Safety and efficacy of tenecteplase versus alteplase in stroke patients with carotid tandem lesions: Results from the AcT trial.

BACKGROUND: Carotid tandem lesions ((TL) ⩾70% stenosis or occlusion) account for 15-20% of acute stroke with large vessel occlusion. AIMS: We investigated the safety and efficacy of intravenous tenecteplase (0.25 mg/kg) versus intravenous alteplase (0.9 mg/kg) in patients with carotid TL. METHODS: This is a substudy of the alteplase compared with the tenecteplase trial. Patients with ⩾70% stenosis of the extracranial internal carotid artery (ICA) and concomitant occlusion of the intracranial ICA, M1 or M2 segments of the middle cerebral artery on baseline computed tomography angiography (CTA) were included. Primary outcome was 90-day-modified Rankin Scale (mRS) 0-1. Secondary outcomes were mRS 0-2, mortality, and symptomatic ICH (sICH). Angiographic outcomes were successful recanalization (revised Arterial Occlusive Lesion (rAOL) 2b-3) on first and successful reperfusion (eTICI 2b-3) on final angiographic acquisitions. Multivariable mixed-effects logistic regression was performed. RESULTS: Among 1577 alteplase versus tenecteplase randomized controlled trial (AcT) patients, 128 (18.8%) had carotid TL. Of these, 93 (72.7%) underwent intravenous thrombolysis plus endovascular thrombectomy (IVT + EVT), while 35 (27.3%) were treated with IVT alone. In the IVT + EVT group, tenecteplase was associated with higher odds of 90-day-mRS 0-1 (46.0% vs. 32.6%, adjusted OR (aOR) 3.21; 95% CI = 1.06-9.71) compared with alteplase. No statistically significant differences in rates of mRS 0-2 (aOR 1.53; 95% CI = 0.51-4.55), initial rAOL 2b-3 (16.3% vs. 28.6%), final eTICI 2b-3 (83.7% vs. 85.7%), and mortality (18.0% vs. 16.3%) were found. SICH only occurred in one patient. There were no differences in outcomes between thrombolytic agents in the IVT-only group. CONCLUSION: In patients with carotid TL treated with EVT, intravenous tenecteplase may be associated with similar or better clinical outcomes, similar angiographic reperfusion rates, and safety outcomes as compared with alteplase.

Caveolin-1 Y14 phosphorylation suppresses tumor growth while promoting invasion.

Caveolin-1 is a transmembrane protein with both tumor promoter and suppressor functions that remain poorly understood. Cav1 phosphorylation by Src kinase on tyrosine 14 is closely associated with focal adhesion dynamics and tumor cell migration, however the role of pCav1 in vivo in tumor progression remains poorly characterized. Herein, we expressed phosphomimetic Y14D, wild type, and non-phosphorylatable Y14F forms of Cav1 in MDA-MB-435 cancer cells. Expression of Cav1Y14D reduced cell proliferation and induced the TP53 tumor suppressor. Ectopic expression in MDA-MB-435 cells of Y14 phosphorylatable Cav1 was required for induction of TP53 in response to oxidative stress. Cav1Y14D promotes an apparent reversal of the Warburg effect and markedly inhibited tumor growth in vivo. However, Cav1 induced pseudopodial recruitment of glycolytic enzymes, and time-lapse intravital imaging showed increased invadopodia protrusion and extravasation into blood vessels for Cav1WT and Y14D but not for Y14F. Our results suggest that Cav1 Y14 phosphorylation levels play a role in the conflicting demands on metabolic resources associated with cancer cell proliferation versus motility.

The phospho-caveolin-1 scaffolding domain dampens force fluctuations in focal adhesions and promotes cancer cell migration.

Caveolin-1 (Cav1), a major Src kinase substrate phosphorylated on tyrosine-14 (Y14), contains the highly conserved membrane-proximal caveolin scaffolding domain (CSD; amino acids 82-101). Here we show, using CSD mutants (F92A/V94A) and membrane-permeable CSD-competing peptides, that Src kinase-dependent pY14Cav1 regulation of focal adhesion protein stabilization, focal adhesion tension, and cancer cell migration is CSD dependent. Quantitative proteomic analysis of Cav1-GST (amino acids 1-101) pull downs showed sixfold-increased binding of vinculin and, to a lesser extent, α-actinin, talin, and filamin, to phosphomimetic Cav1Y14D relative to nonphosphorylatable Cav1Y14F. Consistently, pY14Cav1 enhanced CSD-dependent vinculin tension in focal adhesions, dampening force fluctuation and synchronously stabilizing cellular focal adhesions in a high-tension mode, paralleling effects of actin stabilization. This identifies pY14Cav1 as a molecular regulator of focal adhesion tension and suggests that functional interaction between Cav1 Y14 phosphorylation and the CSD promotes focal adhesion traction and, thereby, cancer cell motility.

p38 MAP kinase-dependent phosphorylation of the Gp78 E3 ubiquitin ligase controls ER-mitochondria association and mitochondria motility.

Gp78 is an ERAD-associated E3 ubiquitin ligase that induces degradation of the mitofusin mitochondrial fusion proteins and mitochondrial fission. Gp78 is localized throughout the ER; however, the anti-Gp78 3F3A monoclonal antibody (mAb) recognizes Gp78 selectively in mitochondria-associated ER domains. Epitope mapping localized the epitope of 3F3A and a commercial anti-Gp78 mAb to an 8-amino acid motif (533-541) in mouse Gp78 isoform 2 that forms part of a highly conserved 41-amino acid region containing 14-3-3- and WW-binding domains and a p38 MAP kinase (p38 MAPK) consensus site on Ser-538 (S538). 3F3A binds selectively to nonphosphorylated S538 Gp78. Using 3F3A as a reporter, we induced Gp78 S538 phosphorylation by serum starvation and showed it to be mediated by p38 MAPK. Mass spectroscopy analysis of Gp78 phosphopeptides confirmed S538 as a major p38 MAPK phosphorylation site on Gp78. Gp78 S538 phosphorylation limited its ability to induce mitochondrial fission and degrade MFN1 and MFN2 but did not affect in vitro Gp78 ubiquitin E3 ligase activity. Phosphomimetic Gp78 S538D mutation prevented Gp78 promotion of ER-mitochondria interaction, and SB203580 inhibition of p38 MAPK increased ER-mitochondria association. p38 MAPK phosphorylation of Gp78 S538 therefore regulates Gp78-dependent ER-mitochondria association and mitochondria motility.

Correction: Actin Cytoskeleton Regulation of Epithelial Mesenchymal Transition in Metastatic Cancer Cells.

[This corrects the article DOI: 10.1371/journal.pone.0119954.].

The galectin lattice at a glance.

Galectins are a family of widely expressed ß-galactoside-binding lectins in metazoans. The 15 mammalian galectins have either one or two conserved carbohydrate recognition domains (CRDs), with galectin-3 being able to pentamerize; they form complexes that crosslink glycosylated ligands to form a dynamic lattice. The galectin lattice regulates the diffusion, compartmentalization and endocytosis of plasma membrane glycoproteins and glycolipids. The galectin lattice also regulates the selection, activation and arrest of T cells, receptor kinase signaling and the functionality of membrane receptors, including the glucagon receptor, glucose and amino acid transporters, cadherins and integrins. The affinity of transmembrane glycoproteins to the galectin lattice is proportional to the number and branching of their N-glycans; with branching being mediated by Golgi N-acetylglucosaminyltransferase-branching enzymes and the supply of UDP-GlcNAc through metabolite flux through the hexosamine biosynthesis pathway. The relative affinities of glycoproteins for the galectin lattice depend on the activities of the Golgi enzymes that generate the epitopes of their ligands and, thus, provide a means to analyze biological function of lectins and of the 'glycome' more broadly.

Actin cytoskeleton regulation of epithelial mesenchymal transition in metastatic cancer cells.

Epithelial-mesenchymal transition (EMT) is associated with loss of the cell-cell adhesion molecule E-cadherin and disruption of cell-cell junctions as well as with acquisition of migratory properties including reorganization of the actin cytoskeleton and activation of the RhoA GTPase. Here we show that depolymerization of the actin cytoskeleton of various metastatic cancer cell lines with Cytochalasin D (Cyt D) reduces cell size and F-actin levels and induces E-cadherin expression at both the protein and mRNA level. Induction of E-cadherin was dose dependent and paralleled loss of the mesenchymal markers N-cadherin and vimentin. E-cadherin levels increased 2 hours after addition of Cyt D in cells showing an E-cadherin mRNA response but only after 10-12 hours in HT-1080 fibrosarcoma and MDA-MB-231 cells in which E-cadherin mRNA level were only minimally affected by Cyt D. Cyt D treatment induced the nuclear-cytoplasmic translocation of EMT-associated SNAI 1 and SMAD1/2/3 transcription factors. In non-metastatic MCF-7 breast cancer cells, that express E-cadherin and represent a cancer cell model for EMT, actin depolymerization with Cyt D induced elevated E-cadherin while actin stabilization with Jasplakinolide reduced E-cadherin levels. Elevated E-cadherin levels due to Cyt D were associated with reduced activation of Rho A. Expression of dominant-negative Rho A mutant increased and dominant-active Rho A mutant decreased E-cadherin levels and also prevented Cyt D induction of E-cadherin. Reduced Rho A activation downstream of actin remodelling therefore induces E-cadherin and reverses EMT in cancer cells. Cyt D treatment inhibited migration and, at higher concentrations, induced cytotoxicity of both HT-1080 fibrosarcoma cells and normal Hs27 fibroblasts, but only induced mesenchymal-epithelial transition in HT-1080 cancer cells. Our studies suggest that actin remodelling is an upstream regulator of EMT in metastatic cancer cells.

Caveolin-1, galectin-3 and lipid raft domains in cancer cell signalling.

Spatial organization of the plasma membrane is an essential feature of the cellular response to external stimuli. Receptor organization at the cell surface mediates transmission of extracellular stimuli to intracellular signalling molecules and effectors that impact various cellular processes including cell differentiation, metabolism, growth, migration and apoptosis. Membrane domains include morphologically distinct plasma membrane invaginations such as clathrin-coated pits and caveolae, but also less well-defined domains such as lipid rafts and the galectin lattice. In the present chapter, we will discuss interaction between caveolae, lipid rafts and the galectin lattice in the control of cancer cell signalling.

Raft endocytosis of AMF regulates mitochondrial dynamics through Rac1 signaling and the Gp78 ubiquitin ligase.

Gp78 is a cell surface receptor that also functions as an E3 ubiquitin ligase in the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway. The Gp78 ligand, the glycolytic enzyme phosphoglucose isomerase (PGI; also called autocrine motility factor, AMF), functions as a cytokine upon secretion by tumor cells. AMF is internalized through a PI3K- and dynamin-dependent raft endocytic pathway to the smooth ER; however, the relationship between AMF and Gp78 ubiquitin ligase activity remains unclear. AMF uptake to the smooth ER is inhibited by the dynamin inhibitor, dynasore, is reduced in Gp78 knockdown cells and induces the dynamin-dependent downregulation of its cell surface receptor. AMF uptake is Rac1-dependent and is inhibited by expression of dominant-negative Rac1 and the Rac1 inhibitor NSC23766, and is therefore distinct from Cdc42- and RhoA-dependent raft endocytic pathways. AMF stimulates Rac1 activation, but this is reduced by dynasore treatment and is absent in Gp78-knockdown cells; therefore, AMF activities require Gp78-mediated endocytosis. AMF also prevents Gp78-induced degradation of the mitochondrial fusion proteins, mitofusin 1 and 2 in a dynamin-, Rac1- and phosphoinositide 3-kinase (PI3K)-dependent manner. Gp78 induces mitochondrial clustering and fission in a manner dependent on GP78 ubiquitin ligase activity, and this is also reversed by uptake of AMF. The raft-dependent endocytosis of AMF, therefore, promotes Rac1-PI3K signaling that feeds back to promote AMF endocytosis and also inhibits the ability of Gp78 to target the mitofusins for degradation, thereby preventing Gp78-dependent mitochondrial fission. Through regulation of an ER-localized ubiquitin ligase, the raft-dependent endocytosis of AMF represents an extracellular regulator of mitochondrial fusion and dynamics.

Regulation of mitophagy by the Gp78 E3 ubiquitin ligase.

Glycoprotein 78 (Gp78) is a critical E3 ubiquitin ligase in endoplasmic reticulum-associated degradation. Overexpression of Flag-tagged Gp78 (Flag-gp78), but not Flag-gp78 mutated in its RING-finger domain (Flag-RINGmut) with deficient ubiquitin ligase activity, induces mitochondrial fragmentation and ubiquitination and proteasome-dependent degradation of the mitofusin (Mfn) mitochondrial fusion factors Mfn1/Mfn2. After mitochondrial depolarization with carbonyl cyanide m-chlorophenylhydrazone (CCCP), Flag-gp78 induced a threefold loss of depolarized mitochondria and significant loss of the inner mitochondrial protein OxPhosV. Flag-gp78-dependent loss of OxPhosV, but not Mfn1 or Mfn2, was prevented by small interfering RNA (siRNA) knockdown of the autophagy protein Atg5 in CCCP-treated cells. Gp78-induced mitophagy required ubiquitin ligase activity, as it is not observed upon transfection of Flag-RINGmut or cotransfection of Flag-gp78 with ubiquitin mutated at three critical lysine residues (K29, 48, 63R) involved in polyubiquitin chain elongation. Short hairpin RNA knockdown of Gp78 in HT-1080 fibrosarcoma cells increased mitofusin levels and reduced depolarization-induced mitophagy, whereas siRNA knockdown showed that Mfn1, but not Mfn2, was required for Gp78-dependent depolarization-induced mitophagy. Mitochondrial depolarization induced Gp78-dependent expression of the autophagic marker LC3II and recruitment of enhanced green fluorescent protein-LC3 to the Gp78- and calnexin-labeled, mitochondria-associated ER. Finally, Gp78-induced mitophagy is Parkin independent, as it occurs in Parkin-null HeLa cells and upon siRNA-mediated Parkin knockdown in HEK293 cells. This study therefore describes a novel role for the ER-associated Gp78 ubiquitin ligase and the Mfn1 mitochondrial fusion factor in mitophagy.

Coordinated expression of galectin-3 and caveolin-1 in thyroid cancer.

Galectin-3 (Gal3) is the single most accurate marker for the diagnosis of differentiated thyroid cancer (DTC). Gal3 overrides the tumour suppressor activity of caveolin-1 (Cav1) and functions in concert with Cav1 to promote focal adhesion turnover and tumour cell migration and invasion. To study their coordinated role in progression of a human cancer, we investigated the expression of Gal3 and Cav1 in specimens of human benign thyroid lesions, DTC and anaplastic thyroid cancer (ATC). Gal3 and Cav1 expression is significantly associated with DTC and ATC, but not benign nodules. Essentially all Cav1-positive DTC cancers express Gal3, supporting the synergistic activity of these two proteins in DTC progression. Similarly, coordinated elevated Gal3/Cav1 expression was observed in three DTC-derived cell lines (papillary TCP1 and KTC1 and follicular FTC133) but only one (ACT1) of five ATC-derived cell lines. Using siRNA knockdown, Gal3 and Cav1 were shown to be required for RhoA GTPase activation, stabilization of focal adhesion kinase (FAK; a measure of focal adhesion signalling and turnover) and increased migration of the DTC cell lines studied, but not the ATC cell lines, including ACT1, which expresses elevated levels of Gal3 and Cav1. Co-expression of Gal3 and Cav1 in the T238 anaplastic cell line stabilized FAK-GFP in focal adhesions. Gal3 and Cav1 therefore function synergistically to promote focal adhesion signalling, migration and progression of DTC.

RNA purification from tumor cell protrusions using porous polycarbonate filters.

Actin-rich cellular protrusions or pseudopodia form via local actin filament polymerization and branching and represent a variety of polarized cellular domains including lamellipodia, filipodia, and neuronal growth cones. RNA localization and local protein translation in these domains are important for various cellular processes. RNA transport and local synthesis have been implicated in cell migration and tumor cell metastasis as well as in neuronal plasticity in neurons. Characterization of the mRNAs present in these domains is key to understanding the functional role of mRNA translocation and local protein translation in cellular processes. We describe here a method to segregate pseudopodia of metastatic cancer cells from the cell body using porous polycarbonate filters. This approach enables the purification and identification of RNAs and proteins in these protrusive cellular domains.

Pseudopodial actin dynamics control epithelial-mesenchymal transition in metastatic cancer cells.

A key cellular process associated with the invasive or metastatic program in many cancers is the transformation of epithelial cells toward a mesenchymal state, a process called epithelial to mesenchymal transition or EMT. Actin-dependent protrusion of cell pseudopodia is a critical element of mesenchymal cell migration and therefore of cancer metastasis. However, whether EMT occurs in human cancers and, in particular, whether it is a prerequisite for tumor cell invasion and metastasis, remains a subject of debate. Microarray and proteomic analysis of actin-rich pseudopodia from six metastatic human tumor cell lines identified 384 mRNAs and 64 proteins common to the pseudopodia of six metastatic human tumor cell lines of various cancer origins leading to the characterization of 19 common pseudopod-specific proteins. Four of these (AHNAK, septin-9, eIF4E, and S100A11) are shown to be essential for pseudopod protrusion and tumor cell migration and invasion. Knockdown of each of these proteins in metastatic cells resulted in reduced actin cytoskeleton dynamics and induction of mesenchymal-epithelial transition (MET) that could be prevented by the stabilization of the actin cytoskeleton. Actin-dependent pseudopodial protrusion and tumor cell migration are therefore determinants of EMT. Protein regulators of pseudopodial actin dynamics may represent unique molecular targets to induce MET and thereby inhibit the metastatic potential of tumor cells.

Engineered Alt a 13 fragment of Alternaria alternata abrogated IgE binding without affecting T-cell stimulation.

RATIONALE: Epitopes were delineated for allergenic proteins, but studies are required to identify residues mediating IgE binding. In the present study, the in silico approach was used to identify IgE-binding residues of Alt a 13(1-50) fragment and confirmed by experimental approach. METHOD AND RESULTS: IgE-binding epitopes of Alt a 13 mapped computationally were cloned, expressed, purified, and characterized using various immunochemical and biophysical methods. Among four fragments of Alt a 13, Alt a 13(1-50) demonstrated maximum IgE binding with two immunodominant regions and was mutated at these regions. The mutation in first region, Alt a 13(1-50)-K4A_S6F, did not show any change in immunological and biophysical properties of protein. However, mutations in the second region, Alt a 13(1-50)-T21F_N27I, caused reduced IgE binding, histamine release, and low IL-4 release on stimulation of Alternaria alternata positive patients peripheral blood mononuclear cells in vitro. CONCLUSION: This suggests that residues T21 and N27 are important for the secondary structure. In conclusion, Alt a 13(1-50)-T21F_N27I with reduced Th 2 response and intact T-cell proliferation capacity has potential for clinical use.

Isolation and characterization of Plasmodium falciparum UAP56 homolog: evidence for the coupling of RNA binding and splicing activity by site-directed mutations.

UAP56 (U2AF65 associated protein) is a member of the DEAD-box helicase family. Helicases are essential enzymes generally involved in the metabolism of nucleic acids. The gene encoding a member of DEAD-box family was cloned and characterized from the human malaria parasite Plasmodium falciparum. PfU52 is homologous to UAP56 and contains the RNA-dependent ATPase, RNA helicase and RNA binding activities. Using the parasite extract we report that PfU52 is involved in splicing reaction. Site-directed mutagenesis studies indicate that the conserved residues glycine 181, isoleucine 182 and arginine 206 are involved in RNA binding and this activity is required for the enzymatic activities of PfU52. PfU52 is expressed in all the intraerythrocytic developmental stages of the parasite. In the present study we have reported the detailed characterization of PfU52 from P. falciparum and these results advance the knowledge regarding the function of UAP56 in general.

UvrD helicase of Plasmodium falciparum.

Malaria caused by the mosquito-transmitted parasite Plasmodium is the cause of enormous number of deaths every year in the tropical and subtropical areas of the world. Among four species of Plasmodium, Plasmodium falciparum causes most fatal form of malaria. With time, the parasite has developed insecticide and drug resistance. Newer strategies and advent of novel drug targets are required so as to combat the deadly form of malaria. Helicases is one such class of enzymes which has previously been suggested as potential antiviral and anticancer targets. These enzymes play an essential role in nearly all the nucleic acid metabolic processes, catalyzing the transient opening of the duplex nucleic acids in an NTP-dependent manner. DNA helicases from the PcrA/UvrD/Rep subfamily are important for the survival of the various organisms. Members from this subfamily can be targeted and inhibited by a variety of synthetic compounds. UvrD from this subfamily is the only member present in the P. falciparum genome, which shows no homology with UvrD from human and thus can be considered as a strong potential drug target. In this manuscript we provide an overview of UvrD family of helicases and bioinformatics analysis of UvrD from P. falciparum.

Recombinant glutathione-S-transferase a major allergen from Alternaria alternata for clinical use in allergy patients.

Recombinant proteins are used for vaccines, therapy and diagnosis of many diseases. Biological activity of these may differ from native counterpart and needs investigation. The present study aimed to compare recombinant (r) and native (n) glutathione-S-transferase (GST) from Alternaria alternata. Glutathione-S-transferase sequence showed an ORF of 696bp encoding 26-kDa protein with N-terminus conserved domain. Secondary structure of both forms was comparable with melting temperature of 57 and 59 degrees C, respectively. rGST and nGST showed similar enzymatic activity, allergenicity and potency by ELISA inhibition. Histamine release was comparable in 14/17 patients for both the GSTs. rGST and nGST induced proliferation in PBMC at different concentration. Cell supernatant revealed higher IL-4 and IL-5 levels with low levels of IFN-gamma. In summary, recombinant and native GST demonstrated similar physio-chemical, biological and immunological properties and induced comparable cell mediated and humoral response to be used for diagnosis and specific immunotherapy for the fungal allergy cases.

Immunobiochemical analysis of cross-reactive glutathione-S-transferase allergen from different fungal sources.

Clinical observations suggest the presence of cross-reactive allergens. There is a need to identify these cross-reactive allergens to improve the treatment used for allergic disorders. The present study was aimed to identify and characterize a cross-reactive allergenic protein from fungi. Allergen extracts of various fungi viz. Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum, Curvularia lunata, and Epicoccum purpurascens showed GST enzymatic activity ranging from 0.765 to 1.004 delta340 nm/min/microg where as activity of rGST was 1.123 delta340 nm/min/microg. Immunoblot with GST antibodies showed a band of approximately 26 kDa in all these fungal extracts. Sera of fungal allergy patients showed the presence of IgE antibodies to GST. Rabbit antibodies raised against the fungal extracts reacted with rGST confirming the presence of GST-like protein in these extract. ELISA inhibition using GST antibodies revealed inhibition with C. herbarum, A. alternata, C. lunata, A. fumigatus, and E. purpurascens demonstrating that fungal GST competes for binding to anti-GST. In summary, a GST-like protein was recognized as cross-reactive allergen in these fungal extracts.