Endothelial monocyte activating polypeptide II interferes with VEGF-induced proangiogenic signaling

In-depth proteomics characterization of ∆Np73 effectors identifies key proteins with diagnostic potential implicated in lymphangiogenesis, vasculogenesis and metastasis in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer‐related death worldwide. Alterations in proteins of the p53‐family are a common event in CRC. ΔNp73, a p53‐family member, shows oncogenic properties and its effectors are largely unknown. We performed an in‐depth proteomics characterization of transcriptional control by ∆Np73 of the secretome of human colon cancer cells and validated its clinical potential. The secretome was analyzed using high‐density antibody microarrays and stable isotopic metabolic labeling. Validation was performed by semiquantitative PCR, ELISA, dot‐blot and western blot analysis. Evaluation of selected effectors was carried out using 60 plasma samples from CRC patients, individuals carrying premalignant colorectal lesions and colonoscopy‐negative controls. In total, 51 dysregulated proteins were observed showing at least 1.5‐foldchange in expression. We found an important association between the overexpression of ∆Np73 and effectors related to lymphangiogenesis, vasculogenesis and metastasis, such as brain‐derived neurotrophic factor (BDNF) and the putative aminoacyl tRNA synthase complex‐interacting multifunctional protein 1 (EMAP‐II)–vascular endothelial growth factor C–vascular endothelial growth factor receptor 3 axis. We further demonstrated the usefulness of BDNF as a potential CRC biomarker able to discriminate between CRC patients and premalignant individuals from controls with high sensitivity and specificity.

Targeted FGFR/VEGFR/PDGFR inhibition with dovitinib enhances the effects of nab-paclitaxel in preclinical gastric cancer models

Standard chemotherapy regimens for gastric adenocarcinoma (GAC) have limited efficacy and considerable toxicity profiles. Nab-paclitaxel has shown promising antitumor benefits in previous GAC preclinical studies. Dovitinib inhibits members of the receptor tyrosine kinase family including FGFR, VEGFR and PDGFR, and has exhibited antitumor effects in many solid tumors including GAC. Based on the antimitotic, antistromal and EPR effects of nab-paclitaxel, we investigated augmentation of nab-paclitaxel response by dovitinib in multiple GAC preclinical models. In MKN-45 subcutaneous xenografts, inhibition in tumor growth by nab-paclitaxel and dovitinib was 75% and 76%, respectively. Dovitinib plus nab-paclitaxel had an additive effect on tumor growth inhibition and resulted in tumor regression (85% of its original value). Dovitinib monotherapy resulted in minimal improvement in animal survival (25 days) compared to control (23 days), while nab-paclitaxel monotherapy or dovitinib plus nab-paclitaxel combination therapy led to a clinically significant lifespan extension of 83% (42 days) and 187% (66 days), respectively. IHC analysis of subcutaneous tumors exhibited reduced tumor cell proliferation and tumor vasculature by dovitinib. In vitro studies demonstrated that dovitinib and nab-paclitaxel individually reduced tumor cell proliferation, with an additive effect from combination therapy. Immunoblot analyses of MKN-45 and KATO-III cells revealed that dovitinib decreased phospho-FGFR, phospho-AKT, phospho-ERK, phospho-p70S6K, phospho-4EBP1, Bcl-2 and increased cleaved PARP-1, cleaved-caspase-3, p27, Bax, Bim, with an additive effect from combination therapy. These results demonstrate that the FGFR/VEGFR/PDGFR inhibitor, dovitinib, has the potential to augment the antitumor effects of nab-paclitaxel, with implications for use in the advancement of clinical GAC therapy.

Changes in the expression of endothelial monocyte‑activating polypeptide II in the rat hippocampus following status epilepticus

Endothelial monocyte-activating polypeptide II (EMAP II) is a sensitive marker of neurotoxic injury, the expression of which increases significantly under conditions of stress, such as hypoxia or apoptosis. Studies have confirmed the extensive apoptosis of nerve cells in the brain following status epilepticus (SE), and the occurrence of SE can confer a hypoxic state on cells. The purpose of the present study was to observe the changes in the expression of EMAP II, and in the numbers and tight junction protein levels of micro-vascular endothelial cells in the hippocampus of rats with pilocarpine-induced SE. The protein expression levels of EMAP II, CD31, zonula occludens 1 (ZO-1) and occludin in the hippocampus were determined by immunofluorescence and western blot analyses. It was found that almost 75.6% of the rats in the SE group developed Racine stage IV-V seizures at approximately 44.7±18.8 min after the pilocarpine administration, and the 24-h mortality rate was almost 10.4%. The weight of the rats in the SE group was significantly decreased within 24 h following SE. Immunofluorescence staining revealed a low EMAP II expression in the hippo-campus of the rats in the control group; however, the numbers of EMAP II-positive cells were significantly increased in the SE group from 2 h to 21 days. The trend of EMAP II protein expression was consistent with that obtained with immunofluorescence staining. The numbers of CD31-positive microvascular endothelial cells were significantly increased from 24 h to 21 days compared with the levels in the control group. The protein expression of ZO-1 and occludin was most significantly decreased in the SE group. On the whole, the present study demonstrated that the expression of EMAP II in the rat hippocampus was upregulated in the SE model, which may promote angiogenesis and alter the TJ integrity of brain microvascular endothelial cells, with an increased number of CD31-positive microvascular endothelial cells and a decreased expression of ZO-1 and occludin.

Mechanistic regulation of SPHK1 expression and translocation by EMAP II in pulmonary smooth muscle cells

Phosphorylation of sphingosine by sphingosine kinase 1 (SPHK1) produces the bioactive sphingolipid sphingosine-1-phosphate (S1P), a microvascular and immuno-modulator associated with vascular remodeling in pulmonary arterial hypertension (PAH). The low intracellular concentration of S1P is under tight spatial-temporal control. Molecular mechanisms that mediate S1P burden and S1P regulation of vascular remodeling are poorly understood. Similarities between two early response pro-inflammatory cytokine gene transcript activation profiles, S1P and Endothelial Monocyte Activating Polypeptide II (EMAP II), suggested a strategic link between their signaling pathways. We determined that EMAP II triggers a bimodal phosphorylation, transcriptional regulation and membrane translocation of SPHK1 through a common upstream process in both macrophages and pulmonary artery smooth muscle cells (PASMCs). EMAP II initiates a dual function of ERK1/2: phosphorylation of SPHK1 and regulation of the transcription factor EGR1 that induces expression of SPHK1. Activated ERK1/2 induces a bimodal phosphorylation of SPHK1 which reciprocally increases S1P levels. This identified common upstream signaling mechanism between a protein and a bioactive lipid initiates cell specific downstream signaling representing a multifactorial mechanism that contributes to inflammation and PASMC proliferation which are cardinal histopathological phenotypes of PAH.

A distinct transcriptional profile in response to endothelial monocyte activating polypeptide II is partially mediated by JAK-STAT3 in murine macrophages

Macrophages are important responders to environmental changes such as secreted factors. Among the secreted factors in injured tissues, the highly conserved endothelial monocyte activating polypeptide II (EMAP II) has been characterized to limit vessel formation, to be locally expressed near sites of injury labeling it a "find-me" signal, and to recruit macrophages and neutrophils. The molecular mechanisms mediated by EMAP II within macrophages once they are recruited are unknown. In this study, using a model of partially activated, recruited thioglycollate-elicited peritoneal macrophages, a transient, transcription profile of key functional genes in macrophages exposed to EMAP II was characterized. We found that EMAP II-mediated changes were elicited mainly through signal transducer and activator of transcription 3 (STAT3) as evidenced by increased Y705 phosphorylation and changes in activity and upstream of it, Janus associated kinase (JAK)1/2 upstream. Both inhibition of JAK1/2 and knockdown of Stat3 abrogated a subset of genes that are upregulated by EMAP II. Our results identify a rapid EMAP II-mediated STAT3 activation that coincides with altered pro- and anti-inflammatory gene expression in macrophages.

Voices from the dead: The complex vocabulary and intricate grammar of dead cells

Of the roughly one million cells per second dying throughout the body, the vast majority dies by apoptosis, the predominant form of regulated cell death in higher organisms. Long regarded as mere waste, apoptotic cells are now recognized as playing a prominent and active role in homeostatic maintenance, especially resolution of inflammation, and in the sculpting of tissues during development. The activities associated with apoptotic cells are continually expanding, with more recent studies demonstrating their ability to modulate such vital functions as proliferation, survival, differentiation, metabolism, migration, and angiogenesis. In each case, the role of apoptotic cells is active, exerting their effects via new activities acquired during the apoptotic program. Moreover, the capacity to recognize and respond to apoptotic cells is not limited to professional phagocytes. Most, if not all, cells receive and integrate an array of signals from cells dying in their vicinity. These signals comprise a form of biochemical communication. As reviewed in this chapter, this communication is remarkably sophisticated; each of its three critical steps-encoding, transmission, and decoding of the apoptotic cell's "message"-is endowed with exquisite robustness. Together, the abundance and intricacy of the variables at each step comprise the vocabulary and grammar of the language by which dead cells achieve their post-mortem voice. The combinatorial complexity of the resulting communication network permits dying cells, through the signals they emit and the responses those signals elicit, to partake of an expanded role in homeostasis, acting as both sentinels of environmental change and agents of adaptation.

Inhibition of the MEK/ERK pathway augments nab-paclitaxel-based chemotherapy effects in preclinical models of pancreatic cancer

Nab-paclitaxel (NPT) combination with gemcitabine (Gem) represents the standard chemotherapy for pancreatic ductal adenocarcinoma (PDAC). Genetic alterations of the RAS/RAF/MEK/ERK (MAPK) signaling pathway yielding constitutive activation of the ERK cascade have been implicated as drivers of PDAC. Inhibition of downstream targets in the RAS-MAPK cascade such as MEK remains a promising therapeutic strategy. The efficacy of trametinib (Tra), a small molecule inhibitor of MEK1/2 kinase activity, in combination with nab-paclitaxel-based chemotherapy was evaluated in preclinical models of PDAC. The addition of trametinib to chemotherapy regimens showed a trend for an additive effect on tumor growth inhibition in subcutaneous AsPC-1 and Panc-1 PDAC xenografts. In a peritoneal dissemination model, median animal survival compared to controls (20 days) was increased after therapy with NPT (33 days, a 65% increase), Tra (31 days, a 55% increase), NPT+Tra (37 days, a 85% increase), NPT+Gem (39 days, a 95% increase) and NPT+Gem+Tra (49 days, a 145% increase). Effects of therapy on intratumoral proliferation and apoptosis corresponded with tumor growth inhibition. Trametinib effects were specifically accompanied by a decrease in phospho-ERK and an increase in cleaved caspase-3 and cleaved PARP-1 proteins. These findings suggest that the effects of nab-paclitaxel-based chemotherapy can be enhanced through specific inhibition of MEK1/2 kinase activity, and supports the clinical application of trametinib in combination with standard nab-paclitaxel-based chemotherapy in PDAC patients.

Endothelial-Monocyte Activating Polypeptide II Suppresses the In Vitro Glioblastoma-Induced Angiogenesis by Inducing Autophagy

The obstacle in delivering therapeutics to glioblastoma (GBM) is tumor-induced angiogenesis which leads to the formation of abnormal vessels and a dysfunctional blood-tumor barrier. Here, we elucidated the effect of endothelial-monocyte activating polypeptide II (EMAP II) on the GBM-induced angiogenesis as well as its potential mechanisms. Our results proved that EMAP II inhibited the viability, mitochondrial membrane potential, migration and tube formation of GBM-induced endothelial cells (GECs) by inducing cell autophagy, demonstrated by cell viability assay, JC-1 staining assay, transwell assay and tube formation assay, respectively. Cell autophagy was induced by EMAP II through the observation of autophagic vacuoles formation and the up-regulation of microtubule-associated protein-1 light chain-3 (LC3)-II and p62/SQSTM1 expression, demonstrated by transmission electron microscopy analysis, immunofluorescence assay and Western blot assay. The activity of PI3K/AKT/mTOR signal pathway could be inhibited by the EMAP II treatment. Furthermore, unfolded protein response (UPR)-related proteins (GRP78, eIF2α, and CHOP) were up-regulated by EMAP II, which suggest that GECs exposed to EMAP II experienced endoplasmic reticulum stress. Further, mechanistic investigations found that EMAP II reduced the miR-96 expression which could directly target the 3′-UTR of these UPR-related proteins, and over-expression of miR-96 inhibited LC3 and p62/SQSTM1 expression by down-regulating these UPR-related proteins in GECs. Moreover, the combination of EMAP II with miR-96 inhibitor showed the inhibitory effect on the viability, migration, and in vitro tube formation of GECs, which are critical for angiogenesis. Taken together, we have demonstrated the fact that EMAP II resulted in the decreased GBM-induced angiogenesis by inducing autophagy, which might contribute to establishing potential strategies for human GBM treatment.

Augmentation of response to nab-paclitaxel by inhibition of insulin-like growth factor (IGF) signaling in preclinical pancreatic cancer models

Nab-paclitaxel has recently shown greater efficacy in pancreatic ductal adenocarcinoma (PDAC). Insulin like growth factor (IGF) signaling proteins are frequently overexpressed in PDAC and correlate with aggressive tumor phenotype and poor prognosis. We evaluated the improvement in nab-paclitaxel response by addition of BMS-754807, a small molecule inhibitor of IGF-1R/IR signaling, in preclinical PDAC models. In subcutaneous xenografts using AsPC-1 cells, average net tumor growth in different therapy groups was 248.3 mm3 in controls, 42.4 mm3 after nab-paclitaxel (p = 0.002), 93.3 mm3 after BMS-754807 (p = 0.01) and 1.9 mm3 after nab-paclitaxel plus BMS-754807 (p = 0.0002). In subcutaneous xenografts using Panc-1 cells, average net tumor growth in different therapy groups was: 294.3 mm3 in controls, 23.1 mm3 after nab-paclitaxel (p = 0.002), 118.2 mm3 after BMS-754807 (p = 0.02) and -87.4 mm3 (tumor regression) after nab-paclitaxel plus BMS-754807 (p = 0.0001). In peritoneal dissemination model using AsPC-1 cells, median animal survival was increased compared to controls (21 days) after therapy with nab-paclitaxel (40 days, a 90% increase, p = 0.002), BMS-754807 (27 days, a 29% increase, p = 0.01) and nab-paclitaxel plus BMS-754807 (47 days, a 124% increase, p = 0.005), respectively. Decrease in proliferation and increase in apoptosis by nab-paclitaxel and BMS-754807 therapy correlated with their in vivo antitumor activity. In vitro analysis revealed that the addition of IC25 dose of BMS-754807 decreased the nab-paclitaxel IC50 of PDAC cell lines. BMS-754807 therapy decreased phospho-IGF-1R/IR and phospho-AKT expression, and increased cleavage of caspase-3 and PARP-1. These results support the potential of BMS-754807 in combination with nab-paclitaxel as an effective targeting option for pancreatic cancer therapy.

Endothelial Progenitor Cell Migration-Enhancing Factors in the Secretome of Placental-Derived Mesenchymal Stem Cells

Therapeutic potentials of mesenchymal stem cells (MSCs) depend largely on their ability to secrete cytokines or factors that modulate immune response, enhance cell survival, and induce neovascularization in the target tissues. We studied the secretome profile of gestational tissue-derived MSCs and their effects on functions of endothelial progenitor cells (EPCs), another angiogenic cell type that plays an important role during the neovascularization. MSCs derived from placental tissues (PL-MSCs) significantly enhanced EPC migration while BM-MSCs, which are the standard source of MSCs for various clinical applications, did not. By using protein fractionation and mass spectrometry analysis, we identified several novel candidates for EPC migration enhancing factor in PL-MSCs secretome that could be used to enhance neovascularization in the injured/ischemic tissues. We recommend that the strategy developed in our study could be used to systematically identify therapeutically useful molecules in the secretomes of other MSC sources for the clinical applications.

SERUM LEVELS OF ENDOTHELIAL MONOCYTE ACTIVATING PEPTIDE II IN TYPE 1 DIABETES

Was investigated serum level of endothelial monocyte activating peptide II (EMAP-II) and endothelium-dependent dilatation in type 1 diabetes and possible relation between those. We found an increase serum level of EMAP-II and decrease of endothelium-dependent dilatation in type 1 diabetes. It was significant correlation between EMAP-II and HbAc1, blood glucose, total cholesterol, LDL, triglycerides and inverse correlation between EMAP-II and HDL, endotheliumdependent dilatation. The revealed change of EMAP-II serum level reflects an endothelial dysfunction in type 1 diabetes, alteration of carbohydrate and lipid metabolism could influence of this pathway.

Endothelial monocyte activating polypeptide II in children and adolescents with type 1 diabetes mellitus: Relation to micro-vascular complications

OBJECTIVES

Endothelial monocyte-activating polypeptide II (EMAP II) is a multifunctional polypeptide with proinflammatory and antiangiogenic activity. Hyperglycemia and dyslipidemia appears to be significant factors contributing to increased EMAP-II levels. We determined serum EMAP II in children and adolescents with type 1 diabetes as a potential marker for micro-vascular complications and assessed its relation to inflammation and glycemic control.

METHODS

Eighty children and adolescents with type 1 diabetes were divided into 2 groups according to the presence of micro-vascular complications and compared with 40 healthy controls. High-sensitivity C-reactive protein (hs-CRP), hemoglobin A1c (HbA1c) and EMAP II levels were assessed.

RESULTS

Serum EMAP II levels were significantly increased in patients with micro-vascular complications (1539 ± 321.5 pg/mL) and those without complications (843.6 ± 212.6 pg/mL) compared with healthy controls (153.3 ± 28.3 pg/mL; p<0.001). EMAP II was increased in patients with microalbuminuria than normoalbuminuric group (p<0.001). Significant positive correlations were found between EMAP II levels and body mass index, fasting blood glucose, HbA1c, serum creatinine, triglycerides, total cholesterol, urinary albumin creatinine ratio (UACR) and hs-CRP (p<0.05). A cutoff value of EMAP II at 1075 pg/mL could differentiate diabetic patients with and without micro-vascular complications with a sensitivity of 93% and specificity of 82%.

CONCLUSIONS

We suggest that EMAP II is elevated in type 1 diabetic patients, particularly those with micro-vascular complications. EMAP II levels are related to inflammation, glycemic control, albuminuria level of patients and the risk of micro-vascular complications.

Differential effects of tetrahydropyridinol derivatives on β-catenin signaling and invasion in human hepatocellular and breast carcinoma cells

In continuation of previous efforts to investigate the biological potency of tetrahydropyridinol derivatives, the present study synthesized three target compounds: N-(bromoacetyl)-3-carboxyethyl-2,6-diphenyl-4-O-(pentafluorobenzoyl)-Δ3-tetra-hydropyridine (5a), N-(chloroacetyl)-3-carboxyethyl-2,6-diphenyl-4-O-(pentafluorobenzoyl)-Δ3-tetrahydropyridine (5b) and N-(2-bromopropanoyl)-3-carboxyethyl-2,6-diphenyl-4-O-(pentafluorobenzoyl)-Δ3-tetrahydropyridine (5c), and examined their anticancer potency. Experiments were performed using the Sk-Hep1 and Hep3B human hepatocellular carcinoma cell lines and MDA-MB-231 breast adenocarcinoma cell line. Among the three compounds, 5a and 5b were comparably and significantly cytotoxic to the Sk-Hep1, Hep3B and MDA-MB-231 cells. The highest level of cytotoxicity was detected in theSk-Hep1 cells with half maximal inhibitory concentrations for compounds 5a and 5b at 12 and 6 µM, respectively. These two compounds induced cell cycle arrest in the Sk-Hep1 and MDA-MB-231 cells through the downregulation of β-catenin and upregulation of glycogen synthase kinase-3β and E-cadherin. By contrast, 5a and 5b induced G1 arrest in the Hep3B cells by modulating the p21 and p27 cell cycle regulatory molecules and cyclin-dependent kinase 2. In addition, 5a and 5b significantly inhibited the invasion of Sk-Hep1 and MDA-MB-231 cells. These results suggested that the 5a and 5b compounds induce cell cycle arrest by suppressing Wnt/β-catenin signaling in highly invasive Sk-Hep1 and MDA-MB-231 cells, and by inducing p53 independent cell cycle arrest in Hep3B cells.

The N terminus of pro-endothelial monocyte-activating polypeptide II (EMAP II) regulates its binding with the C terminus, arginyl-tRNA synthetase, and neurofilament light protein

Pro-endothelial monocyte-activating polypeptide II (EMAP II), one component of the multi-aminoacyl tRNA synthetase complex, plays multiple roles in physiological and pathological processes of protein translation, signal transduction, immunity, lung development, and tumor growth. Recent studies have determined that pro-EMAP II has an essential role in maintaining axon integrity in central and peripheral neural systems where deletion of the C terminus of pro-EMAP II has been reported in a consanguineous Israeli Bedouin kindred suffering from Pelizaeus-Merzbacher-like disease. We hypothesized that the N terminus of pro-EMAP II has an important role in the regulation of protein-protein interactions. Using a GFP reporter system, we defined a putative leucine zipper in the N terminus of human pro-EMAP II protein (amino acid residues 1-70) that can form specific strip-like punctate structures. Through GFP punctum analysis, we uncovered that the pro-EMAP II C terminus (amino acids 147-312) can repress GFP punctum formation. Pulldown assays confirmed that the binding between the pro-EMAP II N terminus and its C terminus is mediated by a putative leucine zipper. Furthermore, the pro-EMAP II 1-70 amino acid region was identified as the binding partner of arginyl-tRNA synthetase, a polypeptide of the multi-aminoacyl tRNA synthetase complex. We also determined that the punctate GFP pro-EMAP II 1-70 amino acid aggregate colocalizes and binds to the neurofilament light subunit protein that is associated with pathologic neurofilament network disorganization and degeneration of motor neurons. These findings indicate the structure and binding interaction of pro-EMAP II protein and suggest a role of this protein in pathological neurodegenerative diseases.

Blockade of EMAP II protects cardiac function after chronic myocardial infarction by inducing angiogenesis

Promoting angiogenesis is a key therapeutic target for protection from chronic ischemic cardiac injury. Endothelial-Monocyte-Activating-Polypeptide-II (EMAP II) protein, a tumor-derived cytokine having anti-angiogenic properties in cancer, is markedly elevated following myocardial ischemia. We examined whether neutralization of EMAP II induces angiogenesis and has beneficial effects on myocardial function and structure after chronic myocardial infarction (MI). EMAP II antibody (EMAP II AB), vehicle, or non-specific IgG (IgG) was injected ip at 30 min and 3, 6, and 9 days after permanent coronary artery occlusion in mice. EMAP II AB, compared with vehicle or non-specific antibody, significantly, p<0.05, improved the survival rate after MI, reduced scar size and attenuated the development of heart failure, i.e., left ventricular ejection fraction was significantly higher in EMAP II AB group, fibrosis was reduced by 24%, and importantly, more myocytes were alive in EMAP II AB group in the infarct area. In support of an angiogenic mechanism, capillary density (193/HPF vs. 172/HPF), doubling of the number of proliferating endothelial cells, and angiogenesis related biomarkers were upregulated in mice receiving EMAP II AB treatment as compared to IgG. Furthermore, EMAP II AB prevented EMAP II protein inhibition of in vitro tube formation in HUVECs. We conclude that blockade of EMAP II induces angiogenesis and improves cardiac function following chronic MI, resulting in reduced myocardial fibrosis and scar formation and increased capillary density and preserved viable myocytes in the infarct area.

Regulation of angiogenesis by aminoacyl-tRNA synthetases

In addition to their canonical roles in translation the aminoacyl-tRNA synthetases (ARSs) have developed secondary functions over the course of evolution. Many of these activities are associated with cellular survival and nutritional stress responses essential for homeostatic processes in higher eukaryotes. In particular, six ARSs and one associated factor have documented functions in angiogenesis. However, despite their connection to this process, the ARSs are mechanistically distinct and exhibit a range of positive or negative effects on aspects of endothelial cell migration, proliferation, and survival. This variability is achieved through the appearance of appended domains and interplay with inflammatory pathways not found in prokaryotic systems. Complete knowledge of the non-canonical functions of ARSs is necessary to understand the mechanisms underlying the physiological regulation of angiogenesis.

Nintedanib, a triple angiokinase inhibitor, enhances cytotoxic therapy response in pancreatic cancer

Angiogenesis remains a sensible target for pancreatic ductal adenocarcinoma (PDAC) therapy. VEGF, PDGF, FGF and their receptors are expressed at high levels and correlate with poor prognosis in human PDAC. Nintedanib is a triple angiokinase inhibitor that targets VEGFR1/2/3, FGFR1/2/3 and PDGFRα/β signaling. We investigated the antitumor activity of nintedanib alone or in combination with the cytotoxic agent gemcitabine in experimental PDAC. Nintedanib inhibited proliferation of cells from multiple lineages found in PDAC, with gemcitabine enhancing inhibitory effects. Nintedanib blocked PI3K/MAPK activity and induced apoptosis in vitro and in vivo. In a heterotopic model, net local tumor growth compared to controls (100%) was 60.8 ± 10.5% in the gemcitabine group, -2.1 ± 9.9% after nintedanib therapy and -12.4 ± 16% after gemcitabine plus nintedanib therapy. Effects of therapy on intratumoral proliferation, microvessel density and apoptosis corresponded with tumor growth inhibition data. In a PDAC survival model, median animal survival after gemcitabine, nintedanib and gemcitabine plus nintedanib was 25, 31 and 38 days, respectively, compared to 16 days in controls. The strong antitumor activity of nintedanib in experimental PDAC supports the potential of nintedanib-controlled mechanisms as targets for improved clinical PDAC therapy.

Kisspeptin effect on endothelial monocyte activating polypeptide II (EMAP-II)-associated lymphocyte cell death and metastases in colorectal cancer patients

Kisspeptin is an antimetastatic agent in some cancers that has also been associated with lymphoid cell apoptosis, a phenomenon favoring metastases. Our aim was to determine the association of kisspeptin with lymphocyte apoptosis and the presence of metastases in colorectal cancer patients. Blood was drawn from 69 colon cancer patients and 20 healthy volunteers. Tissue specimens from healthy and pathological tissue were immunohistochemically analyzed for kisspeptin and endothelial monocyte activating polypeptide II (EMAP-II) expression. Blood EMAP-II and soluble Fas ligand (sFasL) levels were examined by an enzyme-linked immunosorbent assay method. The kisspeptin and EMAP-II expression and secretion levels in the DLD-1 and HT-29 colon cancer cell lines were examined by quantitative real-time polymerase chain reaction, Western analysis and enzyme-linked immunosorbent assay, whereas lymphocyte viability was assessed by flow cytometry. The effect of kisspeptin on the viability of colon cancer cells was examined by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide]. Exogenous, synthetic and naturally produced, kisspeptin induces through the G-protein-coupled receptor 54 (GPR54; also known as the kisspeptin receptor) the EMAP-II expression and secretion in colon cancer cell lines, inducing in vitro lymphocyte apoptosis, as verified by the use of an anti-EMAP-II antibody. These results were reversed with the use of kisspeptin inhibitors and by kisspeptin-silencing experiments. Tumor kisspeptin expression was associated with the tumor EMAP-II expression (p < 0.001). Elevated kisspeptin and EMAP-II expression in colon cancer tissues was associated with lack of metastases (p < 0.001) in colon cancer patients. These data indicate the antimetastatic effect of tumor-elevated kisspeptin in colon cancer patients that may be mediated by the effect of kisspeptin on EMAP-II expression in colon cancer tumors in patients with normal serum EMAP-II levels. These findings provide new insight into the role of kisspeptin in the context of metastases in colon cancer patients.

Vascular mediators in chronic lung disease of infancy: role of endothelial monocyte activating polypeptide II (EMAP II)

Bronchopulmonary dysplasia (BPD) is a chronic lung disease of prematurity. Over the years, the BPD phenotype has evolved, but despite various advances in neonatal management approaches, the reduction in the BPD burden is minimal. With the advent of surfactant, glucocorticoids, and new ventilation strategies, BPD has evolved from a disease of structural injury into a new BPD, marked by an arrest in alveolar growth in the lungs of extremely premature infants. This deficient alveolar growth has been associated with a diminution of pulmonary vasculature. Several investigators have described the epithelial / vascular co-dependency and the significant role of crosstalk between vessel formation, alveologenesis, and lung dysplasia's; hence identification and study of factors that regulate pulmonary vascular emergence and inflammation has become crucial in devising effective therapeutic approaches for this debilitating condition. The potent antiangiogenic and proinflammatory protein Endothelial Monocyte Activating Polypeptide II (EMAP II) has been described as a mediator of pulmonary vascular and alveolar formation and its expression is inversely related to the periods of vascularization and alveolarization in the developing lung. Hence the study of EMAP II could play a vital role in studying and devising appropriate therapeutics for diseases of aberrant lung development, such as BPD. Herein, we review the vascular contribution to lung development and the implications that vascular mediators such as EMAP II have in distal lung formation during the vulnerable stage of alveolar genesis.

Enhancement of nab-paclitaxel antitumor activity through addition of multitargeting antiangiogenic agents in experimental pancreatic cancer

Nanoparticle albumin-bound paclitaxel (nab-paclitaxel, NPT) has recently shown efficacy in pancreatic ductal adenocarcinoma (PDAC). Targeting tumor angiogenesis is a sensible combination therapeutic strategy for cancer, including PDAC. We tested the hypothesis that NPT response in PDAC can be enhanced by the mechanistically different antiangiogenic agents bevacizumab (Bev) or sunitinib (Su), despite its inherently increased tumor penetration and drug delivery. Compared with controls (19 days), median animal survival was increased after NPT therapy (32 days, a 68% increase, P = 0.0008); other regimens with enhanced survival were NPT+Bev (38 days, a 100% increase, P = 0.0004), NPT+Su (37 days, a 95% increase, P = 0.0004), and NPT+Bev+Su (49 days, a 158% increase, P = 0.0001) but not bevacizumab, sunitinib, or Bev+Su therapy. Relative to controls (100 ± 22.8), percentage net local tumor growth was 28.2 ± 23.4 with NPT, 55.6 ± 18 (Bev), 38.8 ± 30.2 (Su), 11 ± 7.2 (Bev+Su), 32.8 ± 29.2 (NPT+Bev), 6.6 ± 10.4 (NPT+Su), and 13.8 ± 12.5 (NPT+Bev+Su). Therapeutic effects on intratumoral proliferation, apoptosis, microvessel density, and stromal density corresponded with tumor growth inhibition data. In AsPC-1 PDAC cells, NPT IC(50) was reduced >6-fold by the addition of sunitinib (IC(25)) but not by bevacizumab. In human umbilical vein endothelial cells (HUVEC), NPT IC(50) (82 nmol/L) was decreased to 41 nmol/L by bevacizumab and to 63 nmol/L by sunitinib. In fibroblast WI-38 cells, NPT IC(50) (7.2 μmol/L) was decreased to 7.8 nmol/L by sunitinib, but not by bevacizumab. These findings suggest that the effects of one of the most active cytotoxic agents against PDAC, NPT, can be enhanced with antiangiogenic agents, which clinically could relate to greater responses and improved antitumor results.

The dual PI3K/mTOR inhibitor NVP-BEZ235 enhances nab-paclitaxel antitumor response in experimental gastric cancer

Gastric cancer is the second most common cause of cancer-related deaths worldwide. Taxanes have shown therapeutic effects against gastric cancer while also activating the PI3K/mTOR signaling pathway. We investigated the effects of NVP-BEZ235 (BEZ235), a novel dual PI3K/mTOR inhibitor, alone and in combination with nanoparticle albumin-bound (nab)-paclitaxel in experimental gastric cancer. Cell proliferation and protein expression were measured by WST-1 assay and immunoblotting. Tumor growth and survival studies were performed in murine xenografts. Phosphorylated mTOR and 4E-BP1 levels were elevated in gastric cancer cells and tumor tissues by nab-paclitaxel. BEZ235 effectively inhibited cell proliferation in vitro and provided additive effects in combination with nab-paclitaxel. Furthermore, BEZ235 blocked the activated PI3K/mTOR pathway either alone or in combination with nab-paclitaxel in gastric cancer cells. BEZ235 and nab-paclitaxel caused an increase in PARP-1 and caspase-3 cleavage. Net local tumor growth inhibition for the BEZ235, nab-paclitaxel and BEZ235+nab-paclitaxel groups was 45.1, 77.9 and 97% compared to controls. The effects of therapy on intratumoral proliferation and apoptosis corresponded with tumor growth inhibition data. BEZ235 also caused a decrease in phospho-mTOR and phospho-Akt in tumor tissue lysates. Median animal survival (controls, 23 days) was 26.5 days after BEZ235 (p=0.227), 90.5 days after nab-paclitaxel (p=0.001) and 97 days in the BEZ235+nab-paclitaxel combination treatment group (p=0.001). Our findings suggest that BEZ235 exerts some antitumor effects against gastric cancer and enhances effects of nab-paclitaxel through inhibition of cell proliferation and modulation of the PI3K/mTOR pathway. This approach may represent a promising combination targeted therapy for gastric cancer.

Enhancing sorafenib-mediated sensitization to gemcitabine in experimental pancreatic cancer through EMAP II

Background

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive human malignancies and tends to be relatively resistant to conventional therapies. Activated Ras oncogene mutations are found in up to 90% of PDAC, leading to activation of the Ras/Raf/MEK/ERK signaling pathway. Sorafenib is a multikinase inhibitor of the Ras/Raf/MEK/ERK pathway and of tumor angiogenesis. Endothelial monocyte activating polypeptide II (EMAP) enhances gemcitabine effects in PDAC. Antitumor activity of sorafenib was evaluated in combination with gemcitabine (Gem) and the antiangiogenic agent EMAP in experimental PDAC.

Methods

Cell proliferation and protein expression were analyzed by WST-1 assay and Western blotting. Animal survival studies were performed in murine PDAC xenografts.

Results

Sorafenib decreased phospho-MEK, phospho-ERK1/2, phospho-p70S6K and phospho-4EBP-1 expression in PDAC cells. Sorafenib inhibited in vitro proliferation of all four PDAC cell lines tested. Additive effects on cell proliferation inhibition were observed in the gemcitabine-sorafenib combination in PDAC cells, and in combinations of sorafenib or EMAP with gemcitabine in endothelial (HUVEC) and fibroblast (WI-38) cells. Sorafenib, alone or in combination with gemcitabine and EMAP, induced apoptosis in HUVECs and WI-38 cells as observed via increased expression of cleaved poly (ADP-ribose) polymerase-1 (PARP-1) and caspase-3 proteins. Compared to controls (median survival: 22 days), animal survival increased after Gem therapy (29 days) but not in sorafenib (23 days) or EMAP therapy alone (25 days). Further increases in survival occurred in combination therapy groups Gem+sorafenib (30 days, p=0.004), Gem+EMAP (33 days, p=0.002), and Gem+sorafenib+EMAP (36 days, p=0.004), but not after the sorafenib+EMAP combination (24 days).

Conclusions

These findings demonstrate that the addition of a polymechanistic antiangiogenic agent such as EMAP can enhance the combination treatment effects of sorafenib and cytotoxic PDAC therapy.

Superior antitumor activity of nanoparticle albumin-bound paclitaxel in experimental gastric cancer

Gastric cancer is the second common cause of cancer related death worldwide and lacks highly effective treatment for advanced disease. Nab-paclitaxel is a novel microtubule-inhibitory cytotoxic agent that has not been tested in gastric cancer as of yet. In this study, human gastric cancer cell lines AGS, NCI-N87 and SNU16 were studied. Nab-paclitaxel inhibited cell proliferation with an IC50 of 5 nM in SNU16, 23 nM in AGS and 49 nM in NCI-N87 cells after 72-hour treatment, which was lower than that of oxaliplatin (1.05 μM to 1.51 μM) and epirubicin (0.12 μM to 0.25 μM). Nab-paclitaxel treatment increased expression of the mitotic-spindle associated phospho-stathmin irrespective of the baseline total or phosphorylated stathmin level, and induced mitotic cell death as confirmed through increased expression of cleaved-PARP and caspase-3. After a two-week nab-paclitaxel, oxaliplatin or epirubicin treatment, the average in vivo local tumor growth inhibition rate was 77, 17.2 and 21.4 percent, respectively (p = 0.002). Effects of therapy on tumoral proliferative and apoptotic indices corresponded with tumor growth inhibition data, while expression of phospho-stathmin also increased in tissues. There was an increase in median animal survival after nab-paclitaxel treatment (93 days) compared to controls (31 days, p = 0.0007), oxaliplatin (40 days, p = 0.0007) or to docetaxel therapy (81 days, p = 0.0416). The strong antitumor activity of nab-paclitaxel in experimental gastric cancer supports such microtubule-inhibitory strategy for clinical application. Nab-paclitaxel benefits were observed independent from phosphorylated stathmin expression at baseline, putting into question the consideration of nab-paclitaxel use in gastric cancer based on this putative biomarker.

Nonclassically Secreted Regulators of Angiogenesis

Many secreted polypeptide regulators of angiogenesis are devoid of signal peptides. These proteins are released through nonclassical pathways independent of endoplasmic reticulum and Golgi. In most cases, the nonclassical protein export is induced by stress. It usually serves to stimulate repair or inflammation in damaged tissues. We review the secreted signal peptide-less regulators of angiogenesis and discuss the mechanisms and biological significance of their unconventional export.

BMS-754807, a small-molecule inhibitor of insulin-like growth factor-1 receptor/insulin receptor, enhances gemcitabine response in pancreatic cancer

Gemcitabine has limited clinical benefits in pancreatic ductal adenocarcinoma (PDAC). Insulin-like growth factor (IGF) signaling proteins are frequently overexpressed in PDAC. The therapeutic potential of BMS-754807, a small-molecule inhibitor of IGF-type 1 receptor (IGF-1R) and insulin receptor (IR), and gemcitabine was evaluated in experimental PDAC. Cell proliferation and protein expression were measured by WST-1 assay and immunoblotting. Tumor growth and survival studies were conducted in murine xenografts. PDAC cells expressed phospho-IGF-1R protein. BMS-754807 and gemcitabine inhibited cell proliferation of PDAC cells; the combination of BMS-754807 with gemcitabine had additive effects. Addition of BMS-754807 decreased gemcitabine IC₅₀ from 9.7 μmol/L to 75 nmol/L for AsPC-1, from 3 μmol/L to 70 nmol/L for Panc-1, from 72 to 16 nmol/L for MIA PaCa-2, and from 28 to 16 nmol/L for BxPC-3 cells. BMS-754807 caused a decrease in phospho-IGF-1R and phospho-AKT proteins in AsPC-1 and Panc-1 cells. BMS-754807 and gemcitabine caused an increase in PARP-1 and caspase-3 cleavage. Net tumor growth inhibition in BMS-754807, gemcitabine, and BMS-754807+gemcitabine groups was 59%, 35%, and 94% as compared with controls. Effects of therapy on intratumoral proliferation and apoptosis corresponded with tumor growth inhibition data. BMS-754807 also caused a decrease in phospho-IGF-1R and phospho-AKT in tumor tissue lysates. Median animal survival (controls: 21 days) with BMS-754807 was 27 days (P = 0.03), with gemcitabine 28 days (P = 0.05), and in the BMS-754807+gemcitabine combination group, 41 days (P = 0.007). The strong antitumor activity of BMS-754807 in experimental PDAC supports the potential of BMS-754807-induced mechanisms for clinical PDAC therapy.

The efficacy of a novel, dual PI3K/mTOR inhibitor NVP-BEZ235 to enhance chemotherapy and antiangiogenic response in pancreatic cancer

Gemcitabine has limited clinical benefits for pancreatic ductal adenocarcinoma (PDAC). The phosphatidylinositol-3-kinase (PI3K)/AKT and mammalian target of rapamycin (mTOR) signaling pathways are frequently dysregulated in PDAC. We investigated the effects of NVP-BEZ235, a novel dual PI3K/mTOR inhibitor, in combination with gemcitabine and endothelial monocyte activating polypeptide II (EMAP) in experimental PDAC. Cell proliferation and protein expression were analyzed by WST-1 assay and Western blotting. Animal survival experiments were performed in murine xenografts. BEZ235 caused a decrease in phospho-AKT and phospho-mTOR expression in PDAC (AsPC-1), endothelial (HUVECs), and fibroblast (WI-38) cells. BEZ235 inhibited in vitro proliferation of all four PDAC cell lines tested. Additive effects on proliferation inhibition were observed in the BEZ235-gemcitabine combination in PDAC cells and in combination of BEZ235 or EMAP with gemcitabine in HUVECs and WI-38 cells. BEZ235, alone or in combination with gemcitabine and EMAP, induced apoptosis in AsPC-1, HUVECs, and WI-38 cells as observed by increased expression of cleaved poly (ADP-ribose) polymerase-1 (PARP-1) and caspase-3 proteins. Compared to controls (median survival: 16 days), animal survival increased after BEZ235 and EMAP therapy alone (both 21 days) and gemcitabine monotherapy (28 days). Further increases in survival occurred in combination therapy groups BEZ235 + gemcitabine (30 days, P = 0.007), BEZ235 + EMAP (27 days, P = 0.02), gemcitabine + EMAP (31 days, P = 0.001), and BEZ235 + gemcitabine + EMAP (33 days, P = 0.004). BEZ235 has experimental PDAC antitumor activity in vitro and in vivo that is further enhanced by combination of gemcitabine and EMAP. These findings demonstrate advantages of combination therapy strategies targeting multiple pathways in pancreatic cancer treatment.

Evaluation of poly-mechanistic antiangiogenic combinations to enhance cytotoxic therapy response in pancreatic cancer

Gemcitabine (Gem) has limited clinical benefits in pancreatic ductal adenocarcinoma (PDAC). The present study investigated combinations of gemcitabine with antiangiogenic agents of various mechanisms for PDAC, including bevacizumab (Bev), sunitinib (Su) and EMAP II. Cell proliferation and protein expression were analyzed by WST-1 assay and Western blotting. In vivo experiments were performed via murine xenografts. Inhibition of in vitro proliferation of AsPC-1 PDAC cells by gemcitabine (10 µM), bevacizumab (1 mg/ml), sunitinib (10 µM) and EMAP (10 µM) was 35, 22, 81 and 6 percent; combination of gemcitabine with bevacizumab, sunitinib or EMAP had no additive effects. In endothelial HUVECs, gemcitabine, bevacizumab, sunitinib and EMAP caused 70, 41, 86 and 67 percent inhibition, while combination of gemcitabine with bevacizumab, sunitinib or EMAP had additive effects. In WI-38 fibroblasts, gemcitabine, bevacizumab, sunitinib and EMAP caused 79, 58, 80 and 29 percent inhibition, with additive effects in combination as well. Net in vivo tumor growth inhibition in gemcitabine, bevacizumab, sunitinib and EMAP monotherapy was 43, 38, 94 and 46 percent; dual combinations of Gem+Bev, Gem+Su and Gem+EMAP led to 69, 99 and 64 percent inhibition. Combinations of more than one antiangiogenic agent with gemcitabine were generally more effective but not superior to Gem+Su. Intratumoral proliferation, apoptosis and microvessel density findings correlated with tumor growth inhibition data. Median animal survival was increased by gemcitabine (26 days) but not by bevacizumab, sunitinib or EMAP monotherapy compared to controls (19 days). Gemcitabine combinations with bevacizumab, sunitinib or EMAP improved survival to similar extent (36 or 37 days). Combinations of gemcitabine with Bev+EMAP (43 days) or with Bev+Su+EMAP (46 days) led to the maximum survival benefit observed. Combination of antiangiogenic agents improves gemcitabine response, with sunitinib inducing the strongest effect. These findings demonstrate advantages of combining multi-targeting agents with standard gemcitabine therapy for PDAC.

Cell proliferation and migration are modulated by Cdk-1-phosphorylated endothelial-monocyte activating polypeptide II

Background

Endothelial-Monocyte Activating Polypeptide (EMAP II) is a secreted protein with well-established anti-angiogenic activities. Intracellular EMAP II expression is increased during fetal development at epithelial/mesenchymal boundaries and in pathophysiologic fibroproliferative cells of bronchopulmonary dysplasia, emphysema, and scar fibroblast tissue following myocardial ischemia. Precise function and regulation of intracellular EMAP II, however, has not been explored to date.

Methodology/Principal Findings

Here we show that high intracellular EMAP II suppresses cellular proliferation by slowing progression through the G2M cell cycle transition in epithelium and fibroblast. Furthermore, EMAP II binds to and is phosphorylated by Cdk1, and exhibits nuclear/cytoplasmic partitioning, with only nuclear EMAP II being phosphorylated. We observed that extracellular secreted EMAP II induces endothelial cell apoptosis, where as excess intracellular EMAP II facilitates epithelial and fibroblast cells migration.

Conclusions/Significance

Our findings suggest that EMAP II has specific intracellular effects, and that this intracellular function appears to antagonize its extracellular anti-angiogenic effects during fetal development and pulmonary disease progression.

Identification of CD23 as a functional receptor for the proinflammatory cytokine AIMP1/p43

ARS-interacting multifunctional protein 1 (AIMP1/p43) can be secreted to trigger proinflammatory molecules while it is predominantly bound to a cytoplasmic macromolecular protein complex that contains several different aminoacyl-tRNA synthetases. Although its activities as a secreted signaling factor have been well-characterized, the functional receptor for its proinflammatory activity has not yet identified. In this study, we have identified the receptor molecule for AIMP1 that mediates the secretion of TNF-α from THP-1 monocytic cells and primary human peripheral blood mononuclear cells (PBMCs). In a screen of 499 soluble receptors, we identified CD23, a known low-affinity receptor for IgE, as a high affinity binding partner of AIMP1. We found that down-regulation of CD23 attenuated AIMP1-induced TNF-α secretion and AIMP1 binding to THP-1 and PBMCs. We also observed that in THP-1 and PBMCs, AIMP1-induced TNF-α secretion mediated by CD23 involved activation of ERK1/2. Interestingly, endothelial monocyte activating polypeptide II (EMAP II), the C-terminal fragment of AIMP1 that is also known to work as a proinflammatory cytokine, was incapable of binding to CD23 and of activating ERK1/2. Therefore, identification of CD23 not only explains the inflammatory function of AIMP1 but also provides the first evidence by which the mode of action of AIMP1 can be distinguished from that of its C-terminal domain, EMAP II.

20-HETE in neovascularization

Cytochrome P450 4A/F (CYP4A/F) converts arachidonic acid (AA) to 20-HETE by ω-hydroxylation. The contribution of 20-HETE to the regulation of myogenic response, blood pressure, and mitogenic actions has been well summarized. This review focuses on the emerging role of 20-HETE in physiological and pathological vascularization. 20-HETE has been shown to regulate vascular smooth muscle cells (VSMC) and endothelial cells (EC) by affecting their proliferation, migration, survival, and tube formation. Furthermore, the proliferation, migration, secretion of proangiogenic molecules (such as HIF-1α, VEGF, SDF-1α), and tube formation of endothelial progenitor cells (EPC) are stimulated by 20-HETE. These effects are mediated through c-Src- and EGFR-mediated downstream signaling pathways, including MAPK and PI3K/Akt pathways, eNOS uncoupling, and NOX/ROS system activation. Therefore, the CYP4A/F-20-HETE system may be a therapeutic target for the treatment of abnormal angiogenic diseases.

Antitumour activity of sunitinib in combination with gemcitabine in experimental pancreatic cancer

BACKGROUND

Gemcitabine (Gem) has limited clinical benefits in pancreatic ductal adenocarcinoma (PDAC). Sunitinib (Su) is a novel, multi-target receptor tyrosine kinase inhibitor that has antitumour activities. This study tested the benefits of combined gemcitabine and sunitinib in PDAC.

METHODS

Cell viability and protein expression were evaluated by WST-1 assay and Western blotting. Tumour growth and survival experiments were performed in murine xenografts.

RESULTS

In PDAC cells, Gem, Su and Su + Gem, respectively, caused 28%, 22% and 48% inhibition in proliferation at 100 nM. In endothelial cells, Gem, Su and Su + Gem, respectively, caused 49%, 32% and 72% inhibition in proliferation. In fibroblasts, Gem, Su and Su + Gem, respectively, caused 65%, 14% and 79% inhibition in proliferation. Su increased apoptosis, as evidenced by the cleavage of caspase-3 and PARP-1 proteins. Net tumour growth compared with controls in the Gem, Su and Su + Gem groups was 57%, 6% and 1%, respectively. Intratumoral proliferative activity was reduced by 33%, 82% and 75% in the Gem, Su and Su + Gem groups, respectively, compared with controls. Median survival in the control, Su, Gem and Su + Gem groups was 16, 21, 24 and 30 days, respectively (P=0.007).

CONCLUSIONS

These findings support a combination approach using multi-target antiangiogenic agents such as sunitinib with standard gemcitabine therapy in the treatment of PDAC.

Impact of aging vs. estrogen loss on cardiac gene expression: estrogen replacement and inflammation

Despite an abundance of evidence to the contrary from animal studies, large clinical trials on humans have shown that estrogen administered to postmenopausal women increases the risk of cardiovascular disease. However, timing may be everything, as estrogen is often administered immediately after ovariectomy (Ovx) in animal studies, while estrogen administration in human studies occurred many years postmenopause. This study investigates the discrepancy by administering 17β-estradiol (E2) in a slow-release capsule to Norway Brown rats both immediately following Ovx and 9 wk post-Ovx (Late), and studying differences in gene expression between these two groups compared with age-matched Ovx and sham-operated animals. Two different types of microarray were used to analyze the left ventricles from these groups: an Affymetrix array (n = 3/group) and an inflammatory cytokines and receptors PCR array (n = 4/group). Key genes were analyzed by Western blotting. Ovx without replacement led to an increase in caspase 3, caspase 9, calpain 2, matrix metalloproteinase (MMP)9, and TNF-α. Caspase 6, STAT3, and CD11b increased in the Late group, while tissue inhibitor of metalloproteinase 2, MMP14, and collagen I α1 were decreased. MADD and fibronectin were increased in both Ovx and Late. TNF-α and inducible nitric oxide synthase (iNOS) protein levels increased with Late replacement. Many of these changes were prevented by early E2 replacement. These findings suggest that increased expression of inflammatory genes, such as TNF-α and iNOS, may be involved in some of the deleterious effects of delayed E2 administration seen in human studies.

Lung endothelial monocyte-activating protein 2 is a mediator of cigarette smoke-induced emphysema in mice

Pulmonary emphysema is a disease characterized by alveolar cellular loss and inflammation. Recently, excessive apoptosis of structural alveolar cells has emerged as a major mechanism in the development of emphysema. Here, we investigated the proapoptotic and monocyte chemoattractant cytokine endothelial monocyte-activating protein 2 (EMAPII). Lung-specific overexpression of EMAPII in mice caused simplification of alveolar structures, apoptosis, and macrophage accumulation, compared with that in control transgenic mice. Additionally, in a mouse model of cigarette smoke-induced (CS-induced) emphysema, EMAPII levels were significantly increased in murine lungs. This upregulation was necessary for emphysema development, as neutralizing antibodies to EMAPII resulted in reduced alveolar cell apoptosis, inflammation, and emphysema-associated structural changes in alveoli and small airways and improved lung function. The mechanism of EMAPII upregulation involved an apoptosis-dependent feed-forward loop, since caspase-3 instillation in the lung markedly increased EMAPII expression, while caspase inhibition decreased its production, even in transgenic EMAPII mice. These findings may have clinical significance, as both current smokers and ex-smoker chronic obstructive pulmonary disease (COPD) patients had increased levels of secreted EMAPII in the bronchoalveolar lavage fluid compared with that of nonsmokers. In conclusion, we suggest that EMAPII perpetuates the mechanism of CS-induced lung emphysema in mice and, given its secretory nature, is a suitable target for neutralization antibody therapy.

Topical dihydroartemisinin inhibits suture-induced neovascularization in rat corneas through ERK1/2 and p38 pathways

AIM

To determine if topical instillation of dihydroartemisinin (DHA) inhibits corneal neovascularization (NV) in rats and to investigate the role of the extracellular regulated kinases (ERK) 1/2 and p38 pathways in this process.

METHODS

Suture-induced corneal NV was produced in rats and the eyes were topically treated with different concentrations of DHA (20mg/L, 10mg/L or 5mg/L) or normal saline 4 times a day for 7 days. The corneal NV was quantified as the proportion of NV area to the whole cornea. Western blot was used to determine the expressions of vascular endothelial growth factor (VEGF) and the phosphorylation status of VEGF receptor-2, ERK1/2 and p38 in the corneas. Immunofluorescent staining was used to determine the expressions of phospho-ERK1/2 and phospho-p38 in the corneal tissues from the eyes treated with 20 mg/L DHA (DHA group) or normal saline (control group).

RESULTS

The proportion of corneal NV area in the eyes treated with normal saline or DHA at dosages of 20mg/L, 10mg/L or 5mg/L was (23.74±3.00)%, (15.73±2.88)%, (19.53±2.42)%, and (23.38±2.79)%, respectively. In the eyes treated with 20mg/L or 10mg/L DHA, the corneal NV area was significantly reduced when compared to that in eyes with normal saline (P<0.05). Western blot analyses revealed that 20mg/L DHA significantly inhibited the expressions of VEGF and phospho-VEGFR-2. Both 20mg/L and 10mg/L DHA inhibited the expressions of phospho-ERK1/2 and phospho-p38. Immunofluorescent staining further demonstrated that 20mg/L DHA lowered the expression levels of phospho-ERK1/2 and phospho-p38 in the corneas with suture-induced NV.

CONCLUSION

Suture-induced NV in rat corneas was significantly inhibited by topical treatment with 20mg/L and 10mg/L DHA. The results suggest that the effects could be partially dependent on the DHA-mediated inhibitions of the ERK1/2 and p38 pathways.

[Congenital diaphragmatic hernia - mechanisms of pulmonary hypoplasia]

Congenital diaphragmatic hernia (CDH) is a common cause of severe neonatal respiratory distress. Mortality and morbidity are determined by the amount of pulmonary hypoplasia (PH) that occurs and by the development of therapy-resistant pulmonary hypertension. The pathogenesis and aetiology of CDH and its associated anomalies are still largely unknown despite all research efforts. The pathogenesis of CDH is based on an assumption linking herniation of abdominal viscera into the thorax with compression of the developing lung. PH, however, can also result from reduced distension of the developing lung secondary to impaired fetal breathing movements. Our understanding of CDH has also been aided by basic research with the use of dietary, teratogen-induced, and knockout models of CDH. These studies indicate that lung hypoplasia may involve disturbances of mitogenic signalling pathways fundamental to embryonic lung development. Recent data reveal the role of disruption of a retinoid-signalling pathway in the pathogenesis of CDH. Although multifactorial inheritance may best explain most cases of CDH in humans, much has been learned about the genetic factors that play a role in the development of CDH by studies of patients with CDH caused by specific genetic syndromes and chromosome anomalies. More research is warranted to improve our understanding of normal and abnormal lung development in relation to CDH. Such investigations will help in the design of new treatment strategies to improve the natural course or even to prevent this anomaly.

Smac mimetic-derived augmentation of chemotherapeutic response in experimental pancreatic cancer

Background

Pancreatic ductal adenocarcinoma (PDAC) is highly resistant to conventional chemotherapy, in part due to the overexpression of inhibitors of apoptosis proteins (IAPs). Smac is an endogenous IAP-antagonist, which renders synthetic Smac mimetics attractive anticancer agents. We evaluated the benefits of combining a Smac mimetic, JP1201 (JP), with conventional chemotherapy agents used for PDAC management.

Methods

Cell viability assays and protein expression analysis were performed using WST-1 reagent and Western blotting, respectively. Apoptosis was detected by annexin V/propidium iodide staining. In vivo tumor growth and survival studies were performed in murine PDAC xenografts.

Results

JP and gemcitabine (Gem) inhibited PDAC cell proliferation with additive effects in combination. The percentage of early apoptotic cells in controls, JP, Gem and JP + Gem was 17%, 26%, 26% and 38%, respectively. JP-induced apoptosis was accompanied by PARP-1 cleavage. Similar additive anti-proliferative effects were seen for combinations of JP with doxorubicin (Dox) and docetaxel (DT). The JP + Gem combination caused a 30% decrease in tumor size in vivo compared to controls. Median animal survival was improved significantly in mice treated with JP + Gem (38 d) compared to controls (22 d), JP (28 d) or Gem (32 d) (p = 0.01). Animal survival was also improved with JP + DT treatment (32 d) compared to controls (16 d), JP (21 d) or DT alone (27 d).

Conclusions

These results warrant further exploration of strategies that promote chemotherapy-induced apoptosis of tumors and highlight the potential of Smac mimetics in clinical PDAC therapy.

Enhancing cytotoxic agent activity in experimental pancreatic cancer through EMAP II combination therapy

PURPOSE

Gemcitabine has limited benefits as single agent or in combination for pancreatic ductal adenocarcinoma (PDAC). Endothelial monocyte-activating polypeptide II (EMAP) enhances gemcitabine effects in PDAC. We evaluated the combination effects of EMAP, doxorubicin, and docetaxel in experimental PDAC.

METHODS

Cell proliferation, protein expression, and apoptosis were analyzed by WST-1 assay, Western blotting, and FACS analysis. Tumor growth and survival experiments were performed in murine xenografts.

RESULTS

PDAC cell proliferation in vitro was not affected by EMAP, compared to a small inhibition through doxorubicin, docetaxel, and gemcitabine. EMAP addition to these agents did not increase the antiproliferative effects. In endothelial cells, EMAP, doxorubicin, docetaxel, and gemcitabine all had antiproliferative effects. Addition of EMAP to these cytotoxic agents had additive effects. In PDAC cells, no agent induced measurable apoptosis, whereas in endothelial cells, all agents either alone or in combination did. Doxorubicin, docetaxel, gemcitabine, and EMAP all decreased tumor growth. EMAP addition increased inhibitory effects of docetaxel and gemcitabine, but not of doxorubicin. However, compared to controls (median survival: 17 days), EMAP (14 days) had no survival benefit, while docetaxel (29 days), gemcitabine (25 days), and docetaxel followed by gemcitabine sequence (37 days) extended animal survival. Addition of EMAP to docetaxel (35 days), gemcitabine (28 days), and docetaxel gemcitabine sequence (41 days) extended the survival. Doxorubicin effects were not enhanced by EMAP.

CONCLUSIONS

The antiendothelial combination therapy benefit through EMAP is not limited to gemcitabine and may facilitate the development of more effective alternative cytotoxic therapy strategies against PDAC.

Albendazole inhibits endothelial cell migration, tube formation, vasopermeability, VEGF receptor-2 expression and suppresses retinal neovascularization in ROP model of angiogenesis

The angiogenic process begins with the cell proliferation and migration into the primary vascular network, and leads to vascularization of previously avascular tissues and organs as well to growth and remodeling of the initially homogeneous capillary plexus to form a new microcirculation. Additionally, an increase in microvascular permeability is a crucial step in angiogenesis. Vascular endothelial growth factor (VEGF) plays a central role in angiogenesis. We have previously reported that albendazole suppresses VEGF levels and inhibits malignant ascites formation, suggesting a possible effect on angiogenesis. This study was therefore designed to investigate the antiangiogenic effect of albendazole in non-cancerous models of angiogenesis. In vitro, treatment of human umbilical vein endothelial cells (HUVECs) with albendazole led to inhibition of tube formation, migration, permeability and down-regulation of the VEGF type 2 receptor (VEGFR-2). In vivo albendazole profoundly inhibited hyperoxia-induced retinal angiogenesis in mice. These results provide new insights into the antiangiogenic effects of albendazole.

Functional expansion of human tRNA synthetases achieved by structural inventions

Known as an essential component of the translational apparatus, the aminoacyl-tRNA synthetase family catalyzes the first step reaction in protein synthesis, that is, to specifically attach each amino acid to its cognate tRNA. While preserving this essential role, tRNA synthetases developed other roles during evolution. Human tRNA synthetases, in particular, have diverse functions in different pathways involving angiogenesis, inflammation and apoptosis. The functional diversity is further illustrated in the association with various diseases through genetic mutations that do not affect aminoacylation or protein synthesis. Here we review the accumulated knowledge on how human tRNA synthetases used structural inventions to achieve functional expansions.

Proteasome inhibition enhances antitumour effects of gemcitabine in experimental pancreatic cancer

BACKGROUND

The clinical benefit of gemcitabine, the standard systemic therapy of pancreatic cancer (PaCa), remains modest as a result of high chemoresistance. The proteasome inhibitor bortezomib has antitumour activity against PaCa in vitro and in vivo. We examined the antitumour activity of combination PaCa therapy with bortezomib and gemcitabine.

METHODS

Cell proliferation assays were performed using WST-1 reagent. Protein expression was determined by Western blotting. Efficacy of bortezomib and/or gemcitabine was tested in vivo in a survival study.

RESULTS

Bortezomib at 10 microM caused 29% and 72% inhibition in AsPC-1 PaCa cell proliferation at 48 and 96 h incubation, respectively. Bortezomib was even more active against PaCa cell lines Panc-1 and MiaPaCa, with 80% inhibition of proliferation at 48 h. The combination of bortezomib and gemcitabine inhibited AsPC-1 proliferation more effectively compared with each single agent alone. Poly(ADP-ribose) polymerase (PARP) cleavage, an apoptotic indicator, reached 6.6-, 2- and 8.5-fold over controls for bortezomib, gemcitabine and the combination. The median survival was 31 (controls and bortezomib), 40 (gemcitabine) and 48 days (combination), respectively (P < 0.002).

CONCLUSIONS

Bortezomib and gemcitabine demonstrate additive antitumour activity in vitro and in an experimental PaCa model, indicating the potential for clinical PaCa benefits of additional multiagent therapies that will be based upon the bortezomib and gemcitabine combination.

A monoclonal rat anti-mouse EMAP II antibody that functionally neutralizes pro- and mature-EMAP II in vitro

EMAP II is an endothelial cell and monocyte activating proinflammatory cytokine, which has been demonstrated to induce endothelial cell apoptosis. In order to analyze its role in disease models linked to inflammation and endothelial cell death, we aimed to develop a neutralizing antibody against mouse EMAP II. Therefore, we generated rat monoclonal anti-mouse EMAP II antibodies by immunization with recombinant full length, mouse pro-EMAP II protein. We could identify by ELISA, hybridoma clones from fusion with mouse myeloma SP2/0 cells which produced antibodies recognizing both full length and mature EMAP II. We further characterized one antibody, M7/1 and demonstrated its ability to detect both EMAP II forms in Western blotting and to neutralize EMAP II directed migration of human peripheral blood monocytes as well as EMAP II induced apoptosis of tumor and endothelial cells. We conclude that this antibody can be useful to both target and analyze murine disease models, in which EMAP II may be involved.