The Experts below are selected from a list of 552 Experts worldwide ranked by ideXlab platform
Anita Sjolander - One of the best experts on this subject based on the ideXlab platform.
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anti angiogenic action of leukotriene c4 induced 15 hydroxyprostaglandin dehydrogenase in colon cancer cells is a tnf α dependent phenomenon
Annals of Oncology, 2018Co-Authors: Shakti Ranjan Satapathy, Anita SjolanderAbstract:Introduction: Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Cyclooxygenase-2 (COX-2), which plays a key role in the biosynthesis of prostaglandin E2 (PGE2), is often up-regulated in CRC and in other types of cancer. PGE2 induces angiogenesis and tumor cell survival, proliferation and migration. The tumor suppressor 15-hydroxyprostaglandin dehydrogenase (15-PGDH) is a key enzyme in PGE2 catabolism, converting it into its inactive metabolite 15-keto-PGE2 and is often down-regulated in cancer. Interesting enough, CRC patients expressing high levels of Cysteinyl leukotriene receptor 2 (CysLTR2) have a good prognosis and therefore, we investigated a potential link between CysLTR2-signaling and the tumor suppressor 15-PGDH in colon cancer cells. In the other hand, TNF-α is considered as the main regulator of COX-2 and mPGES-1 that contribute to the increased synthesis of PGE2, which is inhibited by overexpressed 15-PGDH. Level of the pro-tumorigenic PGE2 is increased in CRC, previously attributed to increased production via TNF-α mediated COX-2 up-regulation but more recently attributed to decreased catabolism due to down-regulation of 15-PGDH.Methods: HT-29 and Caco-2 cells were employed for this study. Unstimulated and LTC4 stimulated cells were compared for various markers through qRT-PCR as well as immunoblotting analysis. Vibrant-DiI labeled HT-29 cells were used for the zebrafish metastasis model. Visualization of the metastatic spread was observed using the light sheet microscopy (SPIM) and tissue sections were analyzed by immunohistochemistry for specific markers. Conditioned media from the unstimulated and LTC4 stimulated HT-29 cells were used to analyze the endothelial tube formation in HUVEC.Results: Elevation of 15-PGDH expression by leukotriene C4 (LTC4), a CysLTR2 ligand, exhibited anti-tumor activity in colon cancer cells with significant phosphorylation of β-catenin and down-regulation of anti-apoptotic marker Bcl-2 with concurrent activation of CASPASE-3 expression. We also observed a dramatic down-regulation of TNF-α on mRNA level and NF-κβ on both mRNA as well as protein level with LTC4 induced 15-PGDH in a TNF-α dependent manner. Moreover, TNF-α regulated anti-angiogenic action of 15-PGDH in HT-29 and Caco-2 colon cancer cells by depleting the mRNA level of MMP-2 and MMP-9 and protein level of VEGFR-1. Furthermore, we also observed disrupted tube formation in HUVEC with LTC4 induced 15-PGDH which is also governed by TNF-α. The angiogenesis study in transgenic zebrafish, Tg(fli1a: EGFP) embryo model suggested significant decrease in early and late metastasis with distinct disruption in the Intersegmental Vessel in the LTC4 induced 15-PGDH treated group. IHC analysis of Ki-67 exhibited decrease with LTC4 and very interestingly CASPASE-3 showed increase in the stimulated group which supported our in vitro observation.Conclusion: Hence, restoration of 15-PGDH expression through CysLTR2-signaling promotes the anti-angiogenic action against colon cancer cells, indicating an anti-tumor as well as the anti-metastatic efficacy of CysLTR2-signaling. (Less)
Chingling Lien - One of the best experts on this subject based on the ideXlab platform.
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platelet derived growth factor receptor β is critical for zebrafish Intersegmental Vessel formation
PLOS ONE, 2010Co-Authors: Katie M Wiens, Hyuna L Lee, Hiroyuki Shimada, Anthony E Metcalf, Michael Y Chao, Chingling LienAbstract:Background Platelet-derived growth factor receptor β (PDGFRβ) is a tyrosine kinase receptor known to affect vascular development. The zebrafish is an excellent model to study specific regulators of vascular development, yet the role of PDGF signaling has not been determined in early zebrafish embryos. Furthermore, vascular mural cells, in which PDGFRβ functions cell autonomously in other systems, have not been identified in zebrafish embryos younger than 72 hours post fertilization. Methodology/Principal Findings In order to investigate the role of PDGFRβ in zebrafish vascular development, we cloned the highly conserved zebrafish homolog of PDGFRβ. We found that pdgfrβ is expressed in the hypochord, a developmental structure that is immediately dorsal to the dorsal aorta and potentially regulates blood Vessel development in the zebrafish. Using a PDGFR tyrosine kinase inhibitor, a morpholino oligonucleotide specific to PDGFRβ, and a dominant negative PDGFRβ transgenic line, we found that PDGFRβ is necessary for angiogenesis of the Intersegmental Vessels. Significance/Conclusion Our data provide the first evidence that PDGFRβ signaling is required for zebrafish angiogenesis. We propose a novel mechanism for zebrafish PDGFRβ signaling that regulates vascular angiogenesis in the absence of mural cells.
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Platelet-derived growth factor receptor beta is critical for zebrafish Intersegmental Vessel formation.
Public Library of Science (PLoS), 2010Co-Authors: Katie M Wiens, Hyuna L Lee, Hiroyuki Shimada, Anthony E Metcalf, Michael Y Chao, Chingling LienAbstract:Platelet-derived growth factor receptor beta (PDGFRbeta) is a tyrosine kinase receptor known to affect vascular development. The zebrafish is an excellent model to study specific regulators of vascular development, yet the role of PDGF signaling has not been determined in early zebrafish embryos. Furthermore, vascular mural cells, in which PDGFRbeta functions cell autonomously in other systems, have not been identified in zebrafish embryos younger than 72 hours post fertilization.In order to investigate the role of PDGFRbeta in zebrafish vascular development, we cloned the highly conserved zebrafish homolog of PDGFRbeta. We found that pdgfrbeta is expressed in the hypochord, a developmental structure that is immediately dorsal to the dorsal aorta and potentially regulates blood Vessel development in the zebrafish. Using a PDGFR tyrosine kinase inhibitor, a morpholino oligonucleotide specific to PDGFRbeta, and a dominant negative PDGFRbeta transgenic line, we found that PDGFRbeta is necessary for angiogenesis of the Intersegmental Vessels.Our data provide the first evidence that PDGFRbeta signaling is required for zebrafish angiogenesis. We propose a novel mechanism for zebrafish PDGFRbeta signaling that regulates vascular angiogenesis in the absence of mural cells
Holger Gerhardt - One of the best experts on this subject based on the ideXlab platform.
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artery vein specification in the zebrafish trunk is pre patterned by heterogeneous notch activity and balanced by flow mediated fine tuning
Development, 2019Co-Authors: Ilse Geudens, Katja Meier, Baptiste Coxam, Silvanus Alt, Veronique Gebala, Anneclemence Vion, Andre Rosa, Holger GerhardtAbstract:ABSTRACT How developing vascular networks acquire the right balance of arteries, veins and lymphatic Vessels to efficiently supply and drain tissues is poorly understood. In zebrafish embryos, the robust and regular 50:50 global balance of Intersegmental veins and arteries that form along the trunk prompts the intriguing question of how does the organism keep ‘count’? Previous studies have suggested that the ultimate fate of an Intersegmental Vessel (ISV) is determined by the identity of the approaching secondary sprout emerging from the posterior cardinal vein. Here, we show that the formation of a balanced trunk vasculature involves an early heterogeneity in endothelial cell behaviour and Notch signalling activity in the seemingly identical primary ISVs that is independent of secondary sprouting and flow. We show that Notch signalling mediates the local patterning of ISVs, and an adaptive flow-mediated mechanism subsequently fine-tunes the global balance of arteries and veins along the trunk. We propose that this dual mechanism provides the adaptability required to establish a balanced network of arteries, veins and lymphatic Vessels.
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Filopodia are dispensable for endothelial tip cell guidance
Development (Cambridge England), 2013Co-Authors: Li-kun Phng, Fabio Stanchi, Holger GerhardtAbstract:Actin filaments are instrumental in driving processes such as migration, cytokinesis and endocytosis and provide cells with mechanical support. During angiogenesis, actin-rich filopodia protrusions have been proposed to drive endothelial tip cell functions by translating guidance cues into directional migration and mediating new contacts during anastomosis. To investigate the structural organisation, dynamics and functional importance of F-actin in endothelial cells (ECs) during angiogenesis in vivo, we generated a transgenic zebrafish line expressing Lifeact-EGFP in ECs. Live imaging identifies dynamic and transient F-actin-based structures, such as filopodia, contractile ring and cell cortex, and more persistent F-actin-based structures, such as cell junctions. For functional analysis, we used low concentrations of Latrunculin B that preferentially inhibited F-actin polymerisation in filopodia. In the absence of filopodia, ECs continued to migrate, albeit at reduced velocity. Detailed morphological analysis reveals that ECs generate lamellipodia that are sufficient to drive EC migration when filopodia formation is inhibited. Vessel guidance continues unperturbed during Intersegmental Vessel development in the absence of filopodia. Additionally, hypersprouting induced by loss of Dll4 and attraction of aberrant Vessels towards ectopic sources of Vegfa165 can occur in the absence of endothelial filopodia protrusion. These results reveal that the induction of tip cells and the integration of endothelial guidance cues do not require filopodia. Anastomosis, however, shows regional variations in filopodia requirement, suggesting that ECs might rely on different protrusive structures depending on the nature of the environment or of angiogenic cues.
Shakti Ranjan Satapathy - One of the best experts on this subject based on the ideXlab platform.
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anti angiogenic action of leukotriene c4 induced 15 hydroxyprostaglandin dehydrogenase in colon cancer cells is a tnf α dependent phenomenon
Annals of Oncology, 2018Co-Authors: Shakti Ranjan Satapathy, Anita SjolanderAbstract:Introduction: Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. Cyclooxygenase-2 (COX-2), which plays a key role in the biosynthesis of prostaglandin E2 (PGE2), is often up-regulated in CRC and in other types of cancer. PGE2 induces angiogenesis and tumor cell survival, proliferation and migration. The tumor suppressor 15-hydroxyprostaglandin dehydrogenase (15-PGDH) is a key enzyme in PGE2 catabolism, converting it into its inactive metabolite 15-keto-PGE2 and is often down-regulated in cancer. Interesting enough, CRC patients expressing high levels of Cysteinyl leukotriene receptor 2 (CysLTR2) have a good prognosis and therefore, we investigated a potential link between CysLTR2-signaling and the tumor suppressor 15-PGDH in colon cancer cells. In the other hand, TNF-α is considered as the main regulator of COX-2 and mPGES-1 that contribute to the increased synthesis of PGE2, which is inhibited by overexpressed 15-PGDH. Level of the pro-tumorigenic PGE2 is increased in CRC, previously attributed to increased production via TNF-α mediated COX-2 up-regulation but more recently attributed to decreased catabolism due to down-regulation of 15-PGDH.Methods: HT-29 and Caco-2 cells were employed for this study. Unstimulated and LTC4 stimulated cells were compared for various markers through qRT-PCR as well as immunoblotting analysis. Vibrant-DiI labeled HT-29 cells were used for the zebrafish metastasis model. Visualization of the metastatic spread was observed using the light sheet microscopy (SPIM) and tissue sections were analyzed by immunohistochemistry for specific markers. Conditioned media from the unstimulated and LTC4 stimulated HT-29 cells were used to analyze the endothelial tube formation in HUVEC.Results: Elevation of 15-PGDH expression by leukotriene C4 (LTC4), a CysLTR2 ligand, exhibited anti-tumor activity in colon cancer cells with significant phosphorylation of β-catenin and down-regulation of anti-apoptotic marker Bcl-2 with concurrent activation of CASPASE-3 expression. We also observed a dramatic down-regulation of TNF-α on mRNA level and NF-κβ on both mRNA as well as protein level with LTC4 induced 15-PGDH in a TNF-α dependent manner. Moreover, TNF-α regulated anti-angiogenic action of 15-PGDH in HT-29 and Caco-2 colon cancer cells by depleting the mRNA level of MMP-2 and MMP-9 and protein level of VEGFR-1. Furthermore, we also observed disrupted tube formation in HUVEC with LTC4 induced 15-PGDH which is also governed by TNF-α. The angiogenesis study in transgenic zebrafish, Tg(fli1a: EGFP) embryo model suggested significant decrease in early and late metastasis with distinct disruption in the Intersegmental Vessel in the LTC4 induced 15-PGDH treated group. IHC analysis of Ki-67 exhibited decrease with LTC4 and very interestingly CASPASE-3 showed increase in the stimulated group which supported our in vitro observation.Conclusion: Hence, restoration of 15-PGDH expression through CysLTR2-signaling promotes the anti-angiogenic action against colon cancer cells, indicating an anti-tumor as well as the anti-metastatic efficacy of CysLTR2-signaling. (Less)
Manuel A S Santos - One of the best experts on this subject based on the ideXlab platform.
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dre mir 2188 targets nrp2a and mediates proper Intersegmental Vessel development in zebrafish embryos
PLOS ONE, 2012Co-Authors: Ana R Soares, Marisa Reverendo, Patricia M Pereira, Olivier Nivelles, Helene Pendeville, Ana R Bezerra, Gabriela Moura, Ingrid Struman, Manuel A S SantosAbstract:Background MicroRNAs (miRNAs) are a class of small RNAs that are implicated in the control of eukaryotic gene expression by binding to the 3′UTR of target mRNAs. Several algorithms have been developed for miRNA target prediction however, experimental validation is still essential for the correct identification of miRNA targets. We have recently predicted that Neuropilin2a (Nrp2a), a vascular endothelial growth factor receptor which is essential for normal developmental angiogenesis in zebrafish, is a dre-miR-2188 target. Methodology Here we show that dre-miR-2188 targets the 3′-untranslated region (3′UTR) of Nrp2a mRNA and is implicated in proper Intersegmental Vessel development in vivo. Over expression of miR-2188 in zebrafish embryos down regulates Nrp2a expression and results in Intersegmental Vessel disruption, while its silencing increases Nrp2a expression and Intersegmental Vessel sprouting. An in vivo GFP sensor assay based on a fusion between the GFP coding region and the Nrp2a 3′UTR confirms that miR-2188 binds to the 3′UTR of Nrp2a and inhibits protein translation. Conclusions We demonstrate that miR-2188 targets Nrp2a and affects Intersegmental Vessel development in zebrafish embryos.
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Analysis of blood Vessel formation in Tg(flk1-GFP)s843 embryos.
2012Co-Authors: Ana R Soares, Marisa Reverendo, Patricia M Pereira, Olivier Nivelles, Helene Pendeville, Ingrid Struman, Ana Rita Bezerra, Gabriela R. Moura, Manuel A S SantosAbstract:A) Representation of the zebrafish circulatory system showing the major structures (DLAV - Dorsal Longitudinal Anastomotic Vessel; ISV – Intersegmental Vessel; DA – Dorsal Aorta; PCV – Posterior Cardinal Vein). B) Visualization of 24 hpf embryo blood Vessels using fluorescence microscopy. After miR-2188 duplex microinjection under developed and absent ISVs were observed, non injected and scrambled duplex injected embryos did not show such defects. C) Visualization of 48 hpf embryo blood Vessels using confocal microscopy (20x). ISVs of miR-2188 injected embryos were thinner than those of non injected and scrambled duplex injected embryos and displayed ISV’s patterning defects (arrows). MOmiR-2188 injected embryos revealed DLAV defects and branching of ISVs (arrows). Images shown in D) and E) are 60x amplification images of miR-2188 duplex and miR-2188-MO injected embryos, respectively.
