Neurotensin expression and outcome of malignant pleural mesothelioma

Neurotensin Receptor Allosterism Revealed in Complex with a Biased Allosteric Modulator

The NTSR1 neurotensin receptor (NTSR1) is a G protein-coupled receptor (GPCR) found in the brain and peripheral tissues with neurotensin (NTS) being its endogenous peptide ligand. In the brain, NTS modulates dopamine neuronal activity, induces opioid-independent analgesia, and regulates food intake. Recent studies indicate that biasing NTSR1 toward β-arrestin signaling can attenuate the actions of psychostimulants and other drugs of abuse. Here, we provide the cryoEM structures of NTSR1 ternary complexes with heterotrimeric Gq and GoA with and without the brain-penetrant small-molecule SBI-553. In functional studies, we discovered that SBI-553 displays complex allosteric actions exemplified by negative allosteric modulation for G proteins that are Gα subunit selective and positive allosteric modulation and agonism for β-arrestin translocation at NTSR1. Detailed structural analysis of the allosteric binding site illuminated the structural determinants for biased allosteric modulation of SBI-553 on NTSR1.

Neuropeptides in Cancer: Friend and Foe?

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

Preparation and Preliminary Evaluation of Neurotensin Radiolabelled with 68Ga and 177Lu as Potential Theranostic Agent for Colon Cancer

The neurotensin is a tridecapeptide involved in the proliferation of colon cancer, the overexpression of neurotensin receptors occurring at an early stage development of many tumours. Targeting neurotensin receptors by using the same biological active molecule is an effective approach for both imaging quantification and treatment. The present work aimed to demonstrate the ability of radiolabelled neurotensin to specifically target colon cancer cells, and substantiate its usefulness in targeted imaging and radiotherapy, depending on the emission of the coupled radioisotope. Syntheses of ⁶⁸Ga–DOTA–NT and ¹⁷⁷Lu–DOTA–NT were developed to obtain a level of quality suitable for preclinical use with consistent high synthesis yields. Radiochemical purity meets the pharmaceutical requirements, and it is maintained 4 h for ⁶⁸Ga–DOTA–NT and 48 h for ¹⁷⁷Lu–DOTA–NT. Extensive in vitro studies were conducted to assess the uptake and retention of ⁶⁸Ga–DOTA–NT, the amount of non-specific binding of neurotensin and the effect of ¹⁷⁷Lu–DOTA–NT on HT–29 cells. In vivo biodistribution of ⁶⁸Ga–DOTA–NT revealed significant uptake at the tumour site, along with fast clearance evidenced by decreasing activity in kidneys and blood after 60 min p.i. ¹⁷⁷Lu–DOTA–NT exhibited similar uptake in the tumour, but also a significant uptake at 14 days p.i. in the bone marrow was reported. These results successfully demonstrated the potential of neurotensin to deliver imaging/therapeutic ⁶⁸Ga/¹⁷⁷Lu radioisotopes pair, but also the need for further evaluation of the possible radiotoxicity effects on the liver, kidneys or bone marrow.

The role of Neurotensin and its receptors in non-gastrointestinal cancers: a review

Background

Neurotensin, originally isolated in 1973 has both endocrine and neuromodulator activity and acts through its three main receptors. Their role in promoting tumour cell proliferation, migration, DNA synthesis has been studied in a wide range of cancers. Expression of Neurotensin and its receptors has also been correlated to prognosis and prediction to treatment.

Main body

The effects of NT are mediated through mitogen-activated protein kinases, epidermal growth factor receptors and phosphatidylinositol-3 kinases amongst others. This review is a comprehensive summary of the molecular pathways by which Neurotensin and its receptors act in cancer cells.

Conclusion

Identifying the role of Neurotensin in the underlying molecular mechanisms in various cancers can give way to developing new agnostic drugs and personalizing treatment according to the genomic structure of various cancers.

The significance of NTR1 expression and its correlation with β-catenin and EGFR in gastric cancer

BACKGROUND

Several reports indicate the high-affinity receptor of NT (neurotensin), NTR1 (neurotensin receptor 1), in numerous detrimental functions linked to neoplastic progression of several cancer types. Recently, it has also been shown that NTR1 gene is a target of the Wnt/APC oncogenic pathways connected with the β-catenin/Tcf transcriptional complex and NT can stimulate cancer proliferation in an EGFR-dependent mechanism. In this study, we explored NTR1, β-catenin and EGFR expression in gastric cancer. The possible associations of NTR1 expression with clinicopathological factors, prognosis, β-catenin and EGFR were analyzed.

METHODS

NTR1, β-catenin and EGFR expression in gastric cancer tissues and the adjacent normal tissues of 210 cases was detected by Immunohistochemistry. The possible associations of NTR1 expression with clinicopathological data, prognosis, β-catenin and EGFR were analyzed.

RESULTS

1. NTR1 expression in tumor tissues was significantly higher than that in adjacent normal tissues (P <0 .01). 2. Its expression was positively correlated with pathological grade, T stage, N stage and TNM stage and was not correlated with sex, age, tumor size and Lauren's classification. 3. A co-expression of NTR1 and nuclear β-catenin was in 53 (25.2 %) of cases and NTR1 expression was positively correlated with β-catenin nuclear translocation. NTR1 expression was not correlated with EGFR expression, but at a critical value (P = 0.05). 4. By log-rank test, higher expression of NTR1, higher pathological grade, diffusion Lauren's classification and advanced TNM stage showed worse prognosis (P <0 .05). Age, sex, tumor size, β-catenin and EGFR had no prognostic significance. Multivariate Cox analysis showed that NTR1 expression and TNM clinical stage (P <0 .05) were the independent prognostic factors for patients with GC.

CONCLUSION

By immunohistochemistry, we found that a high expression of NTR1 in GC specimens, which showed a bad prognosis, besides, NTR1 expression was related to invasion and migration of GC. These findings provide new and important information on the progression of GC. This study indicated that NTR1 may play an important role in tumor progression of GC and have its potential to be a predictive biomarker or a therapeutic molecular target in GC. The interaction between NTR1 and β-catenin may participate in the development of GC. However, the relationship between NTR1 and EGFR needs to be further investigated.

Neurotensin (NTS) and its receptor (NTSR1) causes EGFR, HER2 and HER3 over-expression and their autocrine/paracrine activation in lung tumors, confirming responsiveness to erlotinib

Alterations in the signaling pathways of epidermal growth factor receptors (HERs) are associated with tumor aggressiveness. Neurotensin (NTS) and its high affinity receptor (NTSR1) are up regulated in 60% of lung cancers. In a previous clinical study, NTSR1 overexpression was shown to predict a poor prognosis for 5 year overall survival in a selected population of stage I lung adenocarcinomas treated by surgery alone. In a second study, shown here, the frequent and high expression of NTSR1 was correlated with a pejorative prognosis in 389 patients with stage I to III lung adenocarcinoma, and was an independent prognosis marker. Interactions between NTS and NTSR1 induce pro-oncogenic biological effects associated with neoplastic processes and tumor progression. Here we highlight the cellular mechanisms activated by Neurotensin (NTS) and its high affinity receptor (NTSR1) contributing to lung cancer cell aggressiveness. We show that the NTS autocrine and/or paracrine regulation causes EGFR, HER2, and HER3 over-expression and activation in lung tumor cells. The EGFR and HER3 autocrine activation is mediated by MMP1 activation and EGF "like" ligands (HB-EGF, Neuregulin 1) release. By establishing autocrine and/or paracrine NTS regulation, we show that tumor growth is modulated according to NTS expression, with a low growth rate in those tumors that do not express NTS. Accordingly, xenografted tumors expressing NTS and NTSR1 showed a positive response to erlotinib, whereas tumors void of NTSR1 expression had no detectable response. This is consistent with the presence of a NTS autocrine loop, leading to the sustained activation of EGFR and responsible for cancer aggressiveness. We propose the use of NTS/NTSR1 tumor expression, as a biomarker for the use of EGFR tyrosine kinase inhibitors in patients lacking EGFR mutation.

Neurotensin promotes the progression of malignant glioma through NTSR1 and impacts the prognosis of glioma patients

Background

The poor prognosis and minimally successful treatments of malignant glioma indicate a challenge to identify new therapeutic targets which impact glioma progression. Neurotensin (NTS) and its high affinity receptor (NTSR1) overexpression induces neoplastic growth and predicts the poor prognosis in various malignancies. Whether NTS can promote the glioma progression and its prognostic significance for glioma patients remains unclear.

Methods

NTS precursor (ProNTS), NTS and NTSR1 expression levels in glioma were detected by immunobloting Elisa and immunohistochemistry assay. The prognostic analysis was conducted from internet by R2 microarray platform. Glioma cell proliferation was evaluated by CCK8 and BrdU incorporation assay. Wound healing model and Matrigel transwell assay were utilized to test cellular migration and invasion. The orthotopic glioma implantations were established to analyze the role of NTS and NTSR1 in glioma progression in vivo.

Results

Positive correlations were shown between the expression levels of NTS and NTSR1 with the pathological grade of gliomas. The high expression levels of NTS and NTSR1 indicate a worse prognosis in glioma patients. The proliferation and invasiveness of glioma cells could be enhanced by NTS stimulation and impaired by the inhibition of NTSR1. NTS stimulated Erk1/2 phosphorylation in glioma cells, which could be reversed by SR48692 or NTSR1-siRNA. In vivo experiments showed that SR48692 significantly prolonged the survival length of glioma-bearing mice and inhibited glioma cell invasiveness.

Conclusion

NTS promotes the proliferation and invasion of glioma via the activation of NTSR1. High expression levels of NTS and NTSR1 predict a poor prognosis in glioma patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0290-8) contains supplementary material, which is available to authorized users.

Targeting neuropeptide receptors for cancer imaging and therapy: perspectives with bombesin, neurotensin, and neuropeptide-Y receptors

Receptors for some regulatory peptides are highly expressed in tumors. Selective radiolabeled peptides can bind with high affinity and specificity to these receptors and exhibit favorable pharmacologic and pharmacokinetic properties, making them suitable agents for imaging or targeted therapy. The success encountered with radiolabeled somatostatin analogs is probably the first of a long list, as multiple peptide receptors are now recognized as potential targets. This review focuses on 3 neuropeptide receptor systems (bombesin, neurotensin, and neuropeptide-Y) that offer high potential in the field of nuclear oncology. The underlying biology of these peptide/receptor systems, their physiologic and pathologic roles, and their differential distribution in normal and tumoral tissues are described with emphasis on breast, prostate, and lung cancers. Radiolabeled analogs that selectively target these receptors are highlighted.

Differential expression of neurotensin and specific receptors, NTSR1 and NTSR2, in normal and malignant human B lymphocytes

Neurotensin, a neuropeptide growth factor, and its two specific neurotensin receptors, NTSR1 and NTSR2, were shown to be expressed by human B cell lines. Another NTSR, sortilin, which is common to neurotensin and neurotrophins, was also detected as we have previously described. Neurotensin was functional in B cell lines; it induced their proliferation and inhibited apoptosis induced by serum deprivation or Fas activation. Quantitative study of gene expression in two malignant B cell diseases showed that NTSR2 was overexpressed, NTSR1 decreased, and neurotensin was unexpressed in B cell leukemia patient's cells, as compared with healthy B cells. However, these expressions did not significantly change in large diffuse B cell lymphoma lymph nodes compared with benign ones. This study points out that neurotensin and its two specific receptors are expressed in human B lymphocytes. Such expressions were not described, and their relationship in B cell diseases, especially in chronic B cell leukemia, needs to be considered further in regard to these findings.

Neurotensin and its high affinity receptor 1 as a potential pharmacological target in cancer therapy

Cancer is a worldwide health problem. Personalized treatment represents a future advancement for cancer treatment, in part due to the development of targeted therapeutic drugs. These molecules are expected to be more effective than current treatments and less harmful to normal cells. The discovery and validation of new targets are the foundation and the source of these new therapies. The neurotensinergic system has been shown to enhance cancer progression in various cancers such as pancreatic, prostate, lung, breast, and colon cancer. It also triggers multiple oncogenic signaling pathways, such as the PKC/ERK and AKT pathways. In this review, we discuss the contribution of the neurotensinergic system to cancer progression, as well as the regulation and mechanisms of the system in order to highlight its potential as a therapeutic target, and its prospect for its use as a treatment in certain cancers.

Novel DOTA-neurotensin analogues for 111In scintigraphy and 68Ga PET imaging of neurotensin receptor-positive tumors

Overexpression of the high affinity neurotensin receptor 1 (NTSR1), demonstrated in several human cancers, has been proposed as a new marker for human ductal pancreatic carcinoma and as an independent factor for poor prognosis for ductal breast cancer, head and neck squamous cell carcinoma, and non-small cell lung cancer. The aim of the present study was to develop new DOTA-neurotensin analogues for positron emission tomography (PET) imaging with (68)Ga and for targeted radiotherapy with (90)Y or (177)Lu. We synthesized a DOTA-neurotensin analogue series. Two of these peptides bear two sequence modifications for metabolic stability: DOTA-NT-20.3 shares the same peptide sequence as the previously described DTPA-NT-20.3. In the sequence of DOTA-NT-20.4, the Arg(8)-Arg(9) bond was N-methylated instead of the Pro(7)-Arg(8) bond in DOTA-NT-20.3. An additional sequence modification was introduced in DOTA-LB119 to increase stability. A spacer was added between DOTA and the peptide sequence to increase affinity. Binding to HT29 cells, which express NTSR1, in vivo stability, and biodistribution of the various analogues were compared, and the best candidate was used to image tumors of various sizes with the microPET in mice. (111)In-DOTA-NT-20.3, in spite of a relatively high uptake in kidneys, showed specific tumor uptake and elevated tumor to other organ uptake ratios. High contrast images were obtained at early time points after injection that allowed tumor detection at a time interval postinjection appropriate for imaging with the short-lived radionuclide (68)Ga. (111)In-DOTA-NT-20.4 displayed inferior binding to HT29 cells and reduced tumor uptake. (111)In-DOTA-LB119 displayed at early time points a significantly lower renal uptake but also a lower tumor uptake than (111)In-DOTA-NT-20.3, although binding to HT29 cells was similar. (68)Ga-DOTA-NT-20.3 displayed higher tumor uptake than (68)Ga-DOTA-LB119 and allowed the detection of very small tumors by PET. In conclusion, DOTA-NT-20.3 is a promising candidate for (68)Ga-PET imaging of neurotensin receptor-positive tumors. DOTA-NT-20.3 may also be considered for therapy, as the yttrium-labeled peptide has higher affinity than that of the indium-labeled one. A prerequisite for therapeutic application of this neurotensin analogue would be to lower kidney uptake, for example, by infusion of basic amino acids, gelofusin, or albumin fragments, to prevent nephrotoxicity, as with radiolabeled somatostatin analogues.

The potential use of the neurotensin high affinity receptor 1 as a biomarker for cancer progression and as a component of personalized medicine in selective cancers

A growing challenge in medicine today, is the need to improve the suitability of drug treatments for cancer patients. In this field, biomarkers have become the "flags" to provide additional information in tumor biology. They are a relay between the patient and practitioner and consequently, aid in the diagnosis, providing information for prognosis, or in some cases predicting the response to specific therapies. In addition to being markers, these tumor "flags" can also be major participants in the process of carcinogenesis. Neurotensin receptor 1 (NTSR1) was recently identified as a prognosis marker in breast, lung, and head and neck squamous carcinomas. Neurotensin (NTS) was also shown to exert numerous oncogenic effects involved in tumor growth and metastatic spread. These effects were mostly mediated by NTSR1, making the NTS/NTSR1 complex an actor in cancer progression. In this review, we gather information on the oncogenic effects of the NTS/NTSR1 complex and its associated signaling pathways in order to illuminate its significant role in tumor progression and its potential as a biomarker and a therapeutic target in some tumors.

The role of neurotensin in physiologic and pathologic processes

PURPOSE OF REVIEW

Neurotensin is a 13-amino acid peptide found in the central nervous system central nervous system and the gastrointestinal tract. Since its initial discovery in 1973, neurotensin has been shown to play a role in a wide range of physiologic and pathologic processes throughout the body. Ongoing research efforts continue to clarify the role of neurotensin in various central nervous system and gastrointestinal processes, as well as how disruption of these normal mechanisms may lead to diseases ranging from schizophrenia to colorectal cancer. The goal of this review is to provide an overview of the most recent advances in the field of neurotensin research, in the context of what has been previously published.

RECENT FINDINGS

Because of the seemingly unrelated functions of neurotensin in the central nervous system and the periphery, the scope of the articles reviewed is rather broad. Contributions continue to be made to our understanding of the downstream effects of neurotensin signaling and the complex feedback loops between neurotensin and other signaling molecules. By selective targeting or blockade of specific neurotensin receptors, investigators have identified potential drugs for use in the treatment of schizophrenia, alcoholism, chronic pain, or cancer. Neurotensin-based pharmacologic agents are being used successfully in animal models for a number of these conditions.

SUMMARY

The review highlights the wide array of biological processes in which neurotensin has a role, and summarizes the most recent advances in various fields of neurotensin research. The knowledge gained through this research has led to the development of first-in-class drugs for the treatment of various medical conditions, and it is clear that in the coming years some of these agents will be ready to move from the bench to the bedside in clinical trials.