data provide evidence that nerves of the PanIN microenvironment promote oncogenesis, likely via direct signaling to neoplastic neuroendocrine cells capable of trophic influences. These findings identify neuroepithelial cross-talk as a potential novel target in PDAC treatment. Cancer Res; 77(8); 1868-79. ©2017 AACR.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

The Therapeutic Potential of Targeting Substance P/NK-1R Interactions in Inflammatory CNS Disorders

The inflammatory responses of resident central nervous system (CNS) cells are now known to play a critical role in the initiation and progression of an array of infectious and sterile neuroinflammatory disorders such as meningitis, encephalitis, Parkinson's disease, Alzheimer's disease and multiple sclerosis (MS). Regulating glial inflammatory responses in a timely manner is therefore critical in preserving normal CNS functions. The neuropeptide substance P is produced at high levels within the CNS and its selective receptor, the neurokinin 1 receptor (NK-1R), is abundantly expressed by neurons and is present on glial cell types including microglia and astrocytes. In addition to its functions as a neurotransmitter in the perception of pain and its essential role in gut motility, this tachykinin is widely recognized to exacerbate inflammation at peripheral sites including the skin, gastrointestinal tract and the lungs. Recently, a number of studies have identified a role for substance P and NK-1R interactions in neuroinflammation and described the ability of this neuropeptide to alter the immune functions of activated microglia and astrocytes. In this review article, we describe the expression of substance P and its receptor by resident CNS cells, and we discuss the ability of this neuropeptide to exacerbate the inflammatory responses of glia and immune cells that are recruited to the brain during neurodegenerative diseases. In addition, we discuss the available data indicating that the NK-1R-mediated augmentation of such responses appears to be detrimental during microbial infection and some sterile neurodegenerative disorders, and propose the repurposed use of NK-1R antagonists, of a type that are currently approved as anti-emetic and anti-anxiolytic agents, as an adjunct therapy to ameliorate the inflammatory CNS damage in these conditions.

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

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

Transforming Growth Factor Beta 1 Modulates the Functional Expression of the Neurokinin-1 Receptor in Human Keratocytes

Purpose: Transforming growth factor beta 1 (TGF-β1) is a cytokine involved in a variety of processes, such as differentiation of fibroblasts into myofibroblasts. TGF-β1 has also been shown to delay the internalization of the neurokinin-1 receptor (NK-1 R) after its activation by its ligand, the neuropeptide substance P (SP). NK-1 R comprises two naturally occurring variants, a full-length and a truncated form, triggering different cellular responses. SP has been shown to affect important events in the cornea – such as stimulating epithelial cell proliferation – processes that are involved in corneal wound healing and thus in maintaining the transparency of the corneal stroma. An impaired signaling through NK-1 R could thus impact the visual quality. We hypothesize that TGF-β1 modulates the expression pattern of NK-1 R in human corneal stroma cells, keratocytes. The purpose of this study was to test that hypothesis.

Methods: Cultures of primary keratocytes were set up with cells derived from healthy human corneas, obtained from donated transplantation graft leftovers, and characterized by immunocytochemistry and Western blot. Immunocytochemistry for TGF-β receptors and NK-1 R was performed. Gene expression was assessed with real-time polymerase chain reaction (qPCR).

Results: Expression of TGF-β receptors was confirmed in keratocytes in vitro. Treating the cells with TGF-β1 significantly reduced the gene expression of NK-1 R. Furthermore, immunocytochemistry for NK-1 R demonstrated that it is specifically the expression of the full-length isotype of the receptor that is reduced after treatment with TGF-β1, which was also confirmed with qPCR using a specific probe for the full-length receptor.

Conclusions: TGF-β1 down-regulates the gene expression of the full-length variant of NK-1 R in human keratocytes, which might impact its signaling pathway and thus explain the known delay in internalization after activation by SP seen with TGF-β1 treatment.

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

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

The RNA-binding protein Musashi 1 stabilizes the oncotachykinin 1 mRNA in breast cancer cells to promote cell growth

Substance P and its truncated receptor exert oncogenic effects. The high production of substance P in breast cancer cells (BCCs) is caused by the enhancement of tachykinin (TAC)1 translation by cytosolic factor. In vitro translational studies and mRNA stabilization analyses indicate that BCCs contain the factor needed to increase TAC1 translation and to stabilize the mRNA. Prediction of protein folding, RNA-shift analysis, and proteomic analysis identified a 40 kDa molecule that interacts with the noncoding exon 7. Western blot analysis and RNA supershift identified Musashi 1 (Msi1) as the binding protein. Ectopic expression of TAC1 in nontumorigenic breast cells (BCs) indicates that TAC1 regulates its stability by increasing Msi1. Using a reporter gene system, we showed that Msi1 competes with microRNA (miR)130a and -206 for the 3' UTR of exon 7/TAC1. In the absence of Msi1 and miR130a and -206, reporter gene activity decreased, indicating that Msi1 expression limits TAC1 expression. Tumor growth was significantly decreased when nude BALB/c mice were injected with Msi1-knockdown BCCs. In summary, the RNA-binding protein Msi1 competes with miR130a and -206 for interaction with TAC1 mRNA, to stabilize and increase its translation. Consequently, these interactions increase tumor growth.

Biological and Pharmacological Aspects of the NK1-Receptor

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

Alternative Splicing of G Protein-Coupled Receptors: Relevance to Pain Management

Drugs that target G protein-coupled receptors (GPCRs) represent the primary treatment strategy for patients with acute and chronic pain; however, there is substantial individual variability in both the efficacy and adverse effects associated with these drugs. Variability in drug responses is due, in part, to individuals' diversity in alternative splicing of pain-relevant GPCRs. G protein-coupled receptor alternative splice variants often exhibit distinct tissue distribution patterns, drug-binding properties, and signaling characteristics that may impact disease pathology as well as the extent and direction of analgesic effects. We review the importance of GPCRs and their known splice variants to the management of pain.

Targeting NK-1 Receptors to Prevent and Treat Pancreatic Cancer: a New Therapeutic Approach

Pancreatic cancer (PC) is the fourth leading cause of cancer related-deaths in both men and women, and the 1- and 5-year relative survival rates are 25% and 6%, respectively. It is known that smoking, alcoholism and psychological stress are risk factors that can promote PC and increase PC progression. To date, the prevention of PC is crucial because there is no curative treatment. After binding to the neurokinin-1 (NK-1) receptor (a receptor coupled to the stimulatory G-protein Gαs that activates adenylate cyclase), the peptide substance P (SP)-at high concentrations-is involved in many pathophysiological functions, such as depression, smoking, alcoholism, chronic inflammation and cancer. It is known that PC cells and samples express NK-1 receptors; that the NK-1 receptor is overexpressed in PC cells in comparison with non-tumor cells, and that nanomolar concentrations of SP induce PC cell proliferation. By contrast, NK-1 receptor antagonists exert antidepressive, anxiolytic and anti-inflammatory effects and anti-alcohol addiction. These antagonists also exert An antitumor action since in vitro they inhibit PC cell proliferation (PC cells death by apoptosis), and in a xenograft PC mouse model they exert both antitumor and anti-angiogenic actions. NK-1 receptor antagonists could be used for the treatment of PC and hence the NK-1 receptor could be a new promising therapeutic target in PC.

Immunohistochemical expression of SP-NK-1R-EGFR pathway and VDR in colonic inflammation and neoplasia

AIM: To determine the expression of neurokinin-1 receptor (NK-1R), phosphorylated epidermal growth factor receptor (pEGFR), cyclooxygenase-2 (Cox-2), and vitamin D receptor (VDR) in normal, inflammatory bowel disease (IBD), and colorectal neoplasia tissues from Puerto Ricans.

METHODS: Tissues from patients with IBD, colitis-associated colorectal cancer (CAC), sporadic dysplasia, and sporadic colorectal cancer (CRC), as well as normal controls, were identified at several centers in Puerto Rico. Archival formalin-fixed, paraffin-embedded tissues were de-identified and processed by immunohistochemistry for NK-1R, pEGFR, Cox-2, and VDR. Pictures of representative areas of each tissues diagnosis were taken and scored by three observers using a 4-point scale that assessed intensity of staining. Tissues with CAC were further analyzed by photographing representative areas of IBD and the different grades of dysplasia, in addition to the areas of cancer, within each tissue. Differences in the average age between the five patient groups were assessed with one-way analysis of variance and Tukey-Kramer multiple comparisons test. The mean scores for normal tissues and tissues with IBD, dysplasia, CRC, and CAC were calculated and statistically compared using one-way analysis of variance and Dunnett’s multiple comparisons test. Correlations between protein expression patterns were analyzed with the Pearson’s product-moment correlation coefficient. Data are presented as mean ± SE.

RESULTS: On average, patients with IBD were younger (34.60 ± 5.81) than normal (63.20 ± 6.13, P < 0.01), sporadic dysplasia (68.80 ± 4.42, P < 0.01), sporadic cancer (74.80 ± 4.91, P < 0.001), and CAC (57.50 ± 5.11, P < 0.05) patients. NK-1R in cancer tissue (sporadic CRC, 1.73 ± 0.34; CAC, 1.57 ± 0.53) and sporadic dysplasia (2.00 ± 0.45) were higher than in normal tissues (0.73 ± 0.19). pEGFR was significantly increased in sporadic CRC (1.53 ± 0.43) and CAC (2.25 ± 0.47) when compared to normal tissue (0.07 ± 0.25, P < 0.05, P < 0.001, respectively). Cox-2 was significantly increased in sporadic colorectal cancer (2.20 ± 0.23 vs 0.80 ± 0.37 for normal tissues, P < 0.05). In comparison to normal (2.80 ± 0.13) and CAC (2.50 ± 0.33) tissues, VDR was significantly decreased in sporadic dysplasia (0.00 ± 0.00, P < 0.001 vs normal, P < 0.001 vs CAC) and sporadic CRC (0.47 ± 0.23, P < 0.001 vs normal, P < 0.001 vs CAC). VDR levels negatively correlated with NK-1R (r = -0.48) and pEGFR (r = -0.56) in normal, IBD, sporadic dysplasia and sporadic CRC tissue, but not in CAC.

CONCLUSION: Immunohistochemical NK-1R and pEGFR positivity with VDR negativity can be used to identify areas of sporadic colorectal neoplasia. VDR immunoreactivity can distinguish CAC from sporadic cancer.

Hepatoblastoma cells express truncated neurokinin-1 receptor and can be growth inhibited by aprepitant in vitro and in vivo

BACKGROUND & AIMS

Multidrug resistance presents a major problem in hepatoblastoma (HB), and new anti-tumor strategies are desperately needed. The substance P (SP)/neurokinin-1 receptor (NK1R) complex has been discovered to be pivotal in the development of a variety of human cancers, and NK1R antagonists, such as the clinical drug aprepitant, are promising future anticancer agents. Yet, the role of the SP/NK1R complex as a potential anticancer target in HB is unknown.

METHODS

Human HB cell lines HepT1, HepG2, and HuH6, human tumor samples from 17 children with HB as well as mice xenografted with human HB cell line HuH6 were analyzed regarding the SP/NK1R complex as a potential new anti-tumor target in HB.

RESULTS

Therapeutic targeting with the NK1R antagonists aprepitant, L-733,060, and L-732,138 led to growth inhibition and apoptosis in HepT1, HepG2, and HuH6 cells in a dose-dependent manner. Intriguingly, HB cells predominantly expressed the truncated splice variant of NK1R. Human fibroblasts showed only dismal NK1R expression and were significantly more resistant. Stimulation of HB cells with SP, NK1R's natural ligand, caused increased growth rates and abrogated the anti-proliferative effect of NK1R antagonists. Expression analysis of 17 human HB samples confirmed the clinical relevance of NK1R. Most importantly, oral treatment of a HuH6 xenograft mouse model with 80mg/kg/day aprepitant for 24days resulted in a striking reduction of tumor growth, as evidenced by reduced tumor volume and weight, lowered tumor-specific alpha-fetoprotein (AFP) serum levels, and decreased number of Ki-67 positive cells. Furthermore, aprepitant treatment inhibited in vivo angiogenesis.

CONCLUSIONS

For the first time, we describe the NK1R in its truncated splice variant as a potent target in human HB and an inhibitory effect in vivo and in vitro by NK1R antagonists. Therefore, NK1R antagonists should be considered promising new candidates for innovative therapeutic strategies against HB.

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

Pancreatic cancer is the fourth leading cause of cancer related-death for both men and women and the 1- and 5-year relative survival rates are 25% and 6%, respectively. Thus, it is urgent to investigate new antitumor drugs to improve the survival of pancreatic cancer patients. The peptide substance P (SP) has a widespread distribution throughout the body. After binding to the neurokinin-1 (NK-1) receptor, SP regulates biological functions related to cancer, such as tumor cell proliferation, neoangiogenesis, the migration of tumor cells for invasion, infiltration and metastasis, and it exerts an antiapoptotic effects on tumor cells. It is known that the SP/NK-1 receptor system is involved in pancreatic cancer progression: (1) pancreatic cancer cells and samples express NK-1 receptors; (2) the NK-1 receptor is overexpressed in pancreatic cancer cells in comparison with non-tumor cells; (3) nanomolar concentrations of SP induce pancreatic cancer cell proliferation; (4) NK-1 receptor antagonists inhibit pancreatic cell proliferation in a concentration-dependent manner, at a certain concentration, these antagonists inhibit 100% of tumor cells; (5) this antitumor action is mediated through the NK-1 receptor, and tumor cells die by apoptosis; and (6) NK-1 receptor antagonists inhibit angiogenesis in pancreatic cancer xenografts. All these data suggest that the SP/NK-1 receptor system could play an important role in the development of pancreatic cancer; that the NK-1 receptor could be a new promising therapeutic target in pancreatic cancer, and that NK-1 receptor antagonists could improve the treatment of pancreatic cancer.

Tachykinins and their receptors: contributions to physiological control and the mechanisms of disease

The tachykinins, exemplified by substance P, are one of the most intensively studied neuropeptide families. They comprise a series of structurally related peptides that derive from alternate processing of three Tac genes and are expressed throughout the nervous and immune systems. Tachykinins interact with three neurokinin G protein-coupled receptors. The signaling, trafficking, and regulation of neurokinin receptors have also been topics of intense study. Tachykinins participate in important physiological processes in the nervous, immune, gastrointestinal, respiratory, urogenital, and dermal systems, including inflammation, nociception, smooth muscle contractility, epithelial secretion, and proliferation. They contribute to multiple diseases processes, including acute and chronic inflammation and pain, fibrosis, affective and addictive disorders, functional disorders of the intestine and urinary bladder, infection, and cancer. Neurokinin receptor antagonists are selective, potent, and show efficacy in models of disease. In clinical trials there is a singular success: neurokinin 1 receptor antagonists to treat nausea and vomiting. New information about the involvement of tachykinins in infection, fibrosis, and pruritus justifies further trials. A deeper understanding of disease mechanisms is required for the development of more predictive experimental models, and for the design and interpretation of clinical trials. Knowledge of neurokinin receptor structure, and the development of targeting strategies to disrupt disease-relevant subcellular signaling of neurokinin receptors, may refine the next generation of neurokinin receptor antagonists.

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

Many data suggest the deep involvement of the substance P (SP)/neurokinin (NK)-1 receptor system in cancer: (1) Tumor cells express SP, NK-1 receptors and mRNA for the tachykinin NK-1 receptor; (2) Several isoforms of the NK-1 receptor are expressed in tumor cells; (3) the NK-1 receptor is involved in the viability of tumor cells; (4) NK-1 receptors are overexpressed in tumor cells in comparison with normal ones and malignant tissues express more NK-1 receptors than benign tissues; (5) Tumor cells expressing the most malignant phenotypes show an increased percentage of NK-1 receptor expression; (6) The expression of preprotachykinin A is increased in tumor cells in comparison with the levels found in normal cells; (7) SP induces the proliferation and migration of tumor cells and stimulates angiogenesis by increasing the proliferation of endothelial cells; (8) NK-1 receptor antagonists elicit the inhibition of tumor cell growth; (9) The specific antitumor action of NK-1 receptor antagonists on tumor cells occurs through the NK-1 receptor; (10) Tumor cell death is due to apoptosis; (11) NK-1 receptor antagonists inhibit the migration of tumor cells and neoangiogenesis. The NK-1 receptor is a therapeutic target in cancer and NK-1 receptor antagonists could be considered as broad-spectrum antitumor drugs for the treatment of cancer. It seems that a common mechanism for cancer cell proliferation mediated by SP and the NK-1 receptor is triggered, as well as a common mechanism exerted by NK-1 receptor antagonists on tumor cells, i.e. apoptosis.

Plasminogen activator inhibitor-1 is increased in colonic epithelial cells from patients with colitis-associated cancer

BACKGROUND

Patients with long-term ulcerative colitis are at risk for developing colorectal cancer.

METHODS

Archival formalin-fixed paraffin-embedded tissue from ulcerative colitis patients who underwent a colectomy for high-grade dysplasia or carcinoma was examined for changes in expression of plasminogen activator inhibitor-1 (PAI-1) as well as other mediators of inflammation-associated cancer. Epithelia from areas of colons that showed histologic evidence of carcinoma, high-grade dysplasia, and epithelia that were not dysplastic or malignant but did contain evidence of prior inflammation (quiescent colitis) was microdissected using laser capture microscopy. mRNA was extracted from the microdissected tissue and PCR array analysis was performed. To extend our findings, PAI-1 protein levels were determined using immunohistochemistry.

RESULTS

The mRNA expression of PAI-1 is increased 6-fold (p=0.02) when comparing the carcinoma group to the quiescent colitis group; increases were also observed in NFKB2, REL, SRC, and VEGFA. The protein levels of PAI-1 are increased by 50% (p<0.001) in high-grade dysplasia and by 60% (p<0.001) in carcinoma when compared to the quiescent colitis group.

CONCLUSIONS

The increase in PAI-1 in high-grade dysplasia and carcinoma suggests a functional role for PAI-1 in malignant transformation in colitis-associated cancer. PAI-1 could also prove a useful diagnostic marker to identify patients at risk for neoplasia and it may be a useful therapeutic target to treat colitis-associated cancer.

An indirect role for oncomir-519b in the expression of truncated neurokinin-1 in breast cancer cells

Neurokinin 1 (NK1) encodes full-length (NK1-FL) and truncated (NK1-Tr) receptors, with distinct 3' UTR. NK1-Tr exerts oncogenic functions and is increased in breast cancer (BC). Enhanced transcription of NK1 resulted in higher level of NK1-Tr. The 3' UTR of these two transcripts are distinct with NK1-Tr terminating at a premature stop codon. NK1-Tr mRNA gained an advantage over NK1-FL with regards to translation. This is due to the ability of miR519B to interact with sequences within the 3' UTR of NK1-FL, but not NK1-Tr since the corresponding region is omitted. MiR519b suppressed the translation of NK1-FL in T47D and MDA-MB-231 resulting in increased NK1-Tr protein. Cytokines can induce the transcription of NK1. However, our studies indicated that translation appeared to be independent of cytokine production by the BC cells (BCCs). This suggested that transcription and translation of NK1 might be independent. The findings were validated in vivo. MiR-519b suppressed the growth of MDA-MB-231 in 7/10 nude BALB/c. In total, increased NK1-Tr in BCCs is due to enhanced transcription and suppressed translation of NK1-FL by miR-519b to reduced tumor growth. In summary, we report on miRNA as a method to further regulate the expression of a spiced variant to promote oncogenesis. In addition, the findings have implications for therapy with NK1 antagonists. The oncogenic effect of NK1-Tr must be considered to improve the efficacy of current drugs to NK1.

Activation of neurokinin-1 receptor by substance P inhibits melanogenesis in B16-F10 melanoma cells

Skin pigmentation plays a number of valuable roles and its regulation is a complex process that is controlled by different factors. Substance P (SP) regulates many biological functions, including neurogenic inflammation, pain, and stress. However, to date, the regulatory role of SP in the control of melanogenesis has not been elucidated. The present study was designed to investigate the effects of SP on melanogenesis and to elucidate its underlying mechanism(s). After treatment for 48 h in mouse B16-F10 melanoma cells, SP (1 and 10nM) significantly down-regulated tyrosinase activity and melanin content. Importantly, western blot analysis revealed the presence of neurokinin-1 receptor (NK-1 R) in B16-F10 cells and the activation of it after SP treatment. It was also found that preincubation with NK-1 receptor antagonist Spantide I could partially reversed SP-induced down-regulations of tyrosinase activity, melanin content and the expression of tyrosinase and tyrosinase-related protein 1. Furthermore, SP could remarkably inhibit the expressions of microphtalmia-associated transcription factor (MITF) and p-p38 MAPK and stimulated p-p70 S6K1. These effects could also be partially reversed by the pretreatment with Spantide I. These results collectively suggested that SP inhibited melanogenesis in B16-F10 cells, which might be attributed to the fact that SP induces the activation of NK-1 receptor, stimulates the phosphorylation of p70 S6K1 and inhibits that of p38 MAPK, decreases the tyrosinase and tyrosinase-related protein 1 expression through MITF, finally resulting in the suppression of melanogenesis. These observations in vitro indicated that the regulation of the SP/NK-1 receptor system might be a useful novel management for skin pigmentation.

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

The recent years have witnessed an exponential increase in cancer research, leading to a considerable investment in the field. However, with few exceptions, this effort has not yet translated into a better overall prognosis for patients with cancer, and the search for new drug targets continues. After binding to the specific neurokinin-1 (NK-1) receptor, the peptide substance P (SP), which is widely distributed in both the central and peripheral nervous systems, triggers a wide variety of functions. Antagonists against the NK-1 receptor are safe clinical drugs that are known to have anti-inflammatory, analgesic, anxiolytic, antidepressant, and antiemetic effects. Recently, it has become apparent that SP can induce tumor cell proliferation, angiogenesis, and migration via the NK-1 receptor, and that the SP/NK-1 receptor complex is an integral part of the microenvironment of inflammation and cancer. Therefore, the use of NK-1 receptor antagonists as a novel and promising approach for treating patients with cancer is currently under intense investigation. In this paper, we evaluate the recent scientific developments regarding this receptor system, its role in the microenvironment of inflammation and cancer, and its potentials and pitfalls for the usage as part of modern anticancer strategies.

Visceral hypersensitivity in symptomatic diverticular disease and the role of neuropeptides and low grade inflammation

BACKGROUND

  Recurrent abdominal pain is reported by a third of patients with diverticulosis, particularly those with previous episodes of acute diverticulitis. The current understanding of the etiology of this pain is poor. Our aim was to assess visceral sensitivity in patients with diverticular disease and its association with markers of previous inflammation and neuropeptides.

METHODS

  Patients with asymptomatic and symptomatic diverticular disease underwent a flexible sigmoidoscopy and biopsy followed 5-10 days later by visceral sensitivity testing with barostat-mediated rectal distension. Inflammation was assessed by staining of serotonin (5HT) and CD3 positive cells. mRNA levels of tumor necrosis factor alpha (TNF α) and interleukin-6 (IL-6) were quantitated using RT-PCR. Neuropeptide expression was assessed from percentage area staining with substance P (SP) and mRNA levels of the neurokinin 1 & 2 receptors (NK1 & NK2), and galanin 1 receptor (GALR1).

KEY RESULTS

  Thirteen asymptomatic and 12 symptomatic patients were recruited. The symptomatic patients had a lower first reported threshold to pain (28.4 mmHg i.q.r 25.0-36.0) than the asymptomatic patients (47 mmHg i.q.r 36.0-52.5, P < 0.001). Symptomatic patients had a higher median overall pain rating for the stimuli than the asymptomatic patients (P < 0.02). Symptomatic patients had greater median relative expression of NK1 and TNF alpha mRNA compared with asymptomatic patients. There was a significant correlation between barostat VAS pain scores and NK 1 expression (Figure 4, r(2) 0.54, P < 0.02).

CONCLUSIONS & INFERENCES

  Patients with symptomatic diverticular disease exhibit visceral hypersensitivity, and this may be mediated by ongoing low grade inflammation and upregulation of tachykinins.