Limited neuropeptide Y precursor processing in unfavourable metastatic neuroblastoma tumours

Neuropeptide Y Peptide Family and Cancer: Antitumor Therapeutic Strategies

Currently available data on the involvement of neuropeptide Y (NPY), peptide YY (PYY), and pancreatic polypeptide (PP) and their receptors (YRs) in cancer are updated. The structure and dynamics of YRs and their intracellular signaling pathways are also studied. The roles played by these peptides in 22 different cancer types are reviewed (e.g., breast cancer, colorectal cancer, Ewing sarcoma, liver cancer, melanoma, neuroblastoma, pancreatic cancer, pheochromocytoma, and prostate cancer). YRs could be used as cancer diagnostic markers and therapeutic targets. A high Y1R expression has been correlated with lymph node metastasis, advanced stages, and perineural invasion; an increased Y5R expression with survival and tumor growth; and a high serum NPY level with relapse, metastasis, and poor survival. YRs mediate tumor cell proliferation, migration, invasion, metastasis, and angiogenesis; YR antagonists block the previous actions and promote the death of cancer cells. NPY favors tumor cell growth, migration, and metastasis and promotes angiogenesis in some tumors (e.g., breast cancer, colorectal cancer, neuroblastoma, pancreatic cancer), whereas in others it exerts an antitumor effect (e.g., cholangiocarcinoma, Ewing sarcoma, liver cancer). PYY or its fragments block tumor cell growth, migration, and invasion in breast, colorectal, esophageal, liver, pancreatic, and prostate cancer. Current data show the peptidergic system's high potential for cancer diagnosis, treatment, and support using Y2R/Y5R antagonists and NPY or PYY agonists as promising antitumor therapeutic strategies. Some important research lines to be developed in the future will also be suggested.

Correlation analysis between immune-related genes and cell infiltration revealed prostate cancer immunotherapy biomarkers linked to T cells gamma delta

Prostate cancer (PCa) is a urological malignancy with poor prognosis. Immune-related genes are associated with immune infiltration in prostate cancer, but their role in immunogenic PCa is less well understood. We assessed the infiltration patterns of 22 immune cells in PCa and the relationship of immune-related differentially expressed genes (IDEGs) with them. The 87 IDEGs are involved in the interaction between the extracellular matrix and the tumor microenvironment. The model, including seven IDEGs (SLPI, DES, IAPP, NPY, ISG15, PLA2G2A, and HLA-DMB), showed a good predictive power. The SLPI expression is positively correlated with the infiltration level of T cells gamma delta. In addition, PCa has high infiltration levels in Macrophages M1 (18.07%) and Dendritic cells activated (17.64%). The correlation analysis between IDEGs and immune cell infiltration suggested that PCa immunotherapy biomarkers may be closely related to T cells gamma delta.

Neuropeptide Y expression in cutaneous melanoma

BACKGROUND

Neuropeptide Y (NPY) is widely found in the nervous system and has a role in numerous physiologic processes. In addition, NPY receptors are expressed in neuroendocrine tumors, breast cancer, prostate cancer, kidney cancer, and some types of sarcomas. Different neuropeptides, particularly α-melanocyte-stimulating hormone (MSH), seem to play a role in the pathogenesis of melanoma.

OBJECTIVE

We sought to analyze the expression of NPY in cutaneous melanoma, its association with clinical and histologic features, and its correlation with α-MSH.

METHODS

This was an observational study of the immunohistochemical expression of NPY and α-MSH in tissue samples of cutaneous melanomas, different types of melanocytic nevi, and melanoma metastases diagnosed from 2004 to 2008 in San Jorge Hospital, Huesca, Spain.

RESULTS

A total of 184 lesions were studied: 49 primary cutaneous melanomas, 12 melanoma metastases (9 cutaneous and 3 lymphatic), and 123 melanocytic nevi. Immunostaining revealed that levels of NPY and α-MSH were significantly higher in melanomas than in melanocytic nevi (P < .001). Melanoma metastases were negative for both neuropeptides. Nodular melanomas showed the highest median percentage of NPY positive cells (75% [20-95]) followed by superficial spreading melanoma (25% [2-92]), whereas lentigo maligna were negative (0% [0-0]). Significant, direct associations between NPY expression and vertical growth (P = .0141) and presence of metastasis (P = .0196) were observed. NPY and α-MSH were positively correlated in cutaneous melanoma (0.49, P < .001).

LIMITATIONS

The sample size of melanomas was not very large.

CONCLUSION

Our study demonstrates that NPY is significantly expressed in melanomas, especially the nodular type, being associated with invasiveness independently of proliferative markers such as thickness, ulceration, and mitotic index.

Quantitative analysis of a panel of gene expression in prostate cancer--with emphasis on NPY expression analysis

OBJECTIVE

To investigate molecular alterations associating with prostate carcinoma progression and potentially provide information toward more accurate prognosis/diagnosis.

METHODS

A set of laser captured microdissected (LCM) specimens from 300 prostate cancer (PCa) patients undergoing radical prostatectomy (RP) were defined. Ten patients representing "aggressive" PCa, and 10 representing "non-aggressive" PCa were selected based on prostate-specific antigen (PSA) recurrence, Gleason score, pathological stage and tumor cell differentiation, with matched patient age and race between the two groups. Normal and neoplastic prostate epithelial cells were collected with LCM from frozen tissue slides obtained from the RP specimens. The expressions of a panel of genes, including NPY, PTEN, AR, AMACR, DD3, and GSTP1, were measured by quantitative real-time RT-PCR (TaqMan), and correlation was analyzed with clinicopathological features.

RESULTS

The expressions of AMACR and DD3 were consistently up-regulated in cancer cells compared to benign prostate epithelial cells in all PCa patients, whereas GSTP1 expression was down regulated in each patient. NPY, PTEN and AR exhibited a striking difference in their expression patterns between aggressive and non-aggressive PCas (P=0.0203, 0.0284, and 0.0378, respectively, Wilcoxon rank sum test). The lower expression of NPY showed association with "aggressive" PCas based on a larger PCa patient cohort analysis (P=0.0037, univariate generalized linear model (GLM) analysis).

CONCLUSION

Despite widely noted heterogeneous nature of PCa, gene expression alterations of AMACR, DD3, and GSTP1 in LCM-derived PCa epithelial cells suggest for common underlying mechanisms in the initiation of PCa. Lower NPY expression level is significantly associated with more aggressive clinical behavior of PCa; PTEN and AR may have potential in defining PCa with aggressive clinical behavior. Studies along these lines have potential to define PCa-associated gene expression alterations and likely co-regulation of genes/pathways critical in the biology of PCa onset/progression.

Neuropeptide Y (NPY) in neuroblastoma: effect on growth and vascularization

Neuroblastomas are pediatric tumors of sympathetic origin, expressing neuronal markers, such as NPY and its receptors. Due to this, neuroblastomas are often associated with elevated plasma levels of NPY, which correlates with poor clinical outcome of the disease. This clinical data corroborates the recent discovery of growth-promoting actions of NPY in neuroblastomas. The peptide has been shown to stimulate proliferation of neuroblastoma cells in an autocrine manner and induce tumor vascularization. Since both processes are mediated by the same Y2 and Y5 receptors, targeting this pathway may be a potential bidirectional therapy for these children's tumors.

NPY receptors in human cancer: a review of current knowledge

Many peptide hormone receptors are over-expressed in human cancer, permitting an in vivo targeting of tumors for diagnostic and therapeutic purposes. NPY receptors are novel and promising candidates in this field. Using in vitro receptor autoradiography, Y1 and Y2 receptors have been found to be expressed in breast carcinomas, adrenal gland and related tumors, renal cell carcinomas, and ovarian cancers in both tumor cells and tumor-associated blood vessels. Pathophysiologically, tumoral NPY receptors may be activated by endogenous NPY released from intratumoral nerve fibers or tumor cells themselves, and mediate NPY effects on tumor cell proliferation and tumoral blood supply. Clinically, tumoral NPY receptors may be targeted with NPY analogs coupled with adequate radionuclides or cytotoxic agents for a scintigraphic tumor imaging and/or tumor therapy.

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

Neuropeptide Y (NPY) is a sympathetic neurotransmitter recently found to be a potent growth and angiogenic factor. The peptide and its receptors are abundant in neural crest-derived tumors, such as sympathetic neuroblastomas and pheochromocytomas, as well as parasympathetic Ewing's sarcoma family of tumors. NPY regulates their growth directly, by an autocrine activation of tumor cell proliferation or apoptosis, and indirectly, by its angiogenic activity. The overall effect of the peptide on tumor growth depends on a balance between these processes and the type of receptors expressed in the tumor cells. Thus, NPY and its receptors may become targets for the treatment of neural tumors, directed against both tumor cell proliferation and angiogenesis.

High expression of neuropeptide y receptors in tumors of the human adrenal gland and extra-adrenal paraganglia

PURPOSE

Recently, a role of neuropeptide Y (NPY) in tumor biology was suggested based on the high density of NPY receptors in breast and ovarian cancers. The high frequency of NPY receptors in steroid hormone-producing ovarian sex cord-stromal tumors, together with the known influence of NPY on steroid hormone and catecholamine secretion in the rodent adrenal gland, led to the investigation of NPY receptor expression in the human adrenal gland and related tumors.

EXPERIMENTAL DESIGN

Fifteen adrenal cortical tumors, 20 paragangliomas, 23 pheochromocytomas, 20 neuroblastomas, and 8 normal adrenal glands were investigated by in vitro NPY receptor autoradiography using 125I-labeled peptide YY in competition experiments with receptor subtype selective analogs.

RESULTS

Ninety three percent of cortical tumors express Y1, 35% of pheochromocytomas and 61% of paragangliomas express Y1 and Y2, and 90% of neuroblastomas express Y2 receptors. The NPY receptors in pheochromocytomas, paragangliomas, and neuroblastomas are often expressed concomitantly with the NPY hormone detected immunohistochemically. The adrenal cortex strongly expresses Y1, whereas no NPY receptors are found in the adrenal medulla.

CONCLUSIONS

These receptor data suggest a role of NPY in adrenal cortical tumors and, together with the strong NPY innervation of the cortex, a physiologic role in the adrenal gland, mediated by Y1 receptors. These NPY receptors are a potential new molecular target for the therapy of malignant tumors.

Semisynthesis and characterization of the first analogues of pro-neuropeptide y

Enzymatic cleavage of prohormone neuropeptide Y (proNPY) leads to mature neuropeptide Y (NPY), a widely distributed neuropeptide with multiple functions both peripherally and centrally. A single dibasic pair of amino acids, Lys38-Arg39, represents the recognition motif for a class of hormone-processing enzymes known as prohormone convertases (PCs). Two members of this PC family, PC1/3 and PC2, are involved in proNPY cleavage. The aim of this work was to establish an effective method for the generation of full-length 69-amino acid proNPY analogues for further studies of prohormone convertase interaction. We have chosen two ligation sites in order to perform the semisynthesis of proNPY analogues by expressed protein ligation (EPL). By using the intein-mediated purification system (IMPACT) with improved conditions for intein splicing, we were able to isolate proNPY 1-40 and proNPY 1-54 fragments as Cterminal thioesters. Peptides bearing Nterminal cysteine instead of the naturally occurring Ser41 and Thr55 residues, respectively, were generated by solid-phase peptide synthesis. Moreover, labels (carboxyfluorescein and biotin) were inserted into the peptide sequences. The synthesis of the [C41]proNPY 41-69 fragment, which proved to be a difficult peptide sequence, could be achieved by the incorporation of two pseudo-proline derivatives. Western blot analysis revealed that all five proNPY analogues are recognized by monoclonal antibodies directed against NPY as well as against the Cflanking peptide of NPY (CPON).

Galanin and galanin receptor expression in neuroblastic tumours: correlation with their differentiation status

Neuroblastoma and its benign differentiated counterpart, ganglioneuroma, are paediatric neuroblastic tumours arising in the sympathetic nervous system. Their broad spectrum of clinical virulence is mainly related to heterogeneous biologic background and tumour differentiation. Neuroblastic tumours synthesize various neuropeptides acting as neuromodulators. Previous studies suggested that galanin plays a role in sympathetic tissue where it could be involved in differentiation and development. We investigated the expression and distribution of galanin and its three known receptors (Gal-R1, Gal-R2, Gal-R3) in 19 samples of neuroblastic tumours tissue by immunohistochemistry, in situ hybridization and fluorescent-ligand binding. This study provides clear evidence for galanin and galanin receptor expression in human neuroblastic tumours. The messengers coding for galanin, Gal-R1 and -R3 were highly expressed in neuroblastoma and their amount dramatically decreased in ganglioneuroma. In contrast, Gal-R2 levels remained unchanged. Double labelling studies showed that galanin was mainly co-expressed with its receptors whatever the differentiation stage. In neuroblastic tumours, galanin might promote cell-survival or counteract neuronal differentiation through the different signalling pathways mediated by galanin receptors. Finally, our results suggest that galanin influences neuroblastoma growth and development as an autocrine/paracrine modulator. These findings suggest potential critical implications for galanin in neuroblastic tumours development.