The trimeric serine protease HtrA1 forms a cage-like inhibition complex with an anti-HtrA1 antibody

High temperature requirement A1 (HtrA1) is a trypsin-fold serine protease implicated in the progression of age-related macular degeneration (AMD). Our interest in an antibody therapy to neutralize HtrA1 faces the complication that the target adopts a trimeric arrangement, with three active sites in close proximity. In the present study, we describe antibody 94, obtained from a human antibody phage display library, which forms a distinct macromolecular complex with HtrA1 and inhibits the enzymatic activity of recombinant and native HtrA1 forms. Using biochemical methods and negative-staining EM we were able to elucidate the molecular composition of the IgG94 and Fab94 complexes and the associated inhibition mechanism. The 246-kDa complex between the HtrA1 catalytic domain trimer (HtrA1_Cat) and Fab94 had a propeller-like organization with one Fab bound peripherally to each protomer. Low-resolution EM structures and epitope mapping indicated that the antibody binds to the surface-exposed loops B and C of the catalytic domain, suggesting an allosteric inhibition mechanism. The HtrA1_Cat-IgG94 complex (636 kDa) is a cage-like structure with three centrally located IgG94 molecules co-ordinating two HtrA1_Cat trimers and the six active sites pointing into the cavity of the cage. In both complexes, all antigen-recognition regions (paratopes) are found to bind one HtrA1 protomer and all protomers are bound by a paratope, consistent with the complete inhibition of enzyme activity. Therefore, in addition to its potential therapeutic usefulness, antibody 94 establishes a new paradigm of multimeric serine protease inhibition.

Sustained Brown Fat Stimulation and Insulin Sensitization by a Humanized Bispecific Antibody Agonist for Fibroblast Growth Factor Receptor 1/βKlotho Complex

Dissipating excess calories as heat through therapeutic stimulation of brown adipose tissues (BAT) has been proposed as a potential treatment for obesity-linked disorders. Here, we describe the generation of a humanized effector-less bispecific antibody that activates fibroblast growth factor receptor (FGFR) 1/βKlotho complex, a common receptor for FGF21 and FGF19. Using this molecule, we show that antibody-mediated activation of FGFR1/βKlotho complex in mice induces sustained energy expenditure in BAT, browning of white adipose tissue, weight loss, and improvements in obesity-associated metabolic derangements including insulin resistance, hyperglycemia, dyslipidemia and hepatosteatosis. In mice and cynomolgus monkeys, FGFR1/βKlotho activation increased serum high-molecular-weight adiponectin, which appears to contribute over time by enhancing the amplitude of the metabolic benefits. At the same time, insulin sensitization by FGFR1/βKlotho activation occurs even before the onset of weight loss in a manner that is independent of adiponectin. Together, selective activation of FGFR1/βKlotho complex with a long acting therapeutic antibody represents an attractive approach for the treatment of type 2 diabetes and other obesity-linked disorders through enhanced energy expenditure, insulin sensitization and induction of high-molecular-weight adiponectin.

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A humanized bispecific antibody that selectively activates FGFR1/βKlotho complex was generated.

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Anti-FGFR1/βKlotho agonist antibody induced sustained thermogenesis in brown fat and induced weight loss.

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Anti-FGFR1/βKlotho agonist antibody improved insulin sensitivity even before the onset of weight loss.

Structural basis for the dual recognition of helical cytokines IL-34 and CSF-1 by CSF-1R

Lacking any discernible sequence similarity, interleukin-34 (IL-34) and colony stimulating factor 1 (CSF-1) signal through a common receptor CSF-1R on cells of mononuclear phagocyte lineage. Here, the crystal structure of dimeric IL-34 reveals a helical cytokine fold homologous to CSF-1, and we further show that the complex architecture of IL-34 bound to the N-terminal immunoglobulin domains of CSF-1R is similar to the CSF-1/CSF-1R assembly. However, unique conformational adaptations in the receptor domain geometry and intermolecular interface explain the cross-reactivity of CSF-1R for two such distantly related ligands. The docking adaptations of the IL-34 and CSF-1 quaternary complexes, when compared to the stem cell factor assembly, draw a common evolutionary theme for transmembrane signaling. In addition, the structure of IL-34 engaged by a Fab fragment reveals the mechanism of a neutralizing antibody that can help deconvolute IL-34 from CSF-1 biology, with implications for therapeutic intervention in diseases with myeloid pathogenic mechanisms.

A two-in-one antibody against HER3 and EGFR has superior inhibitory activity compared with monospecific antibodies

Extensive crosstalk among ErbB/HER receptors suggests that blocking signaling from more than one family member may be essential to effectively treat cancer and limit drug resistance. We generated a conventional IgG molecule MEHD7945A with dual HER3/EGFR specificity by phage display engineering and used structural and mutational studies to understand how a single antigen recognition surface binds two epitopes with high affinity. As a human IgG1, MEHD7945A exhibited dual action by inhibiting EGFR- and HER3-mediated signaling in vitro and in vivo and the ability to engage immune effector functions. Compared with monospecific anti-HER antibodies, MEHD7945A was more broadly efficacious in multiple tumor models, showing that combined inhibition of EGFR and HER3 with a single antibody is beneficial.

Recombinant human erythropoietin delays loss of gray matter in chronic schizophrenia

Neurodevelopmental abnormalities together with neurodegenerative processes contribute to schizophrenia, an etiologically heterogeneous, complex disease phenotype that has been difficult to model in animals. The neurodegenerative component of schizophrenia is best documented by magnetic resonance imaging (MRI), demonstrating progressive cortical gray matter loss over time. No treatment exists to counteract this slowly proceeding atrophy. The hematopoietic growth factor erythropoietin (EPO) is neuroprotective in animals. Here, we show by voxel-based morphometry in 32 human subjects in a placebo-controlled study that weekly high-dose EPO for as little as 3 months halts the progressive atrophy in brain areas typically affected in schizophrenia, including hippocampus, amygdala, nucleus accumbens, and several neocortical areas. Specifically, gray matter protection is highly associated with improvement in attention and memory functions. These findings suggest that a neuroprotective strategy is effective against common pathophysiological features of schizophrenic patients, and strongly encourage follow-up studies to optimize EPO treatment dose and duration.

Wnt isoform-specific interactions with coreceptor specify inhibition or potentiation of signaling by LRP6 antibodies

β-Catenin-dependent Wnt signaling is initiated as Wnt binds to both the receptor FZD and coreceptor LRP5/6, which then assembles a multimeric complex at the cytoplasmic membrane face to recruit and inactivate the kinase GSK3. The large number and sequence diversity of Wnt isoforms suggest the possibility of domain-specific ligand-coreceptor interactions, and distinct binding sites on LRP6 for Wnt3a and Wnt9b have recently been identified in vitro. Whether mechanistically different interactions between Wnts and coreceptors might mediate signaling remains to be determined. It is also not clear whether coreceptor homodimerization induced extracellularly can activate Wnt signaling, as is the case for receptor tyrosine kinases. We generated monoclonal antibodies against LRP6 with the unexpected ability to inhibit signaling by some Wnt isoforms and potentiate signaling by other isoforms. In cell culture, two antibodies characterized further show reciprocal activities on most Wnts, with one antibody antagonizing and the other potentiating. We demonstrate that these antibodies bind to different regions of LRP6 protein, and inhibition of signaling results from blocking Wnt binding. Antibody-mediated dimerization of LRP6 can potentiate signaling only when a Wnt isoform is also able to bind the complex, presumably recruiting FZD. Endogenous autocrine Wnt signaling in different tumor cell lines can be either antagonized or enhanced by the LRP6 antibodies, indicating expression of different Wnt isoforms. As anticipated from the roles of Wnt signaling in cancer and bone development, antibody activities can also be observed in mice for inhibition of tumor growth and in organ culture for enhancement of bone mineral density. Collectively, our results indicate that separate binding sites for different subsets of Wnt isoforms determine the inhibition or potentiation of signaling conferred by LRP6 antibodies. This complexity of coreceptor-ligand interactions may allow for differential regulation of signaling by Wnt isoforms during development, and can be exploited with antibodies to differentially manipulate Wnt signaling in specific tissues or disease states.

An anti-Axl monoclonal antibody attenuates xenograft tumor growth and enhances the effect of multiple anticancer therapies

Axl is expressed in various types of cancer and is involved in multiple processes of tumorigenesis, including promoting tumor cell growth, migration, invasion, metastasis as well as angiogenesis. To evaluate further the mechanisms involved in the expression/activation of Axl in various aspects of tumorigenesis, especially its roles in modulating tumor stromal functions, we have developed a phage-derived mAb (YW327.6S2) that recognizes both human and murine Axl. YW327.6S2 binds to both human and murine Axl with high affinity. It blocks the ligand Gas6 binding to the receptor, downregulates receptor expression, inhibits receptor activation and downstream signaling. In A549 non-small-cell lung cancer (NSCLC) and MDA-MB-231 breast cancer models, YW327.6S2 attenuates xenograft tumor growth and potentiates the effect of anti-VEGF treatment. In NSCLC models, YW327.6S2 also enhances the effect of erlotinib and chemotherapy in reducing tumor growth. Furthermore, YW327.6S2 reduces the metastasis of MDA-MB-231 breast cancer cells to distant organs. YW327.6S2 induces tumor cell apoptosis in NSCLC, reduces tumor-associated vascular density and inhibits the secretion of inflammatory cytokines and chemokines from tumor-associated macrophages in the breast cancer model. In conclusion, anti-Axl mAb can enhance the therapeutic efficacy of anti-VEGF, EGFR small-molecule inhibitors as well as chemotherapy. Axl mAb affects not only tumor cells but also tumor stroma through its modulation of tumor-associated vasculature and immune cell functions.

MR angiogenesis imaging with Robo4- vs. alphaVbeta3-targeted nanoparticles in a B16/F10 mouse melanoma model

The primary objective of this study was to utilize MR molecular imaging to compare the 3-dimensional spatial distribution of Robo4 and α(V)β(3)-integrin as biosignatures of angiogenesis, in a rapidly growing, syngeneic tumor. B16-F10 melanoma-bearing mice were imaged with magnetic resonance (MR; 3.0 T) 11 d postimplantation before and after intravenous administration of either Robo4- or α(V)β(3)-targeted paramagnetic nanoparticles. The percentage of MR signal-enhanced voxels throughout the tumor volume was low and increased in animals receiving α(V)β(3)- and Robo4-targeted nanoparticles. Neovascular signal enhancement was predominantly associated with the tumor periphery (i.e., outer 50% of volume). Microscopic examination of tumors coexposed to the Robo4- and α(V)β(3)-targeted nanoparticles corroborated the MR angiogenesis mapping results and further revealed that Robo4 expression generally colocalized with α(V)β(3)-integrin. Robo4- and α(V)β(3)-targeted nanoparticles were compared to irrelevant or nontargeted control groups in all modalities. These results suggest that α(V)β(3)-integrin and Robo4 are useful biomarkers for noninvasive MR molecular imaging in syngeneic mouse tumors, but α(V)β(3)-integrin expression was more detectable by MR at 3.0 T than Robo4. Noninvasive, neovascular assessments of the MR signal of Robo4, particularly combined with α(V)β(3)-integrin expression, may help define tumor character prior to and following cancer therapy.

Volatile Flavor Compounds Produced by Molds of Aspergillus, Penicillium, and Fungi imperfecti

Strains of molds Aspergillus niger, A. ochraceus, A. oryzae, A. parasiticus, Penicillium chrysogenum, P. citrinum, P. funiculosum, P. raistrickii, P. viridicatum, Alternaria, Cephalosporium, and Fusarium sp. were grown on sterile coarse wheat meal at 26 to 28 C for 120 h. The volatiles from mature cultures were distilled at low temperature under reduced pressure. The distillates from traps -40 and -78 C were extracted with methylene chloride and subsequently concentrated. All the concentrates thus obtained were analyzed by gas-liquid chromatography, mass spectrometry, chemical reactions of functional groups, and olfactory evaluation. Six components detected in the culture distillates were identified positively: 3-methylbutanol, 3-octanone, 3-octanol, 1-octen-3-ol, 1-octanol, and 2-octen-1-ol. They represented 67 to 97% of all the volatiles occurring in the concentrated distillate. The following 14 components were identified tentatively: octane, isobutyl alcohol, butyl alcohol, butyl acetate, amyl acetate, octyl acetate, pyridine, hexanol, nonanone, dimethylpyrazine, tetramethylpyrazine, benzaldehyde, propylbenzene, and phenethyl alcohol. Among the volatiles produced by molds, 1-octen-3-ol yielding a characteristic fungal odor was found predominant.

Therapeutic antibody targeting of individual Notch receptors

The four receptors of the Notch family are widely expressed transmembrane proteins that function as key conduits through which mammalian cells communicate to regulate cell fate and growth. Ligand binding triggers a conformational change in the receptor negative regulatory region (NRR) that enables ADAM protease cleavage at a juxtamembrane site that otherwise lies buried within the quiescent NRR. Subsequent intramembrane proteolysis catalysed by the gamma-secretase complex liberates the intracellular domain (ICD) to initiate the downstream Notch transcriptional program. Aberrant signalling through each receptor has been linked to numerous diseases, particularly cancer, making the Notch pathway a compelling target for new drugs. Although gamma-secretase inhibitors (GSIs) have progressed into the clinic, GSIs fail to distinguish individual Notch receptors, inhibit other signalling pathways and cause intestinal toxicity, attributed to dual inhibition of Notch1 and 2 (ref. 11). To elucidate the discrete functions of Notch1 and Notch2 and develop clinically relevant inhibitors that reduce intestinal toxicity, we used phage display technology to generate highly specialized antibodies that specifically antagonize each receptor paralogue and yet cross-react with the human and mouse sequences, enabling the discrimination of Notch1 versus Notch2 function in human patients and rodent models. Our co-crystal structure shows that the inhibitory mechanism relies on stabilizing NRR quiescence. Selective blocking of Notch1 inhibits tumour growth in pre-clinical models through two mechanisms: inhibition of cancer cell growth and deregulation of angiogenesis. Whereas inhibition of Notch1 plus Notch2 causes severe intestinal toxicity, inhibition of either receptor alone reduces or avoids this effect, demonstrating a clear advantage over pan-Notch inhibitors. Our studies emphasize the value of paralogue-specific antagonists in dissecting the contributions of distinct Notch receptors to differentiation and disease and reveal the therapeutic promise in targeting Notch1 and Notch2 independently.

Abstract 4289: Early study on LGR5/GPR49 molecule as a potential colon cancer stem cell target for the antibody conjugated drug treatment

LGR5 (GPR49) is a Wnt pathway downstream target gene. It has already been confirmed that LGR5 gene is up regulated by APC or β-catenin mutation. LGR5 has recently been identified as a biomarker on the human and murine intestinal or colon stem cells. Our gene expression data shows that LGR5 is highly expressed in colon cancer, with minimal expression in normal tissue. Our strategy in this project is to eliminate tumor stem cells by drug conjugated antibody. Our goal is to find a tumor stem cell marker and develop antibody to target the tumor stem cells. Here we developed and characterized both anti-LGR5 phage and monoclonal antibodies by multi molecular techniques. We finally focus on one phage antibody (YW353) and three monoclonal antibodies (2H6, 3G12 and 8E11) as therapeutic drugs for further study. We evaluated antibody drug conjugate (ADC) in vitro and in vivo with different animal tumor models derived from cell lines and human tumor explants. Good efficacy was observed in these animal models following a single dose of 5mg/kg. Conclusion: LGR5 is an attractive colon cancer target for the administration of anti-LGR5 ADC in human cancer. More in vivo models will be tested to confirm the efficacy and evaluate safety.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4289.

Antibody-based targeting of FGFR3 in bladder carcinoma and t(4;14)-positive multiple myeloma in mice

Overexpression of FGF receptor 3 (FGFR3) is implicated in the development of t(4;14)-positive multiple myeloma. While FGFR3 is frequently overexpressed and/or activated through mutations in bladder cancer, the functional importance of FGFR3 and its potential as a specific therapeutic target in this disease have not been elucidated in vivo. Here we report that inducible knockdown of FGFR3 in human bladder carcinoma cells arrested cell-cycle progression in culture and markedly attenuated tumor progression in xenografted mice. Further, we developed a unique antibody (R3Mab) that inhibited not only WT FGFR3, but also various mutants of the receptor, including disulfide-linked cysteine mutants. Biochemical analysis and 2.1-A resolution crystallography revealed that R3Mab bound to a specific FGFR3 epitope that simultaneously blocked ligand binding, prevented receptor dimerization, and induced substantial conformational changes in the receptor. R3Mab exerted potent antitumor activity against bladder carcinoma and t(4;14)-positive multiple myeloma xenografts in mice by antagonizing FGFR3 signaling and eliciting antibody-dependent cell-mediated cytotoxicity (ADCC). These studies provide in vivo evidence demonstrating an oncogenic role of FGFR3 in bladder cancer and support antibody-based targeting of FGFR3 in hematologic and epithelial cancers driven by WT or mutant FGFR3.

Structural and functional analysis of a C3b-specific antibody that selectively inhibits the alternative pathway of complement

Amplification of the complement cascade through the alternative pathway can lead to excessive inflammation. Targeting C3b, a component central to the alternative pathway of complement, provides a powerful approach to inhibit complement-mediated immune responses and tissue injury. In the present study, phage display technology was employed to generate an antibody that selectively recognizes C3b but not the non-activated molecule C3. The crystal structure of C3b in complex with a Fab fragment of this antibody (S77) illustrates the structural basis for this selectivity. Cleavage of C3 to C3b results in a plethora of structural changes within C3, including the rearrangement of macroglobulin domain 6 enabling binding of S77 to the adjacent macroglobulin domain 7 domain. S77 blocks binding of factor B to C3b inhibiting the first step in the formation of the alternative pathway C3 convertase. In addition, S77 inhibits C5 binding to C3b. This results in significantly reduced formations of anaphylatoxins and membrane-attack complexes. This study for the first time demonstrates the structural basis for complement inhibition by a C3b-selective antibody and provides insights into the molecular mechanisms of alternative pathway complement activation.

PirB is a functional receptor for myelin inhibitors of axonal regeneration

A major barrier to regenerating axons after injury in the mammalian central nervous system is an unfavorable milieu. Three proteins found in myelin--Nogo, MAG, and OMgp--inhibit axon regeneration in vitro and bind to the glycosylphosphatidylinositol-anchored Nogo receptor (NgR). However, genetic deletion of NgR has only a modest disinhibitory effect, suggesting that other binding receptors for these molecules probably exist. With the use of expression cloning, we have found that paired immunoglobulin-like receptor B (PirB), which has been implicated in nervous system plasticity, is a high-affinity receptor for Nogo, MAG, and OMgp. Interfering with PirB activity, either with antibodies or genetically, partially rescues neurite inhibition by Nogo66, MAG, OMgp, and myelin in cultured neurons. Blocking both PirB and NgR activities leads to near-complete release from myelin inhibition. Our results implicate PirB in mediating regeneration block, identify PirB as a potential target for axon regeneration therapies, and provide an explanation for the similar enhancements of visual system plasticity in PirB and NgR knockout mice.

Blocking neuropilin-2 function inhibits tumor cell metastasis

Metastasis, which commonly uses lymphatics, accounts for much of the mortality associated with cancer. The vascular endothelial growth factor (VEGF)-C coreceptor, neuropilin-2 (Nrp2), modulates but is not necessary for developmental lymphangiogenesis, and its significance for metastasis is unknown. An antibody to Nrp2 that blocks VEGFC binding disrupts VEGFC-induced lymphatic endothelial cell migration, but not proliferation, in part independently of VEGF receptor activation. It does not affect established lymphatics in normal adult mice but reduces tumoral lymphangiogenesis and, importantly, functional lymphatics associated with tumors. It also reduces metastasis to sentinel lymph nodes and distant organs, apparently by delaying the departure of tumor cells from the primary tumor. Our results demonstrate that Nrp2, which was originally identified as an axon-guidance receptor, is an attractive target for modulating metastasis.

Structural insight into distinct mechanisms of protease inhibition by antibodies

To better understand how the relatively flat antigen-combining sites of antibodies interact with the concave shaped substrate-binding clefts of proteases, we determined the structures of two antibodies in complex with the trypsin-like hepatocyte growth-factor activator (HGFA). The two inhibitory antibodies, Ab58 and Ab75, were generated from a human Fab phage display library with synthetic diversity in the three complementarity determining regions (H1, H2, and H3) of the heavy chain, mimicking the natural diversity of the human Ig repertoire. Biochemical studies and the structures of the Fab58:HGFA (3.5-A resolution) and the Fab75:HGFA (2.2-A resolution) complexes revealed that Ab58 obstructed substrate access to the active site, whereas Ab75 allosterically inhibited substrate hydrolysis. In both cases, the antibodies interacted with the same protruding element (99-loop), which forms part of the substrate-binding cleft. Ab58 inserted its H1 and H2 loops in the cleft to occupy important substrate interaction sites (S3 and S2). In contrast, Ab75 bound at the backside of the cleft to a region corresponding to thrombin exosite II, which is known to interact with allosteric effector molecules. In agreement with the structural analysis, binding assays with active site inhibitors and enzymatic assays showed that Ab58 is a competitive inhibitor, and Ab75 is a partial competitive inhibitor. These results provide structural insight into antibody-mediated protease inhibition. They suggest that unlike canonical inhibitors, antibodies may preferentially target protruding loops at the rim of the substrate-binding cleft to interfere with the catalytic machinery of proteases without requiring long insertion loops.

Structural studies of neuropilin/antibody complexes provide insights into semaphorin and VEGF binding

Neuropilins (Nrps) are co-receptors for class 3 semaphorins and vascular endothelial growth factors and important for the development of the nervous system and the vasculature. The extracellular portion of Nrp is composed of two domains that are essential for semaphorin binding (a1a2), two domains necessary for VEGF binding (b1b2), and one domain critical for receptor dimerization (c). We report several crystal structures of Nrp1 and Nrp2 fragments alone and in complex with antibodies that selectively block either semaphorin or vascular endothelial growth factor (VEGF) binding. In these structures, Nrps adopt an unexpected domain arrangement in which the a2, b1, and b2 domains form a tightly packed core that is only loosely connected to the a1 domain. The locations of the antibody epitopes together with in vitro experiments indicate that VEGF and semaphorin do not directly compete for Nrp binding. Based upon our structural and functional data, we propose possible models for ligand binding to neuropilins.

Improvement of cognitive functions in chronic schizophrenic patients by recombinant human erythropoietin

Schizophrenia is increasingly recognized as a neurodevelopmental disease with an additional degenerative component, comprising cognitive decline and loss of cortical gray matter. We hypothesized that a neuroprotective/neurotrophic add-on strategy, recombinant human erythropoietin (rhEPO) in addition to stable antipsychotic medication, may be able to improve cognitive function even in chronic schizophrenic patients. Therefore, we designed a double-blind, placebo-controlled, randomized, multicenter, proof-of-principle (phase II) study. This study had a total duration of 2 years and an individual duration of 12 weeks with an additional safety visit at 16 weeks. Chronic schizophrenic men (N=39) with defined cognitive deficit (>or=1 s.d. below normal in the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS)), stable medication and disease state, were treated for 3 months with a weekly short (15 min) intravenous infusion of 40,000 IU rhEPO (N=20) or placebo (N=19). Main outcome measure was schizophrenia-relevant cognitive function at week 12. The neuropsychological test set (RBANS subtests delayed memory, language-semantic fluency, attention and Wisconsin Card Sorting Test (WCST-64) - perseverative errors) was applied over 2 days at baseline, 2 weeks, 4 weeks and 12 weeks of study participation. Both placebo and rhEPO patients improved in all evaluated categories. Patients receiving rhEPO showed a significant improvement over placebo patients in schizophrenia-related cognitive performance (RBANS subtests, WCST-64), but no effects on psychopathology or social functioning. Also, a significant decline in serum levels of S100B, a glial damage marker, occurred upon rhEPO. The fact that rhEPO is the first compound to exert a selective and lasting beneficial effect on cognition should encourage new treatment strategies for schizophrenia.

Inhibition of Dll4 signalling inhibits tumour growth by deregulating angiogenesis

Haploinsufficiency of Dll4, a vascular-specific Notch ligand, has shown that it is essential for embryonic vascular development and arteriogenesis. Mechanistically, it is unclear how the Dll4-mediated Notch pathway contributes to complex vascular processes that demand meticulous coordination of multiple signalling pathways. Here we show that Dll4-mediated Notch signalling has a unique role in regulating endothelial cell proliferation and differentiation. Neutralizing Dll4 with a Dll4-selective antibody rendered endothelial cells hyperproliferative, and caused defective cell fate specification or differentiation both in vitro and in vivo. In addition, blocking Dll4 inhibited tumour growth in several tumour models. Remarkably, antibodies against Dll4 and antibodies against vascular endothelial growth factor (VEGF) had paradoxically distinct effects on tumour vasculature. Our data also indicate that Dll4-mediated Notch signalling is crucial during active vascularization, but less important for normal vessel maintenance. Furthermore, unlike blocking Notch signalling globally, neutralizing Dll4 had no discernable impact on intestinal goblet cell differentiation, supporting the idea that Dll4-mediated Notch signalling is largely restricted to the vascular compartment. Therefore, targeting Dll4 might represent a broadly efficacious and well-tolerated approach for the treatment of solid tumours.

Blocking neuropilin-1 function has an additive effect with anti-VEGF to inhibit tumor growth

Neuropilin-1 (NRP1) guides the development of the nervous and vascular systems. Binding to either semaphorins or VEGF, NRP1 acts with plexins to regulate neuronal guidance, or with VEGFR2 to mediate vascular development. We have generated two monoclonal antibodies that bind to the Sema- and VEGF-binding domains of NRP1, respectively. Both antibodies reduce angiogenesis and vascular remodeling, while having little effect on other VEGFR2-mediated events. Importantly, anti-NRP1 antibodies have an additive effect with anti-VEGF therapy in reducing tumor growth. Vessels from tumors treated with anti-VEGF show a close association with pericytes, while tumors treated with both anti-NRP1 and anti-VEGF lack this organization. We propose that blocking NRP1 function inhibits vascular remodeling, rendering vessels more susceptible to anti-VEGF therapy.

Function blocking antibodies to neuropilin-1 generated from a designed human synthetic antibody phage library

Non-immune (naïve) antibody phage libraries have become an important source of human antibodies. The synthetic phage antibody library described here utilizes a single human framework with a template containing human consensus complementarity-determining regions (CDRs). Diversity of the libraries was introduced at select CDR positions using tailored degenerate and trinucleotide codons that mimic natural human antibodies. Neuropilin-1 (NRP1), a cell-surface receptor for both vascular endothelial growth factor (VEGF) and class 3 semaphorins, is expressed on endothelial cells and neurons. NRP1 is required for vascular development and is expressed widely in the developing vasculature. To investigate the possibility of function blocking antibodies to NRP1 as potential therapeutics, and study the consequence of targeting NRP1 in murine tumor models, panels of antibodies that cross-react with human and murine NRP1 were generated from a designed antibody phage library. Antibody (YW64.3) binds to the CUB domains (a1a2) of NRP1 and completely blocks Sema3A induced neuron collapse; antibody (YW107.4.87) binds to the coagulation factor V/VIII domains (b1b2) of NRP1 and blocks VEGF binding and VEGF induced cell migration. YW107.4.87 inhibits tumor growth in animal xenograft models. These antibodies have provided valuable tools to study the roles of NRP1 in vascular and tumor biology.

[Effect of postinfarct left ventricular dysfunction on late occurrence of mitral regurgitation--two year experience]

The aim of this study was to evaluate factors that might influence on the occurrence of mitral regurgitation (MR) in patients (pts) following myocardial infarction (MI) after fibrinolysis--two year experience. The study group comprised 118 pts: 40 women and 78 men (mean age: 58 +/- 9 years) following MI, who underwent Doppler echocardiography which revealed no MR 3 weeks after the MI. The second echocardiographic examination was performed after 2 years. We evaluated the following parameters: presence and stage of MR, left ventricular end-diastolic diameter (LVDD), left atrial diameter (LA), end-diastolic volume (EDV), wall motion score index (WMSI), asynergic area (AA) and ejection fraction (EF). Results after 2 years were as follows: 43 pts (36%) presented without MR, 45 (38%) MR I degree, 27 (23%) MR II degree, 3 (3%) MR III degree. Echocardiographic parameter comparison after 2 years demonstrated the following changes: LVDD increase from 5.0 +/- 0.5 cm to 5.3 +/- 4.6 cm (p < 0.005), LA increase from 3.7 +/- 0.4 cm to 4.3 +/- 0.4 cm (p < 0.00001), EDV increase from 130 +/- 29 ml to 147 +/- 39 ml (p < 0.005), WMSI increase from 1.37 +/- 0.23 to 1.45 +/- 0.21 (p < 0.05), AA increase from 23.5 +/- 10.1% to 27.8 +/- 7.9% (p < 0.005) and significant EF decrease 50.4 +/- 7.9% to 46.9 +/- 7.1% (p < 0.005). These results demonstrate that the occurrence of MR 2 years after the MI is caused by left ventricular remodelling, as well as segmental and global function deterioration.

[The activity of renin-angiotensin-aldosterone system (RAA) and possibilities of application angiotensin converting enzyme inhibitors (ACE I) in selected diseases of endocrine glands]

The aim of this presentation is evaluation of the renin-angiotensin-aldosterone system (RAA) in selected diseases of endocrine glands. In patients with acromegaly, Conn's syndrome, hyperparathyroidism, hyperthyroidism, hypothyroidism, phaeochromocytoma and Cushing's disease is possible to formulate the temporarily conclusions according to subsidiary meaning of angiotensin converting enzyme inhibitors (ACE I) in these endocrinopathies. Whereas the ACE I play an important role in the treatment of nephropathy and hypertension in diabetes mellitus.

[Coronary disease and hormonal treatment during the perimenopausal period]

Hormone replacement therapy (HRT) is widely recognized as probably most advisable treatment of perimenopausal women with cardiovascular disorders. Whenever HRT is administered for gynecological reasons, special attention should be paid to the presence of cardiological risk factors as these may be potentiated by high doses of gestogens. The authors undertake this problem inspired by a cases of a 53-years old patient (given oral lynestrol fair persisting uterine bleedings) who suffered from several complications, including venous thrombosis and myocardial infarction.

[Long term echocardiographic evaluation of thrombolytic therapy effect on regional function of and aneurysm formation in, the left ventricle in myocardial infarction]

The late effects of thrombolytic therapy on regional left ventricular function and ventricular aneurysm formation were evaluated in 91 patients with acute myocardial infarction by two-dimensional echocardiography performed at 12 weeks and after one year follow-up. 53 patients were randomized to streptokinase plus heparin and 38 patients to heparin therapy alone. Wall motion score index (WMSI), asynergic area (AA) and left ventricular aneurysm were assessed in serial echocardiographic examination. During examination at 12 weeks of acute myocardial infarction significant differences between both groups of patients showed: WMSI 1.43 +/- 0.42 vs 1.78 +/- 0.61 (p < 0.005), AA 26.3 +/- 20.4 vs 39.4 +/- 22.8 (p < 0.01), left ventricular aneurysm 3(5.7%) vs 10(26.3%) (p < 0.05). After one year of examination significant differences persisted: WMSI 1.35 +/- 0.42 vs 1.62 +/- 0.59 (p < 0.05) AA 23.2 +/- 22.2 vs 35.8 +/- 24.8 (p < 0.02), left ventricular aneurysm 3(6.1%) vs 9(25.7%) (p < 0.05). Our data indicate that thrombolytic therapy improves late regional left ventricular function in patients with acute myocardial infarction by reducing the extent of regional wall motion abnormalities. We find evident reduction in aneurysm formation due to acute myocardial infarction in survivors after 12 weeks of observation. The mentioned beneficial effects are noted at least up to one year after acute myocardial infarction.

[Clinical significance of mitral valve insufficiency detected by Doppler echocardiography in acute myocardial infarction]

Doppler echocardiography revealed in the third week of the recent myocardial infarction a pattern of mitral insufficiency in 27 (36%) of the 75 patients studied. Mitral insufficiency was usually associated with the more severe clinical course of myocardial infarction, with more frequent supraventricular and ventricular arrhythmias, heart failure, and with more extensive infarction area, as compared with the patients without mitral failure. A decreased contractibility of the left ventricle wall (especially in patients with anterior myocardial infarction accompanied by mitral insufficiency and enlargement ventricular dimension) may suggest its role in the development of mitral insufficiency in myocardial infarction. The results show the need of Doppler echocardiography in recent myocardial infarction to detect patients with an increased risk.

Identification of the predominant volatile compounds produced by Aspergillus flavus

A culture of Aspergillus flavus grown on moistened wheat meal was homogenized with a blendor, and the resulting slurry was vacuum-distilled at 5 mm of Hg and 35 C. The aqueous distillate was collected in traps cooled to -10 to -80 C. The culture volatiles were extracted from the distillate with CH(2)Cl(2), and, after removal of the bulk of the solvent, the concentrated volatiles were examined by packed-column gas chromatography. Nineteen peaks were observed, and coupled gas chromatography-mass spectrometry was employed to identify the larger components. The compounds identified were: 3-methyl-butanol, 3-octanone, 3-octanol, 1-octen-3-ol, 1-octanol, and cis-2-octen-1-ol. The two octenols were the predominant compounds, and sufficient sample was trapped from the gas chromatograph for infrared analyses; this confirmed the mass spectral identifications and permitted the assignment of the cis designation to 2-octen-1-ol. Both oct-1-en-3-ol and cis-2-octen-1-ol are thought to be responsible for the characteristic musty-fungal odor of certain fungi; the latter compound may be a useful chemical index of fungal growth.