Neuromedin B induces angiogenesis via activation of ERK and Akt in endothelial cells

Identification of Epigenetically Regulated Genes Distinguishing Intracranial from Extracranial Melanoma Metastases

Despite remarkable advances in treating patients with metastatic melanoma, the management of melanoma brain metastases remains challenging. Recent evidence suggests that epigenetic reprogramming is an important mechanism for the adaptation of melanoma cells to the brain environment. In this study, the methylomes and transcriptomes of a cohort of matched melanoma metastases were evaluated by integrated omics data analysis. The identified 38 candidate genes displayed distinct promoter methylation and corresponding gene expression changes in intracranial compared with extracranial metastases. The 11 most promising genes were validated on protein level in both tumor and surrounding normal tissue using immunohistochemistry. In accordance with the underlying promoter methylation and gene expression changes, a significantly different protein expression was confirmed for STK10, PDXK, WDR24, CSSP1, NMB, RASL11B, phosphorylated PRKCZ, PRKCZ, and phosphorylated GRB10 in the intracranial metastases. The observed changes imply a distinct intracranial phenotype with increased protein kinase B phosphorylation and a higher frequency of proliferating cells. Knockdown of PRKCZ or GRB10 altered the expression of phosphorylated protein kinase B and decreased the viability of a brain-specific melanoma cell line. In summary, epigenetically regulated cancer-relevant alterations were identified that provide insights into the molecular mechanisms that discriminate brain metastases from other organ metastases, which could be exploited by targeting the affected signaling pathways.

Neuromedin B and its receptor silencing suppresses osteoclast generation by modulating precursor proliferation via M-CSF/c-Fms/D-type cyclins

Neuromedin B (NMB), a mammalian bombesin-like peptide, regulates diverse physiological processes, such as energy metabolism, memory and fear behavior, and cellular growth, through its cognate receptor, NMBR. In this study, we report that NMB expression was upregulated during osteoclast development and that silencing NMB or NMBR attenuated osteoclast generation mediated by macrophage colony-stimulating factor (M-CSF) and receptor activator of NF-κB ligand (RANKL). We found that knockdown of NMB or NMBR using a small hairpin RNA suppressed M-CSF-induced proliferation of osteoclast precursor cells without altering osteoclast differentiation. Interestingly, NMB or NMBR knockdown reduced the expression of the M-CSF receptor, c-Fms, which is an important modulator of osteoclast development. Consequently, NMB or NMBR silencing inhibited M-CSF/c-Fms-mediated downstream signaling pathways like activation of ERK and Akt and induction of D-type cyclins, cyclin D1 and D2. Moreover, knockdown of NMB or NMBR accelerated apoptosis in osteoclast lineage cells by inducing caspase-3, caspase-9, and Bim expression. In summary, our study demonstrates that the NMB/NMBR axis plays a pivotal role in osteoclast generation by modulating the proliferation and survival of osteoclast lineage cells.

Pro-Angiogenic Effects of Low Dose Ethoxidine in a Murine Model of Ischemic Hindlimb: Correlation between Ethoxidine Levels and Increased Activation of the Nitric Oxide Pathway

Ethoxidine, a benzo[c]phenanthridine derivative, has been identified as a potent inhibitor of topoisomerase I in cancer cell lines. Our group has reported paradoxical properties of ethoxidine in cellular processes leading to angiogenesis on endothelial cells. Because low concentration ethoxidine is able to favor angiogenesis, the present study aimed to investigate the ability of 10^-9 M ethoxidine to modulate neovascularization in a model of mouse hindlimb ischemia. After inducing unilateral hindlimb ischemia, mice were treated for 21 days with glucose 5% or with ethoxidine, to reach plasma concentrations equivalent to 10^-9 M. Laser Doppler analysis showed that recovery of blood flow was 1.5 fold higher in ethoxidine-treated mice in comparison with control mice. Furthermore, CD31 staining and angiographic studies confirmed an increase of vascular density in ethoxidine-treated mice. This ethoxidine-induced recovery was associated with an increase of NO production through an enhancement of eNOS phosphorylation on its activator site in skeletal muscle from ischemic hindlimb. Moreover, real-time RT-PCR and western blots have highlighted that ethoxidine has pro-angiogenic properties by inducing a significant enhancement in vegf transcripts and VEGF expression, respectively. These findings suggest that ethoxidine could contribute to favor neovascularization after an ischemic injury by promoting the NO pathway and VEGF expression.

Neuromedin B receptor antagonism inhibits migration, invasion, and epithelial-mesenchymal transition of breast cancer cells

Neuromedin B (NMB) acts as an autocrine growth factor and a pro-angiogenic factor. Its receptor, NMB receptor (NMB-R), is overexpressed in solid tumors. In the present study, we showed that an NMB-R antagonist, PD168368, suppresses migration and invasion of the human breast cancer cell line MDA-MB-231. In addition, PD168368 reduced epithelial-mesenchymal transition (EMT) of breast cancer cells by E-cadherin upregulation and vimentin downregulation. Moreover, we found that PD168368 potently inhibits in vivo metastasis of breast cancer. Taken together, these findings suggest that NMB-R antagonism may be an alternative approach to prevent breast cancer metastasis, and targeting NMB-R may provide a novel therapeutic strategy for breast cancer treatment.

Neuromedin B and Its Receptor: Gene Cloning, Tissue Distribution and Expression Levels of the Reproductive Axis in Pigs

Neuromedin B is one member of a family of bombesin-like peptides, which performs a variety of physiological functions via their receptor (NMBR) in most mammals. However, the genes encoding NMB and NMBR and their functions especially reproduction of the pigs are currently not fully understood. To research the physiological functions of NMB, we cloned and analyzed the NMB and NMBR genes, and systematically investigated the expression levels of NMB and NMBR mRNA using relative real-time PCR and the distribution of NMBR by immunohistochemistry (IHC). Experimental results show that the sequences of the amino acid and gene of NMB and NMBR were highly conservative and homology in many species, Significantly, the relative RT-PCR results revealed that NMB was mainly expressed in the central nervous system (CNS), whereas NMBR is highly expressed in peripheral tissues and organs, such as endocrine tissues, glands and reproductive organs. The IHC results show that NMBR positive cells were widely distributed in the body, such as respiratory and circulatory system, digestive system, urogenital system, in lymphatic organs and in the endocrine system. We also systematically investigated expression levels of NMB and NMBR in the reproductive axis using relative real-time PCR. In sow estrous cycle, the hypothalamic levels of both NMB and NMBR mRAN were similar, but the expression levels of the pituitary were negatively correlated. Expression levels in the ovarian system are lowest in metestrus phases and highest in proestrus and estrus phases. In boar post-natal development stages, the hypothalamic, pituitary and testicular levels of NMB and NMBR mRNAs showed developmental changes on postnatal day 30, 60, 90 and 120. Taken together, this study provided molecular and morphological data necessary for further research of physiological function of NMB/NMBR system in the pigs.

Facile rhenium-peptide conjugate synthesis using a one-pot derived Re(CO)3 reagent

We have synthesized two Re(CO)3-modified lysine complexes (1 and 2), where the metal is attached to the amino acid at the Nε position, via a one-pot Schiff base formation reaction. These compounds can be used in the solid phase synthesis of peptides, and to date we have produced four conjugate systems incorporating neurotensin, bombesin, leutenizing hormone releasing hormone, and a nuclear localization sequence. We observed uptake into human umbilical vascular endothelial cells as well as differential uptake depending on peptide sequence identity, as characterized by fluorescence and rhenium elemental analysis.

Neuromedin B Restores Erectile Function by Protecting the Cavernous Body and the Nitrergic Nerves from Injury in a Diabetic Rat Model

Erectile dysfunction (ED) is a major health problem worldwide and affects approximately 75% of diabetic patients, likely due to severely damaged cavernous body. While screening for cytokines produced by adipose tissue-derived stem cells, we detected neuromedin B (NMB). To explore a potential treatment option for ED, we examined whether NMB was capable of restoring erectile function. We also examined the potential mechanism by which NMB could restore erectile function. Male Wistar rats were injected with streptozotocin (STZ) to induce diabetes. An adenovirus expressing NMB (AdNMB) was injected into the penis 6 weeks after STZ administration. Four weeks after the injection of AdNMB, erectile function, penile histology, and protein expression were analyzed. As assessed by the measurement of intracavernous pressure, AdNMB injection significantly restored erectile function compared with the injection of an adenovirus expressing green fluorescent protein. This restoration was associated with conservation of the cavernous body structure and neural nitric oxide synthase (nNOS)-expressing nerves, together with recovery of α-smooth muscle actin, vascular endothelial-cadherin, and nNOS expression. Furthermore, NMB significantly stimulated the survival of SH-SY5Y cells derived from human neuroblastoma tissue with characteristics similar to neurons. Collectively, these results suggested that NMB restored erectile function via protection of the cavernous body from injury and stimulation of the survival of the associated nerves. NMB may be useful to treat ED patients with a severely damaged cavernous body.

Hypoxia regulates the expression of the neuromedin B receptor through a mechanism dependent on hypoxia-inducible factor-1α

The neuromedin B receptor (NMB-R), a member of the mammalian bombesin receptor family, is frequently overexpressed in various tumors. In the present study, we found that exposure to hypoxic conditions increases the levels of NMBR mRNA and protein in breast cancer cells, which are tightly regulated by hypoxia-inducible factor-1α (HIF-1α). We confirmed the effect of HIF-1α on NMBR transcription by performing an NMBR promoter-driven reporter assay and then identified a functional hypoxia-responsive element (HRE) in the human NMBR promoter region. Further, the binding of HIF-1α to the NMBR promoter was corroborated by electrophoretic mobility shift and chromatin immunoprecipitation assays, which showed that HIF-1α specifically and directly bound to the NMBR promoter in response to hypoxia. Immunohistochemical analysis of a xenograft and a human breast cancer tissue array revealed a significant correlation between NMB-R and HIF-1α expression. Taken together, our findings indicate that hypoxia induces NMB-R expression through a novel mechanism to regulate HIF-1α expression in breast cancer cells.

The anti-angiogenic activities of glycyrrhizic acid in tumor progression

Glycyrrhizic acid (GA) is the bioactive compound of licorice and has been used as a herbal medicine because of its anti-viral, anti-cancer, and anti-inflammatory properties. This study was designed to investigate the effects of GA on tumor growth, angiogenesis, and the mechanisms underlying the anti-angiogenic activities of GA. We observed that GA inhibited tumor growth and angiogenesis in mice. GA decreased angiogenic activities, such as the migration, invasion, and tube formation of endothelial cells. We also demonstrated that GA reduced the production of reactive oxygen species and activation of ERK in endothelial cells. Our findings suggest that GA is a promising anti-angiogenic therapeutic agent that targets the ERK pathway. Considering that angiogenesis is highly stimulated in the majority of cancers, GA could offer a potent therapeutic agent for cancer.

Hyaluronic acid promotes angiogenesis by inducing RHAMM-TGFβ receptor interaction via CD44-PKCδ

Hyaluronic acid (HA) has been shown to promote angiogenesis. However, the mechanism behind this effect remains largely unknown. Therefore, in this study, the mechanism of HA-induced angiogenesis was examined. CD44 and PKCδ were shown to be necessary for induction of the receptor for HA-mediated cell motility (RHAMM), a HA-binding protein. RHAMM was necessary for HA-promoted cellular invasion and endothelial cell tube formation. Cytokine arrays showed that HA induced the expression of plasminogen activator-inhibitor-1 (PAI), a downstream target of TGFβ receptor signaling. The induction of PAI-1 was dependent on CD44 and PKCδ. HA also induced an interaction between RHAMM and TGFβ receptor I, and induction of PAI-1 was dependent on RHAMM and TGFβ receptor I. Histone deacetylase 3 (HDAC3), which is decreased by HA via rac1, reduced induction of plasminogen activator inhibitor-1 (PAI-1) by HA. ERK, which interacts with RHAMM, was necessary for induction of PAI-1 by HA. Snail, a downstream target of TGFβ signaling, was also necessary for induction of PAI-1. The down regulation of PAI-1 prevented HA from enhancing endothelial cell tube formation and from inducing expression of angiogenic factors, such as ICAM-1, VCAM-1 and MMP-2. HDAC3 also exerted reduced expression of MMP-2. In this study, we provide a novel mechanism of HA-promoted angiogenesis, which involved RHAMM-TGFβRI signaling necessary for induction of PAI-1.

Neuromedin B and its receptor influence the activity of myometrial primary cells in vitro through regulation of Il6 expression via the Rela/p65 pathway in mice

The neuromedin B receptor (Nmbr) is an important physiological regulator of spontaneous activities and stress responses through different cascades as well as its autocrine and paracrine effects. Previous studies have revealed that neuromedin B (Nmb) and its receptor signal via the Rela (also known as p65)/Il6 pathway in a mouse model of pregnancy. This study investigated the mechanism of Nmbr signaling via the Rela/p65-Il6 pathway and regulation of the concentration of intracellular free calcium ([Ca(2+)](i)) during the onset of labor in primary mouse myometrial cell cultures isolated from mice in term labor. Data demonstrated Nmbr agonist-mediated upregulation of the DNA binding activity of Rela/p65, Il6 expression, and [Ca(2+)](i) in a concentration-dependent manner. Furthermore, a significant correlation was observed between DNA binding activity of Rela/p65 and Il6 expression. Moreover, this up-regulation was blocked by Nmbr and Rela/p65 knockdown, achieved by RNA interference (RNAi) technology. No significant differences were identified in the inhibition of Il6 expression as a result of Nmbr or Rela/p65 knockdown. However, significant differences were observed between the [Ca(2+)](i) in Rela/p65-specific group and that in the Nmbr-specific small interfering RNA (siRNA)-treated groups. These data demonstrated that the Nmb/Nmbr interaction in pregnant myometrial primary cells in vitro predominantly influenced uterine activity through regulation of Il6 expression via the Rela/p65 pathway, although the effects of Nmbr on [Ca(2+)](i) involved several pathways that remain to be elucidated.

Discriminating different cancer cells using a zebrafish in vivo assay

Despite the expanded understanding of tumor angiogenesis phenomenon and how it impacts cancer treatment outcomes, we have yet to develop a robust assay that can quickly, easily, and quantitatively measure tumor-induced angiogenesis. Since the zebrafish/tumor xenograft represents an emerging tool in this regard, the present study strives to capitalize on the ease, effectiveness, and the adaptability of this model to quantify tumor angiogenesis. In order to test a range of responses, we chose two different tumorigenic cell lines, the human non-small cell lung carcinoma (H1299) and the mouse lung adenocarcinoma (CL13). Non-tumorigenic 3T3-L1 cells served as negative control. The cells were grafted near to the perivitelline space of the zebrafish embryos and the angiogenic response was analyzed using whole-mount alkaline phosphatase (AP) vessel staining and fluorescence microscopy. Angiogenic activity was scored based on the length and number of the newly formed ectopic vessels and the percentage of embryos with ectopic vessels. At 2 day-post-implantation, we detected a significant increase in the length and number of ectopic vessels with H1299 cell implantation compared to CL13 cell transplantation, both are higher than 3T3-L1 control. We also observed a significantly higher percentage of embryos with ectopic vessels with H1299 and CL13 transplantation compared to the 3T3-L1 control, but this parameter is not as robust and reliable as measuring the length and number of ectopic vessels. Furthermore, the systemic exposure of zebrafish embryos to an anti-angiogenesis drug (PTK 787, inhibitor of vascular endothelial growth factor receptor tyrosine kinase) inhibited tumor-induced angiogenesis, suggesting that the assay can be used to evaluate anti-angiogenic drugs. This study implicates the feasibility of using zebrafish xenotransplantation to perform quantitative measurement of the angiogenic activity of cancer cells which can be further extended to measure cancer cell metastasis. This assay represents not only the useful test for patient diagnosis, but also has the potential for evaluating anti-cancer drugs treatment.

Four genetic loci influencing electrocardiographic indices of left ventricular hypertrophy

BACKGROUND

Presence of left ventricular hypertrophy on an ECG (ECG-LVH) is widely assessed clinically and provides prognostic information in some settings. There is evidence for significant heritability of ECG-LVH. We conducted a large-scale gene-centric association analysis of 4 commonly measured indices of ECG-LVH.

METHODS AND RESULTS

We calculated the Sokolow-Lyon index, Cornell product, 12-lead QRS voltage sum, and 12-lead QRS voltage product in 10 256 individuals from 3 population-based cohorts and typed their DNA using a customized gene array (the Illumina HumanCVD BeadChip 50K array), containing 49 094 genetic variants in ≈2100 genes of cardiovascular relevance. We followed-up promising associations in 11 777 additional individuals. We identified and replicated 4 loci associated with ECG-LVH indices: 3p22.2 (SCN5A, rs6797133, P=1.22 × 10(-7)) with Cornell product and 12q13.3 (PTGES3, rs2290893, P=3.74 × 10(-8)), 15q25.2 (NMB, rs2292462, P=3.23 × 10(-9)), and 15q26.3 (IGF1R, rs4966014, P=1.26 × 10(-7)) with the 12-lead QRS voltage sum. The odds ratio of being in the top decile for the 12-lead QRS voltage sum for those carrying 6 trait-raising alleles at the 12q13.3, 15q25.2, and 15q26.3 loci versus those carrying 0 to 1 alleles was 1.60 (95% CI: 1.20 to 2.29). Lead single-nucleotide polymorphisms at the 12q13.3 and 15q25.2 loci showed significant expression quantitative trait loci effects in monocytes.

CONCLUSIONS

These findings provide novel insights into the genetic determination of ECG-LVH. The findings could help to improve our understanding of the mechanisms determining this prognostically important trait.

Neuromedin B receptor antagonist suppresses tumor angiogenesis and tumor growth in vitro and in vivo

Neuromedin B (NMB), a member of the mammalian bombesin-like peptide family, and its receptor were aberrantly expressed in vascularized solid tumors. Here, the NMB receptor (NMB-R) antagonist PD168368 specifically inhibited both NMB-induced in vivo and in vitro angiogenesis. In addition, PD168368 showed growth inhibitory effects on MDA-MB-231 breast cancer cells by inducing cell cycle arrest and apoptosis. Furthermore, PD168368 effectively suppressed tumor growth in a xenograft model of breast tumor in vivo. Overall, NMB-R antagonist exhibited a significant antitumor activity by simultaneously inhibiting neovascularization and cancer cell growth, thereby suggesting that NMB-R could be a potential therapeutic target for cancer treatment.

Biology of mammalian bombesin-like peptides and their receptors

PURPOSE OF REVIEW

This review will highlight recent advances in the understanding of mammalian bombesin receptor-related pathophysiological roles in disease states and new insights into bombesin receptor pharmacology.

RECENT FINDINGS

Studies regarding bombesin-like peptides and mammalian bombesin receptor functions have demonstrated significant biological impact on a broad array of physiological and pathophysiological conditions. Pharmacological experiments in vitro and in vivo as well as utilization of genetic rodent models of the gastrin-releasing peptide receptor (GRP-R/BB2) and neuromedin B receptor (NMB-R/BB1) further delineated roles in memory and fear behavior, inhibition of tumor cell growth, mediating signals for pruritus and male reproductive behavior. All three mammalian bombesin receptors were shown to possess some role in the regulation of energy balance. Novel synthesis of selective high affinity agonists and antagonists of the orphan bombesin receptor subtype-3 (BRS-3/BB3) has been accomplished and will facilitate further studies using animal model systems.

SUMMARY

Mammalian bombesin receptors participate in the regulation of energy homeostasis and may represent an attractive target for pharmacological treatment of obesity and certain eating disorders. Novel pharmacological insights of bombesin-like peptides and the interaction with their respective receptors have been elucidated to aid future treatment and imaging of epithelial cell-derived tumors.

Paradoxical effects of ethoxidine, a topoisomerase I inhibitor, in the cellular processes leading to angiogenesis on endothelial cells

Angiogenesis, a critical step in tumorigenesis, is defined by different processes leading to neovascularization. Topoisomerase I (Top I) is the target for some of the most successful anticancer drugs that decrease tumor cell proliferation. Ethoxidine, a benzo[c]phenanthridines derivative, camptothecin analogue, has been identified as a potent inhibitor of Top I in various cancer cell lines. This study was aimed to investigate the impact of ethoxidine on angiogenesis and cellular processes including migration, proliferation and adhesion since these processes play an important role in tumor progression. Ethoxidine was incubated for 24 h at low (10⁻⁹ M) and high (10⁻⁵ M) concentrations on two types of human endothelial cells: EaHy.926 and human umbilical endothelial cells. Vascular endothelial growth factor (VEGF, 20 ng/ml) was used as a positive control. Ethoxidine at low concentration increased cell proliferation and migration that was associated with enhanced metalloproteinase 2 expression and activity, whereas high concentration of ethoxidine inhibited all of these effects. The two concentrations of ethoxidine did not affect endothelial cell adhesion. Low concentration of ethoxidine increased VEGF expression and endothelial nitric oxide (NO) synthase expression, NO and superoxide anion productions, whereas high concentration of ethoxidine did not induce any effect. Taken together, the present results highlight paradoxical effects of ethoxidine on angiogenesis depending on the concentration used. This study underscores that in addition to its anti-proliferative properties, ethoxidine may affect the generation of vascular network in tumorigenesis.