Histamine via histamine H1 receptor enhances the muscarinic receptor-induced calcium response to acetylcholine in an enterochromaffin cell model.

As a prerequisite for serotonin secretion, the P-STS ileal enterochromaffin cell line responds to acetylcholine (ACh) stimulation with an increase in intracellular calcium mediated by the muscarinic ACh receptor M3 (M3R). Histamine increases intracellular calcium via histamine H1 receptor (H1R) in P-STS cells and pre-incubation with histamine specifically augments the response to ACh but not to epinephrine or nicotine. We aimed to elucidate whether histamine receptors are involved in this synergism.

Transcriptomic Profiling of Tumor-Stromal Cell Paracrine Crosstalk Identifies Involvement of the Integrin Signaling Pathway in the Pathogenesis of Mesenteric Fibrosis in Human Small Intestinal Neuroendocrine Neoplasms.

Aim: Analysis of the pathophysiology of mesenteric fibrosis (MF) in small intestinal neuroendocrine tumors (SI-NETs) in an paracrine model and in human SI-NET tissue samples.

Methods: An indirect co-culture model of SI-NET cells KRJ-I and P-STS with stromal cells HEK293 was designed to evaluate the paracrine effects on cell metabolic activity, gene expression by RT2 PCR Profilers to analyse cancer and fibrosis related genes, and RNA sequencing. The integrin signaling pathway, a specific Ingenuity enriched pathway, was further explored in a cohort of human SI-NET tissues by performing protein analysis and immunohistochemistry.

The Transient Receptor Potential Vanilloid 4 Agonist RN-1747 Inhibits the Calcium Response to Histamine.

Background: Sensitization of transient receptor potential (TRP) cation channels probably contributes to intestinal hypersensitivity, a hallmark of gastrointestinal disorders. Histamine acting via histamine 1 receptor (H1R) to open TRP cation channels might also be involved.

Method: The enterochromaffin cell line P-STS, responsive to histamine via H1R, was used as model to study possible synergism between histamine and TRP vanilloid 4 (TRPV4) pathways.

The avian chorioallantoic membrane as an alternative tool to study medullary thyroid cancer.

Preclinical trials of medullary thyroid cancer (MTC) therapeutics require both in vitro and in vivo analyses. Human tumour xenografted rodent models, which are considered the 'gold standard' to study and validate the efficacy and toxicity of lead compounds before translation to clinical trials, are very expensive, subject to organismal variability and ethical controversies. The avian chorioallantoic membrane (CAM) assay provides an alternative versatile, cost-effective and ethically less objectionable short-term, in vivo model for reliable screening of drugs.

Preclinical characterization of tyrosine kinase inhibitor-based targeted therapies for neuroendocrine thyroid cancer.

Medullary thyroid carcinoma (MTC) is a slow growing neuroendocrine (NE) tumor for which few treatment options are available. Its incidence is rising and mortality rates have remained unchanged for decades. Increasing the repertoire of available treatments is thus crucial to manage MTC progression.

Histamine causes influx via T-type voltage-gated calcium channels in an enterochromaffin tumor cell line: potential therapeutic target in adverse food reactions.

The P-STS human ileal neuroendocrine tumor cells, as a model for gut enterochromaffin cells, are strongly and synergistically activated by histamine plus acetylcholine (ACh), presumably via histamine 4 receptors, and weakly activated by histamine alone. Sensing these signals, enterochromaffin cells could participate in intestinal intolerance or allergic reactions to food constituents associated with elevated histamine levels. In this study we aimed to analyze the underlying molecular mechanisms.

A precision oncology approach to the pharmacological targeting of mechanistic dependencies in neuroendocrine tumors.

We introduce and validate a new precision oncology framework for the systematic prioritization of drugs targeting mechanistic tumor dependencies in individual patients. Compounds are prioritized on the basis of their ability to invert the concerted activity of master regulator proteins that mechanistically regulate tumor cell state, as assessed from systematic drug perturbation assays. We validated the approach on a cohort of 212 gastroenteropancreatic neuroendocrine tumors (GEP-NETs), a rare malignancy originating in the pancreas and gastrointestinal tract.

The neuroendocrine phenotype, genomic profile and therapeutic sensitivity of GEPNET cell lines.

Experimental models of neuroendocrine tumour disease are scarce, and no comprehensive characterisation of existing gastroenteropancreatic neuroendocrine tumour (GEPNET) cell lines has been reported. In this study, we aimed to define the molecular characteristics and therapeutic sensitivity of these cell lines. We therefore performed immunophenotyping, copy number profiling, whole-exome sequencing and a large-scale inhibitor screening of seven GEPNET cell lines.

Cultivation and Immortalization of Human B-Cells Producing a Human Monoclonal IgM Antibody Binding to MDA-LDL: Further Evidence for Formation of Atherogenic MDA-LDL Adducts in Humans .

Oxidatively modified low-density lipoprotein (oLDL) is firmly believed to play an important role in the initiation and development of atherosclerosis, and malonic dialdehyde (MDA) is one of the major lipid peroxidation breakdown products involved in this process. In recent decades, antibodies against MDA-LDL have been detected in human and animal sera. In our study, human B-cells from the peripheral blood of a healthy female donor were fused with the SP2/0 mouse myeloma cell line.

Activation of the ileal neuroendocrine tumor cell line P-STS by acetylcholine is amplified by histamine: role of H3R and H4R.

Neuroendocrine tumors may present with pseudoallergic reactions like diarrhea and idiopathic anaphylaxis. Here we present the P-STS human ileal neuroendocrine cell line as a model cell line for these tumors. Neuroendocrine markers and changes in cytoplasmic calcium concentration ([Ca]i) in response to several possible activators of 5-hydroxytryptamine (5-HT) release were analyzed.

Anti-tumor effects of shikonin derivatives on human medullary thyroid carcinoma cells.

New treatment options are needed for medullary thyroid carcinoma (MTC), a highly metastasizing neuroendocrine tumor that is resistant to standard radiotherapy and chemotherapy. We show that the following shikonin derivatives inhibit cell proliferation and cell viability of the MTC cell line TT: acetylshikonin, β,β-dimethylacrylshikonin, shikonin and a petroleum ether extract of the roots of Onosma paniculata containing several shikonin derivatives. The unsubstituted shikonin derivative was found to be the most effective compound with an IC of 1.

MicroRNAs associated with small bowel neuroendocrine tumours and their metastases.

Novel molecular analytes are needed in small bowel neuroendocrine tumours (SBNETs) to better determine disease aggressiveness and predict treatment response. In this study, we aimed to profile the global miRNome of SBNETs, and identify microRNAs (miRNAs) involved in tumour progression for use as potential biomarkers. Two independent miRNA profiling experiments were performed (n=90), including primary SBNETs (n=28), adjacent normal small bowel (NSB; n=14), matched lymph node (LN) metastases (n=24), normal LNs (n=7), normal liver (n=2) and liver metastases (n=15).

Cytotoxic Effects of Valproic Acid on Neuroendocrine Tumour Cells.

Background/aims: Histone deacetylases (HDACs) modulate lysine acetylation on histones and are frequently deregulated in cancer. HDAC inhibitors with potent anti-tumour effects have been developed and are now being tested in clinical trials. The aim of this study was to investigate the effects of valproic acid (VPA), an inhibitor of class I and class IIa HDACs, on neuroendocrine tumour (NET) cell growth.

Ursolic acid from Trailliaedoxa gracilis induces apoptosis in medullary thyroid carcinoma cells.

Medullary thyroid carcinoma (MTC) originates from the C‑cells of the thyroid and is not sensitive to radiation or chemotherapy. Therefore, surgical removal of the tumor tissue in its entirety is the only curative treatment for MTC. The present study aimed to examine the potential mechanisms of action of extracts of Trailliaedoxa gracilis (TG; WW Smith & Forrest), a plant from the province of Sichuan, China, and of ursolic acid (UA), a pentacyclic triterpen present in TG, on the MTC‑SK MTC cell line.

Differential expression of cell cycle regulators in CDK5-dependent medullary thyroid carcinoma tumorigenesis.

Medullary thyroid carcinoma (MTC) is a neuroendocrine cancer of thyroid C-cells, for which few treatment options are available. We have recently reported a role for cyclin-dependent kinase 5 (CDK5) in MTC pathogenesis. We have generated a mouse model, in which MTC proliferation is induced upon conditional overexpression of the CDK5 activator, p25, in C-cells, and arrested by interrupting p25 overexpression.

GNA15 expression in small intestinal neuroendocrine neoplasia: functional and signalling pathway analyses.

Gastroenteropancreatic neuroendocrine neoplasia (GEP-NEN) comprises a heterogeneous group of tumours that exhibit widely divergent biological behaviour. The identification of new targetable GPCR-pathways involved in regulating cell function could help to identify new therapeutic strategies. We assessed the function of a haematopoietic stem cell heterotrimeric G-protein, Gα15, in gut neuroendocrine cell models and examined the clinical implications of its over expression.

The anti-hypertensive drug prazosin induces apoptosis in the medullary thyroid carcinoma cell line TT.

Background/aim: Medullary thyroid carcinoma (MTC) is a tumor associated with poor prognosis since it exhibits high resistance against conventional cancer therapy. Recent studies have shown that quinazolines exhibit a pro-apoptotic effect on malignant cells. The aim of the present study was to elucidate whether MTC cells are affected by quinazolines, in particular prazosin.

Chromogranin A and its fragments as regulators of small intestinal neuroendocrine neoplasm proliferation.

Introduction: Chromogranin A is a neuroendocrine secretory product and its loss is a feature of malignant NEN de-differentiation. We hypothesized that chromogranin A fragments were differentially expressed during NEN metastasis and played a role in the regulation of NEN proliferation.

Methods: Chromogranin A mRNA (PCR) and protein (ELISA/western blot) were studied in 10 normal human mucosa, 5 enterochromaffin cell preparations, 26 small intestinal NEN primaries and 9 liver metastases.

The stimulatory adenosine receptor ADORA2B regulates serotonin (5-HT) synthesis and release in oxygen-depleted EC cells in inflammatory bowel disease.

Objective: We recently demonstrated that hypoxia, a key feature of IBD, increases enterochromaffin (EC) cell 5-HT secretion, which is also physiologically regulated by the ADORA2B mechanoreceptor. Since hypoxia is associated with increased extracellular adenosine, we wanted to examine whether this nucleotide amplifies HIF-1α-mediated 5-HT secretion.

Design: The effects of hypoxia were studied on IBD mucosa, isolated IBD-EC cells, isolated normal EC cells and the EC cell tumor derived cell line KRJ-1.

Serotonin and the 5-HT7 receptor: the link between hepatocytes, IGF-1 and small intestinal neuroendocrine tumors.

Platelet-derived serotonin (5-HT) is involved in liver regeneration. The liver is also the metastatic site for malignant enterochromaffin (EC) cell "carcinoid" (neuroendocrine) neoplasms, the principal cellular source of 5-HT. We hypothesized that 5-HT produced by metastatic EC cells played a role in the hepatic tumor-microenvironment principally via 5-HT₇ receptor-mediated activation of hepatocyte IGF-1 synthesis and secretion.

The influence of glutamate receptors on proliferation and metabolic cell activity of neuroendocrine tumors.

Neuroendocrine tumors are relatively insensitive to radiation therapy, as well as chemotherapy. Thus, new approaches for alternative therapies are needed. We found that glutamate receptor antagonists are capable of suppressing tumor growth and cell activity of different peripheral malignancies.

Christia vespertilionis plant extracts as novel antiproliferative agent against human neuroendocrine tumor cells.

Neuroendocrine tumors respond poorly to radiation and conventional chemotherapy, hence surgical removal of the neoplastic tissue is still the most effective way of treatment. In an attempt to find new therapeutic plant extracts of Christia vespertilionis (CV) their antitumor potential in human medullary thyroid carcinoma (MTC) and human small intestinal neuroendocrine tumor (SI-NET) cell lines were tested. Proliferation and viability were analyzed using cell counting and WST-1 assay.

Molecular evidence for the bi-clonal origin of neuroendocrine tumor derived metastases.

Background: Reports on common mutations in neuroendocrine tumors (NET) are rare and clonality of NET metastases has not been investigated in this tumor entity yet. We selected one NET and the corresponding lymph node and liver metastases as well as the derivative cell lines to screen for somatic mutations in the primary NET and to track the fate of genetic changes during metastasis and in vitro progression.

Results: Applying microarray based sequence capture resequencing including 4,935 Exons from of 203 cancer-associated genes and high-resolution copy number and genotype analysis identified multiple somatic mutations in the primary NET, affecting BRCA2, CTNNB1, ERCC5, HNF1A, KIT, MLL, RB1, ROS1, SMAD4, and TP53.