Neuropeptide Y in neural crest-derived tumors: effect on growth and vascularization

Correlation of Transcriptomics and FDG-PET SUVmax Indicates Reciprocal Expression of Stemness-Related Transcription Factor and Neuropeptide Signaling Pathways in Glucose Metabolism of Ewing Sarcoma

BACKGROUND

In Ewing sarcoma (EwS), long-term treatment effects and poor survival rates for relapsed or metastatic cases require individualization of therapy and the discovery of new treatment methods. Tumor glucose metabolic activity varies significantly between patients, and FDG-PET signals have been proposed as prognostic factors. However, the biological basis for the generally elevated but variable glucose metabolism in EwS is not well understood.

METHODS

We retrospectively included 19 EwS samples (17 patients). Affymetrix gene expression was correlated with maximal standardized uptake value (SUVmax) using machine learning, linear regression modelling, and gene set enrichment analyses for functional annotation.

RESULTS

Expression of five genes correlated (MYBL2, ELOVL2, NETO2) or anticorrelated (FAXDC2, PLSCR4) significantly with SUVmax (adjusted p-value ≤ 0.05). Additionally, we identified 23 genes with large SUVmax effect size, which were significantly enriched for "neuropeptide Y receptor activity (GO:0004983)" (adjusted p-value = 0.0007). The expression of the members of this signaling pathway (NPY, NPY1R, NPY5R) anticorrelated with SUVmax. In contrast, three transcription factors associated with maintaining stemness displayed enrichment of their target genes with higher SUVmax: RNF2, E2F family, and TCF3.

CONCLUSION

Our large-scale analysis examined comprehensively the correlations between transcriptomics and tumor glucose utilization. Based on our findings, we hypothesize that stemness may be associated with increased glucose uptake, whereas neuroectodermal differentiation may anticorrelate with glucose uptake.

Nervous system and gastric cancer

The nervous system has been recently shown to exert impact on gastric cancer directly and indirectly. Gastric cancer cells invade nerve fibers to induce outgrowth and branching of neural cells, and nerve fibers in turn infiltrate into tumor microenvironment to promote progression of gastric cancer. Additionally, the neuro-immune interaction also plays an important role in gastric cancer development. The interplay of nerves and gastric cancer is mediated by many nervous system-associated factors, which can not only be synthesized and released by both cancer cells and nerve terminals, but also participate in regulation of many aspects of gastric cancer such as cell proliferation, angiogenesis, metastasis and recurrence. Furthermore, clinical researches indicate that some of these factors are significant diagnosis and prognosis biomarkers for gastric cancer. Herein, we reviewed recent advances and future prospects of the interaction between nervous system and gastric cancer.

Neuropeptide Y receptor interactions regulate its mitogenic activity

Neuropeptide Y (NPY) is a multifunctional neurotransmitter acting via G protein-coupled receptors - Y1R, Y2R and Y5R. NPY activities, such as its proliferative effects, are mediated by multiple receptors, which have the ability to dimerize. However, the role of this receptor interplay in NPY functions remains unclear. The goal of the current study was to identify NPY receptor interactions, focusing on the ligand-binding fraction, and determine their impact on the mitogenic activity of the peptide. Y1R, Y2R and Y5R expressed in CHO-K1 cells formed homodimers detectable on the cell surface by cross-linking. Moreover, Y1R and Y5R heterodimerized, while no Y2R/Y5R heterodimers were detected. Nevertheless, Y5R failed to block internalization of its cognate receptor in both Y1R/Y5R and Y2R/Y5R transfectants, indicating Y5R transactivation upon stimulation of the co-expressed receptor. These receptor interactions correlated with an augmented mitogenic response to NPY. In Y1R/Y5R and Y2R/Y5R transfectants, the proliferative response started at picomolar NPY concentrations, while nanomolar concentrations were needed to trigger proliferation in cells transfected with single receptors. Thus, our data identify direct and indirect heterotypic NPY receptor interactions as the mechanism amplifying its activity. Understanding these processes is crucial for the design of treatments targeting the NPY system.

Predictive value of combined analysis of pro-NPY and ERG in localized prostate cancer

This study aimed to investigate if combined analysis of pro-Neuropeptide Y (NPY) and ERG expression in tumor tissue are associated with biochemical failure (BF), castration-based treatment, castration-resistant prostate cancer (CRPC), and prostate cancer (PCa)-specific death for men undergoing radical prostatectomy (RP) for PCa. This study included 315 patients, who underwent RP from 2002 to 2005. Both pro-NPY and ERG expression were analyzed using immunohistochemistry and were scored as low or high and negative or positive, respectively. Risk of BF, castration-based treatment, CRPC, and PCa-specific death were analyzed with multiple cause-specific Cox regression analyses and stratified cumulative incidences using competing risk assessment. Median follow-up was 13.0 years (95% CI: 12.7-13.2). In total, 85.7% were pro-NPY high and 14.3% were pro-NPY low. The combined analyses of pro-NPY and ERG expression was not associated with risk of BF (p = 0.7), castration-based treatment (p = 0.8), CRPC (p = 0.4) or PCa-specific death (p = 0.5). In the multiple cause-specific Cox regression analysis, pro-NPY high and ERG positivity was not associated with BF (HR: 1.02; 95% CI 0.6-1.7; p = 0.94). In conclusion the combination of pro-NPY and ERG expression did not show association with risk of BF, castration-based treatment, CRPC, and PCa-specific death following RP.

The coexistence of peripheral nerve sheath tumors and vitiligo: more than coincidence?

Neurocristopathies arise from abnormal migration, differentiation, or proliferation of neural crest derivatives, leading to diverse clinical and pathological features. They are classified into dysgenetic or neoplastic, and can affect single or multiple sites (simple versus complex). Examples include congenital melanocytic nevi, neuroblastoma, Hirshsprung's disease, Waardenburg's syndrome, neurofibromatosis (NF) 1 and multiple endocrine neoplasia (MEN) 2A and 2B. We report two cases of peripheral nerve sheath tumors associated with vitiligo and discuss the possible implicated embryologic, genetic and molecular mechanisms. To our knowledge, we also report the first case of de novo malignant peripheral nerve sheath tumor (MPNST) associated with vitiligo.

DNA methylation profiles and biomarkers of oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) constitutes >90% of oral cancers and is the sixth most common malignancy among males worldwide and the fourth leading cause of death due to cancer among males in Taiwan. However, most patients do not receive a diagnosis of OSCC until the late stages, which have a lower survival rate. The use of molecular marker analysis to identify early-stage OSCC would permit optimal timing for treatments and consequently prolong survival. The aim of this study was to identify biomarkers of OSCC using the Illumina GoldenGate Methylation Cancer Panel, which comprised a total of 1,505 CpG sites covering 807 genes. Samples of buccal mucosa resected from 40 OSCC patients and normal tissue samples obtained from 15 patients (normal mucosa from OSCC patients or from patients undergoing surgery unrelated to OSCC) were analyzed. Fms-related tyrosine kinase 4 (FLT4) methylation exhibited a perfect specificity for detecting OSCC, with an area under the receiver operating characteristic curve of 0.91 for both all-stage and early-stage OSCC. Methylation of 7 genes (ASCL1, FGF3, FLT4, GAS7, KDR, TERT, and TFPI2) constitutes the top-20 panels for detecting OSCC. The top-20 panels for detecting early-stage OSCC contain 8 genes: ADCYAP1, EPHA7, FLT4, GSTM2, KDR, MT1A, NPY, and TFPI2. FLT4 RNA expression and methylation level were validated using RT-PCR and a pyrosequencing methylation assay. The median level of FLT4 expression was 2.14-fold for normal relative to OSCC tissue samples (P < 0.0001). Among the 8 pyrosequenced FLT4 CpG sites, methylation level was much higher in the OSCC samples. In conclusion, methylation statuses of selected genes, and especially FLT4, KDR, and TFPI2, might be of great potential as biomarkers for early detection of buccal OSCC.

Central and peripheral nervous systems: master controllers in cancer metastasis

Central and sympathetic nervous systems govern functional activities of many organs. Solid tumors like organs are also innervated by sympathetic nerve fibers. Neurotransmitters released from sympathetic nerve fibers can modulate biological behaviors of tumor cells. Multiple physiologic processes of tumor development may be dominated by central and sympathetic nervous systems as well. Recent studies suggest that dysfunction of central and sympathetic nervous systems and disorder of the hormone network induced by psychological stress may influence malignant progression of cancer by inhibiting the functions of immune system, regulating metabolic reprogramming of tumor cells, and inducing interactions between tumor and stromal cells. Over-release of inflammatory cytokines by tumors may aggravate emotional disorder, triggering the vicious cycles in tumor microenvironment and host macroenvironment. It is reasonable to hypothesize that cancer progression may be controlled by central and sympathetic nervous systems. In this review, we will focus on the recent information about the impacts of central and sympathetic nervous systems on tumor invasion and metastasis.

Gallium-68: chemistry and radiolabeled peptides exploring different oncogenic pathways

Abstract Early and specific tumor detection and also therapy selection and response evaluation are some challenges of personalized medicine. This calls for high sensitive and specific molecular imaging such as positron emission tomography (PET). The use of peptides for PET molecular imaging has undeniable advantages: possibility of targeting through peptide-receptor interaction, small size and low-molecular weight conferring good penetration in the tissue or at cellular level, low toxicity, no antigenicity, and possibility of wide choice for radiolabeling. Among β(+)-emitter radioelements, Gallium-68 is a very attractive positron-emitter compared with carbon-11 or fluorine-18 taking into account its easy production via a (68)Ge/(68)Ga generator and well established radiochemistry. Gallium-68 chemistry is based on well-defined coordination complexes with macrocycle or chelates having strong binding properties, particularly suitable for linking peptides that allow resistance to in vivo transchelation of the metal ion. Understanding specific and nonspecific molecular mechanisms involved in oncogenesis is one major key to develop new molecular imaging tools. The present review focuses on peptide signaling involved in different oncogenic pathways. This peptide signalization might be common for tumoral and non-tumoral processes or could be specific of an oncological process. This review describes gallium chemistry and different (68)Ga-radiolabeled peptides already in use or under development aiming at developing molecular PET imaging of different oncological processes.

NPY suppressed development of experimental autoimmune encephalomyelitis in Dark Agouti rats by disrupting costimulatory molecule interactions

Neuropeptide Y (NPY) suppressed clinical experimental autoimmune encephalomyelitis (EAE) and reduced numbers of CD28+, CD11b+ and CD80+ cells among spinal cord infiltrating cells at the peak of disease in Dark Agouti rat strain. Suppression of EAE was accompanied by the reduced expression of costimulatory CD80 and CD86 molecules on ED1+ macrophages and OX62+ dendritic cells in draining lymph nodes during the inductive phase of EAE. An inhibitor of dipeptidyl peptidase 4, an enzyme which terminates the action of NPY on Y1 receptor subtype, did not sustain the suppressive effect of NPY on the EAE development, suggesting involvement of Y2 and Y5 receptors.

Neuropeptide Y stimulates proliferation and migration in the 4T1 breast cancer cell line

Stress has long been thought of to be associated with increased risk of cancer. Chronic stress is associated with elevated levels of sympathetic neurotransmitter (norepinephrine and neuropeptide Y: NPY) release and immunosuppression. The expression of NPY receptors has been reported in human breast carcinomas. Recently, activation of the NPY Y5 receptor was shown to stimulate cell growth and increase migration in human breast cancer cells; however the effects of NPY have yet to be investigated in a murine model of breast cancer. Thus, the specific aims of the current study were to: (i) characterize NPY receptor expression in 4T1 breast cancer cells and orthotopic tumors grown in BALB/c mice and (ii) investigate the impact of NPY receptor activation on 4T1 cell proliferation and migration in vitro. Positive expression of NPY receptors (Y1R, Y2R and Y5R) was observed in cells and tumor tissue. As well, NPY treatment of 4T1 cells promoted a concentration-dependent increase in proliferation, through increased phosphorylation of ERK 1/2. Using NPY receptor antagonists (Y1R:BIBP3226, Y2R:BIIE0246 and Y5R:L-152,804), we found the proliferative response to be Y5R mediated. Additionally, NPY increased chemotaxis through Y2R and Y5R activation. These data are in congruence with those from human cell lines and highlight the 4T1 cell line as a translatable model of breast cancer in which the effects of NPY can be studied in an immunocompetent system.

Neurotransmitters, more than meets the eye--neurotransmitters and their perspectives in cancer development and therapy

The neurotransmitter/receptor system has been shown to modulate various aspects of tumor development including cell proliferation, angiogenesis, invasion, migration and metastasis. It has been found that tumor tissues can not only synthesize and release a wide range of neurotransmitters but also produce different biological effects via respective receptors. These tissues are also innervated by nerve fibers but the biological significance is unknown. Nevertheless neurotransmitters can produce either stimulatory or inhibitory effect in normal and tumor tissues. These effects are dependent on the types of tissues and the kinds of neurotransmitter as well as the subtypes of corresponding receptors being involved. These findings clearly extend the conventional role of neurotransmitters in nervous system to the actions in oncogenesis. In this regard, intervention or stimulation of these neuronal pathways in different cancer diseases would have significant clinical implications in cancer treatments. Here, we summarize the influences of various well-characterized neurotransmitters and their receptors on tumor growth and further discuss the respective possible strategies and perspectives for cancer therapy in the future.

Expression of trophic peptides and their receptors in chromaffin cells and pheochromocytoma

Pheochromocytomas are catecholamine-producing tumors arising from chromaffin cells of the adrenal medulla or extra-adrenal location. Along with catecholamines, tumoral cells produce and secrete elevated quantities of trophic peptides which are normally released in a regulated manner by the normal adrenal medulla. Among these peptides, the amounts of pituitary adenylate cyclase-activating polypeptide (PACAP), adrenomedullin (AM), and neuropeptide Y (NPY) are particularly high. These peptides can exert endocrine, paracrine or autocrine effects in numerous cell types. In particular, they have been shown to be involved in cell proliferation and survival, catecholamine production and secretion, and angiogenesis. Some of these processes are exacerbated in pheochromocytomas, raising the possibility of the involvement of trophic peptides. Here, we review the expression levels of NPY, PACAP, and AM and theirs receptors in chromaffin cells and pheochromocytomas, and address their possible implication in the adrenal medulla tumorigenesis and malignant development of pheochromocytomas.

Combining neuropeptide Y and mesenchymal stem cells reverses remodeling after myocardial infarction

Neuropeptide Y (NPY) induced reentry of differentiated rat neonatal and adult cardiomyocytes into the cell cycle. NPY also induced differentiation of bone marrow-derived mesenchymal stem cells (MSC) into cardiomyocytes following transplantation into infarcted myocardium. Rat neonatal and adult cardiomyocytes were treated in vitro with vehicle, NPY, fibroblast growth factor (FGF; 100 ng/ml), or FGF plus NPY. DNA synthesis, mitosis, and cytokinesis were determined by immunocytochemistry. NPY-induced MSC gene expression, cell migration, tube formation, and endothelial cell differentiation were analyzed. Male rat green fluorescent protein-MSC (2 x 10(6)), pretreated with either vehicle or NPY (10(-8) M) for 72 h, were injected into the border zone of the female myocardium following left anterior descending artery ligation. On day 30, heart function was assessed, and hearts were harvested for histological and immunohistochemical analyses. NPY increased 5-bromo-2'-deoxy-uridine incorporation and promoted both cytokinesis and mitosis in rat neonatal and adult myocytes. NPY also upregulated several genes required for mitosis in MSC, including aurora B kinase, FGF-2, cycline A2, eukaryotic initiation factor 4 E, and stromal cell-derived factor-1alpha. NPY directly induced neonatal and adult cardiomyocyte cell-cycle reentry and enhanced the number of differentiated cardiomyocytes from MSC in the infarcted myocardium, which corresponded to improved cardiac function, reduced fibrosis, ventricular remodeling, and increased angiomyogenesis. It is concluded that a combined treatment of NPY with MSC is a novel approach for cardiac repair.