bluuebunny/crossref_metadata_2025_split huggingface dataset:
Profibrillin‐1 maturation by human dermal fibroblasts: Proteolytic processing and molecular chaperones
Authors: Wallis Debra D. , Putnam Elizabeth A. , Cretoiu Jill S. , Carmical Sonya G. , Cao Shi‐Nian , Thomas Gary , Milewicz Dianna M. 
Published: September 2003

AbstractFibrillin‐1 is synthesized as a proprotein that undergoes proteolytic processing in the unique C‐terminal domain by a member of the PACE/furin family of endoproteases. This family of endoproteases is active in the trans‐Golgi network (TGN), but metabolic labeling studies have been controversial as to whether profibrillin‐1 is processed intracellularly or after secretion. This report provides evidence that profibrillin‐1 processing is not an intracellular event. Bafilomycin A1 and incubation of dermal fibroblasts at 22°C were used to block secretion in the TGN to confirm that profibrillin‐1 processing did not occur in this compartment. Profibrillin‐1 immunoprecipitation studies revealed that two endoplasmic reticulum‐resident molecular chaperones, BiP and GRP94, interacted with profibrillin‐1. To determine the proprotein convertase responsible for processing profibrillin‐1, a specific inhibitor of furin, α‐1‐antitrypsin, Portland variant, was both expressed in the cells and added to cells exogenously. In both cases, the inhibitor blocked the processing of profibrillin‐1, providing evidence that furin is the enzyme responsible for profibrillin‐1 processing. These studies delineate the secretion and proteolytic processing of profibrillin‐1, and identify the proteins that interact with profibrillin‐1 in the secretory pathway. © 2003 Wiley‐Liss, Inc.
Choline phospholipid metabolism: A target in cancer cells?
Authors: Ackerstaff Ellen , Glunde Kristine , Bhujwalla Zaver M. 
Published: September 2003

AbstractThe experience of treating cancer over the past several decades overwhelmingly demonstrates that the disease continues to evade the vast array of drugs and treatment modalities available in the twenty‐first century. This is not surprising in view of the complexity of this disease, and the multiplicities of pathways available to the cancer cell to enable its survival. Although the progression of cancer arrives at a common end point of cachexia, organ failure, and death, common pathways are rare in cancer. Identifying and targeting common pathways that would act across these levels of multiplicity is essential for the successful treatment of this disease. Over the past decade, one common characteristic consistently revealed by magnetic resonance spectroscopic studies is the elevation of phosphocholine and total choline‐containing compounds in cancer cells and solid tumors. This elevation has been observed in almost every single cancer type studied with NMR spectroscopy and can be used as an endogenous biomarker of cancer. In this article, we have summarized some of the observations on the choline phospholipid metabolism of cancer cells and tumors, and make a case for targeting the aberrant choline phospholipid metabolism of cancer cells. © 2003 Wiley‐Liss, Inc.
Molecular magnetic resonance imaging with targeted contrast agents
Authors: Artemov Dmitri 
Published: September 2003

AbstractMagnetic resonance imaging (MRI) produces high‐resolution three‐dimensional maps delineating morphological features of the specimen. Differential contrast in soft tissues depends on endogenous differences in water content, relaxation times, and/or diffusion characteristics of the tissue of interest. The specificity of MRI can be further increased by exogenous contrast agents (CA) such as gadolinium chelates, which have been successfully used for imaging of hemodynamic parameters including blood perfusion and vascular permeability. Development of targeted MR CA directed to specific molecular entities could dramatically expand the range of MR applications by combining the noninvasiveness and high spatial resolution of MRI with specific localization of molecular targets. However, due to the intrinsically low sensitivity of MRI (in comparison with nuclear imaging), high local concentrations of the CA at the target site are required to generate detectable MR contrast. To meet these requirements, the MR targeted CA should recognize targeted cells with high affinity and specificity. They should also be characterized by high relaxivity, which for a wide variety of CA depends on the number of contrast‐generating groups per single molecule of the agent. We will review different designs and applications of targeted MR CA and will discuss feasibility of these approaches for in vivo MRI. © 2003 Wiley‐Liss, Inc.
Identification of γA‐like protocadherin expressed during chick development
Authors: Capehart Anthony A. , Kern Christine B. 
Published: September 2003

AbstractThe protocadherins are calcium‐dependent cell adhesion molecules of the cadherin superfamily that have been described in numerous species. Although less well characterized than classical cadherins, the protocadherins are also thought to facilitate critical cell–cell interactions during embryonic development. We have cloned a novel protocadherin from the embryonic chick utilizing a monoclonal antibody produced against a peanut agglutinin‐binding fraction of cultured chick limb tissue to screen a λZAP cDNA expression library from the stage 25 limb. A 2.8 kb cDNA clone was obtained that encoded multiple cadherin‐like ectodomains. Northern blotting revealed a single 4.6 kb RNA transcript that was highly enriched in the stage 43 chick brain. Utilization of 3′ Rapid amplification of cDNA ends (RACE) identified the entire 2.4 kb reading frame. The chick protocadherin contained five cadherin‐like extracellular repeats and a highly conserved cytoplasmic domain. Amino acid alignment of the extracellular domains revealed marked identity to the human γA protocadherin subfamily. In situ hybridization showed low levels of mRNA localization in several developing chick tissues, but stronger expression in the neural tube and dorsal root ganglia at stage 27. In the stage 43 chick brain, protocadherin mRNA was noted in discrete regions, particularly within the developing optic lobe. As for protocadherins described in other species, these results suggest that this novel γA‐like protocadherin may also play a role in chick neural development. © 2003 Wiley‐Liss, Inc.
A brief introduction to cell‐penetrating peptides
Authors: Lundberg Pontus , Langel Ülo 
Published: September 2003

AbstractCell membranes act as protective walls to exclude most molecules that are not actively imported by living cells. This is an efficient way for a cell to prevent uncontrolled influx or efflux of solutes, which otherwise would be harmful to it. Only compounds within a narrow range of molecular size, polarity and net charge are able to diffuse effectively through cell membranes. In order to overcome this barrier for effective delivery of membrane‐impermeable molecules, several chemical and physical methods have been developed. These methods, e.g. electroporation, and more recent methods as cationic lipids/liposomes, have been shown to be effective for delivering hydrophobic macromolecules. The drawbacks of these harsh methods are, primarily, the unwanted cellular effects exerted by them, and, secondly, their limitation to in vitro applications. The last decade's discovery of cell‐penetrating peptides translocating themselves across cell membranes of various cell lines, along with a cargo 100‐fold their own size, via a seemingly energy‐independent process, opens up the possibility for efficient delivery of DNA, antisense peptide nucleic acids, oligonucleotides, proteins and small molecules into cells both in vitro and in vivo. Copyright © 2003 John Wiley & Sons, Ltd.
Lipid vector for the delivery of peptides towards intracellular pharmacological targets
Authors: Gras‐Masse Hélène 
Published: September 2003

AbstractThe ability of single‐chain lipopeptides to gain access to cellular compartments other than those related to degradation/recycling was first deduced from their capacity to deliver peptide antigens into MHC‐class I loading mechanisms. The ability of lipopeptides to escape complete endosome degradation was further illustrated by the selective inhibition of different protein kinase C isoenzymes and, more recently, the presentation of agonistic activity towards the interferon gamma receptor. Taken together, several independent results indicate that modification of a peptide by a single lipid chain confers upon it intracellular trafficking properties that can be used to deliver functional cargo peptides into living cells; the endoplasmic reticulum, cytosolic protease activity, sites of kinase activity, or even the signalling pathway associated with cytokine stimulation, all appear accessible to peptide modified by a single lipidic moiety. In this context, the interferon gamma receptor can be considered as a very discriminative pharmacological model, useful for the comparative evaluation of the cellular delivery of lipopeptides, as it allows the unambiguous tracking of their intact delivery into a wide range of cellular compartments. This model is now being used to probe the influence of the nature of the lipid moiety on the trafficking properties of lipopeptides. Copyright © 2003 John Wiley & Sons, Ltd.
Synthesis and application of functional peptides as cell nucleus‐directed molecules in the treatment of malignant diseases
Authors: Pipkorn R. , Waldeck W. , Braun K. 
Published: September 2003

AbstractThe unique functions of biomolecules, including transport accross biological membranes (e.g. the cell membrane, the nuclear envelope), modulation of protein function, gene transcription, reconstitution of the malignant transformation, and viral, bacterial and fungal activities underlie a high pharmaceutical potential. The development of combinatorial functional peptide modules in this important area has been slow, in contrast to the rapid development in the synthesis of small biopolymers. The conjugation of a short transmembrane transport peptide module with a cell nucleus address peptide module and with any substance is attractive for preparation of BioShuttle‐based peptides because of the well‐established automated synthesis of peptides. Variation of the different functional modules for drug targeting and the choice of substances can be combined to create novel bioconjugates with unique properties. This article provides an overview of previous work on the BioShuttle technology and outlines the promising use of this approach in combinatorial peptide synthesis and drug discovery. Copyright © 2003 John Wiley & Sons, Ltd.
Radiolabeled α‐melanocyte‐stimulating hormone analogs for receptor‐mediated targeting of melanoma: from tritium to indium
Authors: Eberle Alex N. , Froidevaux Sylvie 
Published: September 2003

AbstractFollowing the first synthesis of tritiated α‐melanocyte‐stimulating hormone (α‐MSH, α‐melanotropin) in 1974 by Medzihradszky et al., several α‐MSH analogs were designed containing between 2 and 12 tritium atoms, the latter of which displayed a specific radioactivity of 12.21 GBq/μmol (330 Ci/mmol). Similarly, radioiodinated α‐MSH analogs of high purity, full biological activity and a specific radioactivity of approximatly 140 GBq/μmol were obtained. Although tritiated and radioiodinated α‐MSH became indispensable tools as tracer molecules for numerous in vitro and in vivo studies, above all for receptor identification and characterization as well as for structure‐activity studies, they did not fulfill the criteria required for therapeutic in vivo targeting of metastatic melanoma. Therefore, we recently developed α‐MSH analogs containing the universal metal chelator 1,4,7,10‐tetraazacyclododecane‐1,4,7,10‐tetraacetic acid (DOTA) in different positions of the molecule. As DOTA can equally well incorporate diagnostic (e.g. 111In, 67,68Ga) and therapeutic (e.g. 90Y, 67Cu) radionuclides, DOTA‐MSH compounds may serve for both melanoma scintigraphy and therapy. The analog DOTA‐[βAla3, Nle4, Asp5, D‐Phe7, Lys10]‐α‐MSH3–10 (DOTA‐MSHOCT), which contains the metal chelator at its N‐terminal end, displayed good in vitro MC1R affinity (IC50 9.21 nm). In vivo, [111In]DOTA‐MSHOCT exhibited a favorable biodistribution profile after injection in B16‐F1 tumor‐bearing mice. The radiopeptide was rapidly cleared from blood through the kidneys and, most importantly, accumulated preferentially in the melanoma lesions. Lung and liver melanoma metastases could be clearly imaged on tissue section autoradiographs 4 h after injection of [111In]DOTA‐MSHOCT. A comparative study of [111In]DOTA‐MSHOCT with [111In]DOTA‐[Nle4, D‐Phe7]‐α‐MSH ([111In]DOTA‐NDP‐MSH) demonstrated the superiority of the DOTA‐MSHOCT peptide, particularly with respect to the amount of radioactivity taken up by non‐malignant organs, including bone, the most radiosensitive tissue. These results demonstrate that [111In]DOTA‐MSHOCT specifically targets melanoma metastases and represents a lead compound for the development of therapeutic DOTA‐MSH analogs. Copyright © 2003 John Wiley & Sons, Ltd.
Molecular tools for targeted imaging and therapy of cancer
Authors: Meares Claude F. , Chmura A. J. , Orton Molly S. , Corneillie Todd M. , Whetstone Paul A 
Published: September 2003

AbstractHere we review an approach to the design and production of antibody/ligand pairs for use in cell targeting procedures, to achieve functional affinity far greater than avidin/biotin. Using fundamental chemical principles, we have developed antibody/ligand pairs that retain the binding specificity of the antibody, but do not dissociate. By eliminating the dissociation of the ligand from the antibody, we have made the affinity functionally infinite. This methodology is applicable to other biological binding pairs. Copyright © 2003 John Wiley & Sons, Ltd.
Membrane permeability commonly shared among arginine‐rich peptides
Authors: Futaki Shiroh , Goto Susumu , Sugiura Yukio 
Published: September 2003

AbstractDelivery of proteins and other macromolecules using membrane‐permeable carrier peptides is a recently developed novel technology, which enables us to modulate cellular functions for biological studies with therapeutic potential. One of the most often used carrier peptides is the arginine‐rich basic peptide derived from HIV‐1 Tat protein [HIV‐1 Tat (48–60)]. Using this peptide, efficient intracellular delivery of molecules including proteins, oligonucleic acids and liposomes has been achieved. We have demonstrated that these features were commonly shared among many arginine‐rich peptides such as HIV‐1 Rev (34–50) and octaarginine. Not only the linear peptides but also branched‐chain peptides showed efficient internalization with an optimum number of arginines (approximately eight residues). The structural and mechanistic features of the translocation of these membrane‐permeable arginine‐rich peptides are reviewed. Copyright © 2003 John Wiley & Sons, Ltd.
Cellular utake of the Tat peptide: an endocytosis mechanism following ionic interactions
Authors: Vives Eric 
Published: September 2003

AbstractThe cellular delivery of various biological compounds has recently been improved by conjugating them to short peptides known as protein transduction domains or cell penetrating peptides. These peptides include Tat, Antennapedia and arginine‐rich peptides. The common feature of these peptides is their highly cationic nature. Up to now, the cellular uptake of about 50 different peptides and proteins coupled to Tat or Antennapedia peptides has been reported. The ability to deliver molecules into cells is not limited to peptide moieties, since oligonucleotides, peptide nucleic acids or other low molecular weight entities have been successfully internalized. Moreover, most of these examples have been accompanied by the expected biological response. More surprisingly, the uptake of large structures such as liposomes, phages, nanoparticles or adenoviruses has also been documented. Indeed the mechanism by which these very different entities could enter cells following a putative common pathway appeared more and more intriguing after each new reported example of cellular uptake mediated by these peptides. After a long period of uncertainty regarding the mechanism of entry, data from several groups now argue for an energy‐dependent process of entry. The entry of most of these molecules is likely to be inhibited by low temperature incubation or in the presence of various drugs applied to inhibit the energy‐dependent pathway of cell entry. Moreover, the binding of the highly cationic Tat peptide to various anionic membrane components probably initiates the first step of the cell internalization process. Copyright © 2003 John Wiley & Sons, Ltd.
Membrane translocation of penetratin and its derivatives in different cell lines
Authors: Letoha T. , Gaál S. , Somlai C. , Czajlik A. , Perczel A. , Penke B. 
Published: September 2003

AbstractThe third helix of the homeodomain of the Antennapedia homeoprotein can translocate through the cell membrane into the nucleus and can be used as an intracellular vehicle for the delivery of oligopeptides and oligonucleotides. A 16‐amino acid‐long peptide fragment, called penetratin, is internalized by the cells in a specific, non‐receptor‐mediated manner. For a better understanding of the mechanism of the transfer, penetratin and two analogs were synthesized:

(1) penetratin

RQIKIWFQNRRMKWKK  (peptide 1);

(2) (6,14‐Phe)‐penetratin,

RQIKIFFQNRRMKFKK  (peptide 2);

(3) dodecapeptide,

RQIKIWF‐R‐KWKK  (peptide 3);

The conformation of penetratin peptides 1–3 was examined in both extracellular matrix‐mimetic and membrane‐mimetic environments. 1H‐NMR and CD spectroscopic measurements were performed in mixtures of TFE/water with different ratios. Peptides 1–3 were labeled by reacting their N‐terminal free amino group with fluorescein isothiocyanate (FITC). Membrane translocation of the labelled peptides was studied with cell cultures [WEHI 164 murine fibrosarcoma cells (WC/1); chicken fibroblast cells (CEC‐32); chicken monocytic cells (HD‐11); human fibroblast (SV 80) and human monocytic cells (MonoMac‐6)]. Confocal laser scanning microscopy and flow cytometry assay were used to study membrane translocation. Amphiphilicity was calculated for each peptide. In our experiments all the penetratin peptides penetrated into the cells. Helical conformation and membrane translocation ability showed little correlation: substitution of the two Trp with Phe increased the stability of helical conformation but decreased membrane translocation activity. The results of fluorescence microscopy and flow cytometry show that penetratin can be translocated into the cells by two mechanisms: endocytosis and direct transport through the cell membrane. Copyright © 2003 John Wiley & Sons, Ltd.
Novel daunorubicin‐carrier peptide conjugates derived from human calcitonin segments
Authors: Krauss Ulrike , Kratz Felix , Beck‐Sickinger Annette G. 
Published: September 2003

AbstractSevere and often therapy‐limiting side effects are a major obstacle in cancer chemotherapy. New delivery concepts reducing systemic side effects are needed in order to optimize anticancer therapies. Several approaches have been followed, most of them concentrating on macromolecular carriers like liposomes, monoclonal antibodies, serum proteins or polyethylene glycol. We present here a novel type of anthracycline conjugate, using a small carrier peptide derived from the peptide hormone human calcitonin (hCT). The carrier peptide hCT(9–32) has so far been shown to be capable of transporting fluorophores or proteins across cellular membranes. Two different carrier peptide–daunorubicin conjugates were prepared, one with an acid‐stable amide bond, the second with an acid‐labile hydrazone bond. In vitro studies with daunorubicin linked to the carrier peptide via an acid‐labile hydrazone bond demonstrated comparable cytotoxicity to daunorubicin in various daunorubicin sensitive cell lines (neuroblastoma cell lines SK‐N‐MC and SMS‐KAN; HEK 293 T cells). In addition, fluorescence microscopy provided further insight into the mechanism of uptake of the carrier peptide hCT(9–32), indicating that endosomal compartments with reduced pH are involved in the intracellular release of daunorubicin. Copyright © 2003 John Wiley & Sons, Ltd.
Drug targeting by macromolecules without recognition unit?
Authors: Hudecz Ferenc , Reményi Judit , Szabó Rita , Kóczán György , Mező Gábor , Kovács Péter , Gaál Dezső 
Published: September 2003

Abstracthis review will summarize available information on the ability of macromolecular conjugates containing no specific recognition motifs to deliver anthracyclines (daunomycin, adriamycin) or methotrexate to target cells such as tumour cells or macrophages. Conjugates with natural (proteins, DNA, carbohydrates) and synthetic macromolecules (linear and branched chain poly‐α‐amino acids, non‐biodegradable DIVEMA, HPMA etc.) will be reviewed. Experimental data from several laboratories indicate that these conjugates are taken up by cells mainly by fluid‐phase or adsorptive endocytosis. It is believed that these processes do not involve ‘specific receptors’. Two examples of methotrexate and daunomycin conjugates will be discussed to show the effect of the chemical structure of branched chain polypeptides on the uptake and antitumour or antiparasitic (Leishmania donovani infection) efficacy of conjugates. Copyright © 2003 John Wiley & Sons, Ltd.
Recombinant antibodies with MHC‐restricted, peptide‐specific, T‐cell receptor‐like specificity: new tools to study antigen presentation and TCR–peptide–MHC interactions
Authors: Cohen Cyril J. , Denkberg Galit , Lev Avital , Epel Malka , Reiter Yoram 
Published: September 2003

AbstractThe advent in recent years of the application of tetrameric arrays of class I peptide–MHC complexes now enables us to detect and study rare populations of antigen‐specific CD8+ T cells. However, available methods cannot visualize or determine the number and distribution of these TCR ligands on individual cells or detect antigen‐presenting cells (APCs) in tissues. Here we describe a new approach that enables study of human class I peptide–MHC ligand‐presentation as well as TCR–peptide–MHC interactions. Such studies are facilitated by applying novel tools in the form of peptide‐specific, HLA‐A2‐restricted human recombinant antibodies directed toward a large variety of tumor‐associated as well as viral T‐cell epitope peptides. Using a large human antibody phage display library, a large panel of recombinant antibodies that are specific for a particular peptide–MHC class I complex in a peptide‐dependent, MHC‐restricted manner was isolated. These antibodies were used to directly visualize the specific MHC–peptide complex on tumor cells, antigen‐presenting cells or virus‐infected cells by flow cytometry. They enabled direct quantitation of the number of MHC–peptide complexes as well as in situ detection of the complex on the surface of APCs after naturally occurring active intracellular processing of the cognate antigen. These studies will enable also the development of a new class of targeting molecules to deliver drugs or toxins to tumor or virus‐infected cells. Thus, we demonstrate our ability to transform the unique fine specificity but low intrinsic affinity of TCRs into high‐affinity soluble antibody molecules endowed with a TCR‐like specificity toward human tumor or viral epitopes. These molecules may prove to be crucial useful tools for studying MHC class I antigen presentation in health and disease as well as for therapeutic purposes in cancer, infectious diseases and autoimmune disorders. Copyright © 2003 John Wiley & Sons, Ltd.