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1.  Identification of p130Cas/ErbB2-dependent invasive signatures in transformed mammary epithelial cells 
Cell Cycle  2013;12(15):2409-2422.
Understanding transcriptional changes during cancer progression is of crucial importance to develop new and more efficacious diagnostic and therapeutic approaches. It is well known that ErbB2 is overexpressed in about 25% of human invasive breast cancers. We have previously demonstrated that p130Cas overexpression synergizes with ErbB2 in mammary cell transformation and promotes ErbB2-dependent invasion in three-dimensional (3D) cultures of human mammary epithelial cells. Here, by comparing coding and non-coding gene expression profiles, we define the invasive signatures associated with concomitant p130Cas overexpression and ErbB2 activation in 3D cultures of mammary epithelial cells. Specifically, we have found that genes involved in amino acids synthesis (CBS, PHGDH), cell motility, migration (ITPKA, PRDM1), and angiogenesis (HEY1) are upregulated, while genes involved in inflammatory response (SAA1, S100A7) are downregulated. In parallel, we have shown that the expression of specific miRNAs is altered. Among these, miR-200b, miR-222, miR-221, miR-R210, and miR-424 are upregulated, while miR-27a, miR-27b, and miR-23b are downregulated. Overall, this study presents, for the first time, the gene expression changes underlying the invasive behavior following p130Cas overexpression in an ErbB2 transformed mammary cell model.
PMCID: PMC3841320  PMID: 23839042
p130Cas; ErbB2; breast cancer; invasion; gene expression; miRNA
2.  Heme Exporter FLVCR1a Regulates Heme Synthesis and Degradation and Controls Activity of Cytochromes P450 
Gastroenterology  2014;146(5):1325-1338.
Background & Aims
The liver has one of the highest rates of heme synthesis of any organ. More than 50% of the heme synthesized in the liver is used for synthesis of P450 enzymes, which metabolize exogenous and endogenous compounds that include natural products, hormones, drugs, and carcinogens. Feline leukemia virus subgroup C cellular receptor 1a (FLVCR1a) is plasma membrane heme exporter that is ubiquitously expressed and controls intracellular heme content in hematopoietic lineages. We investigated the role of Flvcr1a in liver function in mice.
We created mice with conditional disruption of Mfsd7b, which encodes Flvcr1a, in hepatocytes (Flvcr1afl/fl;alb-cre mice). Mice were analyzed under basal conditions, after phenylhydrazine-induced hemolysis, and after induction of cytochromes P450 synthesis. Livers were collected and analyzed by histologic, quantitative real-time polymerase chain reaction, and immunoblot analyses. Hepatic P450 enzymatic activities were measured.
Flvcr1afl/fl;alb-cre mice accumulated heme and iron in liver despite up-regulation of heme oxygenase 1, ferroportin, and ferritins. Hepatic heme export activity of Flvcr1a was closely associated with heme biosynthesis, which is required to sustain cytochrome induction. Upon cytochromes P450 stimulation, Flvcr1afl/fl;alb-cre mice had reduced cytochrome activity, associated with accumulation of heme in hepatocytes. The expansion of the cytosolic heme pool in these mice was likely responsible for the early inhibition of heme synthesis and increased degradation of heme, which reduced expression and activity of cytochromes P450.
In livers of mice, Flvcr1a maintains a free heme pool that regulates heme synthesis and degradation as well as cytochromes P450 expression and activity. These findings have important implications for drug metabolism.
PMCID: PMC4000440  PMID: 24486949
ALAS1; CYP; Flvcr; HO-1; Flvcr1; ALA, 5-aminolevulinic acid; ALAS, 5-aminolevulinic acid synthase; Be(a)P, benzo(a)pyrene; CYP, cytochrome P450; FLVCR1a, feline leukemia virus subgroup C cellular receptor 1a; Fpn, ferroportin; HO, heme oxygenase; mRNA, messenger RNA
3.  Mice lacking mitochondrial ferritin are more sensitive to doxorubicin-mediated cardiotoxicity 
Mitochondrial ferritin is a functional ferritin that localizes in the mitochondria. It is expressed in the testis, heart, brain, and cells with active respiratory activity. Its overexpression in cultured cells protected against oxidative damage and reduced cytosolic iron availability. However, no overt phenotype was described in mice with inactivation of the FtMt gene. Here, we used the doxorubicin model of cardiac injury in a novel strain of FtMt-null mice to investigate the antioxidant role of FtMt. These mice did not show any evident phenotype, but after acute treatment to doxorubicin, they showed enhanced mortality and altered heart morphology with fibril disorganization and severe mitochondrial damage. Signs of mitochondrial damage were present also in mock-treated FtMt−/− mice. The hearts of saline- and doxorubicin-treated FtMt−/− mice had higher thiobarbituric acid reactive substance levels, heme oxygenase 1 expression, and protein oxidation, but did not differ from FtMt+/+ in the cardiac damage marker B-type natriuretic peptide (BNP), ATP levels, and apoptosis. However, the autophagy marker LC3 was activated. The results show that the absence of FtMt, which is highly expressed in the heart, increases the sensitivity of heart mitochondria to the toxicity of doxorubicin. This study represents the first in vivo evidence of the antioxidant role of FtMt.
Key message
Mitochondrial ferritin (FtMt) expressed in the heart has a protective antioxidant role.Acute treatment with doxorubicin caused the death of all FtMt−/− and only of 60 % FtMt+/+ mice.The hearts of FtMt−/− mice showed fibril disorganization and mitochondrial damage.Markers of oxidative damage and autophagy were increased in FtMt−/− hearts.This is the first in vivo evidence of the antioxidant role of FtMt.
Electronic supplementary material
The online version of this article (doi:10.1007/s00109-014-1147-0) contains supplementary material, which is available to authorized users.
PMCID: PMC4118045  PMID: 24728422
Ferritin; Oxidative damage; Mitochondria; Doxorubicin
4.  Identification of two regions in the p140Cap adaptor protein that retain the ability to suppress tumor cell properties 
p140Cap is an adaptor protein that negatively controls tumor cell properties, by inhibiting in vivo tumor growth and metastasis formation. Our previous data demonstrated that p140Cap interferes with tumor growth and impairs invasive properties of cancer cells inactivating signaling pathways, such as the tyrosine kinase Src or E-cadherin/EGFR cross-talk. In breast cancer p140Cap expression inversely correlates with tumor malignancy. p140Cap is composed of several conserved domains that mediate association with specific partners. Here we focus our attention on two domains of p140Cap, the TER (Tyrosine Enriched Region) which includes several tyrosine residues, and the CT (Carboxy Terminal) which contains a proline rich sequence, involved in binding to SH2 and SH3 domains, respectively. By generating stable cell lines expressing these two proteins, we demonstrate that both TER and CT domains maintain the ability to associate the C-terminal Src kinase (Csk) and Src, to inhibit Src activation and Focal adhesion kinase (Fak) phosphorylation, and to impair in vitro and in vivo tumor cell features. In particular expression of TER and CT proteins in cancer cells inhibits in vitro and in vivo growth and directional migration at a similar extent of the full length p140Cap protein. Moreover, by selective point mutations and deletion we show that the ability of the modules to act as negative regulators of cell migration and proliferation mainly resides on the two tyrosines (Y) inserted in the EPLYA and EGLYA sequences in the TER module and in the second proline-rich stretch contained in the CT protein. Gene signature of cells expressing p140Cap, TER or CT lead to the identification of a common pattern of 105 down-regulated and 128 up-regulated genes, suggesting that the three proteins can act through shared pathways. Overall, this work highlights that the TER and CT regions of p140Cap can efficiently suppress tumor cell properties, opening the perspective that short, defined p140Cap regions can have therapeutic effects.
PMCID: PMC3696535  PMID: 23841028
p140Cap; breast cancer; lung cancer; colon cancer; cell signaling; Csk; Src
5.  Mapping of p140Cap Phosphorylation Sites: The EPLYA and EGLYA Motifs Have a Key Role in Tyrosine Phosphorylation and Csk Binding, and Are Substrates of the Abl Kinase 
PLoS ONE  2013;8(1):e54931.
Protein phosphorylation tightly regulates specific binding of effector proteins that control many diverse biological functions of cells (e. g. signaling, migration and proliferation). p140Cap is an adaptor protein, specifically expressed in brain, testis and epithelial cells, that undergoes phosphorylation and tunes its interactions with other regulatory molecules via post-translation modification. In this work, using mass spectrometry, we found that p140Cap is in vivo phosphorylated on tyrosine (Y) within the peptide GEGLpYADPYGLLHEGR (from now on referred to as EGLYA) as well as on three serine residues. Consistently, EGLYA has the highest score of in silico prediction of p140Cap phosphorylation. To further investigate the p140Cap function, we performed site specific mutagenesis on tyrosines inserted in EGLYA and EPLYA, a second sequence with the same highest score of phosphorylation. The mutant protein, in which both EPLYA/EGLYA tyrosines were converted to phenylalanine, was no longer tyrosine phosphorylated, despite the presence of other tyrosine residues in p140Cap sequence. Moreover, this mutant lost its ability to bind the C-terminal Src kinase (Csk), previously shown to interact with p140Cap by Far Western analysis. In addition, we found that in vitro and in HEK-293 cells, the Abelson kinase is the major kinase involved in p140Cap tyrosine phosphorylation on the EPLYA and EGLYA sequences. Overall, these data represent an original attempt to in vivo characterise phosphorylated residues of p140Cap. Elucidating the function of p140Cap will provide novel insights into its biological activity not only in normal cells, but also in tumors.
PMCID: PMC3561454  PMID: 23383002
6.  Ubiad1 Is an Antioxidant Enzyme that Regulates eNOS Activity by CoQ10 Synthesis 
Cell  2013;152(3):504-518.
Protection against oxidative damage caused by excessive reactive oxygen species (ROS) by an antioxidant network is essential for the health of tissues, especially in the cardiovascular system. Here, we identified a gene with important antioxidant features by analyzing a null allele of zebrafish ubiad1, called barolo (bar). bar mutants show specific cardiovascular failure due to oxidative stress and ROS-mediated cellular damage. Human UBIAD1 is a nonmitochondrial prenyltransferase that synthesizes CoQ10 in the Golgi membrane compartment. Loss of UBIAD1 reduces the cytosolic pool of the antioxidant CoQ10 and leads to ROS-mediated lipid peroxidation in vascular cells. Surprisingly, inhibition of eNOS prevents Ubiad1-dependent cardiovascular oxidative damage, suggesting a crucial role for this enzyme and nonmitochondrial CoQ10 in NO signaling. These findings identify UBIAD1 as a nonmitochondrial CoQ10-forming enzyme with specific cardiovascular protective function via the modulation of eNOS activity.
Graphical Abstract
► UBIAD1 is a Golgi prenyltransferase ► UBIAD1 contributes to the nonmitochondrial pool of CoQ10 ► UBIAD1 protects cardiovascular tissues from NOS-dependent oxidative damage ► UBIAD1 is a target for therapeutic strategies by limiting the side effects of statins
UBIAD1 is identified as a nonmitochondrial CoQ10 biosynthetic enzyme required for oxidative damage protection. Through CoQ10 synthesis, UBIAD1 modulates endothelial nitric oxide synthase activity and nitric oxide signaling necessary for cardiovascular development and homeostasis.
PMCID: PMC3574195  PMID: 23374346
7.  p130Cas Over-Expression Impairs Mammary Branching Morphogenesis in Response to Estrogen and EGF 
PLoS ONE  2012;7(12):e49817.
p130Cas adaptor protein regulates basic processes such as cell cycle control, survival and migration. p130Cas over-expression has been related to mammary gland transformation, however the in vivo consequences of p130Cas over-expression during mammary gland morphogenesis are not known. In ex vivo mammary explants from MMTV-p130Cas transgenic mice, we show that p130Cas impairs the functional interplay between Epidermal Growth Factor Receptor (EGFR) and Estrogen Receptor (ER) during mammary gland development. Indeed, we demonstrate that p130Cas over-expression upon the concomitant stimulation with EGF and estrogen (E2) severely impairs mammary morphogenesis giving rise to enlarged multicellular spherical structures with altered architecture and absence of the central lumen. These filled acinar structures are characterized by increased cell survival and proliferation and by a strong activation of Erk1/2 MAPKs and Akt. Interestingly, antagonizing the ER activity is sufficient to re-establish branching morphogenesis and normal Erk1/2 MAPK activity. Overall, these results indicate that high levels of p130Cas expression profoundly affect mammary morphogenesis by altering epithelial architecture, survival and unbalancing Erk1/2 MAPKs activation in response to growth factors and hormones. These results suggest that alteration of morphogenetic pathways due to p130Cas over-expression might prime mammary epithelium to tumorigenesis.
PMCID: PMC3519769  PMID: 23239970
8.  The mitochondrial heme exporter FLVCR1b mediates erythroid differentiation 
The Journal of Clinical Investigation  2012;122(12):4569-4579.
Feline leukemia virus subgroup C receptor 1 (FLVCR1) is a cell membrane heme exporter that maintains the balance between heme levels and globin synthesis in erythroid precursors. It was previously shown that Flvcr1-null mice died in utero due to a failure of erythropoiesis. Here, we identify Flvcr1b, a mitochondrial Flvcr1 isoform that promotes heme efflux into the cytoplasm. Flvcr1b overexpression promoted heme synthesis and in vitro erythroid differentiation, whereas silencing of Flvcr1b caused mitochondrial heme accumulation and termination of erythroid differentiation. Furthermore, mice lacking the plasma membrane isoform (Flvcr1a) but expressing Flvcr1b had normal erythropoiesis, but exhibited hemorrhages, edema, and skeletal abnormalities. Thus, FLVCR1b regulates erythropoiesis by controlling mitochondrial heme efflux, whereas FLVCR1a expression is required to prevent hemorrhages and edema. The aberrant expression of Flvcr1 isoforms may play a role in the pathogenesis of disorders characterized by an imbalance between heme and globin synthesis.
PMCID: PMC3533534  PMID: 23187127
9.  p130Cas/Cyclooxygenase-2 axis in the control of mesenchymal plasticity of breast cancer cells 
Breast Cancer Research : BCR  2012;14(5):R137.
Intrinsic plasticity of breast carcinoma cells allows them to undergo a transient and reversible conversion into mesenchymal cells to disseminate into distant organs, where they can re-differentiate to an epithelial-like status to form a cohesive secondary mass. The p130Cas scaffold protein is overexpressed in human ER+ and HER2+ breast cancer where it contributes to cancer progression, invasion and resistance to therapy. However, its role in regulating mesenchymal aggressive breast cancer cells remains to be determined. The aim of this study was to investigate the molecular and functional involvement of this adaptor protein in breast cancer cell plasticity.
We used silencing strategies and rescue experiments to evaluate phenotypic and biochemical changes from mesenchymal to epithelial traits in breast tumor cell lines. In the mouse A17 cell model previously related to mesenchymal cancer stem cells and basal-like breast cancer, we biochemically dissected the signaling pathways involved and performed functional in vivo tumor growth ability assays. The significance of the signaling platform was assessed in a human setting through the use of specific inhibitors in aggressive MDA-MB-231 subpopulation LM2-4175 cells. To evaluate the clinical relevance of the results, we analyzed publicly available microarray data from the Netherlands Cancer Institute and from the Koo Foundation Sun Yat-Sen Cancer Center.
We show that p130Cas silencing induces loss of mesenchymal features, by downregulating Vimentin, Snail, Slug and Twist transcriptional factors, resulting in the acquirement of epithelial-like traits. Mechanistically, p130Cas controls Cyclooxygenase-2 transcriptional expression, which in turn contributes to p130Cas-dependent maintenance of mesenchymal phenotype. This cascade of events also compromises in vivo tumor growth through inhibition of cell signaling controlling cell cycle progression. c-Src and JNK kinases are sequential players in p130Cas/ Cyclooxygenase-2 axis and their pharmacological inhibition is sufficient to downregulate Cyclooxygenase-2 leading to an epithelial phenotype. Finally, in silico microarray data analysis indicates that p130Cas and Cyclooxygenase-2 concomitant overexpression predicts poor survival and high probability of breast tumor recurrence.
Overall, these data identify a new p130Cas/Cyclooxygenase-2 axis as a crucial element in the control of breast tumor plasticity, opening new therapeutic strategies leading to inhibition of these pathways in aggressive breast carcinoma.
PMCID: PMC4053116  PMID: 23098208
10.  IQGAP1 regulates ERK1/2 and AKT signalling in the heart and sustains functional remodelling upon pressure overload 
Cardiovascular Research  2011;91(3):456-464.
The Raf-MEK1/2-ERK1/2 (ERK1/2—extracellular signal-regulated kinases 1/2) signalling cascade is crucial in triggering cardiac responses to different stress stimuli. Scaffold proteins are key elements in coordinating signalling molecules for their appropriate spatiotemporal activation. Here, we investigated the role of IQ motif-containing GTPase-activating protein 1 (IQGAP1), a scaffold for the ERK1/2 cascade, in heart function and remodelling in response to pressure overload.
Methods and results
IQGAP1-null mice have unaltered basal heart function. When subjected to pressure overload, IQGAP1-null mice initially develop a compensatory hypertrophy indistinguishable from that of wild-type (WT) mice. However, upon a prolonged stimulus, the hypertrophic response develops towards a thinning of left ventricular walls, chamber dilation, and a decrease in contractility, in an accelerated fashion compared with WT mice. This unfavourable cardiac remodelling is characterized by blunted reactivation of the foetal gene programme, impaired cardiomyocyte hypertrophy, and increased cardiomyocyte apoptosis. Analysis of signalling pathways revealed two temporally distinct waves of both ERK1/2 and AKT phosphorylation peaking, respectively, at 10 min and 4 days after aortic banding in WT hearts. IQGAP1-null mice show strongly impaired phosphorylation of MEK1/2-ERK1/2 and AKT following 4 days of pressure overload, but normal activation of these kinases after 10 min. Pull-down experiments indicated that IQGAP1 is able to bind the three components of the ERK cascade, namely c-Raf, MEK1/2, and ERK1/2, as well as AKT in the heart.
These data demonstrate, for the first time, a key role for the scaffold protein IQGAP1 in integrating hypertrophy and survival signals in the heart and regulating long-term left ventricle remodelling upon pressure overload.
PMCID: PMC3294280  PMID: 21493702
IQGAP1; MAPKs; AKT; Heart hypertrophy; Pressure overload
11.  Gene-targeted embryonic stem cells: real-time PCR assay for estimation of the number of neomycin selection cassettes 
In the preparation of transgenic murine ES cells it is important to verify the construct has a single insertion, because an ectopic neomycin phosphortransferase positive selection cassette (NEO) may cause a position effect. During a recent work, where a knockin SCA28 mouse was prepared, we developed two assays based on Real-Time PCR using both SYBR Green and specific minor groove binder (MGB) probes to evaluate the copies of NEO using the comparative delta-delta Ct method versus the Rpp30 reference gene.
We compared the results from Southern blot, routinely used to quantify NEO copies, with the two Real-Time PCR assays. Twenty-two clones containing the single NEO copy showed values of 0.98 ± 0.24 (mean ± 2 S.D.), and were clearly distinguishable from clones with two or more NEO copies.
This method was found to be useful, easy, sensitive and fast and could substitute for the widely used, but laborious Southern blot method.
PMCID: PMC3226651  PMID: 22035318
12.  The adaptor proteins p140CAP and p130CAS as molecular hubs in cell migration and invasion of cancer cells 
The assembly of molecular hubs upon integrin and growth factor stimulation represents a preferential way to transduce signals throughout the cell. Among the intracellular kinases that are responsive to integrin and growth factor activation, Src Family Kinases (SFKs) are crucial regulators of cell migration and invasion. Increasing evidence highlight the importance of adaptor proteins in these processes, based on their ability to create signalling platforms that control downstream signals. Among these adaptors we will discuss the molecular features of p130Cas and p140Cap proteins in terms of regulation of cell migration and invasion in normal and transformed cells.
PMCID: PMC3189826  PMID: 21994904
p130Cas; p140Cap; integrins; receptor tyrosine kinases; migration; invasion
13.  Phosphoinositide 3-Kinase p110β activity: Key Role in Metabolism and Mammary Gland Cancer but not Development # 
Science signaling  2008;1(36):ra3.
The phosphoinositide 3-kinase (PI3K) pathway crucially controls metabolism and cell growth. Although different PI3K catalytic subunits are known to play distinct roles, the specific in vivo function of p110β (the product of the PIK3CB gene) is not clear. Here, we show that mouse mutants expressing a catalytically inactive PIK3CBK805R mutant survived to adulthood but showed growth retardation and developed mild insulin resistance with age. Pharmacological and genetic analyses of p110β function revealed that p110β catalytic activity is required for PI3K signaling downstream of heterotrimeric guanine nucleotide-binding (G protein)-coupled receptors as well as to sustain long term insulin signaling. In addition, PIK3CBK805R mice were protected in a model of ERBB2-driven tumor development. These findings indicate an unexpected role for p110β catalytic activity in diabetes and cancer, opening potential new avenues for therapeutic intervention.
PMCID: PMC2694958  PMID: 18780892
14.  p130Cas-associated Protein (p140Cap) as a New Tyrosine-phosphorylated Protein Involved in Cell Spreading 
Molecular Biology of the Cell  2004;15(2):787-800.
Integrin-mediated cell adhesion stimulates a cascade of signaling pathways that control cell proliferation, migration, and survival, mostly through tyrosine phosphorylation of signaling molecules. p130Cas, originally identified as a major substrate of v-Src, is a scaffold molecule that interacts with several proteins and mediates multiple cellular events after cell adhesion and mitogen treatment. Here, we describe a novel p130Cas-associated protein named p140Cap (Cas-associated protein) as a new tyrosine phosphorylated molecule involved in integrin- and epidermal growth factor (EGF)-dependent signaling. By affinity chromatography of human ECV304 cell extracts on a MBP-p130Cas column followed by mass spectrometry matrix-assisted laser desorption ionization/time of flight analysis, we identified p140Cap as a protein migrating at 140 kDa. We detected its expression in human, mouse, and rat cells and in different mouse tissues. Endogenous and transfected p140Cap proteins coimmunoprecipitate with p130Cas in ECV304 and in human embryonic kidney 293 cells and associate with p130Cas through their carboxy-terminal region. By immunofluorescence analysis, we demonstrated that in ECV304 cells plated on fibronectin, the endogenous p140Cap colocalizes with p130Cas in the perinuclear region as well as in lamellipodia. In addition p140Cap codistributes with cortical actin and actin stress fibers but not with focal adhesions. We also show that p140Cap is tyrosine phosphorylated within 15 min of cell adhesion to integrin ligands. p140Cap tyrosine phosphorylation is also induced in response to EGF through an EGF receptor dependent-mechanism. Interestingly expression of p140Cap in NIH3T3 and in ECV304 cells delays the onset of cell spreading in the early phases of cell adhesion to fibronectin. Therefore, p140Cap is a novel protein associated with p130Cas and actin cytoskeletal structures. Its tyrosine phosphorylation by integrin-mediated adhesion and EGF stimulation and its involvement in cell spreading on matrix proteins suggest that p140Cap plays a role in controlling actin cytoskeleton organization in response to adhesive and growth factor signaling.
PMCID: PMC329393  PMID: 14657239

Results 1-14 (14)