Peptide YY inhibits growth of human breast cancer in vitro and in vivo

Neuropeptide Y receptors 1 and 2 as molecular targets in prostate and breast cancer therapy

Recent advances have revealed the overexpression of Neuropeptide Y (NPY) receptors in multiple cancers, positioning them as attractive molecular targets for cancer diagnostics and therapeutics. Despite this, a comprehensive roadmap for the rational development of anticancer agents targeting NPY receptors remains lacking. Therefore, we present the characteristics of NPY receptor subtypes, their abundance, and the correlation of their expression in different cancer types. It was found that NPY receptor subtypes 1 and 2 were extensively studied, especially in connection with breast and prostate cancer. Many tumors express NPYR, but only breast cancer tissue shows a significant difference in NPYR subtype expression levels between tumor and normal tissues, and, therefore, can represent a promising target. In the context of anticancer therapy, this review provides key findings from the use of wild-type and synthetic NPY analogs. We highlight the critical residues in the NPY sequence that play a critical role in interactions with receptors and provide the recent literature findings on NPY analogues as efficient and specific cancer-targeting agents. Potential solutions to improve NPY analogs' stability are provided, such as sequence modifications of linear peptides, peptide stapling, and conjugation for drug delivery systems. In general, NPY treatment can not be used efficiently as a single therapy but as a combinatorial therapy with anticancer drugs to improve the specificity of the treatment via high-affinity binding to the cancer cells and sensitizing them to chemotherapy.

Peptide YY fragment PYY1-36 disrupts mitochondrial biogenesis via RBM43-dependent PGC-1α translation inhibition

Mitochondrial dysfunction is a key driver of cancer progression, with therapies increasingly targeting metabolic weaknesses. Peptide YY (PYY), a gastrointestinal hormone, regulates cellular activity, but its influence on mitochondrial health in lung cancer remains poorly understood. We explored how PYY1-36, a bioactive fragment of PYY, affects mitochondrial stability in NCI-H1581 lung cancer cells. Using dose-response experiments, we measured oxidative stress by tracking lactate dehydrogenase (LDH) release, mitochondrial ROS levels, and oxidative DNA damage (8-OHdG). Energy production was evaluated through ATP levels, oxygen consumption rates (OCR), and Complex I activity. We also analyzed mitochondrial biogenesis markers (NRF1, TFAM, PGC-1α) and the RNA-binding protein RBM43 via qPCR and immunoblotting. Dose-dependent tests showed that PYY1-36 triggers mitochondrial oxidative damage, marked by higher LDH release and ROS spikes. These changes aligned with sharp drops in ATP production and disrupted respiratory function. Notably, PYY1-36 reduced mitochondrial mass and biogenesis, supported by weaker MitoTracker Red signals and lower mtDNA/nDNA ratios. Key regulators NRF1 and TFAM were strongly suppressed, pointing to widespread mitochondrial failure. Intriguingly, PYY1-36 blocked PGC-1α protein synthesis without altering mRNA levels, suggesting a post-transcriptional control mechanism. PYY1-36 also boosted RBM43 levels. Knocking down RBM43 reversed PYY1-36's effects on PGC-1α and mitochondrial health. Our findings reveal RBM43 as a central player in PYY1-36-induced mitochondrial dysfunction through its suppression of PGC-1α translation. Targeting RBM43 could unlock new strategies to tackle metabolic chaos in lung cancer.

The protective role of PYY in intestinal mucosal defects induced by SATB2 deficiency in inflammatory bowel disease

Impaired colonic mucosal repair is a critical issue in inflammatory bowel diseases (IBD). SATB2 is essential for maintaining colonic epithelial homeostasis, but its role in mucosal repair is unclear. In this study, flow cytometry was used to assess SATB2's role in colonic epithelial repair in a radiation injury model. SATB2 knockout mice exhibited defective epithelial repair, with a marked reduction in goblet and enteroendocrine cells. Mechanistically, SATB2 directly regulated PPAR-γ transcription, and PYY was observed to translocate into the nucleus and promote the transcription of PPAR-γ target genes. In organoids derived from patients with Crohn's disease, PYY supplementation significantly improved epithelial regeneration, outperforming the PPAR-γ agonist rosiglitazone. In conclusion, SATB2 deficiency impairs colonic epithelial repair, which can be rescued by PYY through activation of PPAR-γ-dependent transcription. These findings suggest that PYY may serve as a promising therapeutic molecule to promote epithelial repair in IBD.

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.

The Role of Neuropeptide-Stimulated cAMP-EPACs Signalling in Cancer Cells

Neuropeptides are autocrine and paracrine signalling factors and mainly bind to G protein-coupled receptors (GPCRs) to trigger intracellular secondary messenger release including adenosine 3′, 5′-cyclic monophosphate (cAMP), thus modulating cancer progress in different kind of tumours. As one of the downstream effectors of cAMP, exchange proteins directly activated by cAMP (EPACs) play dual roles in cancer proliferation and metastasis. More evidence about the relationship between neuropeptides and EPAC pathways have been proposed for their potential role in cancer development; hence, this review focuses on the role of neuropeptide/GPCR system modulation of cAMP/EPACs pathways in cancers. The correlated downstream pathways between neuropeptides and EPACs in cancer cell proliferation, migration, and metastasis is discussed to glimmer the direction of future research.

Obesity-related gut hormones and cancer: novel insight into the pathophysiology

The number of cancers attributed to obesity is increasing over time. The mechanisms classically implicated in cancer pathogenesis and progression in patients with obesity involve adiposity-related alteration of insulin, sex hormones, and adipokine pathways. However, they do not fully capture the complexity of the association between obesity-related nutritional imbalance and cancer. Gut hormones are secreted by enteroendocrine cells along the gastrointestinal tract in response to nutritional cues, and act as nutrient sensors, regulating eating behavior and energy homeostasis and playing a role in immune-modulation. The dysregulation of gastrointestinal hormone physiology has been implicated in obesity pathogenesis. For their peculiar function, at the cross-road between nutrients intake, energy homeostasis and inflammation, gut hormones might represent an important but still underestimated mechanism underling the obesity-related high incidence of cancer. In addition, cancer research has revealed the widespread expression of gut hormone receptors in neoplastic tissues, underscoring their implication in cell proliferation, migration, and invasion processes that characterize tumor growth and aggressiveness. In this review, we hypothesize that obesity-related alterations in gut hormones might be implicated in cancer pathogenesis, and provide evidence of the pathways potentially involved.

Structural dynamics of neuropeptide hPYY

We have employed a combination of experiment and simulation to characterize the ensemble of structures sampled by human Peptide YY (hPYY), an important member of the neuropeptide Y family. Experimental structural characterization carried out with far UV circular dichroism spectroscopy and Fourier Transform-Infrared measurements confirmed that the major feature of the secondary structure of hPYY is the α-helix, encompassing about half the peptide residues, with smaller contributions from turn and β-sheet like structures. The peptide undergoes thermal denaturation characterized by a melting temperature of 48°C with an enthalpy change of -24.5 kcal/mol and entropy change of -76.2 cal/(mol K). In our computational studies, based on a 4-μsec MD trajectory generated with the AMBER03 potential, we found excellent agreement of the predicted features with experimental data, including a stable C-terminal helix, a central turn and conservation of about 80% of measured long-range NOE contacts. The main structural fluctuations involved partial helix unwinding and large-scale motions of the N-terminal. Our joint experimental/computational approach leads to several insights into the biological function of PYY. We conclude that the C-terminal helix is crucial for the structural integrity of PYY. The structures and motions found in the simulations suggest microscopic explanations for observed changes in biological activity of the peptide upon mutation and truncation. We also performed microsecond-length MD and replica-exchange simulations of hPYY with the OPLS-AA force field, for which computed structures did not agree well with experimental data, predicting significant loss of helicity and NOE contacts.

Sympathetic Neurotransmitters and Tumor Angiogenesis-Link between Stress and Cancer Progression

Recent evidence supports a longstanding hypothesis that chronic stress can influence tumor growth and progression. It has been shown that sympathetic neurotransmitters, such as catecholamines and neuropeptides, can affect both cancer cell growth and tumor vascularization. Depending on neurotransmitter and type of tumor, these effects can be both stimulatory and inhibitory. Norepinephrine (NE) and epinephrine (E) are potent stimulators of vascularization, acting both by inducing the release of angiogenic factors from tumor cells and directly on endothelial cell (EC) functions. As a result, activation of the adrenergic system increases growth of various types of tumors and has been shown to mediate stress-induced augmentation of tumor progression. Dopamine (DA), on the other hand, interferes with VEGF signaling in endothelial cells, blocks its angiogenic functions and inhibits tumor growth. Another sympathetic neurotransmitter coreleased with NE, neuropeptide Y (NPY), directly stimulates angiogenesis. However, proangiogenic actions of NPY can be altered by its direct effect on tumor cell proliferation and survival. In consequence, NPY can either stimulate or inhibit tumor growth, depending on tumor type. Hence, sympathetic neurotransmitters are powerful modulators of tumor growth and can become new targets in cancer therapy.

Neuropeptide Y Y5 receptor promotes cell growth through extracellular signal-regulated kinase signaling and cyclic AMP inhibition in a human breast cancer cell line

Overexpression of neuropeptide Y (NPY) and its receptor system has been reported in various types of cancers. NPY Y5 receptor (Y5R) has been implicated in cell growth and angiogenesis. However, the role of Y5R in breast cancer is unknown. To identify the role of Y5R in breast cancer, we screened several breast cancer cell lines to examine the expression of Y5R and its function in breast cancer. All screened cell lines express both Y1 receptor and Y5R except BT-549, which expresses mainly Y5R. Binding studies showed that NPY, Y5R-selective agonist peptide, and Y5R-selective antagonist (CGP71683A) displaced (125)I-PYY binding in BT-549 cell membranes in a dose-dependent manner. The displacement studies revealed the presence of two binding sites in Y5R with IC(50) values of 29 pmol/L and 531 nmol/L. NPY inhibited forskolin-stimulated cyclic AMP accumulation with an IC(50) value of 52 pmol/L. NPY treatment of BT-549 cells induced extracellular signal-regulated kinase phosphorylation but did not alter intracellular calcium. Y5R activation stimulates BT-549 cell growth, which is inhibited by CGP71683A, pertussis toxin, and extracellular signal-regulated kinase blockade. CGP71683A alone induced cell death in a time- and dose-dependent manner in Y5R-expressing cells. The stimulation of MDA MB-231 cell migration by NPY is inhibited by CGP71683A. Together, our results suggest that Y5R plays an important role in cancer cell growth and migration and could be a novel therapeutic target for breast cancer.

PYY and the pancreas: inhibition of tumor growth and inflammation

Peptide YY (PYY) orchestrates function of the gut and pancreas by regulating growth, digestion and absorption. In addition to its physiological role, PYY exhibits immune and antitrophic properties in the pancreas by decreasing cytokine and amylase release. Although the exact mechanism(s) of action are still not fully understood, PYY interacts at the acinar level with numerous intracellular transcription factors. In addition to ameliorating pancreatic inflammation, novel synthetic analogs of PYY have been developed that are potent inhibitors in the proliferation of pancreatic cancer. The present paper reviews our current findings with PYY and examines the therapeutic implications of its utility in treating inflammation and cancer.

Differential RNA expression profile by cDNA microarray in sporadic primary hyperparathyroidism (pHPT): primary parathyroid hyperplasia versus adenoma

BACKGROUND

Differential diagnosis between adenoma and hyperplasia in primary hyperparathyroidism (pHPT) remains a dilemma. The aim of this study was to assess differences in transcriptional genomic expression profiles between sporadic (nonfamilial) parathyroid hyperplasia (SPH), adenoma, and normal tissue.

METHODS

Parathyroid tissue from 12 patients with parathyroid adenoma, 3 with SPH, and 2 with normal glands was selected for analysis. Histopathology was reviewed in all cases, and all patients with adenomas presented normocalcemia for a minimum of 6 months after one gland resection. Hybridizations were performed in a microarray containing 19,968 human cDNA clones including contiguous replicates. Direct comparisons were performed with reverse labeling for every different pooled sample entity. Expression levels were analyzed using the SAM, SMA, LIMMA, Cluster, and PAM packages in the R environment for statistical computing.

RESULTS

There were significant statistical differences between SPH and adenomas. In the direct comparison, a total of 200 genes showed differential expression (P < 0.03): 61 genes were upregulated (> 1.65-fold increase) and 139 were downregulated (> 1.58-fold decrease) with a B value > 4.68 (99.08% probability of real differential expression). When SPH was compared to normal parathyroid tissue, 50 genes were differentially expressed: 42 were upregulated (> 1.89) and 8 were downregulated (> 1.7) with a B > 4.26 (98.6% probability of real differential expression). At least 17 genes were differentially expressed and able to discriminate SPH from adenoma or normal tissue. Upregulated genes were related to apoptosis inhibition, cell proliferation, transcriptional activity and cell adhesion, among other activities. Downregulated genes were mainly related to ion channel activity, lipopolysaccharides, prostaglandin-d synthase, and integral membrane proteins.

CONCLUSIONS

Our data suggest that SPH and adenoma have a singular molecular signature that, theoretically, could be used for the differential diagnosis of these entities and normal parathyroid tissue.

Estrogen up-regulates neuropeptide Y Y1 receptor expression in a human breast cancer cell line

Normal breast tissue mainly expresses the neuropeptide Y (NPY) Y2 receptor whereas primary human breast carcinomas express the Y1 receptor (Y1R) subtype. We hypothesized that activation of estrogen signaling systems plays a role in the induction of Y1R. To investigate this possibility, we used estrogen receptor-positive (ER+) human breast carcinoma cell line, MCF-7, and examined the effect of estrogen on Y1R gene expression and its signaling pathways. Saturation binding studies revealed that MCF-7 cells express high-affinity NPY receptor. NPY inhibited forskolin-stimulated adenosine 3'5'-cyclic monophosphate (cAMP) accumulation and mobilized intracellular Ca(2+) in MCF-7 cells. Chronic estrogen treatment enhanced NPY-mediated inhibition of cAMP accumulation by 4-fold and caused a significant increase in Y1R mRNA expression through ERalpha. Similarly, estrogen increased Y1R mRNA expression in T-47D (ER+) but not in MDA-MB231 or MDA-MB468 (ER-) cell lines. Cycloheximide decreased basal Y1R mRNA expression; however, it did not affect its increase by estrogen. Moreover, estrogen treatment of MCF-7 cells did not increase Y1R mRNA stability. The up-regulation of Y1R expression by estrogen is prevented by hydroxyurea but not by nocodazole or IB-MECA (cell cycle inhibitors). Lastly, NPY inhibited estrogen-induced cell proliferation through Y1R. In conclusion, MCF-7 cells express a functional Y1R coupled to both Ca(2+) and cAMP pathways. Estrogen up-regulates Y1R expression through ERalpha. This effect is independent of increased Y1R mRNA stability or new protein synthesis, and likely occurs during S phase completion of the cell cycle. Estrogen plays an important role in the up-regulation of Y1R, which in turn regulates estrogen-induced cell proliferation in breast cancer cells.

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.

Differential effects of neuropeptide Y on the growth and vascularization of neural crest-derived tumors

Neuropeptide Y (NPY) is a sympathetic neurotransmitter recently found to be potently angiogenic and growth promoting for endothelial, vascular smooth muscle and neuronal cells. NPY and its cognate receptors, Y1, Y2 and Y5, are expressed in neural crest-derived tumors; however, their role in regulation of growth is unknown. The effect of NPY on the growth and vascularization of neuroendocrine tumors was tested using three types of cells: neuroblastoma, pheochromocytoma, and Ewing's sarcoma family of tumors (ESFT). The tumors varied in expression of NPY receptors, which was linked to differential functions of the peptide. NPY stimulated proliferation of neuroblastoma cells via Y2/Y5Rs and inhibited ESFT cell growth by Y1/Y5-mediated apoptosis. In both tumor types, NPY receptor antagonists altered basal growth levels, indicating a regulatory role of autocrine NPY. In addition, the peptide released from the tumor cells stimulated endothelial cell proliferation, which suggests its paracrine angiogenic effects. In nude mice xenografts, exogenous NPY stimulated growth of neuroblastoma tumors, whereas it increased apoptosis and reduced growth of ESFT. However, in both tumors, NPY treatment led to an increase in tumor vascularization. Taken together, this is the first report of NPY being a growth-regulatory factor for neuroendocrine tumors, acting both by autocrine activation of tumor cell proliferation or apoptosis and by angiogenesis. NPY and its receptors may become targets for novel approaches in the treatment of these diseases, directed against both tumor cell proliferation and angiogenesis.

Peptide YY inhibits the growth of Barrett's esophageal adenocarcinoma in vitro

BACKGROUND

Peptide YY (PYY) is an endogenous gut hormone that inhibits the growth of certain cancers. Adenocarcinoma of the esophagus usually arises from Barrett's esophagus. We hypothesized that treatment of Barrett's adenocarcinoma with PYY would result in decreased proliferation.

METHODS

Barrett's cancer cell lines (BIC and SEG-1) were treated with PYY (3-36) at 500 pmol/mL. Viability was measured by MTT at 24 and 72 hours. Apoptosis and necrosis was evaluated by flow cytometry.

RESULTS

PYY reduced proliferation in SEG-1 cells at 24 hours (21.2% +/- 3.4%, P <0.001) and 72 hours (14.2% +/- 6.2%, P <0.001). In the BIC cells, growth was inhibited by 7.9% +/- 7.0%, P = 0.021 after 72 hours. PYY increased late apoptotic activity in SEG-1 cells by 31%, P = 0.014.

CONCLUSIONS

This is the first report of antiproliferative effects of PYY against Barrett's carcinoma in vitro. Reductions in cell growth appear to be mediated by proapoptotic mechanisms. Further investigation of PYY in the treatment of Barrett's adenocarcinoma is warranted.

Peptide YY exhibits a mitogenic effect on pancreatic cells while improving acute pancreatitis in vitro

BACKGROUND

Peptide YY (PYY), a gastrointestinal regulatory peptide, improves survival and histologic parameters in animal models of acute pancreatitis. Its effects on pancreatic cell growth and acute pancreatitis in pancreatic acinar and ductal cells are unknown. We hypothesized that PYY would affect cell growth and attenuate acute pancreatitis in pancreatic acinar and ductal cells in vitro.

METHODS

Rat pancreatic acinar and ductal cells were cultured in the presence of 1) cerulein, a synthetic cholecystokinin analog that induces pancreatitis, 2) PYY, or 3) a combination group pretreated with PYY prior to addition of cerulein. Cell survival was measured at 48 h using MTT assay. Amylase secretion, as marker for pancreatitis, was measured at 48 h using an amylase activity assay. Statistical significance was calculated using analysis of variance and the Student's t test.

RESULTS

Peptide yy significantly increased cell growth and decreased amylase secretion compared with control and cerulein groups. Pretreatment with PYY significantly protected against the pancreatitis effects of cerulein.

CONCLUSIONS

We have shown for the first time that PYY has a mitogenic effect on pancreatic acinar and ductal cells in vitro. In addition, it directly protects against cerulein-induced pancreatitis. Its potential therapeutic benefit in acute pancreatitis would therefore be twofold: amelioration of the inflammatory process, and augmenting growth of normal pancreas to replace necrotic or apoptotic cell loss.

Vitamin E and the Y4 agonist BA-129 decrease prostate cancer growth and production of vascular endothelial growth factor

BACKGROUND

A biologically active form of vitamin E, alpha-tocopherol succinate (ATS), has been shown to induce apoptosis of hormone-refractory prostate cancer in vitro and inhibit cell growth in vivo. The gastrointestinal hormone peptide YY (PYY) has growth inhibitory activity against multiple cancer cell lines and is synergistic with ATS against breast and pancreatic cancer growth. BA-129, a specific Y4 receptor agonist, has growth inhibitory effects on pancreatic cancer in vitro. We investigated the effects of BA-129 and ATS on prostate cancer growth and evaluated their effects on vascular endothelial growth factor (VEGF) production.

METHODS

A hormone-refractory human prostate cancer cell line, PC-3, was treated with ATS alone at 10 pg/ml, PYY or BA-129 alone at doses of 75 and 500 pmol/ml, or a combination of the two agents. Cell growth was measured by MTT assay and hemocytometry using trypan blue. Quantitative measurement of VEGF was performed by ELISA. Statistical analysis was achieved by ANOVA.

RESULTS

ATS exhibited significant (P < 0.05) growth inhibitory effects in prostate cancer cells. PYY also inhibited growth (P < 0.05). ATS treatment reduced VEGF production (P < 0.05). PYY treatment increased VEGF. When ATS was given in combination with BA-129, VEGF production was further reduced (P < 0.05).

CONCLUSIONS

Both PYY and ATS inhibit growth in hormone-refractory prostate cancer, with augmentation when used in combination. VEGF production is inhibited by vitamin E, but increased by PYY. ATS abolishes the augmented VEGF response to PYY. Our data suggest that PYY is involved in the regulation of VEGF production and prostate cancer growth.

Peptide YY and cancer: current findings and potential clinical applications

Peptide YY (PYY) is a naturally occurring gut hormone with mostly inhibitory actions on multiple tissue targets. PYY has been identified in several carcinoid tumors and a decreased expression of PYY may be relevant to the development and progression of colon adenocarcinoma. Treatment with PYY decreases growth in pancreatic and breast tumors, most likely through a reduction in intracellular cAMP. In cancer patients, PYY may also improve malnutrition that results from iatrogenic causes or cachexia associated with advanced disease. PYY plays a significant role in multiple aspects of cancer from regulation of cell growth to potential therapeutic applications.