Therapeutic strategies for advanced neuroendocrine carcinomas of jejunum/ileum and pancreatic origin

Multimodal treatment options for advanced gastroenteropancreatic neuroendocrine tumours (NET) of jejunum/ileum and of pancreatic origin are reviewed. Current topics being discussed are: European Neuroendocrine Tumour Society 2006/7, American Joint Cancer Committee/Union Internationale Contre le Cancer 2009 and WHO 2010 recommendations for grading and staging of NET; surgery of the primary tumour in distant metastasised disease; surgery of metastatic liver disease and impact on survival; somatostatin analogues for symptom control and for tumour control; selective internal radiation therapy with 90Y-microspheres as novel local ablative therapy in liver metastases; peptide receptor radionuclide therapy; novel chemotherapy regimens (eg, temozolomide) and novel targeted therapies (eg, sunitinib and everolimus)

Effects of loperamide on the human hypothalamo-pituitary-adrenal axis in vivo and in vitro.

Loperamide, an opiate agonist of high specificity for p-receptors, was recently reported to suppress ACTH and cortisol levels in normal subjects, but not in patients with proven ACTH-dependent Cushing’s disease. However, there is little information on the site of action of loperamide in the hypothalamo-pituitary-adrenal axis of man. We investigated the effect of loperamide on pituitary hormone secretion in uiuo and in vitro. In seven normal subjects, basal ACTH plasma levels were significantly suppressed 3 h after loperamide administration (16 mg, orally) from 5 + 1 to 2 f 0 pmol/L (P < 0.0001). After the combined pituitary stimulation test (100 pg human CRH, 100 rg GnRH, 100 pg GH-releasing hormone, and 200 pg TRH), the ACTH peak (maximum increase at 30 min) was significantly blunted by loperamide from 9 + 1 to 4 of: 1 pmol/L (P < 0.001) and the area under the curve of ACTH from O-120 min was reduced from 35 + 5 to 23 + 4 pmol/L.2 h (P < 0.05). In the insulin-hypoglycemia test (0.15 IU/kg BW), neither the ACTH peak nor the area under the curve of ACTH was affected by loperamide. In six patients with Cushing’s disease and one patient with secondary adrenal insufficency due to hypothalamic failure, neither basal ACTH and cortisol levels nor CRH-stimulated levels were influenced by loperamide. In four cultured human corticotropic adenomas, loperamide was not able to reduce basal and CRH-induced ACTH secretion. In summary, loperamide is able to reduce basal and CRHinduced ACTH and cortisol levels in normal subjects, but not in patients with Cushing’s disease or secondary adrenal failure of hypothalamic origin. Loperamide has no significant effect on insulin-hypoglycemia- induced ACTH and cortisol levels and, therefore, no effect on stress-induced elevation of cortisol levels. Loperamide might act at a suprapituitary site in man in viuo, but, nevertheless, a pituitary site cannot be excluded

Interleukin 31 mediates MAP kinase and STAT1/3 activation in intestinal epithelial cells and its expression is upregulated in inflammatory bowel disease

Background/aim: Interleukin 31 (IL31), primarily expressed in activated lymphocytes, signals through a heterodimeric receptor complex consisting of the IL31 receptor alpha (IL31R\textgreeka) and the oncostatin M receptor (OSMR). The aim of this study was to analyse IL31 receptor expression, signal transduction, and specific biological functions of this cytokine system in intestinal inflammation.Methods: Expression studies were performed by RT-PCR, quantitative PCR, western blotting, and immunohistochemistry. Signal transduction was analysed by western blotting. Cell proliferation was measured by MTS assays, cell migration by restitution assays.Results: Colorectal cancer derived intestinal epithelial cell (IEC) lines express both IL31 receptor subunits, while their expression in unstimulated primary murine IEC was low. LPS and the proinflammatory cytokines TNF-\textgreeka, IL1\textgreekb, IFN-\textgreekg, and sodium butyrate stimulation increased IL31, IL31R\textgreeka, and OSMR mRNA expression, while IL31 itself enhanced IL8 expression in IEC. IL31 mediates ERK-1/2, Akt, STAT1, and STAT3 activation in IEC resulting in enhanced IEC migration. However, at low cell density, IL31 had significant antiproliferative capacities (p<0.005). IL31 mRNA expression was not increased in the TNF\textgreekDARE mouse model of ileitis but in inflamed colonic lesions compared to non-inflamed tissue in patients with Crohn's disease (CD; average 2.4-fold increase) and in patients with ulcerative colitis (UC; average 2.6-fold increase) and correlated with the IL-8 expression in these lesions (r = 0.564 for CD; r = 0.650 for UC; total number of biopsies analysed: n = 88).Conclusion: IEC express the functional IL31 receptor complex. IL31 modulates cell proliferation and migration suggesting a role in the regulation of intestinal barrier function particularly in intestinal inflammation

The role of the novel Th17 cytokine IL-26 in intestinal inflammation

Background and aims: Interleukin 26 (IL-26), a novel IL-10-like cytokine without a murine homologue, is expressed in T helper 1 (Th1) and Th17 cells. Currently, its function in human disease is completely unknown. The aim of this study was to analyse its role in intestinal inflammation.Methods: Expression studies were performed by reverse transcription-PCR (RT-PCR), quantitative PCR, western blot and immunohistochemistry. Signal transduction was analysed by western blot experiments and ELISA. Cell proliferation was measured by MTS (3-(4,5-dimethylthiazol-2-yl)-5-(carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. IL-26 serum levels were determined by an immunoluminometric assay (ILMA).Results: All examined intestinal epithelial cell (IEC) lines express both IL-26 receptor subunits IL-20R1 and IL-10R2. IL-26 activates extracellular signal-related kinase (ERK)-1/2 and stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) mitogen-activated protein (MAP) kinases, Akt and signal transducers and activators of transcription (STAT) 1/3. IL-26 stimulation increases the mRNA expression of proinflammatory cytokines but decreases cell proliferation. In inflamed colonic lesions of patients with Crohn's disease, an elevated IL-26 mRNA expression was found that correlated highly with the IL-8 and IL-22 expression. Immunohistochemical analysis demonstrated IL-26 protein expression in colonic T cells including Th17 cells expressing the orphan nuclear receptor ROR\textgreekgt, with an increased number of colonic IL-26-expressing cells in active Crohn's disease.Conclusion: Intestinal cells express the functional IL-26 receptor complex. IL-26 modulates IEC proliferation and proinflammatory gene expression and its expression is upregulated in active Crohn's disease, indicating a role for this cytokine system in the innate host cell response during intestinal inflammation. For the first time, IL-26 expression is demonstrated in colonic ROR\textgreekgt-expressing Th17 cells in situ, supporting a role for this cell type in the pathogenesis of Crohn's disease

Contrast-Enhanced Ultrasound for Surveillance of Choroidal Carcinoma Patients: Features of Liver Metastasis Arising Several Years after Treatment of the Primary Tumor

Choroidal carcinoma is an insidious tumor frequently causing late liver metastases which are associated with a poor outcome. Since metastatic liver lesions are potentially resectable with curative intention, tight follow-up schedules after treatment of primary tumors for the early detection of liver metastasis have been proposed. The methods employed so far, however, have proven to be of limited sensitivity, and it is likely that a combined approach comprising the use of both imaging techniques and biohumoral markers will, in the future, improve the sensitivity of methods aiming at detecting liver metastasis early. Contrast-enhanced ultrasound (CEUS) is increasingly used in the clinic due to its advantage over conventional sonography for the early detection of tumor lesions and thus represents a promising accurate and cost-effective diagnostic tool. Its use for the early diagnosis of metastatic choroidal cancer has never been proposed before in the literature. Here, we describe for the first time the CEUS features of a large liver metastasis originating from choroidal cancer occurring 13 years after diagnosis in comparison to PET-CT, MRI and conventional sonography. Furthermore, we propose CEUS as a routine follow-up method for the early detection of liver metastasis of patients affected by choroidal carcinoma

Comparative study of gp130 cytokine effects on corticotroph AtT-20 cells - Redundancy or specificity of neuroimmunoendocrine modulators?

Objective: This comparative in vitro study examined the effects of all known gp130 cytokines on murine corticotroph AtT-20 cell function. Methods: Cytokines were tested at equimolar concentrations from 0.078 to 10 nM. Tyrosine phosphorylation of the signal transducer and activator of transcription ( STAT) 3 and STAT1, the STAT-dependent suppressor of cytokine signaling (SOCS)-3 promoter activity, SOCS-3 gene expression, STAT-dependent POMC promoter activity and adrenocorticotropic hormone ( ACTH) secretion were determined. Results: Leukemia inhibitory factor (LIF), human oncostatin M (OSM) and cardiotrophin (CT)-1 (LIFR/gp130 ligands), as well as ciliary neurotrophic factor ( CNTF) and novel neurotrophin1/B-cell stimulating factor-3 (CNTFRalpha/LIFR/gp130 ligands) are potent stimuli of corticotroph cells in vitro. In comparison, interleukin (IL)-6 (IL-6R/gp130 ligand) and IL-11 (IL-11R/gp130 ligand) exhibited only modest direct effects on corticotrophs, while murine OSM (OSMR/gp130 ligand) showed no effect. Conclusion: (i) CNTFR complex ligands are potent stimuli of corticotroph function, comparable to LIFR complex ligands; (ii) IL-6 and IL-11 are relatively weak direct stimuli of corticotroph function; (iii) differential effects of human and murine OSM suggest that LIFR/gp130 (OSMR type I) but not OSMR/gp130 (OSMR type II) are involved in corticotroph signaling. (iv) CT-1 has the hitherto unknown ability to stimulate corticotroph function, and (v) despite redundant immuno-neuroendocrine effects of different gp130 cytokines, corticotroph cells are preferably activated through the LIFR and CNTFR complexes. Copyright (C) 2004 S. Karger AG, Basel

Cabozantinib and Tivantinib, but Not INC280, Induce Antiproliferative and Antimigratory Effects in Human Neuroendocrine Tumor Cells in vitro: Evidence for 'Off-Target' Effects Not Mediated by c-Met Inhibition

Background/Aims: The hepatocyte growth factor/transmembrane tyrosine kinase receptor c-Met has been defined as a potential target in antitumoral treatment of various carcinomas. We aimed to investigate the direct effect of c-Met inhibition on neuroendocrine tumor cells in vitro. Methods: The effects of the multi-tyrosine kinase inhibitors cabozantinib and tivantinib and of the highly specific c-Met inhibitor INC280 were investigated in human pancreatic neuroendocrine BON1, bronchopulmonary NCI-H727 and midgut GOT1 cells in vitro. Results: INC280, cabozantinib and tivantinib inhibited c-Met phosphorylation, respectively. However, while equimolar concentrations (10 mu M) of cabozantinib and tivantinib inhibited cell viability and cell migration, INC280 had no inhibitory effect. Knockdown experiments with c-Met siRNA also did not demonstrate effects on cell viability. Cabozantinib and tivantinib caused a G2 arrest in neuroendocrine tumor cells. Conclusions: Our in vitro data suggest that c-Met inhibition alone is not sufficient to exert direct antitumoral or antimigratory effects in neuroendocrine tumor cells. The multi-tyrosine kinase inhibitors cabozantinib and tivantinib show promising antitumoral and antimigratory effects in neuroendocrine tumor cells, which are most probably 'off-target' effects, not mediated by c-Met. (C) 2015 S. Karger AG, Base

The novel mTOR inhibitor RAD001 (Everolimus) induces antiproliferative effects in human pancreatic neuroendocrine tumor cells

Background/Aim: Tumors exhibiting constitutively activated PI(3) K/Akt/mTOR signaling are hypersensitive to mTOR inhibitors such as RAD001 (everolimus) which is presently being investigated in clinical phase II trials in various tumor entities, including neuroendocrine tumors (NETs). However, no preclinical data about the effects of RAD001 on NET cells have been published. In this study, we aimed to evaluate the effects of RAD001 on BON cells, a human pancreatic NET cell line that exhibits constitutively activated PI(3) K/Akt/mTOR signaling. Methods: BON cells were treated with different concentrations of RAD001 to analyze its effect on cell growth using proliferation assays. Apoptosis was examined by Western blot analysis of caspase-3/PARP cleavage and by FACS analysis of DNA fragmentation. Results: RAD001 potently inhibited BON cell growth in a dose-dependent manner which was dependent on the serum concentration in the medium. RAD001-induced growth inhibition involved G0/G1-phase arrest as well as induction of apoptosis. Conclusion: In summary, our data demonstrate antiproliferative and apoptotic effects of RAD001 in NET cells in vitro supporting its clinical use in current phase II trials in NET patients. Copyright (c) 2007 S. Karger AG, Basel

Distinct expression patterns of VEGFR 1-3 in gastroenteropancreatic neuroendocrine neoplasms: supporting clinical relevance, but not a prognostic factor

Introduction: Gastroenteropancreatic neuroendocrine neoplasms (GEP-NENs) are an increasing tumor entity. Since many patients are diagnosed at an advanced stage, treatment is still challenging and dependent on many tumor and patient specific factors. Therefore, the aim of the present study was to elucidate the expression rates and the prognostic value of vascular endothelial growth factor receptor (VEGFR) 1-3 in GEP-NENs. A potential association to immune checkpoint markers was further investigated. Material and Methods: The expression levels of VEGFR 1-3 were analyzed by immunohistochemistry and correlated with the expression of the checkpoint markers PD-1 and PD-L1. Furthermore, the tumor samples of 249 GEP-NEN patients were studied and correlated with overall survival rates and clinicopathological features. Kaplan–Meier analyses and the log rank test were used for survival analyses. Categorical variables were compared by the χ2 test. Results: The most common primary tumor site was the small intestine (50.6%), followed by the pancreas (25.7%). VEGFR 1 was highly expressed in 59%, VEGFR 2 in 6.4%, and VEGFR 3 in 61.8% of the analyzed samples. The expression of VEGFR 1-3 was not significantly associated with survival rates. Pancreatic NENs had the highest expression of VEGFR 1 and 3 in 80% of the cases. VEGFR 1-3 positivity correlated with the expression levels of immune checkpoint markers. Discussion: VEGFR 1-3 show a distinct expression pattern in different subgroups of neuroendocrine neoplasias indicating a conceivable target. Moreover, there was a substantial association between VEGFRs andimmune checkpoint markers. Taken together, anti-VEGFR therapy represents a promising therapeutic approach in GEP-NEN patients and should be addressed in future studies

RSUME is implicated in tumorigenesis and metastasis of pancreatic neuroendocrine tumors

The factors triggering pancreatic neuroendocrine tumor (PanNET) progression are largely unknown. Here we investigated the role and mechanisms of the sumoylation enhancing protein RSUME in PanNET tumorigenesis. Immunohistochemical studies showed that RSUME is strongly expressed in normal human pancreas, in particular in β-cells. RSUME expression is reduced in insulinomas and is nearly absent in other types of PanNETs suggesting a role in PanNET tumorigenesis. In human pancreatic neuroendocrine BON1 cells, RSUME stimulates hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor-A (VEGF-A), which are key components of tumor neovascularisation. In contrast, RSUME suppresses nuclear factor-κB (NF-κB) and its target interleukin-8 (IL-8). Correspondingly, PanNET cells with RSUME knockdown showed decreased HIF-1α activity and increased NF-κB and IL-8 production leading to a moderate reduction of VEGF-A release as reduced HIF-1α/VEGF-A production is partly compensated by NF-κB/IL-8-induced VEGF-A. Notably, RSUME stabilizes the tumor suppressor PTEN, which is frequently lost in PanNETs and whose absence is associated with metastasis formation. In vivo orthotopic transplantation of PanNET cells with or without RSUME expression into nude mice showed that PanNETs without RSUME have reduced PTEN expression, grow faster and form multiple liver metastases. In sum, RSUME differentially regulates key components of PanNET formation suggesting that the observed loss of RSUME in advanced PanNETs is critically involved in PanNET tumorigenesis, particularly in metastasis formation.Fil: Wu, Yonghe. Max Planck Institute of Psychiatry; AlemaniaFil: Tedesco, Lucas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires - Instituto Partner de la Sociedad Max Planck; ArgentinaFil: Kristin, Lucia. Max Planck Institute of Psychiatry; AlemaniaFil: Schlitter, Anna M.. Universitat Technical Zu Munich; AlemaniaFil: Monteserin Garcia, Jose. Max Planck Institute of Psychiatry; AlemaniaFil: Esposito, Irene. Universitat Technical Zu Munich; AlemaniaFil: Auernhammer, Christoph J.. Universitat Technical Zu Munich; AlemaniaFil: Theodoropoulou, Marily. Max Planck Institute of Psychiatry; AlemaniaFil: Arzt, Eduardo Simon. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigación en Biomedicina de Buenos Aires - Instituto Partner de la Sociedad Max Planck; ArgentinaFil: Renner, Ulrich. Max Planck Institute of Psychiatry; AlemaniaFil: Stalla, Günter K.. Max Planck Institute of Psychiatry; Alemani