19 results on '"Milanini, Julie"'
Search Results
2. In situ artificial contact sites (ISACS) between synthetic and endogenous organelle membranes allow for quantification of protein-tethering activities.
- Author
-
Milanini, Julie, Magdeleine, Maud, Fuggetta, Nicolas, Ikhlef, Souade, Brau, Frédéric, Abelanet, Sophie, Alpy, Fabien, Tomasetto, Catherine, and Drin, Guillaume
- Subjects
- *
MEMBRANE proteins , *IMMOBILIZED proteins , *RECOMBINANT proteins , *ENDOPLASMIC reticulum , *CELL membranes - Abstract
Membrane contact sites are specialized areas where the membranes of two distinct organelles are physically connected and allow for the exchange of molecules and for signaling processes. Understanding the mechanisms whereby proteins localize to and function in these structures is of special interest; however, methods allowing for reconstitution of these contact sites are few and only based on synthetic membranes and recombinant proteins. Here, we devised a strategy to create in situ artificial contact sites between synthetic and endogenous organelle membranes. Liposomes functionalized with a peptide containing a two phenylalanines in an acidic tract (FFAT) motif were added to adherent cells whose plasma membrane was perforated. Confocal and super-resolution microscopy revealed that these liposomes associated with the endoplasmic reticulum via the specific interaction of the FFAT motif with endoplasmic reticulum-resident vesicle-associated membrane protein-associated proteins. This approach allowed for quantification of the attachment properties of peptides corresponding to FFAT motifs derived from distinct proteins and of a protein construct derived from steroidogenic acute regulatory protein-related lipid transfer domain-3. Collectively, these data indicate that the creation of in situ artificial contact sites represents an efficient approach for studying the membranetethering activity of proteins and for designing membrane contact site reconstitution assays in cellular contexts. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Gene expression profiling of normal human pulmonary fibroblasts following coculture with non-small-cell lung cancer cells reveals alterations related to matrix degradation, angiogenesis, cell growth and survival
- Author
-
Fromigué, Olivia, Louis, Krystel, Dayem, Manal, Milanini, Julie, Pages, Gilles, Tartare-Deckert, Sophie, Ponzio, Gilles, Hofman, Paul, Barbry, Pascal, Auberger, Patrick, and Mari, Bernard
- Published
- 2003
- Full Text
- View/download PDF
4. Evidences that β1 integrin and Rac1 are involved in the overriding effect of laminin on myelin-associated glycoprotein inhibitory activity on neuronal cells
- Author
-
Laforest, Sullivan, Milanini, Julie, Parat, Fabrice, Thimonier, Jean, and Lehmann, Maxime
- Published
- 2005
- Full Text
- View/download PDF
5. Signaling Angiogenesis via p42/p44 MAP Kinase Cascade
- Author
-
PAGÈS, GILLES, MILANINI, JULIE, RICHARD, DARREN E., BERRA, EDURNE, GOTHIÉ, EMMANUEL, VIÑALS, FRANCESC, and POUYSSÉGUR, JACQUES
- Published
- 2000
6. EFA6 proteins regulate lumen formation through α-actinin 1
- Author
-
Milanini, Julie, Fayad, Racha, Partisani, Mariagrazia, Lecine, Patrick, Borg, Jean-Paul, Franco, Michel, Luton, Frédéric, MITOYAN, Louciné, Institut de pharmacologie moléculaire et cellulaire (IPMC), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA), Centre de Recherche en Cancérologie de Marseille (CRCM), Aix Marseille Université (AMU)-Institut Paoli-Calmettes, Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA), Centre National de la Recherche Scientifique (CNRS)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut Paoli-Calmettes, and Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Fédération nationale des Centres de lutte contre le Cancer (FNCLCC)-Aix Marseille Université (AMU)
- Subjects
[SDV] Life Sciences [q-bio] ,[SDV.CAN] Life Sciences [q-bio]/Cancer ,[SDV]Life Sciences [q-bio] ,Lumen ,[SDV.CAN]Life Sciences [q-bio]/Cancer ,Contractility ,EFA6 ,ACTN1 ,Epithelium - Abstract
International audience; A key step of epithelial morphogenesis is the creation of the lumen. Luminogenesis by hollowing proceeds through the fusion of apical vesicles at cell–cell contacts. The small nascent lumens grow through extension, coalescence and enlargement, coordinated with cell division, to give rise to a single central lumen. Here, by using MDCK cells grown in 3D-culture, we show that EFA6A (also known as PSD) participates in luminogenesis. EFA6A recruits α-actinin 1 (ACTN1) through direct binding. In polarized cells, ACTN1 was found to be enriched at the tight junction where it acts as a primary effector of EFA6A for normal luminogenesis. Both proteins are essential for the lumen extension and enlargement, where they mediate their effect by regulating the cortical acto-myosin contractility. Finally, ACTN1 was also found to act as an effector for the isoform EFA6B (also known as PSD4) in the human mammary tumoral MCF7 cell line. EFA6B restored the glandular morphology of this tumoral cell line in an ACTN1-dependent manner. Thus, we identified new regulators of cyst luminogenesis essential for the proper maturation of a newly-formed lumen into a single central lumen.
- Published
- 2018
7. EFA6 regulates lumen formation through alpha-actinin 1.
- Author
-
Milanini, Julie, Fayad, Racha, Partisani, Mariagrazia, Lecine, Patrick, Borg, Jean-Paul, Franco, Michel, and Luton, Frédéric
- Subjects
- *
GUANINE nucleotide exchange factors , *ACTININ , *CELL communication - Abstract
A key step of epithelial morphogenesis is the creation of the lumen. Luminogenesis by hollowing proceeds through the fusion of apical vesicles at cell-cell contact. The small nascent lumens grow through extension, coalescence and enlargement coordinated with cell division to give rise to a single central lumen. Here, using MDCK cells grown in 3D-culture, we show that EFA6A participates in luminogenesis. EFA6A recruits α-actinin 1 (ACTN1) through direct binding. In polarized cells, ACTN1 was found to be enriched at the tight junction where it acts as a primary effector of EFA6A for normal luminogenesis. Both proteins are essential for the lumen extension and enlargement, where they mediate their effect by regulating the cortical acto-myosin contractility. Finally, ACTN1 was also found to act as an effector for the isoform EFA6B in the human mammary tumoral MCF7 cell line. EFA6B restored the glandular morphology of this tumoral cell line in an ACTN1-dependent manner. Thus, we identified new regulators of cyst luminogenesis essential for the proper maturation of a newly-formed lumen into a single central lumen. [ABSTRACT FROM AUTHOR]
- Published
- 2017
8. USP9x-mediated deubiquitination of EFA6 regulates de novo tight junction assembly.
- Author
-
Théard, Delphine, Labarrade, Florian, Partisani, Mariagrazia, Milanini, Julie, Sakagami, Hiroyuki, Fon, Edward A., Wood, Stephen A., Franco, Michel, and Luton, Frédéric
- Subjects
TIGHT junctions ,PERMEABILITY ,ENZYMATIC analysis ,GENETIC regulation ,EPITHELIAL cells ,ORIGIN of life ,GENE expression - Abstract
In epithelial cells, the tight junction (TJ) functions as a permeability barrier and is involved in cellular differentiation and proliferation. Although many TJ proteins have been characterized, little is known about the sequence of events and temporal regulation of TJ assembly in response to adhesion cues. We report here that the deubiquitinating enzyme USP9x has a critical function in TJ biogenesis by controlling the levels of the exchange factor for Arf6 (EFA6), a protein shown to facilitate TJ formation, during a narrow temporal window preceding the establishment of cell polarity. At steady state, EFA6 is constitutively ubiquitinated and turned over by the proteasome. However, at newly forming contacts, USP9x-mediated deubiquitination protects EFA6 from proteasomal degradation, leading to a transient increase in EFA6 levels. Consistent with this model, USP9x and EFA6 transiently co-localize at primordial epithelial junctions. Furthermore, knockdown of either EFA6 or USP9x impairs TJ biogenesis and EFA6 overexpression rescues TJ biogenesis in USP9x-knockdown cells. As the loss of cell polarity is a critical event in the metastatic spread of cancer, these findings may help to understand the pathology of human carcinomas. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
9. Gα(q/11)-coupled P2Y2 nucleotide receptor inhibits human keratinocyte spreading and migration.
- Author
-
Taboubi, Salma, Milanini, Julie, Delamarre, Estelle, Parat, Fabrice, Garrouste, Françoise, Pommier, Gilbert, Takasaki, Jun, Hubaud, Jean-Claude, Kovacic, Hervé, and Lehmann, Maxime
- Subjects
- *
NUCLEOTIDES , *KERATINOCYTES , *CELL migration , *WOUND healing , *MITOGEN-activated protein kinases - Abstract
Reepithelialization is a critical step in wound healing. It is initiated by keratinocyte migration at the wound edges. After wounding, extracellular nucleotides are released by keratinocytes and other skin cells. Here, we report that activation of P2Y2 nucleotide receptor by ATP/UTP inhibits keratinocyte cell spreading and induces lamellipodium withdrawal. Kymography analysis demonstrates that these effects correlate with a durable decrease of lamellipodium dynamics. P2Y2 receptor activation also induces a dramatic dismantling of the actin network, the loss of α3 integrin expression at the cell periphery, and the dissolution of focal contacts as indicated by the alteration of αv integrins and focal contact protein distribution. In addition, activation of P2Y2R prevents growth factor-induced phosphorylation of Erk1,2 and Akt/PkB. The use of a specific pharmacological inhibitor (YM-254890), the depletion of Gα(q/11) by siRNA, or the expression of a constitutively active Gα(q/11) mutant (Q209L) show that activation of Gα(q/11) is responsible for these ATP/ UTP-induced effects. Finally, we report that ATP delays growth factor-induced wound healing of keratinocyte monolayers. Collectively, these findings provide evidence for a unique and important role for extracellular nucleotides as efficient autocrine/paracrine regulators of keratinocyte shape and migration during wound healing. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
10. EFA6B Antagonizes Breast Cancer.
- Author
-
Zangan, Joséphine, Partisani, Mariagrazia, Bertucci, François, Milanini, Julie, Bidaut, Ghislain, Berruyer-Pouyet, Carole, Finetti, Pascal, Long, Elodie, Brau, Frédéric, Cabaud, Olivier, Chetaille, Bruno, Birnbaum, Daniel, Lopez, Marc, Hofman, Paul, Franco, Michel, and Luton, Frédéric
- Subjects
- *
GUANINE nucleotide exchange factors , *BREAST cancer research , *CARCINOGENESIS , *CANCER cells , *IMMUNOHISTOCHEMISTRY - Abstract
One of the earliest events in epithelial carcinogenesis is the dissolution of tight junctions and cell polarity signals that are essential for normal epithelial barrier function. Here, we report that EFA6B, a guanine nucleotide exchange factor for the Ras superfamily protein Arf6 that helps assemble and stabilize tight junction, is required to maintain apico-basal cell polarity and mesenchymal phenotypes in mammary epithelial cells. In organotypic three-dimensional cell cultures, endogenous levels of EFA6B were critical to determine epithelial-mesenchymal status. EFA6B downregulation correlated with a mesenchymal phenotype and ectopic expression of EFA6B hampered TGFβ-induced epithelial-to-mesenchymal transition (EMT). Transcriptomic and immunohistochemical analyses of human breast tumors revealed that the reduced expression of EFA6B was associated with loss of tight junction components and with increased signatures of EMT, cancer stemness, and poor prognosis. Accordingly, tumors with low levels of EFA6B were enriched in the aggressive triple-negative and claudin-low breast cancer subtypes. Our results identify EFA6B as a novel antagonist in breast cancer and they point to its regulatory and signaling pathways as rational therapeutic targets in aggressive forms of this disease. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
11. Mechanisms Regulating Tumor Angiogenesis by 12-Lipoxygenase in Prostate Cancer Cells.
- Author
-
Daotai Nie, Krishnamoorthy, Sriram, Rongxian Jin, Keqin Tang, Yuchyu Chen, Van Qiao, Zacharek, Alex, Yande Guo, Milanini, Julie, Pages, Gilles, and Honn, Kenneth V.
- Subjects
- *
NEOVASCULARIZATION , *TUMORS , *LIPOXYGENASES , *OXYGENASES , *PROSTATE cancer , *CANCER cells - Abstract
12-Lipoxygenase utilizes arachidonic acid to synthesize 12(S)-hydroperoxyeicosatetraenoic acid, which is converted to the end product 12(S)-hydroxyeicosatetraenoic acid, an eicosanoid that promotes tumorigenesis and metastasis. Increased expression of 12-lipoxygenase has been documented in a number of carcinomas. When overexpressed in human prostate or breast cancer, 12-lipoxygenase promotes tumor angiogenesis and growth in vivo. The present study was undertaken to delineate the mechanisms by which 12-lipoxygenase enhances angiogenesis. Herein we report that nordihydroguaiaretic acid, a pan inhibitor of lipoxygenases and baicalein, a selective inhibitor of 12-lipoxygenase, reduced VEGF expression in human prostate cancer PC-3 cells. Overexpression of 12-lipoxygenase in PC-3 cells resulted in a 3-fold increase in VEGF protein level when compared with vector control cells. An increase in PI 3-kinase activity was found in 12-LOX-transfected PC-3 cells and inhibition of PI 3-kinase by LY294002 significantly reduced VEGF expression. Northern blot and real time PCR analyses revealed an elevated VEGF transcript level in PC-3 cells transfected with a 12-lipoxygenase expression construct. Using a VEGF promoter luciferase construct (-1761+54), we found a 10-fold increase in VEGF promoter activity in 12-lipoxygenase-transfected PC-3 cells. The region located between -88 and -66 of the VEGF promoter was identified as 12-lipoxygenase responsive using VEGF promoter-based luciferase assays. Further analysis with mutant constructs indicated Sp1 as a transcription factor required for 12-lipoxygenase stimulation of VEGF. Neutralization of VEGF by a function-blocking antibody significantly decreased the ability of 12-lipoxygenase-transfected PC-3 cells to stimulate endothelial cell migration, suggesting VEGF as an important effector for 12-lipoxygenase-mediated stimulation of tumor angiogenesis. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
12. Lipid Exchangers: Cellular Functions and Mechanistic Links With Phosphoinositide Metabolism.
- Author
-
Lipp NF, Ikhlef S, Milanini J, and Drin G
- Abstract
Lipids are amphiphilic molecules that self-assemble to form biological membranes. Thousands of lipid species coexist in the cell and, once combined, define organelle identity. Due to recent progress in lipidomic analysis, we now know how lipid composition is finely tuned in different subcellular regions. Along with lipid synthesis, remodeling and flip-flop, lipid transfer is one of the active processes that regulates this intracellular lipid distribution. It is mediated by Lipid Transfer Proteins (LTPs) that precisely move certain lipid species across the cytosol and between the organelles. A particular subset of LTPs from three families (Sec14, PITP, OSBP/ORP/Osh) act as lipid exchangers. A striking feature of these exchangers is that they use phosphatidylinositol or phosphoinositides (PIPs) as a lipid ligand and thereby have specific links with PIP metabolism and are thus able to both control the lipid composition of cellular membranes and their signaling capacity. As a result, they play pivotal roles in cellular processes such as vesicular trafficking and signal transduction at the plasma membrane. Recent data have shown that some PIPs are used as energy by lipid exchangers to generate lipid gradients between organelles. Here we describe the importance of lipid counter-exchange in the cell, its structural basis, and presumed links with pathologies., (Copyright © 2020 Lipp, Ikhlef, Milanini and Drin.)
- Published
- 2020
- Full Text
- View/download PDF
13. EFA6 proteins regulate lumen formation through α-actinin 1.
- Author
-
Milanini J, Fayad R, Partisani M, Lecine P, Borg JP, Franco M, and Luton F
- Subjects
- Animals, Dogs, Guanine Nucleotide Exchange Factors, Humans, MCF-7 Cells, Madin Darby Canine Kidney Cells, Protein Binding, Actinin metabolism, Morphogenesis, Nerve Tissue Proteins metabolism
- Abstract
A key step of epithelial morphogenesis is the creation of the lumen. Luminogenesis by hollowing proceeds through the fusion of apical vesicles at cell-cell contacts. The small nascent lumens grow through extension, coalescence and enlargement, coordinated with cell division, to give rise to a single central lumen. Here, by using MDCK cells grown in 3D-culture, we show that EFA6A (also known as PSD) participates in luminogenesis. EFA6A recruits α-actinin 1 (ACTN1) through direct binding. In polarized cells, ACTN1 was found to be enriched at the tight junction where it acts as a primary effector of EFA6A for normal luminogenesis. Both proteins are essential for the lumen extension and enlargement, where they mediate their effect by regulating the cortical acto-myosin contractility. Finally, ACTN1 was also found to act as an effector for the isoform EFA6B (also known as PSD4) in the human mammary tumoral MCF7 cell line. EFA6B restored the glandular morphology of this tumoral cell line in an ACTN1-dependent manner. Thus, we identified new regulators of cyst luminogenesis essential for the proper maturation of a newly-formed lumen into a single central lumen., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2018. Published by The Company of Biologists Ltd.)
- Published
- 2018
- Full Text
- View/download PDF
14. EFA6B antagonizes breast cancer.
- Author
-
Zangari J, Partisani M, Bertucci F, Milanini J, Bidaut G, Berruyer-Pouyet C, Finetti P, Long E, Brau F, Cabaud O, Chetaille B, Birnbaum D, Lopez M, Hofman P, Franco M, and Luton F
- Subjects
- Breast Neoplasms pathology, Cell Line, Tumor, Claudin-3 metabolism, Epithelial-Mesenchymal Transition, Female, Guanine Nucleotide Exchange Factors genetics, Guanine Nucleotide Exchange Factors metabolism, Humans, Middle Aged, RNA, Messenger genetics, Tight Junctions physiology, Breast Neoplasms physiopathology, Guanine Nucleotide Exchange Factors physiology
- Abstract
One of the earliest events in epithelial carcinogenesis is the dissolution of tight junctions and cell polarity signals that are essential for normal epithelial barrier function. Here, we report that EFA6B, a guanine nucleotide exchange factor for the Ras superfamily protein Arf6 that helps assemble and stabilize tight junction, is required to maintain apico-basal cell polarity and mesenchymal phenotypes in mammary epithelial cells. In organotypic three-dimensional cell cultures, endogenous levels of EFA6B were critical to determine epithelial-mesenchymal status. EFA6B downregulation correlated with a mesenchymal phenotype and ectopic expression of EFA6B hampered TGFβ-induced epithelial-to-mesenchymal transition (EMT). Transcriptomic and immunohistochemical analyses of human breast tumors revealed that the reduced expression of EFA6B was associated with loss of tight junction components and with increased signatures of EMT, cancer stemness, and poor prognosis. Accordingly, tumors with low levels of EFA6B were enriched in the aggressive triple-negative and claudin-low breast cancer subtypes. Our results identify EFA6B as a novel antagonist in breast cancer and they point to its regulatory and signaling pathways as rational therapeutic targets in aggressive forms of this disease., (©2014 American Association for Cancer Research.)
- Published
- 2014
- Full Text
- View/download PDF
15. G alpha(q/11)-coupled P2Y2 nucleotide receptor inhibits human keratinocyte spreading and migration.
- Author
-
Taboubi S, Milanini J, Delamarre E, Parat F, Garrouste F, Pommier G, Takasaki J, Hubaud JC, Kovacic H, and Lehmann M
- Subjects
- Cell Line, Tumor, Cells, Cultured, Humans, Pseudopodia physiology, Receptors, Purinergic P2Y2, Wound Healing physiology, Cell Migration Inhibition, Cell Movement physiology, GTP-Binding Protein alpha Subunits, Gq-G11 metabolism, Keratinocytes cytology, Keratinocytes metabolism, Receptors, Purinergic P2 physiology
- Abstract
Reepithelialization is a critical step in wound healing. It is initiated by keratinocyte migration at the wound edges. After wounding, extracellular nucleotides are released by keratinocytes and other skin cells. Here, we report that activation of P2Y2 nucleotide receptor by ATP/UTP inhibits keratinocyte cell spreading and induces lamellipodium withdrawal. Kymography analysis demonstrates that these effects correlate with a durable decrease of lamellipodium dynamics. P2Y2 receptor activation also induces a dramatic dismantling of the actin network, the loss of alpha3 integrin expression at the cell periphery, and the dissolution of focal contacts as indicated by the alteration of alpha(v) integrins and focal contact protein distribution. In addition, activation of P2Y2R prevents growth factor-induced phosphorylation of Erk(1,2) and Akt/PkB. The use of a specific pharmacological inhibitor (YM-254890), the depletion of G alpha(q/11) by siRNA, or the expression of a constitutively active G alpha(q/11) mutant (Q209L) show that activation of G alpha(q/11) is responsible for these ATP/UTP-induced effects. Finally, we report that ATP delays growth factor-induced wound healing of keratinocyte monolayers. Collectively, these findings provide evidence for a unique and important role for extracellular nucleotides as efficient autocrine/paracrine regulators of keratinocyte shape and migration during wound healing.
- Published
- 2007
- Full Text
- View/download PDF
16. Mechanisms regulating tumor angiogenesis by 12-lipoxygenase in prostate cancer cells.
- Author
-
Nie D, Krishnamoorthy S, Jin R, Tang K, Chen Y, Qiao Y, Zacharek A, Guo Y, Milanini J, Pages G, and Honn KV
- Subjects
- 12-Hydroxy-5,8,10,14-eicosatetraenoic Acid metabolism, Cell Line, Tumor, Cell Movement genetics, Chromones pharmacology, Endothelium, Vascular enzymology, Endothelium, Vascular pathology, Flavanones pharmacology, Humans, Lipoxygenase Inhibitors pharmacology, Male, Masoprocol pharmacology, Morpholines pharmacology, Neovascularization, Pathologic drug therapy, Neovascularization, Pathologic genetics, Phosphatidylinositol 3-Kinases biosynthesis, Phosphoinositide-3 Kinase Inhibitors, Promoter Regions, Genetic, Prostatic Neoplasms enzymology, Vascular Endothelial Growth Factor A genetics, Arachidonate 12-Lipoxygenase biosynthesis, Gene Expression Regulation, Neoplastic drug effects, Neovascularization, Pathologic enzymology, Prostatic Neoplasms blood supply, Vascular Endothelial Growth Factor A biosynthesis
- Abstract
12-Lipoxygenase utilizes arachidonic acid to synthesize 12(S)-hydroperoxyeicosatetraenoic acid, which is converted to the end product 12(S)-hydroxyeicosatetraenoic acid, an eicosanoid that promotes tumorigenesis and metastasis. Increased expression of 12-lipoxygenase has been documented in a number of carcinomas. When overexpressed in human prostate or breast cancer, 12-lipoxygenase promotes tumor angiogenesis and growth in vivo. The present study was undertaken to delineate the mechanisms by which 12-lipoxygenase enhances angiogenesis. Herein we report that nordihydroguaiaretic acid, a pan inhibitor of lipoxygenases and baicalein, a selective inhibitor of 12-lipoxygenase, reduced VEGF expression in human prostate cancer PC-3 cells. Overexpression of 12-lipoxygenase in PC-3 cells resulted in a 3-fold increase in VEGF protein level when compared with vector control cells. An increase in PI 3-kinase activity was found in 12-LOX-transfected PC-3 cells and inhibition of PI 3-kinase by LY294002 significantly reduced VEGF expression. Northern blot and real time PCR analyses revealed an elevated VEGF transcript level in PC-3 cells transfected with a 12-lipoxygenase expression construct. Using a VEGF promoter luciferase construct (-1176/+54), we found a 10-fold increase in VEGF promoter activity in 12-lipoxygenase-transfected PC-3 cells. The region located between -88 and -66 of the VEGF promoter was identified as 12-lipoxygenase responsive using VEGF promoter-based luciferase assays. Further analysis with mutant constructs indicated Sp1 as a transcription factor required for 12-lipoxygenase stimulation of VEGF. Neutralization of VEGF by a function-blocking antibody significantly decreased the ability of 12-lipoxygenase-transfected PC-3 cells to stimulate endothelial cell migration, suggesting VEGF as an important effector for 12-lipoxygenase-mediated stimulation of tumor angiogenesis.
- Published
- 2006
- Full Text
- View/download PDF
17. Evidences that beta1 integrin and Rac1 are involved in the overriding effect of laminin on myelin-associated glycoprotein inhibitory activity on neuronal cells.
- Author
-
Laforest S, Milanini J, Parat F, Thimonier J, and Lehmann M
- Subjects
- Animals, Antibodies pharmacology, Cattle, Cell Differentiation drug effects, Cell Differentiation physiology, Cell Line, Cell Line, Tumor, Cell Movement drug effects, Cell Movement physiology, Central Nervous System cytology, Central Nervous System embryology, Central Nervous System metabolism, Collagen metabolism, Collagen pharmacology, Dose-Response Relationship, Drug, Feedback, Physiological drug effects, Feedback, Physiological physiology, Growth Cones drug effects, Growth Cones metabolism, Growth Cones ultrastructure, Humans, Integrin alpha1beta1 metabolism, Laminin pharmacology, Mice, PC12 Cells, Rats, Receptors, Cell Surface drug effects, Receptors, Cell Surface metabolism, Signal Transduction drug effects, Signal Transduction physiology, Integrin beta1 metabolism, Laminin metabolism, Myelin-Associated Glycoprotein metabolism, Neurons metabolism, rac1 GTP-Binding Protein metabolism
- Abstract
During neurite elongation, migrating growth cones encounter both permissive and inhibitory substrates, such as laminin and MAG (myelin-associated glycoprotein), respectively. Here, we demonstrated on two neuronal cell lines (PC12 and N1E-115), that laminin and collagen hampered, in a dose-dependent manner, MAG inhibitory activity on several integrin functions, i.e., neurite growth, cell adhesion and cell spreading. Using a function blocking antibody, in PC12 cells, we showed that alpha1beta1 integrin is required in these phenomena. In parallel, we observed that MAG perturbs actin dynamics and lamellipodia formation during early steps of cell spreading. This seemed to be independent of RhoA activation, but dependent of Rac-1 inhibition by MAG. Laminin overrode MAG activity on actin and prevented MAG inhibition NGF-induced Rac1 activation. In conclusion, we evidenced antagonistic signaling between MAG receptors and beta1 integrins, in which Rac-1 may have a central function.
- Published
- 2005
- Full Text
- View/download PDF
18. Differential regulation of tumor angiogenesis by distinct ErbB homo- and heterodimers.
- Author
-
Yen L, Benlimame N, Nie ZR, Xiao D, Wang T, Al Moustafa AE, Esumi H, Milanini J, Hynes NE, Pages G, and Alaoui-Jamali MA
- Subjects
- Adenocarcinoma metabolism, Adenocarcinoma pathology, Animals, Butadienes metabolism, Cell Line, DNA-Binding Proteins metabolism, Dimerization, Endothelial Growth Factors genetics, Enzyme Inhibitors metabolism, ErbB Receptors chemistry, ErbB Receptors genetics, Genes, Reporter, Humans, Immunohistochemistry, Intercellular Signaling Peptides and Proteins genetics, Kruppel-Like Transcription Factors, Lymphokines genetics, Mice, Mice, Nude, Mitogen-Activated Protein Kinase 1 metabolism, Mitogen-Activated Protein Kinase 3, Mitogen-Activated Protein Kinases metabolism, Neoplasm Transplantation, Neoplasms metabolism, Neoplasms pathology, Neuregulin-1 metabolism, Nitriles metabolism, Promoter Regions, Genetic, Receptor, ErbB-2 chemistry, Receptor, ErbB-2 genetics, Receptor, ErbB-3 chemistry, Receptor, ErbB-3 genetics, Receptor, ErbB-4, Recombinant Fusion Proteins genetics, Recombinant Fusion Proteins metabolism, Signal Transduction physiology, Sp1 Transcription Factor metabolism, Transcription Factors metabolism, Transcription, Genetic, Transplantation, Heterologous, Up-Regulation, Vascular Endothelial Growth Factor A, Vascular Endothelial Growth Factors, Endothelial Growth Factors metabolism, ErbB Receptors metabolism, Intercellular Signaling Peptides and Proteins metabolism, Lymphokines metabolism, Neoplasms blood supply, Neovascularization, Pathologic, Receptor, ErbB-2 metabolism, Receptor, ErbB-3 metabolism
- Abstract
Interactions between cancer cells and their microenvironment are critical for the development and progression of solid tumors. This study is the first to examine the role of all members of the ErbB tyrosine kinase receptors (epidermal growth factor receptor [EGFR], ErbB-2, ErbB-3, or ErbB-4), expressed singly or as paired receptor combinations, in the regulation of angiogenesis both in vitro and in vivo. Comparison of all receptor combinations reveals that EGFR/ErbB-2 and ErbB-2/ErbB-3 heterodimers are the most potent inducers of vascular endothelial growth factor (VEGF) mRNA expression compared with EGFR/ErbB-3, EGFR/ErbB-4, ErbB-2/ErbB-4, and ErbB-3/ErbB-4. Immunohistochemistry of tumor xenografts overexpressing these heterodimers shows increased VEGF expression and remarkably enhanced vascularity. Enhanced VEGF expression is associated with increased VEGF transcription. Deletional analysis reveals that ErbB-mediated transcriptional up-regulation of VEGF involves a hypoxia-inducible factor 1-independent responsive region located between nucleotides -88 to -66 of the VEGF promoter. Mutational analysis reveals that the Sp-1 and AP-2 transcription factor binding elements within this region are required for up-regulation of VEGF by heregulin beta1 and that this up-regulation is dependent on the activity of extracellular signal-related protein kinases. These results emphasize the biological implications of cell signaling diversity among members of the ErbB receptor family in regulation of the tumor microenvironment.
- Published
- 2002
- Full Text
- View/download PDF
19. Transcriptional regulation of vascular endothelial growth factor by estradiol and tamoxifen in breast cancer cells: a complex interplay between estrogen receptors alpha and beta.
- Author
-
Buteau-Lozano H, Ancelin M, Lardeux B, Milanini J, and Perrot-Applanat M
- Subjects
- Breast Neoplasms genetics, Endothelial Growth Factors genetics, Estrogen Receptor alpha, Estrogen Receptor beta, Gene Expression Regulation, Neoplastic drug effects, Humans, Lymphokines genetics, Promoter Regions, Genetic, RNA, Messenger biosynthesis, RNA, Messenger genetics, Response Elements genetics, Transcription, Genetic drug effects, Transcription, Genetic physiology, Tumor Cells, Cultured, Up-Regulation drug effects, Vascular Endothelial Growth Factor A, Vascular Endothelial Growth Factors, Breast Neoplasms metabolism, Endothelial Growth Factors biosynthesis, Estradiol pharmacology, Lymphokines biosynthesis, Receptors, Estrogen physiology, Tamoxifen pharmacology
- Abstract
Vascular endothelial growth factor (VEGF) is a potent angiogenic and prognostic factor for many tumors, including those of endocrine-responsive tissues such as the breast and uterus. Recent studies indicate that 17beta-estradiol (E(2)) modulates VEGF expression in breast and uterine cells, involving transcriptional activation through estrogen receptor (ER) alpha. However, molecular mechanisms of VEGF regulation mediated by the two ER subtypes and the potential role of ERbeta in the control of breast cancer angiogenesis have not yet been investigated. In transient transfection assays using the VEGF(-2275/+54) promoter-luciferase construct, E(2) (1 nM) increased transcription activity in MCF-7 cells (either untransfected or cotransfected with ERalpha) and it increased transcription activity in MDA-MB-231 cells cotransfected with ERalpha or ERbeta (1.8- and 2-fold induction, respectively). The positive effect was abolished when MCF-7 cells were treated with pure antiestrogen ICI 182,780 or the agonist/antagonist tamoxifen (1 micro M). To identify response elements involved in this transcriptional regulation, MCF-7 or MDA-MB-231 cells were transfected with several deletion constructs of the VEGF promoter. Deletion of 1.2-2.3 kb upstream to the transcription start in the VEGF promoter abrogated E(2)-dependent transcription in these cells. This region contains an imperfect estrogen-responsive element (ERE), ERE1520, and one activator protein 1 site. Transfection of MCF-7 cells (ERalpha) with the ERE1520-luciferase construct conferred transcriptional activity with 1 nM E(2) (1.9-fold induction). Also, the imperfect ERE formed a complex with ERalpha or ERbeta proteins in gel shift assay using MCF-7 or MDA-MB-231 nuclear extracts. In contrast to ERalpha, ERbeta could transactivate VEGF reporter construct in MDA-MB-231 cells, in the presence of E(2) or tamoxifen, suggesting different transactivational mechanisms between ERalpha and ERbeta in the presence of tamoxifen. Interestingly, E(2) inhibited VEGF transcription in MCF-7 cells transfected with ERbeta or MDA-MB-231 cells cotransfected with ERalpha and ERbeta, suggesting that heterodimerization of ERalpha/ERbeta has the ability to inhibit E(2)-induced VEGF expression in breast cancer cells. These results demonstrate that VEGF is a target gene for ERalpha and ERbeta in breast cancer cells; it remains to be determined whether ERalpha and ERbeta expression in breast biopsies correlates with VEGF expression and vascular density.
- Published
- 2002
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.